# US 10,479,776 B2 · Process for the preparation of Efinaconazole

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- Number: US 10,479,776 B2
- Document ID: US10479776B2
- Status: Granted
- Kind: B2
- Application number: 15/573,082
- Filed: 2016-05-10
- Published: 2018-05-03
- Granted: 2019-11-19
- Earliest claimed: 2015-05-12
- Assignees: Lupin Limited
- Applicants: Lupin Limited
- Inventors: Sachin Arun Sasane; Devendrakumar Paramsukh Varma; Rajesh Harishankar Vyas; Nandu Baban Bhise; Girij Pal Singh; Krishnat Hanmant Kumbhar
- Web page: https://patentgrep.com/patent/US10479776B2

## CPC

- C07D 401/06: linked by a carbon chain containing only aliphatic carbon atoms
- C07B 2200/13: Crystalline forms, e.g. polymorphs
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- C07B: GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR (preparation of carboxylic acid esters by telomerisation C07C67/47; telomerisation C08F)

## Abstract

The present invention provides an improved process for the preparation of Efinaconazole in higher yield by the ring-opening addition reaction of epoxytriazole with 4-methylenepiperidine or its acid addition salt under mild conditions without using a large excess of 4-methylenepiperidine in the presence of an alkali or an alkaline earth metal halide.

## Claims

### Claim 1

An improved process for the preparation of Efinaconazole or pharmaceutically acceptable salts thereof comprises reacting (2R,3S)-2-(2,4-difluorophenyl)-3-methyl-2-[(1H-1,2,4-triazol-1-yl)methyl]oxirane with 4-methylenepiperidine or its acid addition salt in the presence of an alkali or an alkaline earth metal halide.

### Claim 2 (depends on 1)

The process according to claim 1, wherein an alkali or an alkaline earth metal halide is selected from lithium halide, sodium halide, potassium halide, rubidium halide, cesium halide, beryllium halide, magnesium halide, calcium halide, strontium halide and barium halide.

### Claim 3 (depends on 2)

The process according to claim 2, wherein an alkali or an alkaline earth metal halide is lithium halide.