Process for manufacture of a cyclopenta thiophene derivative

A process for manufacturing alkyl (4S)-13-(2-chlorophenyl)-10-oxo-7-thia-9,12-diazatricyclo[6.5.0.02,6]trideca-1(8),2(6),12-triene-4-carboxylate (4)

• wherein R is C1-3-alkyl,
• comprising the following reaction steps:
• (a) reacting compound 1, wherein R is C1-3-alkyl, and N-(tert-butyloxycarbonyl)-glycine in the presence of a suitable amide coupling reagent in a suitable solvent to obtain compound 2, wherein R is C1-3-alkyl and Boc is tert-butyloxycarbonyl;
• (b) optionally isolating compound 2;
• (c) reacting compound 2, wherein R is C1-3-alkyl and Boc is tert-butyloxycarbonyl, with a suitable acid in a suitable solvent to obtain compound 3, wherein R is C1-3-alkyl;
• (d) optionally isolating compound 3;
• (e) reacting compound 3, wherein R is C1-3-alkyl, with a suitable acid in a suitable solvent to obtain compound 4, wherein R is C1-3-alkyl;
• and
• (f) isolating compound 4.