Regioselective Synthesis of Pyrimido[5,4-c][2,1]benzothiazines by Reactions of beta-Chloroaldehydes with N-C-N Binucleophiles

摘要

The method of pyrimidine ring fusion at the [c] side of benzothiazines based on the reaction of their chloroaldehyde derivatives with amidines is described. Formation of the structural isomers of reaction products was investigated, and regioselectivity of heterocyclization reactions was shown. A number of novel pyrimidobenzothiazines were synthesized.