反应详情

The N-hydroxy-5-norbornene-2,3-dicarboximide active ester of N-benzyloxycarbonyl DL-2-hydroxy-4-aminoburyric acid was prepared according to the procedure of M. Fujino, et al [Chem. Pharm. Bull. Japan, 22, 1857 (1974)]. To an ice cold solution of 0.40 g. of N-benzyloxycarbonyl-DL-2-hydroxy-4-aminoburyric acid and 0.32 g. of N-hydroxy-5-norbornene-2,3-dicarboximide in 3 ml. of tetrahydrofuran-dioxane (1:1 v/v), there was added, with stirring, 0.36 g. of N,N'-dicyclohexylcarbodiimide and 1 ml. of the above solvent mixture. The solution was stirred in the cold for 30 minutes and then at room temperature for 2 hours. The N,N'-dicyclohexylurea which formed in the above reaction was collected on a filter and washed with three 1-ml. portions of tetrahydrofuran-dioxane (1:1 v/v).

1. stirringThe solution was stirred in the cold for 30 minutes