A new synthesis of 1,2,4-benzothiadiazines and a selective preparation of o-aminobenzenesulphonamides

A potent diazoxide analogue activating ATP-sensitive K + channels and inhibiting insulin release

“…1) was obtained from the reaction of an excess of isopropylamine with 7-chloro-3-methylsulphanyl-4H-1,2,4-benzothiadiazine 1,1-dioxide, a useful synthetic intermediate in the access way to 3-alkylamino-substituted benzothiadiazine 1,1-dioxides [22,23]. The synthesis of the 3-methylsulphanyl-substituted intermediate was done in three steps starting from 4-chloroaniline and following methods described previously [24,27].…”

Synthesis and Preliminary Cytotoxic Evaluation of Novel 3,4-Dihydro-2h-1,2,4-Benzotiadiazine-1,1-Dioxide Derivatives

“…Reagents were obtained from Aldrich (Milwaukee, MI, USA) or Merck (Darmstadt, Germany) and used without further purification. 5-halo substituted 2-aminobenezenesulfonamides la,b were prepared from the appropriate aniline following the procedure described in the literature (19).…”

Facile Synthesis of 4H-1,2,4-Benzothiadiazine-1,1-dioxides

“…An alternative one-pot approach to the 1,2,4-benzothiadiazine-1,1-dioxide ring is based on the Michael addition of chlorosulfonyl isocyanate to aniline derivatives followed by the ring closure under Friedel-Crafts conditions. [8] Despite the ease of the latter procedure, the resulting sulfonylated urea was shown to be hydrolytically unstable under acidic conditions, giving rise to an open-chain aminosulfonamide. Recently, a Cu(I)-catalyzed coupling of o-bromobenzylsulfonyl azide with functionalized terminal acetylene and ammonium chloride was used for the synthesis of the 4H-1,2,4-benzothiadiazine-1,1-dioxides.…”