Title of Invention

AN IMPROVED PROCESS FOR PREPARATION OF SUBSTITUTED 3-HYDROXY,1,2,4-TRIAZOLES

Abstract

A process for manufacturing 3-hydroxy 1,2,4—triazoles of the formula, where R is phenyl or substituted phenyl such as chloro, bromo, iodo, alkoxy or alkyl, using one pot synthesis comprising steps of (a) diazotizing aniline or substituted aniline at a temperature of-10°C to 5°C by using sodium nitrite in the concentration of one mole per mole of aniline or substituted aniline and thereafter reducing the compound thus obtained with sodium sulfite having concentration of 2.0 moles to 4.0 moles per mole of aniline or substituted aniline between 20°C to 100°C in presence of an inorganic acid as a catalyst in one pot forming in-situ phenyl hydrazine salt; (b) and further reacting this phenyl hydrazine salt in the same said pot without isolating it, with urea and formic acid in the presence of solvents or diluents such as herein described in the specification at an atmospheric pressure to form a substituted hydroxy triazole of formula I given above.

Full Text

FORM-2 THE PATENTS ACT. 1970 (39 of 1970) COMPLETE SPECIFICATION (SeetionlO) "AN IMPROVED PROCESS FOR PREPARATION OF SUBSTITUTED 3-HYDROXY, 1,2,4-TRIAZOLES" SUDARSHAN CHEMICAL INDUSTRIES LTD., 162, Wellesley Road, PUNE-411001. Maharashtra State, India An Indian Company registered under the provisions of the Companies Act, 1956 The following specification particularly describes the nature of the invention and the manner in which it is to be performed: - Present invention relates to a process for the manufacturing of substituted 3-hydroxy 1,2,4-triazoles using one pot synthesis. More particularly, present invention relates to an improved process for preparation of 3-Hydroxy, 1,2,4 - Triazoles using one pot synthesis and in-situ phenyl hydrazine preparation using corresponding aniline or substituted anilines. According to present invention the 3-Hydroxy, 1,2,4 - Triazoles are obtained in high yield and in high purity, which is subsequently used for production of pesticide. In the prior art, it is known to prepare, l-phenyl-3-hydroxy-1, 2,4-triazole by heating 1-phenyl semicarbazide with formic acid. However, this process, although using a great excess of formic acid and requiring long reaction times, gives a yield of less than 50% of the theory and is therefore unsatisfactory. It is further known to prepare compounds of the 3-Hydroxytriazoles by reacting corresponding semicarbazides with orthoformic acid esters. It is further known process preparing substituted 3-hydroxy-l, 2,4-triazoles by cyclization of correspondingly substituted semicarbazides with formic acid, which comprises carrying out the reaction in the presence of an inorganic or strong organic acid, or their halides or anhydrides. Further in this process phenyl hydroxy triazole is prepared by reacting formic acid with urea in xylene as a solvent in presence of inorganic acid under pressure in autoclave with 81.2% yield. But, the same process if carried out at atmospheric pressure in presence of phenyl hydrazine, ammonium chloride, urea and formic acid with inorganic acid results into only 72% yield (US 4467098). Thus Process for the manufacture of substituted 3-hydroxy-1,2,4-triazoles ,by isolating phenyl hydrazine has the following drawbacks : Therefore, for manufacturing of substituted 3-hydroxy, 1,2,4 - trizoles using one pot synthesis, aniline is diazotized at -10 °C to 5 °C and reduced by sodium sulphite at 20 °C to 100 °C in presence of inorganic acid to form phenyl hydrazine salt. Phenyl hydrazine salt obtained by above process which is taken in-situ for further reaction without isolating phenyl hydrazine, in same pot with urea and formic acid, condensed at 40 °C to 100 °C to form substituted hydroxy triazole in good yields. All the reactions in the above-mentioned manufacturing process of 3-hydroxy 1,2,4- trizoles are carried out under atmospheric pressure. The reaction time is dependent upon quantity of sodium sulphite, formic acid and inorganic acid used. A process for manufacturing 3-hydrozy 1,2,4-trizole gives 85.16%yield of 1-phenyl-3-hydroxy 1,2,4-triazole having 98% purity. Therefore, according to the present invention a process for manufacturing of substituted 3-hydroxy 1,2,4—trizoles of the formula, where R is phenyl or substituted phenyl such as chloro, bromo, iodo, alkoxy or alkyl, using one pot synthesis comprises steps of (a) diazotizing aniline or substituted aniline at a temperature of -10°C to 5°C by using sodium nitrite in the concentration of one mole per mole of aniline or substituted aniline and thereafter reducing the compound thus obtained with sodium sulfite having concentration of 2.0 moles to 4.0 moles per mole of aniline or substituted aniline between 20°C to 100°C in presence of an inorganic acid as a catalyst in one pot forming in-situ phenyl hydrazine salt; (b) and further reacting this phenyl hydrazine salt in the same said pot without isolating it, with urea and formic acid in the presence of solvents or diluents such as herein described in the specification at an atmospheric pressure to form a substituted hydroxy triazole of formula I given above. We Claim: 1. A process for manufacturing 3-hydroxy 1,2,4—triazoles of the formula, where R is phenyl or substituted phenyl such as chloro, bromo, iodo, alkoxy or alkyl, using one pot synthesis comprising steps of (a) diazotizing aniline or substituted aniline at a temperature of-10°C to 5°C by using sodium nitrite in the concentration of one mole per mole of aniline or substituted aniline and thereafter reducing the compound thus obtained with sodium sulfite having concentration of 2.0 moles to 4.0 moles per mole of aniline or substituted aniline between 20°C to 100°C in presence of an inorganic acid as a catalyst in one pot forming in-situ phenyl hydrazine salt; (b) and further reacting this phenyl hydrazine salt in the same said pot without isolating it, with urea and formic acid in the presence of solvents or diluents such as herein described in the specification at an atmospheric pressure to form a substituted hydroxy triazole of formula I given above. 2. A process as claimed in claim (1) wherein, the concentration of said inorganic acid is in the range of 3.5 to 6.0 moles per mole of aniline or substituted aniline. 3. A process as claimed in claim (1) wherein, the inorganic acid is sulphuric acid or hydrochloric acid or phosphoric acid or p-toluenesulphonic acid. 4 A process as claimed in claim (1) wherein, sodium sulfite is in a concentration of 2.0 to 4.0 moles per mole of aniline or substituted aniline and urea is in the concentration of 1 mole to 3 per mole preferably at least 1 mole of aniline or substituted aniline. 5. A process as claimed in claim (1) wherein, solvents or diluents are DMF, hydrocarbons such as xylene, chloro benzene preferably, water.

Documents:

310-mum-2004-cancelled pages(15-4-2005).pdf

310-mum-2004-claims(granted)-(15-4-2005).doc

310-mum-2004-claims(granted)-(15-4-2005).pdf

310-mum-2004-correspondence(15-4-2005).pdf

310-mum-2004-correspondence(ipo)-(7-1-2008).pdf

310-mum-2004-form 1(12-3-2004).pdf

310-mum-2004-form 19(12-3-2004).pdf

310-mum-2004-form 2(granted)-(15-4-2005).doc

310-mum-2004-form 2(granted)-(15-4-2005).pdf

310-mum-2004-form 3(12-3-2004).pdf

310-mum-2004-power of authority(27-2-2004).pdf