Reactions of Vinylthiophens and Related Compounds

Reactions of Vinylthiophens and Related Compounds. - 2-Aroyl-5-vinyl-thiophens react with triphenylphosphine, palladium chloride, and carbon monoxide to give 2-(5-aroyl-2-thienyl)propionic acid. Cycloaddition of sulphene, from methanesulphonyl chloride and triethylamine, to 2-(a-dimethylaminovinyl)thiophen gave (160). The synthesis of some substituted 3-(2-thienyl)acryloylamino-acids has been described. Some reactions of 3-chloro-j8-(2-thienyl)vinylphosphonic acid dichlorides have been studied,  

Reactions at Benzylic Positions. - The catalytic oxidation, using a cobalt bromide catalyst, of 2,5-dimethylthiophen to the dialdehydeof 3-methyl-2-ethylthiophen to 2-acetyl-3-methylthiophen and l-(3-methyl-2-thienyl)-ethyl acetate, of the four isomeric methyl acetothienones to the corresponding acetylthiophencarboxylic acids, and of 2-acetoxymethylthio-phen to thiophen-2-carboxylic acid has been reported. The Wittig reaction between 2- and 3-thenyltriphenylphosphonium salts and crocetin dialdehyde has been used for the synthesis of carotenoid analogues with terminal thiophen rings.  

Esters of 3,4,5-trichloro-2-hydroxymethylthiophen have been prepared.  

Nazvanova, V. V. Moskva, T. Sh. Sitdikova, and F. A. Kashfarova, Izv. Vyssh. Ucheb. Zaved. Khim. Khim. TekhnoU, 1982, 25, 37. 

Brahmana, K. Katsuyama, J. Inanaga, T. Katsuki, and M. Yamaguchi, Tetrahedron Lett., 1981, 22,1695. 

---

Diels-Alder Reactions of Vinylthiophenes and Related Compounds... 

---