Herein, we report transition metal-catalyzed intramolecular cyclization of o-(1-alkynyl)benzenesulfonamides to afford 3-substituted benzothiazines regioselectively via a C-N bond forming reaction and Cu-catalyzed sequential C-N and C-C bond formation leading to the corresponding 3,4-disubstituted derivatives.

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Fused pyrimidine derivatives R 0515 Reactivity of the -C(Cl)=C-C=N-Moiety Towards AlCl3-Induced C-C Bond Forming Reactions: A New Synthesis of 7-(Hetero)aryl-Substituted Pyrazolo[1,5-a]pyrimidines. -A useful AlCl3-mediated coupling of 7-chloro pyrazolo pyrimidines with arenes or hetarenes allows the synthesis of title compounds (III). -(KODIMUTHALI, A.; NISHAD, T. C.; PRASUNAMBA, P. L.; PAL*, M.; Tetrahedron Lett. 50 (2009) 3, 354-358; New Drug Discovery, Matrix

A Remarkable Accelerating Effect of Ag-Salt on Intramolecular Cyclization of o-(1-Alkynyl)benzenesulfonamides. -It is found that CuI and AgSbF 6 efficiently promote cyclization of a wide range of substrates to benzothiazines. -(BARANGE, D. K.; NISHAD, T. C.; SWAMY, N. K.; BANDAMEEDI, V.; KUMAR, D.; SREEKANTH, B. R.; VYAS, K.; PAL*, M.; J. Org. Chem. 72 (2007) 22, 8547-8550; Chem.-Discovery Res., Dr. Reddy's Lab. Ltd., Hyderabad 500 049, India; Eng.) -Jannicke 10-177