GB885950A - Process for the manufacture of cyclic amides - Google Patents

Abstract

The invention comprises (1) sulphamyl-nitrobenzene derivatives of the formula <FORM:0885950/IV (b)/1> wherein R1 and R4 each represent hydrogen or aliphatic or araliphatic hydrocarbon radicals optionally substituted, for example, by halogen atoms or by alkoxy, carboxyl, carboxylic ester, thioether, amino, acyl, nitro and alkylenedioxy groups, R2 represents hydrogen, a hydrocarbon radical optionally substituted, for example, by halogen atoms (including fluorine) or by amino, hydroxy, acylamino, acyloxy, carboxyl, carboxylic ester, alkoxy, alkylenedioxy, nitro, mercapto or alkoxycarbonic acid radicals, or a substituted or unsubstituted heterocyclic radical, for example, pyridyl, thienyl, furyl, quinolyl, pyrrolidino, piperidino, hydroxy or acetoxy piperidino, morpholino, hexamethyleneimino, piperazino and hydroxy or acetoxy piperazino, and R3 represents halogen (including fluorine), or an alkyl or halogen alkyl group, for example, trifluoromethyl; (2) the preparation of sulphamyl-nitrobenzene derivatives as defined in (1) by reacting a 2 : 4-dihalogen-5-R3-nitrobenzene with a mercaptan of the formula R-SH or with a halide of the formula R-Halogen in the presence of thiourea (where R represents an aliphatic or araliphatic hydrocarbon radical), oxidizing and halogenating the resulting 2 : 4-di-R-mercapto-5-R3-nitrobenzene, reacting the resulting 5-R3-nitrobenzene-2 : 4-disulphonyl halide with a compound of the formula R1-NH2 and reacting the resulting compound of the formula <FORM:0885950/IV (b)/2> with an aldehyde of the formula R2-CHO; and (3) the preparation of 3 : 4-dihydro-1 : 2 : 4-benzothiadiazine-1 : 1-dioxides of the formula <FORM:0885950/IV (b)/3> or a salt thereof (R1 to R4 being as defined in (1)) by simultaneously reducing and ring closing a compound of the formula <FORM:0885950/IV (b)/4> by means of a hydrogenation treatment.