Patent ID: 7671196

Claim:
A method for preparing a compound of formula II: or a pharmaceutically acceptable salt thereof, wherein: n is 1; R 1 and R 2 are each independently halogen, —CN, phenyl, —R, —OR, —C 1-6 perfluoroalkyl, or —OC 1-6 perfluoroalkyl; each R is independently hydrogen or a C 1-6 alkyl group; and R 7 is hydrogen or C 1-6 alkyl, comprising the steps of: (a) providing a compound of formula E wherein: R 1 and R 2 are each independently halogen, —CN, phenyl, —R, —OR, —C 1-6 perfluoroalkyl, or —OC 1-6 perfluoroalkyl; and each R is independently hydrogen or a C 1-6 alkyl group, (b) treating said compound of formula E with a chiral agent to form a compound of formula D-1: wherein: R 1 and R 2 are each independently halogen, —CN, phenyl, —R, —OR, —C 1-6 perfluoroalkyl, or —OC 1-6 perfluoroalkyl; each R is independently hydrogen or a C 1-6 alkyl group; and X is a chiral agent, (c) obtaining a compound of formula D by suitable physical means: wherein: R 1 and R 2 are each independently halogen, —CN, phenyl, —R, —OR, —C 1-6 perfluoroalkyl, or —OC 1-6 perfluoroalkyl; each R is independently hydrogen or a C 1-6 alkyl group; and X is a chiral agent, (d) treating said compound of formula D with a suitable base to provide a compound of formula C: wherein: R 1 and R 2 are each independently halogen, —CN, phenyl, —R, —OR, —C 1-6 perfluoroalkyl, or —OC 1-6 perfluoroalkyl; and each R is independently hydrogen or a C 1-6 alkyl group, (e) alkylating said compound of formula C to form a compound of formula B: wherein: n is 1; R 1 and R 2 are each independently halogen, —CN, phenyl, —R, —OR, —C 1-6 perfluoroalkyl, or —OC 1-6 perfluoroalkyl; each R is independently hydrogen or a C 1-6 alkyl group; and PG 2 is a suitable amino protecting group, (f) deprotecting said compound of formula B to form a compound of formula A wherein: n is 1; R 1 and R 2 are each independently halogen, —CN, phenyl, —R, —OR, —C 1-6 perfluoroalkyl, or —OC 1-6 perfluoroalkyl; and each R is independently hydrogen or a C 1-6 alkyl group, and (g) reacting said compound of formula A with formaldehyde, or an equivalent thereof, to form a compound of formula II.