Dimethylformamide → HCID 68891810, compound

Participants

Reaction Steps

A stirred solution of a mixture of 8-cyano-6-cyclopropyl-3,4-dihydro-1H-pyrrolo[1,2-a]pyrazine-2-carboxylic acid tert-butyl ester and 7-cyano-6-cyclopropyl-3,4-dihydro-1H-pyrrolo[1,2-a]pyrazine-2-carboxylic acid tert-butyl ester (6.67 g, Reference Example 9) in dry acetonitrile (370 mL) under a blanket of nitrogen at 0° C. was treated with chlorosulfonyl isocyanate (2.75 mL) dropwise whilst maintaining the temperature below 5° C. After stirring below 5° C. for a further 2.5 hours the reaction mixture was treated with dimethylformamide (18.5 mL), allowed to warm to room temperature and then stirred for a further 1 hour. The reaction mixture was then treated with triethylamine (21.7 mL), stirred for a further 1 hour and then left to stand overnight. The reaction mixture was evaporated and the residue treated with dichloromethane (200 mL) and water (80 mL). The organic phase was separated, further washed with water (80 mL), then dried over magnesium sulfate and evaporated. The residue was subjected to column chromatography on silica eluting with a mixture of ethyl acetate and pentane (2:3, v/v) to give the title compound (4.97 g) as a yellow oil, Rf 0.29 (ethyl acetate:pentane, 2:3). 1H NMR [(CDCl3]: δ 4.70 (s, 2H), 4.03 (t, 2H), 3.87 (t, 2H) 1.73–1.65 (m, 1H), 1.51 (s, 9H), 1.14–1.07 (m, 2H) and 0.99–0.93 (m, 2H).

Provenance & Evidence