Toluene → 6-Cyano-3-(3,5-dibromo-4-hydroxy-benzylidene)-1,3-dihydro-indol-2-one

Participants

Reaction Steps

6-cyano-1,3-dihydro-indol-2-one (46.3 mg, 0.29 mmol) and 3,5-dibromo-4-hydroxybenzaldehyde (80 mg, 0.39 mmol) and p-toluenesulfonic acid monohydrate (1 mg, 0.005 mmol) were treated with toluene (30 mL) and the reaction refluxed with stirring with a Dean-Stark water trap attached for 1.5 h. During this time an orange solid deposited, which, on cooling, was filtered off, washed with toluene and dried in vacuo at 125° C. for 3 days to give 80 mg of 6-cyano-3-(3,5-dibromo-4-hydroxy-benzylidene)-1,3-dihydro-indol-2-one; 1H-NMR (DMSO-d6): δ11.05 (bs, 1H), 8.86 (s, 2H), 7.97 (s, 1H), 7.85 (d, J=7.9 Hz, 1 H), 7.50 (d, J=7.9 Hz, 1 H), 7.20 (s, 1H). Mass spectrum (negative ion electrospray): m/z=417 (M−1, 48%), 419 (M−1, 100%), 421 (M−1, 48%).

Provenance & Evidence