Patent ID: 8877947
Filing Date: 2014-11-04
Classification: C07D,C07F,G01N

Abstract:
1. A process for preparation of fosamprenavir calcium (Ia) substantially free of R-isomer impurity (Ib) comprising: a) analyzing the level of intermediate R-isomer impurity (IIb) in a sample of (S)-3-tetrahydrofuranyl-N-succinimidyl carbonate (IIa); b) selecting a sample of (S)-3-tetrahydro furanyl-N-succinimidyl carbonate (IIa) containing less than 0.2% area percentage of HPLC of intermediate R-isomer impurity (IIb); c) reacting said (S)-3-tetrahydrofuranyl-N-succinimidyl carbonate (IIa) with (2R,3S)—N-(3-amino-2-hydroxy-4-phenylbutyl)-N-isobutyl-4-nitrobenzene sulphonamide (III) to obtain (3S)-tetrahydro-3-furanyl N-[(1S,2R)-1-benzyl-2-hydroxy-3-(N-isobutyl-4-nitrobenzene sulphonamido)propyl]carbamate (IV); and d) conversion of compound (IV) to fosamprenavir calcium (Ia).