Investigation of porphyrin-forming reactions. Part 4. Examination of the reaction course in syntheses of porphyrins via dipyrromethanecarbinols †
- 20 April 2001
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 5,p. 712-718
- https://doi.org/10.1039/b009101o
Abstract
The dipyrromethanecarbinol motif is a key component in rational routes to a wide variety of porphyrinic macrocycles. We have investigated the dipyrromethane-monocarbinol self-condensation and the dipyrromethane-dicarbinol + dipyrromethane condensation under four different acid-catalysis conditions and have characterized the oligomer composition (by LD-MS), yield of porphyrin (by UV–Vis), and yield of N-confused porphyrin (by HPLC). Under conditions giving “no-scrambling”, the condensations are rapid and afford an oligomer composition characterized by (1) absence of scrambling, (2) suppression of acidolysis, and (3) a disproportionate amount of long oligomers from which recovery does not occur. The irreversibility of the reaction and lack of recovery from the long oligomers may explain the lower yields of dipyrromethanecarbinol condensations (meso-substituted porphyrins without scrambling.Keywords
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