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Synthesis of some 5‐aryl‐2,2′‐dipyrromethenes as analogs of prodigiosin
Author(s) -
Campaigne E.,
Shutske G. M.
Publication year - 1976
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570130315
Subject(s) - chemistry , ethyl chloroformate , pyrrole , prodigiosin , aryl , medicinal chemistry , condensation , organic chemistry , stereochemistry , biochemistry , alkyl , physics , escherichia coli , serratia marcescens , gene , thermodynamics
Abstract Three new dipyrromethenes have been synthesized as analogs of prodigiosin: 3‐methoxy‐5‐phenyl‐2,2′‐dipyrromethene (10a) , 3‐methoxy‐4 ‐pentyl‐5‐phenyl‐5′‐methyl‐2,2′‐dipyrromethene (10b) , and 3‐methoxy‐4′‐pentyl‐5′‐methyl‐5‐(2″‐thienyl)‐2,2′‐dipyrromethene (10c). The Michael addition of ethyl glycinate to an appropriate arylidenemalonate, quenched with ethyl chloroformate and followed by a Dieckmann cyclization gave diethyl 1‐ethoxycarbonyl‐3‐oxo‐5‐phenyl and thienylpyrrolidine‐2,4‐dicarboxylate, 2a and 2b. Methylation of the highly enolic keto‐esters, followed by oxidation to N ‐ethoxycarbonylpyrroles led, after appropriate elaboration of the pyrrole nucleus, to 2‐phenyl‐ and 2‐thienyl‐4‐methoxypyrroles. The acid catalyzed condensation of these arylmethoxypyrroles with either pyrrole‐2‐carboxaldehyde or 5‐methyl‐4‐pentylpyrrole‐2‐carboxaldehyde led to 10a, 10b and 10c.