title: Four bromo-substituted pyrazoline and isoxazolinone spiro derivatives.
abstract: Conformational analyses and a structural comparison of the four spiro compounds 3-bromo-1,9-diphenyl-4-p-tolyl-7-oxa-1,2,8-triazaspiro[4.4]nona-2,8-dien-6-one, (I), C(24)H(18)BrN(3)O(2), 3-bromo-4-(4-methoxyphenyl)-1,9-diphenyl-7-oxa-1,2,8-triazaspiro[4.4]nona-2,8-dien-6-one, (II), C(24)H(18)BrN(3)O(3), 3-bromo-4-(4-chlorophenyl)-1,7,9-triphenyl-1,2,7,8-tetraazaspiro[4.4]nona-2,8-dien-6-one, (III), C(29)H(20)BrClN(4)O, and 3-bromo-1,7,9-triphenyl-4-p-tolyl-1,2,7,8-tetraazaspiro[4.4]nona-2,8-dien-6-one, (IV), C(30)H(22.89)Br(1.11)N(4)O, are presented. The molecular structures are rather similar, which is as expected since the compounds are all products of concerted 1,3-dipolar attack on (Z)-4-arylidene oxazolone and pyrazolone derivatives. The observed conformations tend to favour extended pi conjugation of the benzene rings and other pi systems, as shown by a comparison of selected geometric parameters of the four structures.
authors.affiliation: Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Universitá degli Studi di Messina, Via Salita Sperone 31, 98166 Vill. S. Agata - Messina, Italy. bruno@chem.unime.edu
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bruno
authors.forename: Francesco
authors.initials: F
authors.lastname: Nicoló
authors.forename: Archimede
authors.initials: A
authors.lastname: Rotondo
authors.forename: Francesco
authors.initials: F
authors.lastname: Foti
authors.forename: Francesco
authors.initials: F
authors.lastname: Risitano
authors.forename: Giovanni
authors.initials: G
authors.lastname: Grassi