Title

Syntheses and preliminary in vivo photodynamic efficacy of benzoporphyrin derivatives from phylloerythrin and rhodoporphyrin XV methyl esters and aspartyl amides

Document Type

Article

Publication Date

4-8-1996

Abstract

Efficient approaches to the synthesis of methyl esters and aspartyl amides of so-called ring 'A'-benzoporphyrin derivatives from rhodoporphyrin XV dimethyl ester 10 and 3-vinylphylloerythrin methyl ester 22 are reported. The benzo-rings in the products are obtained by way of Diels-Alder (4+2) cyclizations which employ a dienophile and the vinyl and 2,3-double bonds in the starting materials as the diene. In the 3-vinyl-phylloerythrin series, the presence of the 131-keto-group in ring E inhibits the Diels-Alder reaction with dimethyl acetylenedicarboxylate, but with more reactive dienophiles, such as tetracyanoethylene, the Diels-Alder adduct was isolated in modest yield. Protection of the 131-keto-group as a ketal or thioketal afforded the intermediate benzoporphyrin adducts, which were rearranged to trans- and cis-isomers on reacting with triethylamine and 1,8-diazabiclo[5.4.0]undec-7-ene, respectively. Among the sensitizers tested so far, the benzoporphyrin derivative (cis-isomer) obtained from rhodoporphyrin XV di-tert-butyl aspartate showed the best in vivo photosensitizing activity in DBA/2 mice transplanted with SMT/F tumors.

Publication Source (Journal or Book title)

Tetrahedron

First Page

5349

Last Page

5362

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