Water → (S)-tert-Butyl (4-oxo-2,3,4,5-tetrahydrobenzo[b][1,4]oxazepin-3-yl)carbamate

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Reaction Steps

In 120 ml of N,N-dimethylformamide is dissolved 21.4 g of O-(o-aminophenyl)-Boc-L-serine obtained in Example 2, and 14 g of diethyl phosphorocyanidate is added dropwise to the solution with stirring at ice bath temperature. The mixture is stirred for 10 minutes, and 7 g of triethylamine is added dropwise to the mixture. After stirring for 1 hour, the mixture is poured in ice-cooled water. The deposited material is collected by filtration, washed with water, dried and recrystallized from ethyl acetate-hexane to give 12.3 g of 3(S)-tert-butoxycarbonylamino-2,3,4,5-tetrahydro-1,5-benzoxazepine-4-one as colorless plates, melting at 202°-203° C.

Provenance & Evidence