Potassium Carbonate → tert-Butyl 8-bromo-3,4-dihydropyrazino[1,2-a]benzimidazole-2(1H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

2-(5-Bromo-2-((tert-butoxycarbonylamino)methyl)-1H-benzo[d]imidazol-1-yl)ethyl methanesulfonate (883 mg, crude, 1.76 mmol estimated) was stirred in TFA (10 mL) for 1 h and then concentrated. Water/i-PrOH (32 mL/8 mL) and K2CO3 (2.31 g, 16.7 mmol) were added, and the mixture was heated at 105° C. for 2 h and then cooled to room temperature. Di-tert-butyl dicarbonate (812 mg, 3.73 mmol) was added, and the reaction mixture was stirred for 48 h and then diluted with water. The solid was filtered off and dried under vacuum to provide the title compound (549 mg, 89%) as a brown solid: ESI MS m/z 352 [M+H]+.

Provenance & Evidence