Preparation of potentially bioactive aza and thiaza polycyclic compounds containing a bridgehead nitrogen atom synthesis and antimicrobial activity of some pyrrolo[1,2,3-de]-1,4-benzothiazines.

The synthesis of the 2,3-dihydro-pyrrolo[1,2,3-de]-1,4-benzothiazine 1a and 11b, 12-dihydro-isoquino[1,2-c]-1,4-benzothiazine 8 has been accomplished by using a Bischler type cyclization of the N-(2,2-diethoxyethyl)-3,4-dihydro-2H-1,4-benzothiazines 3a and 3d, respectively. The new compounds 1a and 8 together with the known pyrrolobenzothiazines 1b,c and some their derivatives and intermediates of preparation were tested in vitro for their antimicrobial activity. Compound 1b was the most active against the Gram-positive Bacillus subtilis. Compound 7b showed interesting antifungal activity when tested against Saccharomyces cerevisiae.