Acetic Acid → N-(7-Oxo-4,5,6,7-tetrahydro-1-benzothiophen-4-yl)formamide

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Reaction Steps

Ceric ammonium nitrate (726.9 grams) is added portionwise to a stirred solution of 59.6 grams of (-)-N-(4,5,6,7-tetrahydrobenzo[b]thien-4-yl)formamide in 1712 ml. of 50% aqueous acetic acid. The addition is completed in half an hour and the temperature is kept at 25°-28° C. After 15 minutes of stirring, the mixture is saturated with NaCl and extracted with CH2Cl2 (2 × 1200 ml., 600 ml.) and the combined extracts are washed with 600 ml. of brine and then with 250 ml. of water. The water is counter-extracted with 250 ml. of CH2Cl2 and the CH2Cl2 solution is added to the main CH2Cl2 solution. The CH2Cl2 solution is evaporated to dryness in vacuo and the residual dark, gummy residue is stirred with 500 ml. of dry diethyl ether for 1.5 hour and the large lumps of solid are pulverized. The title compound is then collected, washed with diethyl ether, and dried. This gives 48.65 g., m.p. 130°-136° C., [α]D24 = 144.4° (c, 0.51 in HOAc).

Provenance & Evidence