Atempted Synthesis of Ethyl 3,4-Dihydro-2H-1,4-benzoxazine-3-carboxylate and 3-Acetate Derivatives

摘要

Ethyl 3,4-dihydro-2H-1,4-benzoxazine-3-carboxylate derivatives 2 were obtained and isolated in low yields from the condensation of 2-aminophenol and ethyl 2,3-dibromopropanoate.They can be obtained by hydrogenation of ethyl 2H-1,4-benzoxazine-3-carboxylate in satisfactory yield.Using 2-iminophenol did not direct the condensation wiht ethyl 2,3-dibromopropanoate towards 2 but was fruitfull for the preparation of ethyl 2-(4-benzyl-3,4-dihydro-2H-1,4-benzoxazin-3-yl)acetate from ethyl bromocrotonate.