RESEARCH ON POTENTIALLY BIOZACTIVE AZA AND THIAZA POLYCYCLIC COMPOUNDS CONTAINING A BRIDGEHEAD NITROGEN ATOM - SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SOME PYRROLO[1,2,3-DE]-1,4-BENZOTHIAZINES, PART 2

Acid catalyzed cyclization reactions of both 3-alkyl- and 3-aryl-subst ituted 2-dialkoxyethyl)-3,4-dihydro-2H-1,4-benzothiazines (2) lead to 2,3-dihydro-pyrrolo[1,2,3-de]-1,4-benzothiazines (3). The pyrrolobenzo thiazine structure was deduced on the basis of 2D H-1 NMR-NOESY experi ments and fully determined by X-ray data. Compounds 3a-c showed poor a ntibacterial activity. However, the 2-dimethoxyethyl)-3,4-dihydro-2H-1 ,4-benzothiazine (2b') showed antifungal activity against Aspergillus niger 16-fold greater than miconazole.