Dimethylformamide → HCID 19870558, compound

Participants

Reaction Steps

Phosphorous oxychloride (48.2 ml) was added dropwise to stirred N,N-dimethylformamide (72.8 ml) at 0° (internal temperature). Stirring was continued for about 1 hour, and a solution of 6-formylindole (32.7 g) (see Example 12, part b) in N,N-dimethylformamide (444 ml) was added dropwise, while maintaining the internal temperature at 0°. The cooling bath was removed and the mixture stirred for 18 hours before water (1 liter) was added and the mixture heated under reflux for 15 min. The mixture was cooled in an ice bath; and the precipitated product isolated by filtration, washed with water and dried under vacuum to give 3,6-diformylindole (33.97 g, 87%); mp 200°-203°; NMR (250 MHz, DMSO-d6): 7.75(dd, J=8.25, 1.25 Hz, 1H, H5 -indole), 8.10(s, 1H, H2 -indole), 8.24(d, J=8.25 Hz, 1H, H4 -indole), 8.57(s, 1H, H7 -indole), 10.00(s, 1H, CHO), 10.06(s, 1H, CHO); 12.61(br s, 1H, NH).

Provenance & Evidence