Patent ID: 8765948

Claim:
A process for preparing a compound of structure (VI): or a stereoisomer or pharmaceutically acceptable salt thereof, wherein: R 1a , R 1b and R 1c are the same or different and independently hydrogen, halogen, C 1-4 alkyl, hydroxy or alkoxy; R 2a and R 2b are the same or different and independently hydrogen, halogen, trifluoromethyl, cyano or —SO 2 CH 3 ; R 3 is hydrogen or methyl; and R 4 is H, —C 1-6 alkanediyl-COOH, or —C(═O)O-(t-butyl); comprising as an intermediate synthesis step: reacting a compound of structure (VII): wherein R 2 a, R 2b and R 3 are as defined above; with a compound of structure (VIII): wherein R is H or C 1-4 -alkyl, R′ is H or C 1-4 -alkyl or R and R′ taken together form C 1-6 alkanediyl; and R 1a , R 1b , and R 1c are as defined above; and reacting methanesulfonic acid-(S)-3-tert-butoxycarbonyl-amino-3-phenyl-propyl ester with the compound formed by reacting compound (VII) with compound (VIII), which compound has the structure: in the presence of a base.