1.2- Dithiole-3-thiones with benzyne

Isothiazoles are reported to yield the lactam (101) on reaction with diphenyl ketene <85BSB149>. Ethyne dicarboxylate esters add to 2,1-benzisothiazole to generate quinoline esters (102), and benzyne reacts to yield aeridine <83H(20)489, 88JCS(Pl)2l4l>. 2-Methyl-2,l-benzisothiazolin-3-thione with acetylene esters forms 2-iminobenzoquinone methides (103), which dimerize to give diazocines (104) or further react with the ethyne ester to yield diadducts (105). The initial adduct formed with phenylethyne and 2-methyl-2,l-benzisothiazolin-3-thione rearranges to produce l,2-dithiole[3,26]... 

Experimental details have been published for addition reactions between acetylenes (21 R, R = COgMe, COgEt, or H) and l,2-dithiole-3-thiones (20), and for the conversion of the resulting isothiathiophthens (22) into thiathio-phthens with thioacetamide or thiobenzamide. The similar reaction between l,2-dithiole-3-thiones and benzyne, variously generated, has been described. ... 

In a study of the oxidation of various heterocyclic thiones with peroxyacetic acid, l,2-dithiole-3-thiones (10) carrying electron-withdrawing substituents have been found to give l,2-dithiole-3-ones rather than dithiolium salts. Experimental details have been published for addition reactions of l,2-dithiole-3-thiones with acetylenes, and with benzyne. Reactions with enamines, leading to thiopyran derivatives (11), have been described. ... 

Benzyne (145) also reacts with l,2-dithiole-3-thiones (7).208,209 The 1,6,6ai4-trithiapentalene seems not to be formed by isomerization of the 1,3-dithiole derivative in this case. 

Dithiole-3-thione derivatives can be used as starting materials for the synthesis of 1,3-dithioles. Thus, l,2-dithiole-3-thiones (312) react with alkynes or even benzyne to afford (313) (Equation (64)) <68CB1428, 80ZOR883). 

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