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Process for the preparation of methyl 2-((5-bromo-4-(4-cyclopropylnaphthalen-1-yl)-4H-1,2,4-triazol-3-yl)thio)acetate Disclosure Number: IPCOM000245979D
Publication Date: 2016-Apr-21
Document File: 1 page(s) / 130K

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Process for the preparation of methyl 2-((5-bromo-4-(4-


     Provided herein is a process for preparing methyl 2-((5-bromo-4-(4- cyclopropylnaphthalen-1-yl)-4H-1,2,4-triazol-3-yl)thio)acetate which is an intermediate in the preparation of 2-((5-bromo-4-(4-cyclopropylnaphthalen-1-yl)-4H-1,2,4-triazol-3-yl)thio)acetic acid and salts thereof.

The process is described in the following examples:

Stage-1: Preparation of 5-Amino-4-(4-cyclopropylnaphthalen-1-yl)-4H-1,2,4-triazole-3-thiol from 1-cyclopropyl-4-isothiocyanatonaphthalene

1-cyclopropyl-4-isothiocyanatonaphthalene (100 gr) was taken in polar aprotic solvent, such as, DMF (Dimethylformamide), DMAc (Dimethylacetamide), ACN or DMSO; and aminoguanidine hydrochloride (59.0-148.0 gr) was added to it followed by addition of diisopropyl ethyl amine
(69.0 -172.0 gr). Reaction mass was stirred at 20-50ÂșC for 3-10 hours followed by addition of the reaction mass to hot sodium hydroxide solution (18-53 gr in 800-3000 ml water) to effect cyclisation. Product so formed was isolated by pH adjustment using hydrochloric acid. Isolated product was filtered under vacuum, washed with water and dried in vacuum to give 5-Amino-4- (4-cyclopropylnaphthalen-1-yl)-4H-1,2,4-triazole-3-thiol.

Stage-2: Preparation of Methyl 2-((5-amino-4-(4-cyclopropylnaphthalen-1-yl)-4H-1,2,4- triazol-3-yl)thio)acetate from 5-Amino-4-(4-cyclopropylnaphthalen-1-yl)-4H-1,2,4-triazole- 3-thiol