Síntese de diazatriciclos e propriedade solvatocrômica de 1,10-fenantrolinas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

This work describes a new methodology for a variety of diazatricycles from the termocyclisation of phenylenediamine-bis(methylene Meldrumss acid) derivatives. The key intermediates 4,5-dimethyl-1,2-bis[(2,2-dimethyl-4,6-dioxo- 1,3-dioxan-5-ylidenemethyl)amino]benzene (58), 5-chloro-1,3-bis[(2,2-dimethyl-4, 6-dioxo-1,3-dioxan-5-ylidenemethyl)amino]benzene (62), 1,4-bis[(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidenemethyl)amino]benzene (67a), 2,3-dimethyl-1,4-bis[(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidenemethyl)amino]benzene (67b), 2,5-dimethyl-1,4-bis[(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidenemethyl)amino]benzene (70a) and 2,5-Dichloro-1,4-bis[(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidenemethyl)amino]benzene (70b) were prepared in good overall yield, by the condensation of Meldrums acid with the corresponding phenylenediamines in trimethylorthoformate. Termocyclisation of the bis-adducts in refluxing diphenylether was accompanied by spontaneous elimination of acetone and carbon dioxide to furnish the diazatricycles. These were chlorinated as crude products with phosphorus oxychloride to provide 4,7-dichloro-5,6-dimethyl-1,10-phenanthroline (60), 4,5,10-trichloro-1,7-phenanthroline (64), 1,10-dichloro-4,7-phenanthroline (68a), 1,10-dichloro-5,6-dimethyl-4,7-phenanthroline (68b), 4,9-dichloro-5,10-dimethylpyrido[ 2,3-g]quinoline (73), in satisfactory 30-50% overall yields. o-Phenylenediamines gave the corresponding 1,10-phenanthroline derivatives, and m- and p-phenylenediamines formed preferentially the angular diazatricycles. The 2,5-dichloro-1,4-phenylenediamine gave, via ipso-substitution, the unexpected angular product, although the two possible isomers 1,2,5,10-tetrachloro-4,7-phenanthroline (72a) e 1,2,6,10-tetrachloro-4,7-phenanthroline (72b) could not be distinguished from one another by spectroscopic analysis. The compound 73 can be regarded as a potential citotoxic drug due to its structural similarity the ellipticine, a potent antitumoral agent. It was also investigated the properties of the first solvatochromic dye based on 1,10-phenanthroline ring. Thus, it was prepared the 1,7-Dimethyl-4-[2-(p- hydroxiphenyl)vinylidene]-1,10-phenanthrolinium iodide (54) and 1,8-bis(etene-phidroxyphenil)- 4,5-dihidro-3a-5a-diazapirene dibromide (56). These compounds were obtained by the condensation in basic medium of N-alkyl and N,N-dialkyl-1,10-phenahrolines with p-hydroxybenzaldehyde in good overall yields. The solvatochromic properties were confirmed for both compounds, where 56 was showed to be an efficient acidity indicator. The synthesis of 5-amino-1,10-phenanthroline (77) was carried out starting from the commercially available 1,10-phenanthroline. This compound is an important intermediate in the preparation of the iminophenanthroline dye (52)

ASSUNTO(S)

quimica síntese de diazatriciclos química orgânica; compostos heterociclicos; síntese orgânica variety of diazatricycles reação de termociclização from the termocyclisation

ACESSO AO ARTIGO

Documentos Relacionados