作者:Isao Shibuya、Kazumasa Honda、Yasuo Gama、Masao Shimizu
DOI:10.3987/com-01-9396
日期:——
Silver ion-mediated desulfurization of N-(2-hydroxythiobenzoyl)morpholine (1a) or -piperidine (1b) was used to develop a new synthetic method for heterocycles such as 1,3-benzoxazin-1-ium salts. 2-Amino-4-morpholino- and 2-amino-4-piperidino-1,3-benzoxazin-1-ium perchlorate (2a, 2b) or 2-(NN-dimethylamino)-4-morpholino- and 2-(N,N-dimethylamino)-4-piperidino-1,3-benzoxazin-1-ium perchlorate (3a, 3b) were obtained by treatment of la and 1b, respectively, with silver perchlorate in the presence of excess cyanamide or N,N-dimethylcyanamide, and the structure of 3a was confirmed by X-Ray crystallography. Desulfurization of 1 with AgOCN afforded 1,3-benzoxazin-2-ones (4). In addition, treatment of 1 with methyl cyanoacetate in the presence of silver trifluoroacetate and triethylamine gave 3-cyanochromen-2-ones (5).