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Titolo:
SOLVENT-DEPENDENT AMBIDENT NUCLEOPHILICITY OF PHENOXIDE ION TOWARDS NITROPORPHYRINS - SYNTHESIS OF 2-HYDROXYARYL-5,10,15,20-TETRAPHENYLPORPHYRIN AND 2-ARYLOXY-5,10,15,20-TETRAPHENYLPORPHYRIN BY DISPLACEMENT OFA NITRO-GROUP
Autore:
CROSSLEY MJ; KING LG; SIMPSON JL;
Indirizzi:
UNIV SYDNEY,SCH CHEM SYDNEY NSW 2006 AUSTRALIA
Titolo Testata:
Journal of the Chemical Society. Perkin transactions. I
fascicolo: 20, , anno: 1997,
pagine: 3087 - 3096
SICI:
0300-922X(1997):20<3087:SANOPI>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
MEISENHEIMER COMPLEX-FORMATION; EXTENDED PORPHYRIN SYSTEMS; BETA-PYRROLIC POSITION; SIGMA-COMPLEX; CONVENIENT SYNTHESIS; EFFICIENT SYNTHESIS; ALPHA-DIONES; REACTIVITY; METALLO-2-NITRO-5,10,15,20-TETRAPHENYLPORPHYRINS; SUBSTITUTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
27
Recensione:
Indirizzi per estratti:
Citazione:
M.J. Crossley et al., "SOLVENT-DEPENDENT AMBIDENT NUCLEOPHILICITY OF PHENOXIDE ION TOWARDS NITROPORPHYRINS - SYNTHESIS OF 2-HYDROXYARYL-5,10,15,20-TETRAPHENYLPORPHYRIN AND 2-ARYLOXY-5,10,15,20-TETRAPHENYLPORPHYRIN BY DISPLACEMENT OFA NITRO-GROUP", Journal of the Chemical Society. Perkin transactions. I, (20), 1997, pp. 3087-3096

Abstract

The reaction of phenoxide ion with the copper(II), nickel(II) and free-base 2-nitro-5,10,15,20-tetraphenylporphyrins, 1-3 respectively, hasbeen investigated as a means of introducing inwards-directed functionality to the periphery of pre-existing porphyrin systems. It has been found that phenoxide ion shows highly selective solvent-dependent ambident nucleophilicity towards the nitroporphyrin system. Porphyrins 1-3react with phenoxide ion in refluxing phenol to afford the corresponding 2-(o-hydroxyphenyl)- and (p-hydroxyphenyl)-5,10,15,20-tetraphenylporphyrins in good yields; in each case the ortho isomer is the major product and none of the meta isomer is detected. The scope of the reaction has been extended by the use of the substituted phenols which are blocked from reaction para to the hydroxy (p-cresol and 2,4-dimethylphenol) or blocked from reaction in the ortho-positions (2,6-dimethylphenol). In this way the copper(II) 2-(2-hydroxy-5-methylphenyl)porphyrin14 (86%), 2-(2-hydroxy-5-methyphenyl)-porphyrin 15 (65%), copper(II) 2-(2-hydroxy-3,5-dimethylphenyl)porphyrin 16 (77%), 2-(2-hydroxy-3,5-dimethylphenyl)porphyrin 17 (69%) and 2-(4-hydroxy-3,5-dimethylphenyl)porphyrin 19 (63%) have all been obtained in good yields by reaction ofthe appropriate 2-nitroporphyrin 1 or 3 with the requisite substituted phenolate in the corresponding phenol, Reaction of the metalloporphyrins 1 and 2 with phenoxide ion in refluxing HCONMe2 in contrast givesthe corresponding 2-phenoxy-metalloporphyrins 10 and 11 in good yield. The results of mechanistic studies using the deuteriated compound, nickel(II) 2-nitro-5,10,15,20-tetraphenyl[3-H-2]porphyrin, 37, suggest that both sets of products (from phenoxide as a C-nucleophile and as an O-nucleophile) can arise from ipso-substitution of the nitro group.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 05:41:36