GB821002A - Process for the production of dihydro-m-thiazines-í¸-3,4 - Google Patents

Abstract

Dihydro-m-thiazines- D -3,4 are prepared by reacting together a b -mercapto ketone, an oxocompound and ammonia or the ammonium salt of a weak acid such as ammonium carbonate or acetate, the simultaneous presence of ammonia or ammonium salt and mercapto ketone in the absence of oxo compound being avoided. The reaction proceeds exothermically at room temperature, but in many cases cooling to 10 DEG C. gives better yields. The oxo-compound may be an aliphatic, alicyclic, aromatic, heterocyclic or aralkyl ketone or aldehyde, and may contain substituent groups. The b -mercapto ketone may be purely aliphatic or may contain alicyclic, aromatic or heterocyclic radicals and/or substituent groups. The products have medicinal uses and are effective as vulcanization accelerating agents, pest-control media, wood-preservatives, weed killers, rust-preventing agents and "anti-agers". In examples: (1) 4,6,6 - trimethyl - dihydro - m - thiazine - D - 3,4 is prepared from 2-methyl-2-mercaptopentanone-4, formaldehyde (or urotropine) solution and ammonia; (2) 2-ethyl-2,4,6,6-tetramethyl-dihydro-m-thiazine- D -3,4 is prepared by adding ammonia and 2-methyl-2-mercaptopentanone-4 to butanone containing some water; (3) and (4) 4,6,6 - trimethyl - 2 - o - oxy-phenyl - dihydro - m-thiazine- D -3,4 is prepared from salicylaldehyde, 2 - methyl - 2 - mercaptopentanone - 4 and ammonia and ammonium carbonate respectively.