Hydrochloric Acid → 1-Benzylisatin

Participants

Reaction Steps

Dissolve isatin (7.36 g, 50 mmol) in anhydrous DMF (100 mL) under nitrogen and cool in an ice bath. Treat with 1M potassium tert-butoxide in THF (53 mL, 53 mmol) stir 15-20 min. Add benzyl bromide (6.2 mL, 52.5 mmol) and after 10 min remove bath and allow to warm to room temperature over 16 h. Pour into 1N HCl and wash with ethyl acetate (500 mL). Wash ethyl acetate with 1N HCl (150 mL) and then wash combined acidic portions with more ethyl acetate (150 mL). Wash the combined organic portions with brine (2×150 ml), dry (MgSO4), filter and concentrate in vacuo to give 13.5 g of an orange solid. Triturate in diethyl ether and filter to give 10.0 g (84%) of the title compound. MS (ES): m/z=238 (M+1); 1H NMR(CDCl3): δ7.64 (dd, J=7.6 Hz, J=1 Hz, 1H), 7.5 (dt, J=7.8 Hz, J=1.3 Hz, 1H), 7.37 (m, 5H), 7.12 (t, J=7.6 Hz, 1H), 6.80 (d, J=8.0 Hz, 1H), 4.97 (s, 2H).

Provenance & Evidence