Diisopropylethylamine → 3-Bromo-7-(1-methyl-1-triethylsilanyloxyethyl)imidazo[1,2-alpha]pyrimidine

Participants

Reaction Steps

Triethylsilyl trifluoromethanesulfonate (4.85 ml, 21.5 mmol) was added dropwise over 15 min to a cooled (−50° C.) solution of 2-(3-bromoimidazo[1,2-α]pyrimidin-7-yl)propan-2-ol (5.0 g, 19.5 mmol) and diisopropylethylamine (4.76 ml, 27.5 mmol) in dichloromethane (150 ml). The mixture was stirred for 20 min then allowed to warm to ambient temperature overnight. The reaction mixture was diluted with dichloromethane (100 ml) and washed with 1N hydrochloric acid (100 ml) and water (100 ml), dried over anhydrous magnesium sulfate, filtered and evaporated. The red oil was purified by dry flash column chromatography on silica eluting with dichloromethane on a gradient of methanol (0-3%). Collecting the appropriate fractions gave 3-bromo-7-(1-methyl-1-triethylsilanyloxyethyl)imidazo[1,2-α]pyrimidine as a pale yellow oil which crystallised on standing (6.21 g, 86%): δH (400 MHz, CDCl3) 0.64 (6H, q, J 8), 0.97 (9H, t, J 8), 7.50 (1H, d, J 7), 7.72 (1H, s), 8.35 (1H, d, J 7).

Provenance & Evidence