Synthesis of pyrido-1,2,4-thiadiazines related to antihypertensive 1,2,4-benzothiadiazine-1,1-dioxides

✍ Scribed by Colin G. Neill; Peter N. Preston; Richard H. Wightman

• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 717 KB
• Volume: 54
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(98)00841-2

✦ Synopsis

Oxidation of 3-phenyl-2H-pyrido[2,3-e]-l,2,4-thiadiazine with sodium hypochlorite and, separately, mchloroperoxybenzoic acid afforded a l,l-dioxide and a 5-oxide derivative, respectively. Further examples of such 1,1dioxide derivatives were synthesised by treating 2-amino-5-methylpyridin¢ with orthoesters and these were subsequently oxidised to novel 1,1,5-trioxides. A short route has been developed for the synthesis of 4-aminopyridine-3-sulfonamide which was used for the preparation of4H-pyrido[4,3-e]-l,2,4-thiadiazine l,l-dioxides; oxidation of the parent member of the series gave a 1,1,7-trioxide derivative. 3-Aminopyridine-4-sulfonamide has been prepared, and then condensed with triethyl orthoformate to afford 4H-pyrido[3,4-e]-1,2,4-thiadiazine 1,1-dioxide.