An elegant synthesis of some new potential biologically active pyrido[3,2-b][1,4]benzothiazine derivatives and their nucleosides by phase transfer catalysis

(1)0H-7-Trinuoromethyl/-9-ethoxy/-9-methoxy-3-nitro-pyrido[3,2-b][1,4]benzo thiazine, 10-acetyl-7-trifluoromethyl/ 9-ethoxy/-9-methoxy-3-nitro-pyrido[3 ,2-b][1,4]benzothiazine and 10H-7-trifluoromethyl/-9-ethoxy/-9-methoxy-nitr o-pyrido[3,2-b][1,4]benzothiazine-5-oxide have been synthesized. The nucleo sides viz., 10-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)-7-trifluoromethyl /-9-ethoxy/-9-methoxy-3-nitro-pyrido[3,2-b][1,4]benzothiazine have been pre pared by using phase transfer catalysis, Structural assignments were made o n the basis of analytical and spectral data. All the synthesized compounds were screened for their antimicrobial activity.