Example 4
To a mixture of 1-butanol and MEK (60 mL, 1:1 V/V) was added compound (I) (502 mg, 1 equiv). The slurry was heated at 60° C. and HBr (4.8% solution in 1-butanol and MEK (2.5 mL, 2 equiv) was added. The mixture was stirred at 60° C. for 2 h and then 5° C. overnight. The solid was then recovered by filtration, washed with diethyl ether and characterized as a hydrobromide by XRPD, TGA, IR, Raman and DSC.