N-bromobutanimide → HCID 86112953, compound

Participants

Reaction Conditions

Reaction Steps

Following a general procedure,50 a stirred solution of 3-methyl-pyrrole-2-carboxaldehyde (2, 5.63 g, 51.6 mmol) in THF (52 mL) was cooled to 0° C. NBS (9.19 g, 51.6 mmol; reagent grade, unrecrystallized) was added all at once. The reaction mixture was stirred for 15 min at 0° C. under argon before the solvent was removed on a rotary evaporator. The resulting solid was dried under high vacuum for 2 h. Water (100 mL, room temperature) was added to the flask and the suspension was filtered (Büchner funnel). The filter cake was washed with an additional 100 mL of water. The solid filtered material was recrystallized from water/ethanol as follows. The solid filtered material was transferred to a 250 mL round bottom flask equipped with a reflux condenser. Water/ethanol (150 mL, 5:1) were added and the mixture was refluxed in a hot water bath until all solid material had dissolved. Upon allowing the solution to cool to room temperature the product crystallized. The mixture was cooled to 4° C. for 2 h to promote more crystallization. The mixture was vacuum-filtered and the resulting off-white crystals were dried under high vacuum for 24 h (7.78 g, 80%): mp 140-143° C.; 1H NMR δ 2.32 (s, 3H), 7.08 (d, J=3.3 Hz, 1H), 9.60 (s, 1H), 9.95 (brs, 1H); 13C NMR δ 9.8, 101.7, 126.0, 129.3, 131.7, 177.9; ESI-MS obsd 187.9708, calcd 187.9706 [(M+H)+, M=C6H6BrNO].

Provenance & Evidence