Process for the preparation of 2-imino-thiazolidin-4-one derivatives

A process for the preparation of a compound of the Formula (III):

• wherein
• R14 represents phenyl which is optionally mono-, di- or tri-substituted wherein the substituents are independently selected from C1-7-alkyl and halogen;
• R15 represents C1-7-alkyl;
• R16 represents hydrogen, hydroxy, C1-7-alkoxy, or halogen;
• R17 represents hydrogen, lower alkyl, or hydroxymethyl;
• R18, R19, R21 and R22 each represents independently hydrogen or methyl;
• R20 represents hydrogen or lower alkyl, and in case m represents the integer 1, R20 in addition represents lower alkoxy, hydroxy, —NH2, —NHR5 or —NR5R6, wherein R5 and R6 each represents independently lower alkyl;
• R23 represents hydrogen, lower alkyl, hydroxycarbonyl-lower alkyl, 1-glyceryl, or 2-glyceryl;
• and
• m represents the integer 0 or 1;
• or a pharmaceutically acceptable salt thereof;
• and wherein the terms “lower alkyl” and “lower alkoxy” have the following meanings:
• “lower alkyl”, alone or in combination with other groups, means saturated, straight or branched chain groups with one to seven carbon atoms;
• and
• “lower alkoxy” means an R—O group, wherein R is a lower alkyl;
• which process comprises reacting a compound of the formula R14—N═C═S, wherein R14 is as defined for Formula (III), with a compound of the formula R15—NH2, wherein R15 is as defined for Formula (III), followed by reaction with bromo-acetyl bromide and a pyridine base in the presence of the solvent dichloromethane.