Patent ID: 8742170

Claim:
A process for preparing a compound comprising Formula (III) or a pharmaceutically acceptable salt thereof, the process comprising: a) contacting a compound comprising Formula (I) with a compound comprising X and a proton donor to form a salt of the compound comprising Formula (II), wherein the compound comprising X and the proton donor are different compounds; and b) contacting the compound comprising Formula (II) with a compound comprising MeZ to form the compound comprising Formula (III) or the pharmaceutically acceptable salt thereof: wherein: the compound comprising MeZ is sodium methanethiolate; R is hydrogen; and the compound comprising X is HCl; the proton donor is H 2 SO 4 ; the molar ratio of the compound comprising Formula (I) to the compound comprising X to the proton donor is about 1:1.1:0.01; step (a) is conducted in the presence of water as a solvent, at a temperature of about 70° C., and at a pressure of about 80 psig; the molar ratio of the compound comprising Formula (II) to sodium methanethiolate is about 1:3; step (b) is conducted in the presence of n-butanol as a solvent; the molar ratio of the solvent to the salt of the compound comprising the salt of Formula (II) is about 10:1; step (b) is conducted at a temperature of about 80° C.; and the compound comprising Formula (III) or its salt has a yield of at least about 90% w/w.