Substitution chemistry of 3,5-dichloro-4H-1,2,6-thiadiazine 4,4-ketals

Abstract

The reactivity of 3,5-dichloro-4H-1,2,6-thiadiazine 4,4-ketals towards nucleophilic substitution or palladium-catalyzed C–C coupling at the C-3/5 positions led to seven new 3,5-disubstituted 4H-1,2,6-thiadiazine ethylene glycol 4,4-ketals and seven 3,5-disubstituted 4H-1,2,6-thiadiazine catechol 4,4-ketals in 83–98% yields. Furthermore, 3,5-diphenyl-4H-1,2,6-thiadiazine ethylene glycol and catechol 4,4-ketals were successfully hydrolysed in conc. H2SO4at 20 °C to afford 3,5-diphenyl-4H-1,2,6-thiadiazin-4-one in 74% and 89% yields. © 2016 Elsevier Ltd