Stilbene, dicyano

The synthesis of 4,5-dicyano-l,2,3-trithiole 2-oxide (172) starts from sodium cyanide and carbon disulfide which via (170) gave the disodium salt of 2,3-mercaptomaleonitrile (171 M = Na). Treatment of the corresponding silver salt (171 M = Ag) with thionyl chloride yielded (172) <66HC(2l-l)l). Phenylsulfine (174), prepared in situ by dehy-drohalogenation of phenylmethanesulfinyl chloride (173), slowly decomposed in ether solution at room temperature to give cis- and trans-stilbenes, mms-4,5-diphenyl-l,2,3-trithiolane 1,1-dioxide (36) and a 5,6-diphenyl-l,2,3,4-tetrathiane dioxide (68JCS(C)1612). The mechanisms of formation of these heterocycles are obscure. 

Dicyano(phthalazm-l-io)methanide (166) with acetylethylene gave a separable mixture of 1-emfo-acetyl- and l-ev >-acetyl-l, 340b-tetrahydropyrrolo[2,l-a] phthalazine-2,3-dicarbonitrile (167) (MeCN, 20 C, 4h 72% and 23%, respectively), with stilbene gave l,2-diphenylpyrrolo[2,l-a]phthalazine-3-carbonitrile (168) (MeCN, reflux, 24 h 60%), or with 7V-p-methoxyphenylmale-imide gave 9,1 l-dioxo-8a,9,10,l 1,1 la,llb-hexahydro-8/7-pyrrolo[3, 4 3,4]pyr-rolo[2, l-a]phthalazme-8,8-dicarbonitrile (169) (MeCN, 20°C, 24 h 91%)P ... 

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