Title of Invention	METHOD FOR PREPARING 4-DEMETHYLDAUNORUBICIN
Abstract	A method of preparing the anthracyclin carminomycin using a starting material comprising daunorubicin. The method comprises reacting daunorubicin or N-protected daunorubicin with soft Lewis acids for the demethylation of the 4-methoxy group, resulting in a reaction mass. The reaction mass is treated with an aqueous solution of a strong organic acid or a mineral acid. After decomposition of the resulting carminomycin and Lewis acids reactive complex, the reaction mass is extracted using a water insoluble organic solvent. As a result, carminomycin is extracted as a base.

Title of Invention

METHOD FOR PREPARING 4-DEMETHYLDAUNORUBICIN

Abstract

A method of preparing the anthracyclin carminomycin using a starting material comprising daunorubicin. The method comprises reacting daunorubicin or N-protected daunorubicin with soft Lewis acids for the demethylation of the 4-methoxy group, resulting in a reaction mass. The reaction mass is treated with an aqueous solution of a strong organic acid or a mineral acid. After decomposition of the resulting carminomycin and Lewis acids reactive complex, the reaction mass is extracted using a water insoluble organic solvent. As a result, carminomycin is extracted as a base.

Full Text	SPECIFICATION METHOD FOR PREPARING 4-DEMETHYLDAUNORUBICIN Related Applications [0001] This Application claims the benefit of U.S. provisional Application No. 60/749,464, filed on December 13, 2005, in accordance with 35 U.S.C. Section 119(e), and any other applicable laws. U.S. provisional Application No. 60/749,464 is hereby incoiporated by reference in its entirety as if set forth fully herein. Field of the Invention [0002] The field of the invention generally relates to chemical methods used to produce anthracyclines, a compound which is useful as an anticancer chemotherapeutic drug. More specifically, the field of the invention relates to methods of producing cytostatic anthracyclin antibiotic 4-demethyldaunorubicin (commonly referred to as "carminomycin") in the form of Formula (1) (wherein An" is an anion of any strong acid; for example, in one non-limiting case of 4'-epirubicin, An" comprises Cf). Background of the Invention [0003] Anthracyclines form one of the largest families of naturally occurring bioactive compounds. Several members of this family have shown to be clinically effective anti- neoplastic agents. These include, for example, daunorubicin, doxorubicin, idarubicin, epirubicin, pirarubicin, zorubicin, aclarubicin, and carminomycin. For instance, these compounds have shown to be useful in the treatment of breast carcinoma, acute lymphocytic and non-lymphocytic leukemia, chronic lymphocytic leukemia, non-Hodgkin's lymphoma, and other solid cancerous tumors. [0004] Carminomycin (in the form of Formula (l))is a well-known anthracyclin antibiotic that is used both in defined clinical applications and as a starting material for synthesis of multiple 4-modified anthracylins, and in particular, idarubicin (see for example, U.S. Patent No. 7,053,191, the contents of which is hereby incorporated by reference herein in its entirety). [0005] Microbiological production of carminomycin is complicated by a very low productivity of the known strains of microorganisms, at the level of 0.1 -0.3 g/L. Up until the present, the synthetic method of preparing carminomycin has been very protracted (involving 10-12 chemical stages) and expensive. In the previously described methods of 4-methoxy group demethylation, the substrate was daunorubicinone because there had been no known methods of 4-methoxy group demethylation without breaking of the C-7 glycoside bond. The most common method of the 4-methoxy group demethylation involves treatment of the daunorubicinone with a strong Lewis acid, AICI3, in inert solvents such as chlorinated hydrocarbons (ex. dichloromethane) at boiling temperature. In an attempt to conduct the same synthesis with daunorubicin, the daunosamine glycoside bond is severed, and the anthracyclin nucleus is destroyed. Summary of the Invention [0006] The present invention is directed to an innovative method for producing carminomycin using a novel method for the 4-methoxy group demethylation of a widely- available starting substance daunorubicin, that does not result in the destruction of the C-7 glycoside bond, and that decreases the number of synthesis stages from 10-12 to 1-3. [0007] Demethylation is achieved by the treatment of daunorubicin or N-protected daunorubicin (Formula 2 and Formula 3, respectively) with soft Lewis acids, such as TiHal4, BHal3, MgHal2, where Hal = F, Cl, Br, I in anhydrous solvents, such as alkanes, cycloalkanes, arenes, halogenoalkanes, simple ethers, CS2, all of which are stable in Lewis acids, at temperatures 10-80°C. [0008] Extraction of carminomycin or N-protected carminomycin is achieved by treating the reaction mass with an aqueous solution of strong organic or mineral acids. After decomposition of the carminomycin and Lewis acids reactive complex, the reactive mass (in the case of utilization of water-soluble simple ethers) is extracted with water-insoluble (hydrophobic) organic solvents such as halogenoalkanes, cycloalkanes, arenes, C4-C6 alcohols and mixtures thereof. Carminomycin is then extracted as a base. Detailed Description of the Invention [0009] The method of preparing a carminomycin compound using daunorubicin as the starting material according to the present invention comprises the following steps. [0010] I. Demethylation of daunorubicin or N-protected daunorubicin [0011] The demethylation reaction is completed by treating daunorubicin or N-protected daunorubicin (Formula 2 and Formula 3, respectively) with soft Lewis acids, such as TiHal4, BHal3, MgHal2, where Hal = F, Cl, Br, I in anhydrous solvents, such as alkanes, cycloalkanes, arenes, halogenoalkanes, simple ethers, CS2, all of which are stable in Lewis acids, at temperatures in the range of about 10 - 80 °C (as shown in Diagram 1). [0012] With utilization of the N-protected daunorubicin, the reaction is accomplished with lesser amounts of by-products (impurities) and a higher yield. [0013] The amount of Lewis acid used in the reaction is 1-5 moles per 1 mole of daunorubicin, preferably 1.5-3 moles. [0014] The reaction temperature depends on the strength of the Lewis acid and must provide for the maximum regioselectivity of the process involving breakage of the 4-OMe bond with preservation of the 7-O-daunosamine bond, preferably 40-60 °C. [0015] The solvents suitable for conduction of the reaction are selected based on the same principles as for the temperature selection. Preference is given to halogenoalkanes, simple ethers, and CS2. [0016] Extraction of carmmomycin or N-protected carminomycin is performed by treating the reaction mass with an aqueous solution of strong organic acids, such as oxalic acid, trifluoroacetic acid or such mineral acids as sulfuric acid or hydrochloric acids pH 2.5±1. After decomposition of the carminomycin and Lewis acids reactive complex, the reactive mass (in the case of utilization of water-soluble simple ethers) is extracted with water-insoluble (hydrophobic) organic solvents such as halogenoalkanes, cycloalkanes, arenes, C4-C6 alcohols and mixtures thereof. Carminomycin may then be extracted as a base. [0017] The 3'N-Prot-group, in the case of utilization of N-protected daunorubicin, is removed immediately upon completion of the synthesis or after further modification of the 4-R substituent, depending on the goals of synthesis. [0018] Example [0019] 6.25 grams of N-trifluoroacetyldaunorubicin is dissolved in 150 ml of tetrahydrofurane, and 2.9 grams of unhydrous magnesium chloride is slowly added under conditions that exclude contact with atmospheric moisture. The resulting mixture is incubated for 1.5 hours at 40 °C, then poured into ice water, titrated to pH 2.5 with trifluoroacetic acid, and then extracted with 2 x 50 ml aliquots of dichloromethane. The organic layer is separated and dried with anhydrous MgSO4. The solvent is then evaporated at below-atmospheric pressure. The result is about 4.8 grams of N-TFA-carminomycin with purity of about 65-80% (this is confirmed by HPLC). [0020] The N-TFA-carminomycin, obtained from the above synthesis, is then suspended in 200 ml of distilled water at a temperature of 30 °C, and 15 ml of 1.0 N NaOH solution is added. The mixture is incubated for 30 minutes and then neutralized to pH 7 with a solution of hydrochloric acid and is then sent to preparative chromatography. After evaporation of eluate, 3.0-3.8 grams of carminomycin is produced with a purity of about 96% (this is confirmed by HPLC). We Claim: 1. A method of preparing the anthracyclin Carminomycin represented by Formula 1, from anthracyclin daunorubicin, comprising the following step: reacting one of daunorubicin represented by Formula 2, or N-protected daunorubicin represented by Formula 3, with soft Lewis acids for the demethylation of the 4-methoxy group of , said one of daunorubicin represented Formula 2, or N-protected daunorubicin represented by Formula 3, resulting in a reaction mass. 2. The method of claim 1, wherein the mild Lewis acids are TiHal4, BHal3, MgHal2 where Hal = F, Cl, Br, I. 3. The method of claim 1, wherein the reaction is conducted using a solvent selected from the group of: anhydrous alkanes, cycloalkanes, arenes, halogenoalkanes, simple ethers, or CS2. 4. The method of claim 1, wherein the reaction is conducted at a temperature of about 10 to about 80 °C for between 1 to 10 hours. 5. The method of claim 1, further comprising the steps of: treating the reaction mass with an aqueous solution of one of strong organic acid or mineral acid; and extracting carminomycin as a base from the treated reaction mass using a water-insoluble organic solvent. 6. The method of claim 5, wherein said one of strong organic acid or mineral acid is selected from the group consisting of sulfuric acid or hydrochloric acid. 7. The method of claim 5, wherein said water-insoluble organic solvent comprises one of halogenoalkanes, cycloalkanes, arenas, C4-C6 alcohols, or mixtures of the preceding. A method of preparing the anthracyclin carminomycin using a starting material comprising daunorubicin. The method comprises reacting daunorubicin or N-protected daunorubicin with soft Lewis acids for the demethylation of the 4-methoxy group, resulting in a reaction mass. The reaction mass is treated with an aqueous solution of a strong organic acid or a mineral acid. After decomposition of the resulting carminomycin and Lewis acids reactive complex, the reaction mass is extracted using a water insoluble organic solvent. As a result, carminomycin is extracted as a base.

Full Text

SPECIFICATION
METHOD FOR PREPARING 4-DEMETHYLDAUNORUBICIN
Related Applications
[0001] This Application claims the benefit of U.S. provisional Application No. 60/749,464,
filed on December 13, 2005, in accordance with 35 U.S.C. Section 119(e), and any other
applicable laws. U.S. provisional Application No. 60/749,464 is hereby incoiporated by
reference in its entirety as if set forth fully herein.
Field of the Invention
[0002] The field of the invention generally relates to chemical methods used to produce
anthracyclines, a compound which is useful as an anticancer chemotherapeutic drug. More
specifically, the field of the invention relates to methods of producing cytostatic anthracyclin
antibiotic 4-demethyldaunorubicin (commonly referred to as "carminomycin") in the form of
Formula (1) (wherein An" is an anion of any strong acid; for example, in one non-limiting case
of 4'-epirubicin, An" comprises Cf).

Background of the Invention
[0003] Anthracyclines form one of the largest families of naturally occurring bioactive
compounds. Several members of this family have shown to be clinically effective anti-
neoplastic agents. These include, for example, daunorubicin, doxorubicin, idarubicin,
epirubicin, pirarubicin, zorubicin, aclarubicin, and carminomycin. For instance, these

compounds have shown to be useful in the treatment of breast carcinoma, acute lymphocytic
and non-lymphocytic leukemia, chronic lymphocytic leukemia, non-Hodgkin's lymphoma, and
other solid cancerous tumors.
[0004] Carminomycin (in the form of Formula (l))is a well-known anthracyclin antibiotic
that is used both in defined clinical applications and as a starting material for synthesis of
multiple 4-modified anthracylins, and in particular, idarubicin (see for example, U.S. Patent No.
7,053,191, the contents of which is hereby incorporated by reference herein in its entirety).
[0005] Microbiological production of carminomycin is complicated by a very low
productivity of the known strains of microorganisms, at the level of 0.1 -0.3 g/L. Up until the
present, the synthetic method of preparing carminomycin has been very protracted (involving
10-12 chemical stages) and expensive. In the previously described methods of 4-methoxy
group demethylation, the substrate was daunorubicinone because there had been no known
methods of 4-methoxy group demethylation without breaking of the C-7 glycoside bond. The
most common method of the 4-methoxy group demethylation involves treatment of the
daunorubicinone with a strong Lewis acid, AICI3, in inert solvents such as chlorinated
hydrocarbons (ex. dichloromethane) at boiling temperature. In an attempt to conduct the same
synthesis with daunorubicin, the daunosamine glycoside bond is severed, and the anthracyclin
nucleus is destroyed.
Summary of the Invention
[0006] The present invention is directed to an innovative method for producing
carminomycin using a novel method for the 4-methoxy group demethylation of a widely-
available starting substance daunorubicin, that does not result in the destruction of the C-7
glycoside bond, and that decreases the number of synthesis stages from 10-12 to 1-3.
[0007] Demethylation is achieved by the treatment of daunorubicin or N-protected
daunorubicin (Formula 2 and Formula 3, respectively) with soft Lewis acids, such as TiHal4,

BHal3, MgHal2, where Hal = F, Cl, Br, I in anhydrous solvents, such as alkanes, cycloalkanes,
arenes, halogenoalkanes, simple ethers, CS2, all of which are stable in Lewis acids, at
temperatures 10-80°C.

[0008] Extraction of carminomycin or N-protected carminomycin is achieved by treating the
reaction mass with an aqueous solution of strong organic or mineral acids. After decomposition
of the carminomycin and Lewis acids reactive complex, the reactive mass (in the case of
utilization of water-soluble simple ethers) is extracted with water-insoluble (hydrophobic)
organic solvents such as halogenoalkanes, cycloalkanes, arenes, C4-C6 alcohols and mixtures
thereof. Carminomycin is then extracted as a base.
Detailed Description of the Invention
[0009] The method of preparing a carminomycin compound using daunorubicin as the
starting material according to the present invention comprises the following steps.
[0010] I. Demethylation of daunorubicin or N-protected daunorubicin
[0011] The demethylation reaction is completed by treating daunorubicin or N-protected
daunorubicin (Formula 2 and Formula 3, respectively) with soft Lewis acids, such as TiHal4,
BHal3, MgHal2, where Hal = F, Cl, Br, I in anhydrous solvents, such as alkanes, cycloalkanes,

arenes, halogenoalkanes, simple ethers, CS2, all of which are stable in Lewis acids, at
temperatures in the range of about 10 - 80 °C (as shown in Diagram 1).

[0012] With utilization of the N-protected daunorubicin, the reaction is accomplished with
lesser amounts of by-products (impurities) and a higher yield.
[0013] The amount of Lewis acid used in the reaction is 1-5 moles per 1 mole of
daunorubicin, preferably 1.5-3 moles.
[0014] The reaction temperature depends on the strength of the Lewis acid and must provide
for the maximum regioselectivity of the process involving breakage of the 4-OMe bond with
preservation of the 7-O-daunosamine bond, preferably 40-60 °C.
[0015] The solvents suitable for conduction of the reaction are selected based on the same
principles as for the temperature selection. Preference is given to halogenoalkanes, simple
ethers, and CS2.
[0016] Extraction of carmmomycin or N-protected carminomycin is performed by treating
the reaction mass with an aqueous solution of strong organic acids, such as oxalic acid,
trifluoroacetic acid or such mineral acids as sulfuric acid or hydrochloric acids pH 2.5±1. After
decomposition of the carminomycin and Lewis acids reactive complex, the reactive mass (in the
case of utilization of water-soluble simple ethers) is extracted with water-insoluble

(hydrophobic) organic solvents such as halogenoalkanes, cycloalkanes, arenes, C4-C6 alcohols
and mixtures thereof. Carminomycin may then be extracted as a base.
[0017] The 3'N-Prot-group, in the case of utilization of N-protected daunorubicin, is
removed immediately upon completion of the synthesis or after further modification of the 4-R
substituent, depending on the goals of synthesis.
[0018] Example
[0019] 6.25 grams of N-trifluoroacetyldaunorubicin is dissolved in 150 ml of
tetrahydrofurane, and 2.9 grams of unhydrous magnesium chloride is slowly added under
conditions that exclude contact with atmospheric moisture. The resulting mixture is incubated
for 1.5 hours at 40 °C, then poured into ice water, titrated to pH 2.5 with trifluoroacetic acid,
and then extracted with 2 x 50 ml aliquots of dichloromethane. The organic layer is separated
and dried with anhydrous MgSO4. The solvent is then evaporated at below-atmospheric
pressure. The result is about 4.8 grams of N-TFA-carminomycin with purity of about 65-80%
(this is confirmed by HPLC).
[0020] The N-TFA-carminomycin, obtained from the above synthesis, is then suspended in
200 ml of distilled water at a temperature of 30 °C, and 15 ml of 1.0 N NaOH solution is
added. The mixture is incubated for 30 minutes and then neutralized to pH 7 with a solution of
hydrochloric acid and is then sent to preparative chromatography. After evaporation of eluate,
3.0-3.8 grams of carminomycin is produced with a purity of about 96% (this is confirmed by
HPLC).

We Claim:
1. A method of preparing the anthracyclin Carminomycin represented by Formula 1, from
anthracyclin daunorubicin, comprising the following step:
reacting one of daunorubicin represented by Formula 2, or N-protected daunorubicin
represented by Formula 3, with soft Lewis acids for the demethylation of the 4-methoxy group
of ,
said one of daunorubicin represented Formula 2, or N-protected daunorubicin represented by
Formula 3, resulting in a reaction mass.
2. The method of claim 1, wherein the mild Lewis acids are TiHal4, BHal3, MgHal2 where
Hal = F, Cl, Br, I.
3. The method of claim 1, wherein the reaction is conducted using a solvent selected from
the group of: anhydrous alkanes, cycloalkanes, arenes, halogenoalkanes, simple ethers, or CS2.
4. The method of claim 1, wherein the reaction is conducted at a temperature of about 10 to
about 80 °C for between 1 to 10 hours.
5. The method of claim 1, further comprising the steps of:
treating the reaction mass with an aqueous solution of one of strong organic acid or
mineral acid; and
extracting carminomycin as a base from the treated reaction mass using a water-insoluble
organic solvent.
6. The method of claim 5, wherein said one of strong organic acid or mineral acid is
selected from the group consisting of sulfuric acid or hydrochloric acid.

7. The method of claim 5, wherein said water-insoluble organic solvent comprises one of
halogenoalkanes, cycloalkanes, arenas, C4-C6 alcohols, or mixtures of the preceding.

A method of preparing the anthracyclin carminomycin using a starting material comprising daunorubicin. The
method comprises reacting daunorubicin or N-protected daunorubicin with soft Lewis acids for the demethylation of the 4-methoxy
group, resulting in a reaction mass. The reaction mass is treated with an aqueous solution of a strong organic acid or a mineral acid.
After decomposition of the resulting carminomycin and Lewis acids reactive complex, the reaction mass is extracted using a water
insoluble organic solvent. As a result, carminomycin is extracted as a base.

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Patent Number

271395

Indian Patent Application Number

2394/KOLNP/2008

PG Journal Number

09/2016

Publication Date

26-Feb-2016

Grant Date

18-Feb-2016

Date of Filing

13-Jun-2008

Name of Patentee

SOLUX CORPORATION

Applicant Address

4455 MORENA BLVD., SUITE 214 SAN DIEGO, CA

Inventors:

#	Inventor's Name	Inventor's Address
1	MATVEEV ALEXEY	PANFILOVA 20, FL. 30, DONETSK, 83114
2	ITKIN ALEKSANDR	13760 KERRY LANE, SAN DIEGO, CA 92130
3	ZABUDKIN ALEXANDER	UNIVERSITETSKAJA STR. 27, FL.26, DONETSK, 83055
4	MATVIENKO VICTOR	PANFILOVA 20, FL. 37, DONETSK, 83114

PCT International Classification Number

C07H 15/24

PCT International Application Number

PCT/US2006/061978

PCT International Filing date

2006-12-13

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/749464	2005-12-13	U.S.A.