Patent ID: 8785633

Claim:
A process for preparing a compound selected from 4-((R)-2-cyclopentyl-2-hydroxy-2-phenylacetyl)-N-furan-2-ylmethylpiperazine-1-carboxamidine and 4-((R)-2-cyclopentyl-2-hydroxy-2-phenylacetyl)-N-thiophen-2-ylmethyl-piperazine-1-carboxamidine, or a pharmaceutically acceptable salt thereof, comprising: (a) coupling compound (1) and compound (2) under amide bond-forming conditions and deprotecting the product to form compound (3): where a is 0; R 1 is cyclopentyl; R 2 is phenyl; R 3 is —OH; and P is an amino-protecting group; (b) reacting compound (3) with compound (6) to form compound (7): where X is a bond, Y is —CH 2 —, Y′ is —N—, Y″ is —CH 2 —, and R 6 is H; and; (c) reacting compound (7) and compound (8) to provide a compound of formula I: where R 7 is H, Z is —CH 2 -Q, and Q is furanyl or thiophenyl.