Title of Invention

A NOVEL PROCESS FOR PREPARATION OF ATOSIBAN

Abstract The present invention relates to a novel process for the preparation of 1-(3- Mercaptopropionic acid)-2-[3-(p-ethoxyphrnyl)-D-slsinr]-4-L-thtroninr -8-L-ornithine oxytocin of formula 1 namely Atosiban.
Full Text
Form 2
THE PATENTS ACT, 1970 COMPLETE SPECIFICATION
(Section 10)
"A NOVEL PROCESS FOR THE PREPARATION OF ATOSIBAN"






Cadila Healthcare Limited, a company incorporated under the Companies Act, 1956, of Zydus Tower, Satellite Road, Ahmedabad 308 015, Gujarat India.
The following specification particularly describes and ascertains the nature of the invention and manner in which it is to be performed:




Field of invention
The present invention relates to a novel solution phase process for the preparation of 1 -(3-Mercaptopropionic acid)-2-[3-(/?-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithine oxytocin of formula 1 namely Atosiban. Atosiban is an oxytocin antagonist, which inhibits the effects of oxytocin in a female mammal.
Background of the invention
This invention relates to a novel process for the preparation of
1-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-
ornithineoxytocin of formula i namely Atosiban.
Atosiban is an N-blocked cyclic octapeptide that exhibits in vitro activity in the inhibition of posterior pituitary hormones such as oxytocin and vasopressin. This compound is efficacious in inhibiting the uterine hyperactivity associated with preterm labor in female mammals.



,NH3
XX0HVH3 O \ D H °
O'
^N^N^N^NV%^N^^N-Y^

CH3 ~ ^NH2
1
Des(amino) Cys-D-Tyr-(4-OEt)-lle-Thr-Asn~Cys-Pro-Orn-Gly-NH2(1,6 S-S )-disulfide.
In terms of peptide synthetic methodology, two major synthetic techniques dominate current practice. These are synthesis in solution and synthesis in solid phase. Majority of synthetic strategies reported for Atosiban are in solid phase. Although biotech methods using recombinant DNA are also useful for peptide synthesis, but their applicability has limitations with unnatural D-amino acids. In Atosiban, one of the amino acid has D-configuration.
Vasotocin derivatives were firstly reported by Ferring Pharmaceuticals, Sweden in its US 4504469 which is incorporated as reference in its entirety. The synthetic strategy reported here is in solid state. US 5373089 discloses oxytocin antagonist and its process of preparation. The synthetic strategy used is also solid phase. WO 9501368 discloses improved synthesis of cyclic peptides, in which the starting material for preparing


Atosiban has been synthesized using solid phase technique and the final product is obtained by partial solution phase, whose purity reported is only 90%.
There are several draw backs associated with solid phase synthetic strategies reported in these prior arts for the synthesis of Atosiban e.g. difficult to synthesize on a large scale leading to lots of waste. Further in such a synthetic strategy, the isolation of intermediate compounds is not possible. Therefore, it is not possible to detect side reactions including incomplete deprotection and coupling reaction.
In solution phase synthesis, the intermediate compounds can be isolated and characterised at every step which provides convenience in detection of side reaction including incomplete deprotection and coupling reaction. The unwanted side products can then be removed before proceeding any further.
Further, this approach has the advantage of allowing chemist to know exactly which chemical species they are dealing with at any stage of the process. It is in light of this extensive background that the applicants entered their study in an attempt to discover a novel solution phase process for the preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithine oxytocin of the formula 1 namely Atosiban or its pharmaceutical^ acceptable salt la.
Summary of the Invention
An embodiment of the present invention describes a novel solution phase process for the preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithine oxytocin of formula 1 namely Atosiban.
Another embodiment of the present invention provides a pharmaceutical composition comprising Atosiban 1 or its pharmaceutically acceptable acetate salt la prepared according to the present invention and involves use of additives to avoid recemization and other side reaction.
Accordingly, the present invention provides a novel solution phase process for the preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithine oxytocin of formula I namely Atosiban. This process involves novel synthetic strategies, which is operationally simple, and therefore offers opportunities for better industrial applicability.
Another embodiment of the present invention describes the synthesis of novel intermediates namely, Des-amino-Cys(SH)-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(SH)-Pro-Orn-Gly-NH2 (2), Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (3), Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (4), Boc-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(5), Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-OH (6), Des-amino-Cys(Bzl)-D-


Tyr(4-OEt)-IIe-Thr-OEt(7), Boc-D-Tyr(4-OEt)-IIe-Thr-OEt (8), Boc-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(15), Boc-D-Tyr(4-OEt)-IIe-Thr-OH (16), Boc-Asn-Cys(Tr)-Pro-Orn(Tos)-Gly-NH2(18) and Fmoc-Cys(Trt)-Pro-Orn(Tos)-Gly-NH2 (19). Detailed Description of the Invention
According to the present invention, Atosiban is prepared by one or more of the processes described in strategies I, IA and II. The strategy in these processes is mainly to avoid the use of costly D-tyrosine in multiple steps. This is why the initial coupling of amino acids begins from Glycinamide side and subsequently, other amino acids are attached with Glycinamide with protected ornithine and proline and the like. Thus, one-by-one protected pentapeptide, for example Boc-Asn-Cys(Bzl)-Pro-Om(Tos)-Gly-NH2 (4) orBoc-Asn-Cys(Tr)-Pro-Orn(Tos)-Gly-NH2 (18) is synthesized.
Conceptually, one can synthesize peptides by employing a variety of protecting groups for nitrogen, thiol, and C-terminus which are mentioned in the literature ("M. Bodanszky, Principles of peptide synthesis, Springer-Verlag, Berlin heidelberg, 1993, 2nd edition" and "Theodora W. Greene and Peter G. M. Wuts, Protective groups in organic synthesis, Wiley-Interscience, New York, 1998, 3rd edition") using activating groups for coupling and subsequent deprotection. More specifically, protecting groups such as Cbz(carbonylbenzyloxy), Boc(tert-butoxy carbonyl), Fmoc (9-fluorenyl methoxy carbonyl) and the like are used for nitrogen; benzyl, tert-butyl, trityl, acetamidomethyl and the like are used for thiol and ter-butyl ester, benzyl ester, phenacyl ester, ethyl ester, 4-nitrophenyl ester and the like are used for C-terminus (see Table 1). But person skilled in the art can also replace these protecting groups with other protecting groups and similar objectives may be achieved.
The scope of the present invention should be construed as encompassing such obvious alterations or extrapolations.
Similarly, above mentioned pentapeptide has also been prepared by altering the sequence of addition of amino acid and ultimately achieving the same objective. The protection of amines of amino acids with Boc or FmoC, Cbz, benzyl and the like was accomplished by reacting the corresponding amino acid with either Boc-anhydride or Fmoc-formyl or corresponding chlorides such as Fmoc chloride, Cbz chloride, benzyl chloride in a suitable solvent and in the presence of a suitable base. The reaction was carried out at a temperature in the range from 0 °C to 100 °C. Some of the suitable solvents commonly employed may be acetonitrile, ethanol, methanol, water, dioxane, tetrahydrofuran, ether, ethyl acetate and the like or mixtures thereof. The organic and inorganic bases commonly used may be triethyl amine, pyridine, diethyl isopropyl amine,


sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium hydroxide and the like or mixtures thereof. Other specialized nitrogen protecting groups for bifunctional amino acids such as L-tyrosin, L-ornithine may be chosen from either above mentioned protecting groups or orthogonally protected groups such as tosylate, mesylate, besylate and the like. The chemoselective protection of the side chain amino group in L-ornithine is carried out by intramolecular in situ protection using cupric carbonate in water and subsequent treatment with tosyl chloride, mesyl chloride or besyl chloride in the presence of either organic or inorganic bases as mentioned above.
Similarly, the coupling of two protected amino acids, one protected at N-terminus and other protected at C-terminus, is accomplished by using commonly used coupling agents such as DCCI (1,3-dicyclohexylcarbodiimide), CDI (Carbonyldiimidazole), Bop-Cl(bis-2-(oxo-3-oxazolidinyl)phosphinic chloride or by formation of mixed anhydride with pivaloyl chloride or isobutyl chloroformate or DPC (2,2'-dipyridyl carbonate) (see table 2 & 3). Water soluble derivatives such as l-ethyl-3-(3'-dimethylamino propyl)carbodiimide (EDCI) may be used for clearer reactions and operational simplicity. During such couplings, 1-hydroxybenzotriazole (HOBt) may be used to avoid side reactions, catalyse the reaction and prevent racemization. While coupling two amino acids, it becomes essential that the amino group of one amino acid and carboxyl group of the other amino acid is protected. Protection of carboxylic acid is carried out as methyl, benzyl or ethyl esters. Such esters may be prepared from corresponding carboxylic acids and alcohols by using either thionyl chloride or dry HC1 gas. Alternatively, after the coupling, the carboxylate esters may be hydrolysed by aqueous sodium hydroxide or potassium hydroxide. The deprotection of amino protecting agents (PG-1/ PG-2, table 1) may be carried out either in the presence of acid mainly TFA or by catalytic hydrogenation or by treatment with sodium in liquid ammonia, but keeping the sensitivity of other protecting groups in mind. Similarly, the deprotection of either Acm or Trityl for thiol may be carried out under acidic conditions.
Once again, similar to N-terminus protecting groups, a wide variety of protecting groups for C-terminus are reported in the literature and a person skilled in the art may alter them advantageously to obtain the desired results. The scope of present invention should not be limited to deny the inventors protection to such obvious alterations.
Followings are the examples of various protecting groups, coupling reagents and mixed anhydrides used in the specification:
Table 1: Protecting Groups


Protecting Group Name
PG-1 Na Protection Z(Cbz) Benzyloxycarbonyl
Boc tert-butoxycarbonyl
Fmoc 9-fluorenylmethoxycarbonyl
PG-2 Nd Protection Tos 4-Toluenesulfonate
Z Benzyloxycarbonyl
Boc tert-butoxycarbonyl
PG-3 Thiol group Bn Benzyl
tBu tert-butyl
Trt Trityl
Acm Acetamidomethyl
PG-4 C -Terminus tert-Butyl ester
benzyl ester
phenacyl ester
ethyl ester or methyl ester
ONp 4-Nitrophenyl ester
Table 2: Coupling Reagents

Sr.No. Name
1 O-acylisoureas
2 Dicyclohexylcarbodiimide(DCCI)
3 Ethoxyacetylene
4 1 -ethoxycarbonyl 1 -2-ethoxy-1,2-dihydroquinoline (EEDQ)
5 Benzotriazolyloxy-tris-(di-methylamino)phosphonium hexafluorophosphate (Bop)
6 N-N' -Carbonylimidazole(CDI)
7 bis-2-(oxo-3-oxazolidinyl) phosphinic chloride(Bop-Cl)
8 1 -ethyl-3-(3 '-dimethylamino propyl) carbodiimide(EDCI)
9 1-hydroxybenzo triazole(HOBt)


Table 3: Mixed Anhydride

Sr. No. Name
1 Isobutyl chloroformate(IBCF)
2 Pivaloyl cholride
3 2,2'-Dipyridyl carbonate (DPC)
4 N-N' -Carbonylimidazole(CDI)
5 1-hydroxybenzo triazole(HOBt)





The key features of the current process for Atosiban are the coupling strategies of different amino acid fragments, such as 1+3+5 (4+5) and 1+8 as depicted in strategies I, IA and II respectively. Additionally, trityl group has been used for S-H protection of Cysteine as shown in 1J$ (strategy IA). Naturally, the synthesis of nonapeptide starting from Glycinaminde is accomplished through pentapeptide as discussed, but other obvious permutations and combinations are also possible by those skilled in the art and are incorporated herein with the scope of this invention.
The novel process described in the present invention is demonstrated in the examples is given below. These examples are provided as illustration and should not be considered as limiting the scope of the invention in any way. In the following examples, all temperatures are in °C and [OC]D20 values are uncorrected. The key intermediates are characterized by ESMS.
Example 1
Boc-Pro-Orn(Tos)-Gly-NH2 (14)
Boc-Orn(Tos)-Gly-NH2 (21) (60 g, 0.135 mol) was suspended in dichloromethane (DCM) (130 ml) at 30 °C to which was added TFA (180 ml) at 0 °C and stirring was


continued for 1 hour at 25-30 °C. TFA and DCM were evaporated under reduced pressure, and the residue was solidified by adding ether (150 ml) with stirring. The filtered precipitate was dissolved into THF (250 ml) and TEA (55 ml) at 0 °C.
The free base solution was charged in the mixed anhydride prepared from a solution of Boc-Pro-OH (22) (29 g , 0.135 mol), NMM (14.9 ml, 0.135 mol), THF (500 ml) & IBCF (17.6 ml, 0.135 mol) at 0°C. The reaction mixture was stirred overnight at 30 °C. THF was concentrated under reduced pressure and 1 % NaHCO3 solution was added under stirring to the residue. The precipitate was filtered and dried under reduced pressure to obtain Boc-Pro-Orn(Tos)-Gly-NH2 (14). Yield 64 g (87 %), ESMS = 540.4 (M+H), 557.3(M+NH4), 562.3 (M+Na), [a]D20= -32.7 ° (c=l in DMF).
Example 2
Boc-Pro-Orn(Tos)-Gly-NH2 (14)
The process was carried out similar to that of Example 1 except DCCI and HOBt being used as coupling reagents instead of NMM and IBCF in approximately equimolar quantities and substantially similar results were achieved to obtain Boc-Pro-Orn(Tos)-Gly-NH2 (14). Yield 45.9 g (63 %), ESMS = 540.3 (M+H) , [a]D20= -31.9° (c=l in DMF). Example 3
Boc-Pro-Orn(Tos)-Gly-NH2 (14)
The process was carried out similar to that of Example 1 except DIEA being used instead of TEA in approximately equimolar quantities and substantially similar results have been achieved to obtain Boc-Pro-Orn(Tos)-Gly-NH2 Q4). Yield 51.2 g (70 %), ESMS = 540.4 (M+H), [a]D20= -32.5 ° (c=l in DMF).
Example 4
Boc-Pro-Orn(Tos)-Gly-NH2 (14)
The process was carried out similar to that of Example 1 except 2,6-dimethyl pyridine being used as base instead of NMM in approximately equimolar quantities and substantially similar results were achieved. Yield 42.9 g (59 %), ESMS = 540.5 (M+H), [a]D20=-31.5°(c=l in DMF).
Example 5
Boc-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(5)
Stirring of Boc-Pro-Orn(Tos)-gly-NH2 (14} (50 g, 0.092 mol) and TFA (300 ml) was carried out at 0 °C for 1 to 3 hours. TFA was evaporated under reduced pressure, ether (900 ml) was added to the residue and precipitated solid compound was filtered. The solid compound was dissolved in THF (500 ml) and TEA (43 ml) at 0 °C.


The solution was charged into a mixed anhydride solution prepared from Boc-Cys(Bzl)-OH (13) (25.5 g , 0.082 mol), THF (500 ml) and HOBt (11 g, 0.082 mol) at 25-30 °C with addition of DCCI (18.9 g, 0.092 mol) into the reaction mixture at 0 °C and the stirring was continued overnight at 25-30 °C. The reaction mixture was filtered and the filtrate THF was concentrated to obtain Boc-Cys(Bzl)-Pro-Ora(Tos)-Gly-NH2 (5). Yield 39 g (58 %) ESMS = 733.3 (M+H), 750.3 (M+NH4), 755.4 (M+Na), [a]D20= -31.64 ° (c=l in DMF).
Example 6
Boc-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(5)
The process was carried out similar to that of Example 5 except DMF being used instead of THF as a solvent and substantially similar results were achieved. Yield 27 g (40 %), ESMS = 733.5 (M+H), [a]D20= -29.1° (c=l in DMF).
Example 7
Boc-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(5)
The process was carried out similar to that of Example-5 except NMM and IBCF being used as coupling agents instead of DCCI and HOBt in approximately equimolar quantities and substantially similar results were achieved. Yield 19.5 g (29 %), ESMS = 733.2 (M+H), [a]D20= -28.7 ° (c=l in DMF).
Example 8
Boc-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(5)
The process was carried out similar to that of Example 5 except without adding HOBt and substantially similar results were achieved. Yield 25.1 g (37 %), ESMS = 733.1 (M+H), [a]D20= -28.2 ° (c=l in DMF).
Example 9
Fmoc-Cys(Trt)-Pro-Orn(Tos)-Gly-NH2(19)
To a mixture of Boc-Pro-Orn(Tos)-Gly-NH2 (14) (1 g, 1.85 m.mol) and DCM (2 ml) was added TFA (4 ml) at 0 °C in one hour and stirred for 3 hours. TFA was evaporated under reduced pressure, ether (50 ml) was added to the residue and the precipitated solid compound filtered. The solid compound was dissolved in DMF (5 ml) and TEA (0.2 ml) at 0 °C.
The solution was charged into a solution of Fmoc-Cys(Trt)-OH (20) (1.085 g, 1.86 mmol), DMF (5 ml) and HOBt (0.097 g, 0.713 mmol) at 25-30 °C with addition of DCCI (0.384g, 1.86 mmol) to the reaction mixture at 0 °C. The stirring was continued overnight at 25-30 °C. The reaction mixture was filtered and the filtrate was stirred with water (100


ml) to obtain Fmoc-Cys(Trt)-Pro-Orn(Tos)-Gly-NH2 (19). Yield 1.2 g (65 %), ESMS = 1008.2 (M+H).
Example 10
Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(4)
To a mixture of Boc-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (5) (100 g, 0.136 mol) and DCM (100 ml) was added TFA (400 ml) at 0-5 °C. Reaction mixture was stirred at 25-30 °C for 4 hours. The solvents were evaporated under reduced pressure, ether (500 ml) was added to the residue under stirring, and subsequently the ether was removed under reduced pressure. The solid residue was dissolved in DMF (500 ml) and TEA (20 ml).
The solution was added to a solution of Boc-Asn-OH (12) (31.6 g, 0.136 mol), DMF (500 ml) and HOBt (18.4 g, 0.136 mol) at 25-30 °C, with addition of DCCI (28 g, 0.136 mol) at 0 °C.The stirring was continued for one hour at same temperature and then stirred overnight at 25-30 °C. The reaction mixture was filtered and the filtrate was dumped in 5 % NaHCO3 soln. The precipitate was filtered and dried to obtain Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (4). Yield 95 g (83 %), ESMS = 847.3 (M+H), 864.6 (M+NH4), 869.2 (M+Na), 885.3(M+K), [a]D2°= -42.43 ° (c=l in DMF).
Example 11
Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(4)
The process was carried out similar to that of Example 10 except DIEA being used instead of TEA and substantially similar results were achieved. Yield 68. lg (59 %), ESMS = 847.2 (M+H), 864.7 (M+NH4), [a]D20= -41.43 ° (c=l in DMF).
Example 12
Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(4)
The process was carried out similar to that of Example 10 except BOP being used instead of DCCI as a coupling agent and substantially similar results were achieved. Yield 41.9g (36 %), ESMS = 847.4 (M+H), 864.6 (M+NH4), [a]D20= -41.93 ° (c=l in DMF). Example 13
Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(4)
The process was carried out similar to that of Example 10 except without adding HOBt and substantially similar results were achieved. Yield 75.3g (65 %), ESMS = 847.2 (M+H), 864.3 (M+NH4), [a]D2°= -42.03 ° (c=l in DMF).
Example 14
Boc-D-Tyr(4-OEt)-He-Thr-OEt (8)
Boc-He-Thr-OEt (9) (175 g, 0.485 mol) was suspended in DCM (350 ml) at 30 °C to which was added TFA (700 ml) at 0°C . Stirring was continued for 1 hour at 25-30


°C. After evaporating TFA and DCM under reduced pressure, the residue was solidified by adding ether (150 ml) under stirring. The precipitate was filtered and dissolved in THF(1050 ml) and TEA (25 ml) at 0 °C.
The free base solution was charged to a mixed anhydride prepared from Boc-D-Tyr(4-OEt) (10) (150 g, 0.485 mol), NMM (59 ml, 0.534 mol), THF (1050 ml) & IBCF (63 ml, 0.485 mol) at 0 °C. The reaction mixture was stirred overnight at 30 °C. THF was evaporated under reduced pressure and 5 % NaHCO3 solution was added under stirring to the residue. The precipitate was filtered and dried under reduced pressure to obtain Boc-D-Tyr(4-OEt)-IIe-Thr-OEt (8). Yield 227 g (85 %), ESMS = 552.4 (M+H), 574.4 (M+Na), [a]D20= +14.27 ° (c=l in DMF).
Example 15
Boc-D-Tyr(4-OEt)-He-Thr-OEt (8)
The process was carried out similar to that of Example 14 except DIE A being used instead of TEA and substantially similar results were achieved. Yield 175.9 g (66 %), ESMS = 552.65 (M + H), 574.4(M+Na), [a]D20= +15.10 ° (c=l in DMF).
Example 16
Boc-D-Tyr(4-OEt)-IIe-Thr-OEt (8)
The process was carried out similar to that of Example 14 except DMF being used instead of THF and substantially similar results were achieved. Yield 139 g (52 %), ESMS = 552.6(M+H), [a]D20= +14.10 ° (c=l in DMF).
Example 17
Boc-D-Tyr(4-OEt)-He-Thr-OEt (8)
The process was carried out similar to that of Example 14 except pivaloyl chloride being used as a coupling reagent instead of IBCF in approximately equimolar quantities and substantially similar results were achieved. Yield: 127 g (47 %), ESMS = 552.4(M + H), [a]D20= +14.8 ° (c=l in DMF).
Example 18
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-OEt(7)
Boc-D-Tyr(4-OEt)-IIe-Thr-OEt (8) (225 g, 0.408 mol) was suspended in DCM (900 ml) at 30 °C to which was added TFA (900 ml) at 0 °C and stirring was continued for 1 hour at 25-30 °C. TFA and DCM were evaporated under reduced pressure, ether (400 ml) was added to the residue under stirring and the precipitate was filtered. The solid was dissolved in THF(2250 ml) and TEA (50 ml) at 0 °C.
The free base solution was charged to a mixed anhydride prepared from Des-amino-Cys(Bzl)-OH (11) (80 g, 0.408 mol), NMM (44 ml, 0.408 mol), THF (1100 ml) &


IBCF (53 ml, 0.408 mol) at -10 °C. The reaction mixture was stirred at same temperature for 1-2 hours with overnight stirring at 30 °C. THF was evaporated under reduced pressure and sodium bicarbonate solution was added under stirring. The precipitate was filtered and dried under reduced pressure to obtain Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-OEt (7). Yield 217 g (85 %), ESMS = 630.3 (M+H), 652.3 (M+Na), [a]D20= +6.91 ° (c=l in DMF).
Example 19
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-OEt(7)
The process was carried out similar to that of Example 18 except DCCI and HOBt were used in approximately equimolar quantities as coupling agents instead of NMM and IBCF and substantially similar results were achieved. Yield 191.1 g (75 %), ESMS = 630.2 (M+H), 652.2 (M+Na), [a]D20= +6.93 ° (c=l in DMF).
Example 20
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-OEt(7)
The process was carried out similar to that of Example 18 except DMF being used as a solvent instead of THF and substantially similar results were achieved. Yield 201.1 g (78 %), ESMS = 630.3 (M+H) , [a]D2°= +5.99 ° (c=l in DMF).
Example 21
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-OEt (7)
The process was carried out similar to that of Example 18 except 2,6-dimethyl pyridine being used as a base instead of NMM in approximately equimolar quantities and substantially similar results were achieved. Yield 174.9 g (68 %), ESMS = 630.1 (M+H), [a]D2°= +6.13 ° (c=l in DMF).
Example 22
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-OH(6)
A mixture of sodium hydroxide (27.3 g, 0.684 mol) and water (215 ml) was added to a solution of Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-OEt (7) (215 g, 0.342 mol) and methanol (2.15 L) at 25-30 °C. The reaction mixture was stirred at 30-35 °C for four hours and the solution was evaporated under reduced pressure, and acidified with (1M) hydrochloric acid under cooling and ethyl acetate was added. The organic layer was separated, dried and concentrated under reduced pressure to give Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-OH (6). Yield 184 g.(90 %), ESMS = 602.3 (M+H), 624.3 (M+Na), [a]D2°= +14.2 ° (c=l in DMF).


Example 23 Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-OH(6)
The process was carried out similar to that of Example 22 without adding methanol and substantially similar results were achieved. Yield 159.5 g (78 %), ESMS = 602.4 (M+H), 624.3 (M+Na), [a]D20= +13.8 ° (c=l in DMF).
Example 24
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-OH(6)
The process was carried out similar to that of Example 22 except KOH being used, instead of NaOH and substantially similar results were achieved. Yield 145.1 g (71 %), ESMS = 602.3 (M+H), 624.3 (M+Na), [a]D20= +14.5 ° (c=l in DMF).
Example 25
Boc-Asn-Cys(Tr)-Pro-Orn(Tos)-Gly-NH2(18)
A mixture of Fmoc-Cys(Trt)-Pro-Orn(Tos)-Gly-NH2 (19) (1 g, 0.99 mmol) and 20 % piperidine soln.(12 ml) was stirred for 1 hour. The reaction mixture was dumped into water (60 ml) and pH was adjusted with 5 % citric acid to 6. The solid compound was extracted with DCM, DCM was evaporated and the residue was dissolved in a solution of DMF (5 ml) and TEA (0.2 ml) at 0 °C.
The solution was charged into a solution of Boc-Asn-OH (12) (0.23 g , 0.99 m.mol) , DMF (5 ml) and HOBt (0.053 g, 0.39 m.mol) at 25-30 °C with addition of DCCI (0.205 g, 0.99 mmol) at 0 °C. The stirring was continued overnight at 25-30 °C. The reaction mixture was filtered and the filtrate was stirred with water (90 ml) to obtain Boc-Asn-Cys(Tr)-Pro-Orn(Tos)-Gly-NH2 (18)- Yield 0.51 g (51 %), ESMS = 1000.2 (M+H). Example 26
Boc-D-Tyr(4-OEt)-IIe-Thr-OH (16)
To a stirred mixture of water (5 ml) and methanol (5 ml), sodium hydroxide (290 mg, 7.25 mmol) was added, followed by addition of Boc-D-Tyr(4-OEt)-IIe-Thr-OEt (8) (2 g, 3.62 mmol) and the reaction mixture was stirred at 25-30 °C for one hour. The reaction mixture was acidified with IN HC1 and the product was extracted with ethyl acetate. The organic layer was washed by brine solution and subsequently ethyl acetate was evaporated to obtain Boc-D-Tyr(4-OEt)-IIe-Thr-OH (16). Yield 1.2 g (63 %), ESMS = 524.3 (M+H) ,541.1 (M+NH4), 546.3(M+Na) [a]D20= +25.7 ° (c=l in DMF).


Example 27
Boc-D-Tyr(4-OEt)-IIe-Thr-OH (16)
The process was carried out similar to that of Example 26 without adding methanol and substantially similar results were achieved. Yield 0.89 g (47 %), ESMS = 524.4 (M+H) [a]D20= +23.9 ° (c=l in DMF).
Example 28
Boc-D-Tyr(4-OEt)-ne-Thr-OH (16)
The process was carried out similar to that of Example 26 except LiOH being used and substantially similar results were achieved. Yield 1.09 g (57 %), ESMS = 524.4 (M+H) [a]D20= +23.9 ° (c=l in DMF).
Example 29
Boc-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(15)
TFA (2 ml) was added to a solution of Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (4) (250 mg, 0.295 m.mol) and DCM (20 ml) at 0 °C and was stirred for 1 hour at 25-30 °C. After evaporating TFA and DCM under reduced pressure, the residue was solidified by adding ether (20 ml) under stirring. The filtered precipitate was dissolved in THF (5 ml) and TEA (0.2 ml) at 10 °C.
The free base solution was charged to a mixed anhydride prepared from Boc-D-Tyr(4-OEt)-IIe-Thr-OH (16) (140 mg, 0.267 mmol), NMM (32.3 mg, 0.32 mmol), THF (5 ml) & IBCF (43.5 mg, 0.32 mmol) at 0 °C and the reaction mixture was stirred overnight at 25-30 °C. THF was evaporated under reduced pressure and the product was extracted with ethyl acetate. The organic layer was separated, concentrated and purified to obtain Boc-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (15). Yield 85 mg (23 %), ESMS = 1252.9 (M+H), 1269.3 (M+NH4).
Example 30
Boc-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (15)
The process was carried out similar to that of Example 29 except DCCI being used as a condensing agent instead of NMM and IBCF in approximately equimolar quantities, DMF being used as a solvent instead of THF and substantially similar results were achieved. Yield 71.9 mg (20 %), ESMS = 1252.8 (M+H).
Example 31
Des-Cys(S-Bzl)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(S-Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (4) (50 g, 0.059 mol) was suspended in DCM (125 ml) and stirred at -5 °C and TFA (200 ml) was added and the stirring was continued for one hour. TFA and DCM were evaporated under reduced pressure, ether


(500 ml) was added to residue under stirring, and diethyl ether was evaporated under reduced pressure.
The solid was dissolved in THF (500 ml) and DIEA (28 ml) was added in the mixed anhydride prepared from a mixture of Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-OH (6) (35.4 g, 0.059 mol), NMM (13.1 ml, 0.118 mol), THF (900 ml) & IBCF (7.74 ml,0.059 mol) at -10 °C and the stirring was continued for one hour at same temperature and then overnight at 30 °C.The reaction mixture was concentrated under reduced pressure, and the residue was dissolved in DMF (400 ml) which was dumped in 1 % NaHC03 solution to get Des-Cys(S-Bzl)-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(S-Bzl)-Pro-Orn(Tos)-Gly-NH2 (3). Yield 58.2 g (74 %), ESMS = 1330.8 (M+H), [a]D20= -13.5 ° (c=l in DMF). Example 32
Des-Cys(S-Bzl)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(S-Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
The process was carried out similar to that of Example 31 except DMF being used as a solvent instead of THF and substantially similar results were achieved. Yield 54.5g (69 %), ESMS = 1330.7 (M+H), [a]D20= -14.1 ° (c=l in DMF). Example 33 Des-Cys(S-BzI)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(S-Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
The process was carried out similar to that of Example 31 except DCCI and HOBt being used as coupling agents instead of NMM and IBCF in approximately equimolar quantities and substantially similar results were achieved. Yield 40 g (51 %), ESMS = 1330.5 (M+H), [a]D20= -13.6 ° (c=l in DMF).
Example 34
Des-Cys(S-Bzl)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(S-Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
The process was carried out similar to that of Example 31 except pivaloyl chloride was used as coupling agent instead of IBCF in approximately equimolar quantities and substantially similar results were achieved. Yield 38 g (48 %), ESMS = 1330.4 (M+H), [a]D20=-13.9°(c=linDMF).
Example 35
Des-Cys(S-Bzl)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(S-Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
The process was carried out similar to that of Example 31 except 2,6-dimethyl pyridine being used as a base instead of NMM in approximately equimolar quantities and substantially similar results were achieved. Yield 27.9 g (36 %), ESMS = 1330.5 (M+H), [a]D20=-13.1°(c=linDMF).


Example 36
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
Boc-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(15) (150 mg, 0.119 mmol) was suspended in DCM (5 ml) at 30 °C to which was added TFA (1 ml) at 0 °C and stirring was continued at same temperature for 1.5 hours at 25-30 °C. TFA and DCM were evaporated under reduced pressure, and the residue was solidified by adding ether (50 ml) under stirring. The filtered precipitate was dissolved in DMF (1 ml) and TEA (0.1 ml) at 25 °C.
The free base solution was charged to a mixture of Des-amino-Cys(Bzl)-OH (11) (16.8 mg, 0.086 mmol), DCCI (27 mg, 0.131 mmol), DMF (1 ml) & HOBt (11.6 mg, 0.086 mmol) at 25-30 °C and the reaction mixture was stirred overnight at 30 °C and filtered. The solid filtrate was stirred with water. The precipitate was filtered and dried under reduced pressure to obtain Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (3). Yield 34 mg (21 %), ESMS = 1329.7 (M+H), 1347.7 (M+Na). Example 37
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
The process was carried out similar to that of Example 36 except NMM and IBCF being used as coupling agents instead of DCCI and HOBt in approximately equimolar quantities and THF as a solvent instead of DMF and substantially similar results were achieved. Yield 29.5 mg (19 %), ESMS = 1329.8 (M+H).
Example 38
Des-amino-Cys(BzI)-D-Tyr(4-OEt)-ne-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2(3)
The process was carried out similar to that of Example 36 except DIE A being used instead of TEA and substantially similar results were achieved. Yield 19.5 mg (12 %), ESMS = 1329.7 (M+H).
Example 39
Des(amino) Cys-D-Tyr-(4-OEt)-De-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )- disulfide (1)
Step 1:
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-IIe-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2 (3) (5 g, 3.76 mmol) was stirred with 2.5 L of freshly distilled liquid ammonia for 15 minutes, and the protecting group was removed from 3 by adding sodium (2 g, 0.87 g atom) until blue colour persisted. The excess of sodium was destroyed by adding ammonium chloride with removal of ammonia and the residue was lyophilized to give


crude compound, which was purified by column chromatography to give Des-amino-Cys(SH)-D-Tyr(4-OEt)-IIe-Thr-OH-Asn-Cys(SH)-Pro-Orn-Gly-NH2{2}. Yield 2.1 g. (56 %), ESMS = 997.1
Step 2:
Des-amino-Cys(SH)-D-Tyr(4-OEt)-IIe-Thr-OH-Asn-Cys(SH)-Pro-Orn-Gly-NH2 (D was dissolved in water (1000 ml) and TFA (10 ml) and the pH of the solution was adjusted to about 8 with ammonium hydroxide solution. 0.1 N KaFe[CN]6 (100 ml) solution was added and the mixture was stirred at 30 °C temperature overnight, usual work-up gave crude material which was purified by preparative chromatography to give Des(amino)Cys-D-Tyr-(4-OEt)-Ile-Thr-Asn-Cys-Pro-Orn-Gly-NH2( 1,6 S-S)-disulfide (1). Yield 1.42 g (38 %), ESMS = 994.7, HPLC Purity >95 %.
Example 40
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except 300 vol. of sodium-dried ammonia being used, and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.37 g. (49 %); Yield of final compound Q): 0.20 g (26 %).
Example 41
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except pH of the solution being adjusted to about 6.2 with ammonium hydroxide during oxidation of 2 to 1, and substantially similar results were achieved.
Yield of deprotected nonapeptide 2: 0.42 g. (56 %) and final compound 1: 0.18 g (24 %). Example 42
Des(amino) Cys-D-Tyr-(4-OEt)-Ile-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )- disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except 1 N K3Fe[CN]6 solution being added during oxidation of 2 to 1, and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.42 g. (56 %), and final compound 1: 0.17 g (23%).


Example 43
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-
disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except oxygen gas being bubbled through the reaction mixture overnight during oxidation of 2 to I, and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.42 g. (56 %), and final compound 1: 0.15 g (20 %).
Example 44
Des(amino) Cys-D-Tyr-(4-OEt)-De-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 2 g scale, except air being bubbled through the reaction mixture overnight during oxidation of 2 to I, and substantially similar results were obtained. Yield of deprotected nonapeptide 2 : 0.84 g (56 %), and final compound 1: 0.29 g (19 %).
Example 45
Des(amino) Cys-D-Tyr-(4-OEt)-De-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except 0.1 mM of iodine in methanol being used during oxidation of 2 to i and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.39 g.(52 %), and final compound 1 : 0.085 g (11 %).
Example 46
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except 250 vol. of liquid ammonia being used at deprotection stage and 0.5 N KaFe[CN]6 solution used during oxidation of 2 to 1, and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.31 g (41%), and final compound 1: 0.18 g (24%).
Example 47
Des(amino) Cys-D-Tyr-(4-OEt)-Ile-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 to 1 g scale, except pH of the solution being adjusted to about 6.2 and oxygen gas being bubbled through the reaction mixture during oxidation of 2 to 1, and substantially similar results were


achieved. Yield of deprotected nonapeptide 2: 0.41 g (55 %), and final compound i: 0.16
g (21 %).
Example 48
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-
disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except pH of the solution being adjusted to about 4 during oxidation of 2 to 1, and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.43 g (57 %), and final compound 1: 0.072 g (10 %).
Example 49
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 2 g scale, except 50 vol. of liquid ammonia being used at deprotection stage, and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.50 g (33 %), and final compound 1: 0.18 g (12%).
Example 50
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except 100 vol. of liquid ammonia being used at deprotection stage, and substantially the similar results were achieved. Yield of deprotected nonapeptide 2: 0.29 g (39 %), and final compound 1: 0.135 g (18 %).
Example 51
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 1 g scale, except sodium being used (0.3 g,0.013 g atom) at reductive deprotection stage, and substantially similar results were achieved. Yield of deprotected nonapeptide 2: 0.30 g (40 %), and final compound 1: 0.08 g (11 %).
Example 52
Des(amino) Cys-D-Tyr-(4-OEt)-ne-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S )-disulfide (1)
The process was carried out similar to that of Example 39 at 2 g scale, except sodium being used (0.4 g, 0.017 g atom) at reductive deprotection stage, and substantially similar


results were achieved. Yield of deprotected nonapeptide 2: 0.55 g. (37%), and final
compound 1: 0.14 g (9%).
Abbreviations:
Boc = tert.Butyloxycarbonyl
Bzl = Benzyl
BOP = Benzotriazole-l-yl-oxy-tris-(dimethylamino) -phosphonium
hexafluorophosphate.
DCCI = Dicyclohexylcarbodiimide
DCM = Dichloromethane
DIEA = Diisopropylethylamine
DMF = Dimethylformamide
ESMS = Electrospray Mass Spectrometry EtO = Ethanol
Fmoc = Flourenylmethoxycarbonyl HOBt = 1-Hydroxybenzotriazole IBCF = Isobutylchloroformate NMM = N-methylmorpholine
TEA = Triethylamine
TFA = Trifluoroacetic acid
Trt = Triphenyl methyl(Trityl)
Advantages of the present invention
• The intermediates involved in the present invention are solids, which are isolated and characterised at any stage.
• The present invention involves non-linear and convergent synthesis.
• The present invention involves use of cost effective protecting and coupling reagents.
• The present invention involves use of additives to catalyze the reaction and to avoid racemization and other side reactions.
• The present invention avoids use of cryogenic reaction conditions as disclosed in some of the prior arts.
• The process involves less number of steps.
• This process is easily applicable on a large scale.
• All the above advantages make this process operationally simple and cost effective, which are essential for manufacturing.


We claim:
1. A novel process for the preparation of l-(3-Mercaptopropionic &cid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin or Des-amino- Cys-D-Tyr-(4-OEt)-Ile-Thr-Asn-Cys-Pro-Orn-Gly-NH2(l,6 S-S)-disulfide, namely, Atosiban of formula 1, which comprises,



n l O "\^H2 O ° K °
3 NH2
Des(amino) Cys-D-Tyr-(4-OEt)-lle-Thr--Asn-Cys-Pro-Orn-Gly-NH2(1,6 S-S )-disulfide.

oxidation of deprotected nonapeptide of formula 2, the said oxidation being carried out using oxidizing agents selected from potassium ferricyanide, oxygen, air or iodine in the pH range 4 to 8.
Des-amino-Cys(SH)-D-Tyr(4-OEt)-lle-Thr-Asn-Cys(SH)-Pro-Orn-Gly-NH2
Deprotected 9PP 2
Oxidation

Des-amino- Cys-D-Tyr-(4-OEt)-lle-Thr-Asn-Cys-Pro-Om-Gly-NH2(1,6 S-S )-disulfide
1
2. A novel process for preparing Atosiban 1 as claimed in claim 1, comprising, a) deprotecting nonapeptide of formula 3 with deprotecting groups selected from sodium, liquid ammonia to yield deprotected nonapeptide of formula 2,
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-lle-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2
3 I „ * ». Protected 9PP
1 Deprotection
Des-amino-Cys(SH)-D-Tyr(4-OEt)-lle-Thr-OH-Asn-Cys(SH)-Pro-Om-Gly-NH2
2


b) alternatively, deprotecting nonapeptide of formula 17 with deprotecting groups
selected from sodium and liquid ammonia to yield deprotected nonapeptide 2.
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-lle-Thr-Asn-Cys(Trt)-Pro-Orn(Tos)-Gly-NH2
17 Protected 9PP „ , 4.
Deprotection
Des-amino-Cys(SH)-D-Tyr(4-OEt)-lle-Thr-Asn-Cys(SH)-Pro-Orn-Gly-NH2
2
c) oxidation of deprotected nonapeptide of formula 2 as claimed in claim 1 to yield
Atosiban 1.
3. A process as claimed in claim 1 or 2, wherein,
a) (i) said nonapeptide 3 is prepared by coupling of deprotected (de-Boc) pentapeptide 4 and tetrapeptide 6 using suitable coupling reagents selected from Dicyclohexylcarbodiimide(DCCI), Ethoxyacetylene, 1 -ethoxycarbonyl 1 -2-ethoxy-1,2-dihydroquinoline (EEDQ), N-N'-Carbonylimidazole(CDI), Benzotriazole-1-yl-oxy-tris-(dimethylamino) -phosphonium hexafluorophosphate (Bop), l-ethyl-3-(3'-dimethylaminopropyl) carbodiimide(EDCI) with or without 1-hydroxybenzo triazole (HOBt); mixed anhydride selected from pivaloyl chloride, isobutyl chloroformate (IBCF) in the presence of base(s) selected from triethyl amine, pyridine, diethyl isopropyl amine, 2,6-dimethyl pyridine or mixtures thereof in suitable solvent(s) selected from acetonitrile, dimethylformamide, tetrahydrofuran, ether, ethyl acetate or mixtures thereof.








(ii) alternatively, said nonapeptide 3 is prepared by coupling of octapeptide 15 and Des-amino-Cys (Bzl)-OH (IV) using suitable coupling reagents selected from Dicyclohexylcarbodiimide(DCCI), Ethoxyacetylene, 1 -ethoxycarbonyl 1 -2-ethoxy-1,2-dihydroquinoline (EEDQ), N-N'-Carbonylimidazole(CDI), Benzotriazole-1-yl-oxy-tris- (dimethylamino)- phosphonium hexafluorophosphate (Bop), l-ethyl-3-


(3'-dimethylaminopropyl) carbodiimide (EDCI) with or without 1-hydroxybenzo triazole (HOBt); mixed anhydride selected from pivolyl chloride, isobutyl chloroformate (IBCF) in the presence of base(s) selected from triethyl amine, pyridine, diethyl isopropyl amine, 2,6-dimethyl pyridine or mixtures thereof in suitable solvent(s) selected from acetonitrile, dimethylformamide, tetrahydrofuran, ether, ethyl acetate or mixtures thereof to obtain nonapeptide 3.



b) deprotecting nonapeptide 3 as claimed in any of the preceeding claims to yield deprotected nonapeptide 2.
c) oxidizing deprotected nonapeptide 2 as claimed in any of the preceeding claims to yield Atosiban of formula 1.
4. A process as claimed in claims 1 or 2, comprising
a) coupling of tetrapeptide 6 with deprotected (de-Boc) pentapeptide 1J$ using coupling
reagents as claimed in any of the preceeding claims to obtain nonapeptide 17.




b) deprotecting nonapeptide 17 as claimed claim 2a to yield nonapeptide 2.
c) oxidizing deprotected Nonapeptide 2 as claimed in claim 2c to yield Atosiban of formula 1.
5. A novel tripeptide ester of formula 8.


Boc-D-Tyr(4-OEt)-lle-Thr-OEt 8 Boc-3PP-Est
6. A novel process of preparing tripeptide ester 8 as claimed in claim 5, comprising, coupling of deprotected (de-Boc) BOC-IIe-Thr-OEt (9) and BOC-D-Tyr(4-OEt) (10) using suitable coupling agents as claimed in any of the preceeding claims to obtain tripeptide ester 8.
7. A novel tetrapeptide of formula 19.
Fmoc-Cys(Trt)-Pro-Orn(Tos)-Gly-NH2 19
8. A novel process for preparing tetrapeptide 19, as claimed in claim 7 comprising,
coupling of deprotected (de-Boc) tripeptide 14 and Fmoc-Cys(Trt)-OH (20) using
suitable coupling reagents as claimed in any of the preceeding claims to yield
tetrapeptide 19.



9. A novel tetrapeptide of formula 5.
Boc-Cys(Bzl)-Pro-Om(Tos)-Gly-NH2 5 Boc-4PP-NH2
10. A novel process of preparing tetrapeptide of formula 5 as claimed in claim 9,
comprising, coupling of deprotected (de-Boc) tripeptide 14 and Boc-Cys(Bzl)-OH (13)
using suitable coupling reagents as claimed in any of the preceeding claims to form
tetrapeptide 5.







11. A novel tetrapeptide of formula 7.
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-lle-Thr-OEt
7 4PP-Est
12. A novel process for preparing tetrapeptide 7 as claimed in claim 11, comprising,
coupling of deprotected (de-Boc) tripeptide ester 8 and Des-Cys(S-Bzl)-OH (11) using
suitable coupling reagents as claimed in any of the preceeding claims to obtain








11
13. A novel tripeptide of the formula 16.
Boc-D-Tyr(4-OEt)-lle-Thr-OH 16 BOC-3PP-OH
14. A novel process for preparing tripeptide 16 as claimed in claim 13 comprising, hydrolysis of tripeptide ester 8_ using hydrolyzing agents selected from water, methanol, NaOH, KOH or mixtures thereof to form tripeptide 16.
Boc-D-Tyr(4-OEt)-lle-Thr-OEt 8 Boc-3PP-Est

Boc-D-Tyr(4-OEt)-lle-Thr-OH 16 BOC-3PP-OH


15. A novel pentapeptide of the formula 18.
Boc-Asn-Cys(Tr)-Pro-Orn(Tos)-Gly-NH2 18 Boc-5PP-NH2
16. A novel process for preparing pentapeptide 18 as claimed in 15 comprising, coupling of deprotected (de-Boc) tetrapeptide 19 and Boc-Asn-OH (L2) using suitable coupling reagents as claimed in any of the preceeding claims to give pentapeptide 18.






17. A novel pentapeptide of formula 4.
Boc-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2
4 Boc-5PP-NH2


18. A novel process of preparing pentapeptide of formula 4 as claimed in claim 17, comprising, coupling of deprotected (de-Boc) tetrapeptide 5 and Boc-Asn-OH (12) as claimed in any of the preceeding claims to give pentapeptide 4.





19. A novel octapeptide of formula 15.
Boc-D-Tyr(4-OEt)-lle-Thr-Asn-Cys(Bzl)-Pro-Orn(Tos)-Gly-NH2
15 Boc-8PP-NH2
20. A novel process of preparing octapeptide of formula 15 as claimed in claim 19,
comprising, coupling of tripeptide 16 with deprotected (de-Boc) pentapeptide 4 using
suitable coupling reagents as claimed in any of the preceeding claims to yield
octapeptide 15.



21. A novel tetrapeptide of formula 6.

22. A novel process of preparing tetrapeptide of formula 6 as claimed in claim 21,
comprising, hydrolysis of tetrapeptide ester 7 using hydrolyzing agents as claimed in
claim 14 to yield tetrapeptide 6.


Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-lle-Thr-OEt
4PP-Est 7
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-lle-Thr-OH
4PP-0H 6
23. A novel protected nonapeptide of formula 3
Des-amino-Cys(Bzl)-D-Tyr(4-OEt)-lle-Thr-Asn-Cys(Bzl)-Pro-Om(Tos)-Gly-NH2
3 Protected 9PP
24. A novel process of preparing protected nonapeptide of formula 3 as claimed in claim
23, comprising,
a) coupling of tetrapeptide 6 with deprotected (de-Boc) pentapeptide 4 using suitable
coupling reagents as claimed in any of the preceeding claims to yield nonapeptide 3.





b) alternatively, coupling of deprotected (de-Boc) octapeptide 15 and Des-Cys(S-Bzl)-
OH (11) using suitable coupling reagents as claimed in any of the preceeding claims to
give nonapeptide 3.





25. A novel deprotected nonapeptide of formula 2.
Des-amino-Cys(SH)-D-Tyr(4-OEt)-lle-Thr-Asn-Cys(SH)-Pro-Om-Gly-NH2
2
26. A novel process for preparing nonapeptide of formula 2 as claimed in claim 25,
comprising of steps,
a) coupling of deprotected (de-Boc) tripeptide 14 and Boc-Cys(Bzl)-OH (13) as claimed in any of the preceeding claims to form tetrapeptide 5.
b) coupling of deprotected (de-Boc) tetrapeptide 5 and Boc-Asn-OH (12) as claimed in any of the preceeding claims to give pentapeptide 4.
c) coupling of deprotected (de-Boc) BOC-IIe-Thr-OEt (9) and BOC-D-Tyr(4-OEt) (10) as claimed in any of the preceeding claims to obtain tripeptide ester 8.
d) coupling of deprotected (de-Boc) tripeptide ester 8 and Des-amino-Cys(Bzl)-OH (11.) as claimed in any of the preceeding claims to give tripeptide ester 7.
e) hydrolysis of tripeptide ester 7 as claimed in any of the preceeding claims to give tetrapeptide 6.
f) coupling of tetrapeptide 6 and deprotected (de-Boc) pentapeptide 4 as claimed in any of the preceeding claims to give nonapeptide 3.
g) deprotecting nonapeptide 3_as claimed in any of the preceeding claims to give deprotected nonapeptide 2.
27. A novel process for preparing nonapeptide of formula 2 as claimed in claim 25,
comprising of steps,
a) coupling of deprotected (de-Boc) tripeptide H and Fmoc-Cys(Trt)-OH (20) as claimed in any of the preceeding claims to form tetrapeptide 19.
b) coupling of deprotected (de-Boc) tetrapeptide 19 and Boc-Asn-OH (12) as claimed in any of the preceeding claims to give pentapeptide 18.
c) coupling of deprotected (de-Boc) BOC-IIe-Thr-OEt (9) and BOC-D-Tyr(4-OEt) (10) as claimed in any of the preceeding claims to obtain tripeptide ester 8.
d) coupling of deprotected (de-Boc) tripeptide ester 8 and Des-amino-Cys(Bzl)-OH (IV) as claimed in any of the preceeding claims to give tetraptide ester 7.
e) Hydrolysis of tetrapeptide ester 7 as claimed in any of the preceeding claims to give tetrapeptide 6.
f) coupling of tetrapeptide 6 and deprotected (de-Boc) pentapeptide 18 as claimed in any of the preceeding claims to give nonapeptide 17.


g) deprotecting nonapeptide 17 as claimed in any of the preceeding claims to give deprotected nonapeptide 2.
28. A novel process for preparing nonapeptide of formula 2 as claimed in claim 25,
comprising of steps,
a) coupling of deprotected (de-Boc) tripeptide 14 and Boc-Cys(Bzl)-OH (13) as claimed in any of the preceeding claims to form tetrapeptide 5.
b) coupling of deprotected (de-Boc) tetrapeptide 5 and Boc-Asn-OH (12) as claimed in any of the preceeding claims to give pentapeptide 4.
c) coupling of deprotected (de-Boc) BOC-IIe-Thr-OEt (9) and BOC-D-Tyr(4-OEt) (10) as claimed in any of the preceeding claims to obtain tripeptide ester 8.
d) Hydrolysis of tripeptide ester 8 as claimed in any of the preceeding claims to give tripeptide 16.
e) coupling of tripeptide 16 and deprotected (de-Boc) pentapeptide 4 as claimed in any of the preceeding claims to give octapeptide 15.
f) coupling of deprotected (de-Boc) octapeptide 15 and Des-amino-Cys(Bzl)-OH (11) as claimed in any of the preceeding claims to give nonapeptide 3.
g) deprotecting nonapeptide 3 as claimed in any of the preceeding claims to give deprotected nonapeptide 2.
29. A novel process of preparing Atosiban of formula I comprising,
a) preparation of deprotected nanopeptide 2_as claimed in claim 26 or 27 or 28,
b) oxidation of deprotected nanopeptide 2 as claimed in any of the preceeding claims to yield Atosiban 1.
30. A novel process of preparing Atosiban acetate la, wherein Atosiban prepared as per
the process claimed in any of the preceeding claims is purified by using acetic acid.
Des(amino) Cys-D-Tyr-(4-OEt)-lle-Thr--Asn-Cys-Pro-Om-Gly-NH2(1,6 S-S )-disulfide
Des(amino) Cys-D-Tyr-(4-OEt)-lle-Thr-Asn-Cys-Pro-Orn-Gly-NH2(1,6 S-S )-disulfide.acetate.
la


31. A pharmaceutical composition comprising Atosiban 1 or its pharmaceutically acceptable salt, namely Atosiban acetate la prepared according to the present invention.
32. A method of treatment comprising administering to a person in need thereof Atosiban 1, or its pharmaceutically acceptable salt, namely Atosiban acetate la as prepared by the present invention.
33. A method as claimed in claim 32, wherein the disease is selected from delay of


Abstract:
The present invention relates to a novel process for the preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithine oxytocin of formula 1, namely Atosiban.


Form 2
THE PATENTS ACT, 1970 PROVISIONAL SPECIFICATION
(See section 10; rule 13)
"A Novel Process for Preparation of Atosiban "


We, CADILA HEALTHCARE LIMITED, a company incorporated Companies Act, 1956, of Zydus Tower, Satellite Cross Roads, Ahmedabad - 380 015, Gujarat, India
The following specification describes the nature of the invention:



ZRC-NPR-010
Field of invention
The present invention relates to a novel process for the preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin of formula 1 namely Atosiban. Atosiban is an oxytocin antagonist, which inhibits the effects of oxytocin in a female mammal.
Background of the invention
This invention relates to a novel process for the preparation of l-(3-Mercaptopropionic acid)-2-[3-(/?-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin of formula! namely Atosiban.
Atosiban is an N-blocked cyclic octapeptide that exhibits in vitro activity in the inhibition of posterior pituitary hormones such as oxytocin and vasopressin. This compound is efficacious in inhibiting the uterine hyperactivity associated with preterm labor in female mammals.

O^


,0 CH3
,CH3
sMJ> oHOVCH3 o I /^ H °

NH,

CH3 O .NHz
1
[Cys1-6]Deamino-Cys-DTyr(OEt)-lle-Thr-Asn-Cys-Pro-Orn-Gly-NH2
In terms of peptide synthetic methodology, two major synthetic techniques dominate current practice. These are synthesis in solution and synthesis on solid phase. Majority of synthetic strategies reported for Atosiban are in solid phase. Although biotech methods using recombinant DNA are also useful for peptide synthesis, but their applicability has limitations with unnatural D-amino acids. In Atosiban, one of the amino acid has D-configuration.


ZRC-NPR-010
Vasotocin derivatives are firstly reported by Ferring Pharmaceuticals, Sweden in its
US 4504469 which is incorporated as reference in its entirity. The synthetic strategy
reported here is in solid state. US 5373089 discloses oxytocin antagonist.
There are several draw backs associated with solid phase synthetic strategies reported
in these prior arts for the synthesis of Atosiban e.g. difficult to synthesize on a large
scale leading to lots of waste. Further in such a synthetic strategy, the isolation of
intermediate compounds is not possible. Therefore, it is not possible to detect side
reactions including incomplete deprotection and coupling reaction.
In solution phase synthesis, the intermediate compounds can be isolated and
characterised at every step which provides convenience in detection of side reaction
including incomplete deprotection and coupling reaction. The unwanted side
products can then be removed before proceeding any further.
Further this approach has the advantage of allowing chemist to know exactly which
chemical species they are dealing with at any stage of the process.
It is in light of this extensive background that the applicants entered their study in an
attempt to discover a novel process for the preparation of l-(3-Mercaptopropionic
acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin of
formula 1 namely Atosiban.
Objectives of the Invention
An objective of the present invention is to provide a novel process for the preparation of 1 -(3 -Mercaptopropionic acid)-2-[3 -(-p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin of formula i namely Atosiban.
A further object of the present invention is to provide a novel process for the preparation of 1-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin which is easily applicable at a large scale. Another object of the present invention is to provide a novel process for the preparation of 1-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin which involves non-linear and convergent systhesis. Yet another object of the present invention is to provide a novel process for the preparation of 1-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin which has a minimum number of steps.


ZRC-NPR-010
Another object of the invention is to provide a pharmaceutical composition
comprising Atosiban prepared according to the present invention.
Still further object of the present invention is to provide a novel process for the
preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-
threonine-8-L-ornithineoxytocin which involves solid intermediates.
A further object of the present invention is to provide a novel process for the
preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-
threonine-8-L-ornithineoxytocin which avoids use of costly amino acids in several
steps.
A further object of the present invention is to provide a novel process for the
preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-
threonine-8-L-ornithineoxytocin which involves use of additives to avoid
recemization and other side reaction.
The Summary of the Invention
Accordingly, the present invention provides a novel process for the preparation of l-(3-Mercaptopropionic acid)-2-[3-(p-ethoxyphenyl)-D-alanine]-4-L-threonine-8-L-ornithineoxytocin of formula 1 namely Atosiban. This process involves novel synthetic strategies, which is operationally simple, and therefore offers opportunities for better industrial applicability.
Detailed Description of the Invention
According to the present invention Atosiban may be prepared by on or more of the processes described in schemes I-IV. The strategy in these processes is mainly to avoid the use of costly D-tyrosine in multiple steps. This is why the initial coupling of amino acids begins from Glycinamide side and subsequently, other amino acids are attached with Glycinamide with protected ornithine and proline and the like. Thus, one-by-one protected penta peptide, for example PG-l-Asn-Cys-S-(PG-3)L-Pro-Orn-(PG-2)-Gly-NH2 is synthesized. Conceptually, one can synthesize peptides by employing a variety of protecting groups for nitrogen, thiol, and C-terminus which are mentioned in the literature ("M. Bodanszky, Principles of peptide synthesis, Springer-Verlag, Berlin heidelberg, 1993, 2nd edition" and "Theodora W. Greene and Peter G. M. Wuts, Protective groups in organic synthesis, Wiley-Interscience, New York,


ZRC-NPR-010
1998, 3 edition") using activating groups for coupling and subsequent deprotection. More specifically, protecting groups such as Cbz(carbonylbenzyloxy), Boc(tert-butoxy carbonyl), Fmoc (9-fluorenyl methoxy carbonyl) and the like is used for nitrogen; Benzyl, tert-butyl, Trityl, Acetamidomethyl and the like is used for thiol and Tert-Butyl ester, Benzyl ester, Phenacyl ester, Ethyl ester, 4-Nitrophenyl ester and the like is used for C-terminus(see Table 1). But person skilled in the art can also change to other protecting groups and similar objectives can be achieved. The scope of the present invention should not be limited in such obvious alterations or extrapolations. Similarly, above mentioned penta peptide can also be prepared by altering the sequence of addition of amino acid and ultimately achieving the same objective. The protection of amines of amino acids with Boc or FmoC, Cbz, benzyl and the like is accomplished by reacting corresponding amino acid with either Boc-anhydride or corresponding chlorides such as Fmoc chloride, cbz chloride, benzyl chloride in a polar solvent and in the presence of a suitable base. The reaction is carried out at a temprature in the range from 0 °C to 100 °C. Some of the polar solvents commonly employed are acetonitrile, ethanol, methanol, water, dioxane, tetrahydrofiiran, ether, ethyl acetate and the like or mixture thereof. The organic and inorganic bases commonly used are triethyl amine, pyridine, diethyl isopropyl amine, sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium hydroxide and the like or mixture thereof. Other specialized nitrogen protecting groups for bifunctional amino acids such as L-tyrosin, L-ornithine can be chosen from either above mentioned protecting groups or diagonally protected groups such as tosylate, mesylate, besylate and the like. The chemoselective protection of side chain amino group in L-ornithine is carried out by intramolecular in situ protection by copper using cupric carbonate in water and subsequent treatment with tosyl chloride, mesyl chloride or besyl chloride in the presence of either organic or inorganic bases mentioned above.
Similarly, the coupling of two protected amino acids, one protected at N-terminus and other protected at C-terminus is accomplished by using commonly used coupling agents such as DCC (1,3-dicyclohexylcarbodiimide), CDI (Carbonyldiimidazole), Bop-Cl(bis-2-(oxo-3-oxazolidinyl) phosphinic chloride or by formation of mixed anhydride with pivaloyl chloride or isobutyl chloformate or DPC (2,2'-dipyridyl


ZRC-NPR-010
carbonate)(see table 2 & 3). Usually, water soluble derivatives such as l-ethyl-3-(3'-dimethylamino propyl) carbodiimide (EDO) is also used for clearer rections and operational simplicity. During such couplings 1-hydroxybenzo triazole (HOBt) is used to avoid side reactions, catalyse the reaction and prevent racemization. While coupling two amino acids, it becomes essential that the amino group of one amino acid and carboxyl group of the amino acid is protected. Usually, protection of carboxylic acid are carried out as methyl, benzyl or ethyl esters. Such esters are prepared from corresponding carboxylic acids and alcohols by using either thionyl chloride or dry HC1 gas. Alternatively, after the coupling, the carboxylate esters are hydrolysed by aqueous sodium hydroxide or potassium hydroxide. The deprotection of amino protecting agents (PG-1/ PG-2, table 1) is also carried out either in the presence of acid or by catalytic hydrogenation or by treatment with lithium in liquid ammonia, but keeping the sensitivity of other protecting groups in mind. Once again, similar to N-terminus protecting groups, wide variety of protecting groups for C-terminus are reported in the literature and a person skilled in the art can alter them advantageously, as reported in the literature. The scope Of present invention should not be limited due to such obvious alterations.
Followings are the examples of various protecting groups, coupling reagents and
mixed anhydrides:
Table 1: Protecting Groups
Protecting Group Name
PG-1 Na Protection Z(Cbz) Benzyloxycarbonyl
Boc tert-butoxycarbonyl
Fmoc 9-fluorenylmethoxycarbonyl
PG-2 N5 Protection Tos 4-Toluenesulfonate
Z Benzyloxycarbonyl
Boc tert-butoxycarbonyl
PG-3 Thiol group Bn Benzyl
tBu tert-butyl
Trt Trityl
Acm Acetamidomethyl
PG-4 C -Terminus tert-Butyl ester
benzyl ester
phenacyl ester
ethyl ester or methyl ester
ONp 4-Nitrophenyl ester


Table 2 Coupling Reagents
Sr.No. Name
1 O-acylisoureas
2 Dicyclohexylcarbodiimide(DCC)
3 Ethoxyacetylene
4 1 -ethoxycarbonyl 1 -2-ethoxy-1,2-dihydroquinoline (EEDQ)
5 Benzotriazolyloxy-tris-(di-methylamino)phosphonium hexafluorophosphate (Bop)
6 N-N'-Carbonylimidazole(CDI)
7 bis-2-(oxo-3-oxazolidinyl) phosphinic chloride(Bop-Cl)
8 1 -ethyl-3 -(3' -dimethylamino propyl) carbodiimide(EDCI)
9 1-hydroxybenzo triazole(HOBt)

Table 3 I: Mixed Anhydride
Sr. No. Name
1 Isobutyl chloroformate(IBCF)
2 Pivaloyl cholride
3 2,2'-Dipyridyl carbonate (DPC)
4 N-N'-Carbonylimidazole(CDI)
5 1-hydroxybenzo triazole(HOBt)
Followings schemes depicts the novel process for the preparation Atosiban:






The key features of current process for Atosiban are the coupling strategies of different amino acid fragments, such as 1+3+5 (4+5), 2+2+5(4+5), 2+7 and 1+8 as depicted in schemes 1 to 4 respectively. Naturally, the synthesis of octapeptide starting from Glycinaminde is accomplished through penta peptide as discussed, but other obvious permutation and combinations are also possible by those skilled in the art and are incorporated herein with the scope of this invention.
Advantages of the present invention
• The intermediates involved in the present invention are solids, which are isolated and characterised at any stage.
• The present invention involves non-linear and convergent synthesis.
• The present invention avoids use of costly amino acids in several steps.
• The process according to present invention avoids use of costly intermediates in several steps.


ZRC-NPR-010
• The present invention involves use of cost effective protecting and coupling reagents.
• The present invention involves use of additives to catalyze the reaction and to avoid recamization and other side reactions.
• The present invention avoids use of cryogenic reaction conditions as disclosed in the prior art.
• The process involves less number of steps.
• This process is easily applicable on a large scale.
• All the above advantages make this process operationally simple and cost effective, which are essential for manufacturing.







Documents:

284-mum-2004-abstract (complete).doc

284-mum-2004-abstract (complete).pdf

284-mum-2004-abstract(7-3-2005).pdf

284-MUM-2004-AMANDED CLAIMS-(27-7-2011).pdf

284-MUM-2004-CANCELLED PAGES(26-3-2012).pdf

284-mum-2004-claims (complete).doc

284-mum-2004-claims (complete).pdf

284-mum-2004-claims(7-3-2005).pdf

284-MUM-2004-CLAIMS(AMENDED)-(26-3-2012).pdf

284-MUM-2004-CLAIMS(GRANTED)-(12-6-2012).pdf

284-MUM-2004-CORRESPONDENCE(12-6-2012).pdf

284-MUM-2004-CORRESPONDENCE(2-9-2011).pdf

284-MUM-2004-CORRESPONDENCE(20-5-2010).pdf

284-mum-2004-correspondence(22-2-2008).pdf

284-MUM-2004-CORRESPONDENCE(31-1-2012).pdf

284-MUM-2004-CORRESPONDENCE(9-8-2011).pdf

284-MUM-2004-CORRESPONDENCE(IPO)-(12-6-2012).pdf

284-mum-2004-correspondence(ipo)-(4-3-2005).pdf

284-mum-2004-correspondence-received-050305.pdf

284-mum-2004-correspondence-received.pdf

284-mum-2004-description (complete).pdf

284-mum-2004-description (provisional).pdf

284-mum-2004-description(complete)-(7-3-2005).pdf

284-MUM-2004-DESCRIPTION(GRANTED)-(12-6-2012).pdf

284-mum-2004-digram.doc

284-mum-2004-form 18(22-2-2008).pdf

284-mum-2004-form 2(7-3-2005).pdf

284-MUM-2004-FORM 2(GRANTED)-(12-6-2012).pdf

284-mum-2004-form 2(title page)-(7-3-2005).pdf

284-MUM-2004-FORM 2(TITLE PAGE)-(GRANTED)-(12-6-2012).pdf

284-MUM-2004-FORM 2(TITLE PAGE)-(PROVISIONAL)-(8-3-2004).pdf

284-MUM-2004-FORM 5(7-3-2005).pdf

284-mum-2004-form-1.pdf

284-mum-2004-form-2 (complete).doc

284-mum-2004-form-2 (complete).pdf

284-mum-2004-form-2 (provisional).doc

284-mum-2004-form-2 (provisional).pdf

284-mum-2004-form-26.pdf

284-mum-2004-form-3.pdf

284-mum-2004-form-5.pdf

284-MUM-2004-GENERAL POWER OF AUTHORITY(27-7-2011).pdf

284-MUM-2004-REPLY TO EXAMINATION REPORT(27-7-2011).pdf

284-MUM-2004-REPLY TO HEARING(14-10-2011).pdf

284-MUM-2004-REPLY TO HEARING(26-3-2012).pdf


Patent Number 252970
Indian Patent Application Number 284/MUM/2004
PG Journal Number 24/2012
Publication Date 15-Jun-2012
Grant Date 12-Jun-2012
Date of Filing 08-Mar-2004
Name of Patentee CADILA HEALTHCARE LIMITED
Applicant Address ZYDUS TOWER, SATELITE CROSS ROADS, AHMEDABAD 380 015
Inventors:
# Inventor's Name Inventor's Address
1 PANDEY BIPIN CADILA HEALTHCARE LIMITED ZYDUS TOWER, SATELITE CROSS ROADS, AHMEDABAD 380 015
2 LOHARY BRAJ BHUSHAN CADILA HEALTHCARE LIMITED ZYDUS TOWER, SATELITE CROSS ROADS, AHMEDABAD 380 015
3 LOHERY VIDYA BHUSAN CADILA HEALTHCARE LIMITED ZYDUS TOWER, SATELITE CROSS ROADS, AHMEDABAD 380 015
PCT International Classification Number C07K7/06; C07K1/04
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA