A mixture of crude 8-azido-6-(2,4-dichloro-phenyl)-3-morpholin-4-yl-imidazo[1,2-a]pyridine-7-carbonitrile (144 mg, 0.33 mmol) and triphenylphosphine (133 mg, 0.51 mmol) in MeOH (4 mL) was stirred and refluxed for 1 h. 2M HCl in water (1 mL) was added and the reaction mixture was further refluxed for 1 h. The reaction mixture was cooled to RT, concentrated under vacuum and the remaining residue was dissolved in water. The aqueous solution was basified to pH 12 by the addition of a 2M NaOH solution in water. The resulting slurry was extracted with DCM (3×) and the combined organic fractions were dried over Na2SO4, filtered and evaporated. The remaining residue was purified by Combi-Flash Companion™ (Isco Inc.) column chromatography (SiO2; gradient elution, DCM/MeOH 99:1→92:8) to yield the title compound (112 mg, 0.29 mmol, 87%). MS: 388 [M+1]+; HPLC: AtRet=1.91; TLC: RF 0.56 (DCM/MeOH 95:5).
