92608-37-2Relevant academic research and scientific papers
Studies on 1,4-Benzothiazines. IV. Reactions of 2-Acyl-4H-1,4-benzothiazines with Hydroxylamine, Hydrazine, Guanidine and Acetamidine
Sugiyama, Kazuaki,Yamashita, Mayumi,Takamatsu, Masanori,Tobioka, Takako,Hirano, Hiroshi
, p. 1593 - 1596 (2007/10/02)
2-Acyl-4-methyl-4H-1,4-benzothiazines (1a,b) reacted with hydroxylamine to give dihydroisoxazolobenzothiazines (3a,b).However, the reaction of 1a with hydrazine did not give the dihydropyrazolobenzothiazine derivative corresponding to 3a, but gave its dehydro compound (6).On the other hand, in the reaction of 1b with hydrazine, formation of a pyrazole ring and opening of the thiazine ring occurred to afford a 4-(2-aminophenylthio)pyrazole derivative (7).Guanidine and acetamidine also reacted with 1a, b to give 5-pyrimidines (10a-d).Keywords - 2-acyl-4H-1,4-benzothiazine; dihydroisoxazolobenzothiazine; pyrazolobenzothiazine; 4--3-methylpyrazole; 2,4-disubstituted 5-pyrimidine; autoxidation
