Reazioni di sostituzione elettrofila su 3-fenil-1,2,5-selena—, —tia—, e —ossadiazolo
Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 64 (1978) no. 4, pp. 385-392
Citer cet article
Voir la notice de l'article provenant de la source Biblioteca Digitale Italiana di Matematica
3-phenyl-1,2,5-selenadiazole (I), 3-phenyl-1,2,5-thiadiazole (II), and 3-phenyl-1,2,5-oxadiazole (III) undergo bromination at the para position of the phenyl ring. Compound I undergoes mononitration and also dinitration at the position para and ortho of the phenyl ring in analogy to II and III. Towards either bromination or nitration the more reactive of the examined substrates is compound II which is known to have interatomic ring distances in agreement with a higher delocalization of $\pi$-electrons. The electrophilic substitution never involves the heterocyclic ring, which is still an ortho-para directing group.
[1] , , e (1977) - 6th Int. Congr. of Heterocyclic Chem., Tehran 1977, B 4-2, 400.
[2] , , , e (1977) - «Chimica e Industria», 59, 453.
[3] (1969) - «Atti Soc. Tosc. Sci. Nat.», ser. A, 76, 326.
[4] , , e (1974) - «Atti Soc. Tosc. Sci. Nat.», ser. A, 81, 334.
[5] e (1908) - «Chem. Ber.», 41, 4121,
[6] e (1965) - «Chimica e Industria», 47, 996.
[7] , e (1968) - «Chem. Pharm. Bull.», 16, 160.
[8] (1967) - «Gazz. Chim. Ital.», 97, 1870.
[9] e (1976) - «Acta Cryst.», B 32, 1074.
[10] e (1976) - «Acta Cryst.», B 32, 1079.