Chloroacetaldehyde → Methyl 6-bromoimidazo[1,2-a]pyridine-7-carboxylate

Participants

Reaction Steps

A mixture of 2-amino-5-bromo-isonicotinic acid methyl ester (500 mg, 2.16 mmol), NaHCO3 (309 mg, 3.68 mmol) and chloracetaldehyde (1.16 mL, 9.8 mmol) in EtOH (15 mL) was vigorously stirred and refluxed for 14 h. The reaction mixture was cooled to RT, concentrated under vacuum and the remaining residue was suspended in AcOEt (100 mL). The organic fraction was washed with water (2×50 mL), then dried over Na2SO4, filtered, and evaporated. The residue was purified by Combi-Flash Companion™ (Isco Inc.) column chromatography (SiO2; gradient elution, [hexane/DCM 1:1]/TBME 95:5-100% TBME) to yield the title compound (505 mg, 1.98 mmol, 91%). MS: 255 [M+1]+; HPLC: AtRet=0.58 TLC: RF 0.16 (hexane/DCM/TBME 1:1:2).

Provenance & Evidence