GB2552919A — Stable amorphous form of daclatasvir

USPTO Abstract

A process for the preparation daclatasvir or a pharmaceutically acceptable salt thereof, wherein the process includes the synthetic step of reacting a compound of Formula (I) with a compound of Formula (II): Wherein LG is a leaving group and Z is a protecting group. The protecting group Z may be selected from Boc, Cbz, Tosyl, Mesyl, Benzyl, Fmoc, substituted acetyl, Benzoyl and Tolyl. A process for the production of amorphous daclatasvir-2 HCl is also provided, comprising the steps of contacting daclatasvir-2 HCl with a pharmaceutically acceptable solvent; filtering off the solution or dispersion of the first step; and the immediate removal of the solvent from the filtered solution or dispersion of the second step, characterised in that the solvent removal is performed within a timescale of 10 seconds to 5 hours after the filtering step.