New type of transannular reactions in azirine-fused medium-size heterocycles: Selective transformations of azirino[2,1-e][1,6]benzoxazocines and -benzothiazocines into oxa(thia)zine and oxa(thia)zole derivatives
作者:E. Yu. Shinkevich、M. S. Novikov、A. F. Khlebnikov、R. R. Kostikov、J. Kopf、J. Magull
DOI:10.1134/s1070428007070214
日期:2007.7
Opening of the three-membered ring in heterocyclic systems incorporating a dichloroaziridine ring fused to eight-membered O,N-or S,N-heterocycles is accompanied by transannular reactions with participation of the endocyclic oxygen and sulfur atoms. Depending on the conditions, the products are 1,4-benzoxazine (1,4-benzothiazine) or 1,3-benzoxazole (1,3-benzothiazole) derivatives. The discovered transformations were used as a basis of methods for the preparation of new heterocyclic systems, 2,3,4,4a-tetrahydro-1H-pyrido-[3,2-b][1,4]benzoxa(thia)zine derivatives, in domino or consecutive modes, as well as of pyrrolidinyl-substituted 1,3-benzoxa(thia)zoles.