反应详情

263 mg of N,N'-dicyclohexylcarbodiimide was added under ice-cooling to a solution of 401 mg of 2-{[N-(9-fluorenylmethoxycarbonyl)-L-valyl]amino}-6-methylbenzoic acid in 5 ml of N,N-dimethylformamide. After stirring for 3 hours, dicyclohexyl urea precipitated was filtered off and the filtrate was condensed. The residue was purified by a silica gel column chromatography (eluting solution: hexane-ethyl acetate) to afford 337 mg of 2-{1(S)-[(9-fluorenylmethoxycarbonyl)amino]-2-methylpropyl}-5-methyl-4H-3,1-benzoxazin-4-one, as a white foam. The physicochemical data are shown in Table 1.

1. customdicyclohexyl urea precipitated
2. filtrationwas filtered off
3. customcondensed
4. customThe residue was purified by a silica gel column chromatography (eluting solution: hexane-ethyl acetate)