Formaldehyde → HCID 89639167, compound

Participants

Reaction Conditions

Reaction Steps

Under argon, a 1 M solution of methylmagnesium bromide in THF (13.3 ml) was added over 15 min to a solution of tert-butyl (4-bromo-2-cyano-1H-pyrrol-1-yl)carbamate (3.7 g, 12.09 mmol; preparation described in PCT Int. Pat. Appl. WO 2007/064883, Intermediate AAE, Step 3) in THF (37 ml) cooled to −60° C. After 30 min, a 1.6 M solution of n-butyllithium in hexane (15.1 ml, 24.2 mmol) was added over 10 min to the reaction, and the resulting mixture was stirred between −60° C. and −40° C. for 1 h. Then, paraformaldehyde (1.09 g, 36.3 mmol) was added to the reaction, and the reaction mixture was slowly warmed to rt and stirred overnight. After quenching with sat. aq. ammonium chloride solution, the aqueous layer was extracted twice with ethyl acetate. The combined organic phases were washed with sat. aq. sodium chloride solution, dried over sodium sulfate and evaporated. Purification by column chromatography on silica gel (cyclohexane/ethyl acetate 2:1→1:1) afforded 2.04 g (69% of th.) of the title compound.

Provenance & Evidence