Patent ID: 7875630

Claim:
A process for preparing a compound of formula (IA) or (IB): in which: m is 0, 1 or 2; R 1 is vinyl or ethyl; R 2 is exo-8-methyl-8-azabicyclo[3.2.1]oct-3-yl; R 3 is H; or a pharmaceutically acceptable salt thereof; which process comprises reacting in the presence of a phase transfer catalyst a compound of formula (IIA) or (IIB): in which: Y is hydrogen or a hydroxy protecting group; R 1A and R 3A are R 1 and R 3 respectively as defined for formulae (IA) and (IB); and R L is a leaving group; with a thiol compound of formula (III): R 2A —(CH 2 ) m —SH (III) in which: R 2A is R 2 as defined for formulae (IA) and (IB), and m is as defined for formulae (IA) and (IB).