GB637182A - Improvements in and relating to a process for preparing mercapto vinyl derivatives - Google Patents

Abstract

Mercapto-vinyl compounds of the formula <FORM:0637182/IV (b)/1> where D are the atoms necessary to complete a benzothiazole or benzoselenazole ring which may form part of a condensed system, R is substituted or unsubstituted alkyl, aryl, or aralkyl, or an alkylene group joining two such benzothiazole or benzoselenazole rings or ring systems. R1 and R2 are substituted or unsubstituted alkyl, aryl or aralkyl and R1 may also be hydrogen, X- is an acid residue, are prepared by treatment of a N-substituted base of the formula <FORM:0637182/IV (b)/2> in an acid medium with a mercaptan of formula R2SH, X- may be, e.g. a halogen or perchlorate ion. In the examples: (1) 2-(b -ethylmercapto - b - methylvinyl) - benzothiazole ethyl chloride is prepared from ethyl mercaptan and 2-acetylmethylene-3-ethyl-2 : 3-dihydrobenzothiazole in methanolic hydrogen chloride; (2) ethyl mercaptan is replaced by thiophenol, and (3)-(9) ethyl mercaptan is similarly treated with benzothiazole, benzoselenazole, and naphthothiazole derivatives. The Specification as open to inspection under Sect. 91 discloses the preparation of compounds of the formula <FORM:0637182/IV (b)/3> where the symbols R, R1, and R2 are as above defined and in addition, R2 may be alkylene or arylene; n is 1 or 2, and D represents the atoms necessary to complete a 5- or 6-membered N-containing heterocyclic ring or ring system known in the chemistry of the cyamines. Additional examples are given, including the preparation of S : S-dimethylene-di-(2-b -mercapto - b - methylvinyl) - benzothiazole ethyl bromide from ethylene mercaptan and the appropriate benzothiazole. This subject-matter does not appear in the Specification as accepted.