- Studies on the tetramerization of substituted monopyrroles to type I porphyrins
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Investigation of the tetramerization of pyrroles bearing two different electron-donating groups as substituents led to the rapid preparation under slightly acidic conditions of a porphyrin analog family with a high ratio of type I isomer for enzymatic act
- Pichon-Santander,Scott
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- Syntheses of type-I porphyrins via monopyrrole tetramerization
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Treatment of 2-[(N,N-dialkylamino)methyl]pyrrole-5-carboxylic acids (e.g. 10,12 or 11,13) in methanol with K3Fe(CN)6 gives type-I porphyrins (etioporphyrin-I 7, coproporphyrin-I tetramethyl ester 16, respectively); with pyrroles 10,12 the product 7 is contaminated with about 8% of other type-isomer(s).
- Nguyen, Liem T.,Smith, Kevin M.
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p. 7177 - 7180
(2007/10/03)
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- Porphyrin synthesis from nitrocompounds
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A new porphyrin synthesis starting from nitroalkenes or their equivalents is described. For example, octaethylporphyrin, coproporphyrin, porphyrin-1,2,3,4,5,6,7,8 octapropionic acid, and 2,7,12,17 tetraarylporphyrin are prepared in good yield from readily available materials such as 1-nitropropane, nitroethane, nitromethane, and aldehydes.
- Ono, Noboru,Kawamura, Hisayuki,Bougauchi, Masahiro,Maruyama, Kazuhiro
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p. 7483 - 7496
(2007/10/02)
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- SYNTHESIS OF UROPORPHYRIN-III, AND RELATED HEPTA- AND PENTA-CARBOXYLIC PORPHYRINS BY MODIFICATIONS OF THE MACDONALD METHOD
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A modification of the MacDonald route has been developed in which all four pyrrole units of uroporphyrin-III have been derived from the same conveniently prepared starting pyrrole.Related hepta- and penta-carboxylic porphyrins have also been synthesised by condensation of appropriate α-formyl pyrromethane-α'-carboxylic acids; in each case other porphyrins with different numbers of acidic side-chains were also produced but the desired products were easily separated (as their methyl esters) by h.p.l.c.
- Chakrabarty, M.,Ali, S. A.,Philip, G.,Jackson, A. H.
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p. 1199 - 1204
(2007/10/02)
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- Biosynthesis of Porphyrins and Related Macrocycles. Part 15. Chemical and Enzymic Formation of Uroporphyrinogen Isomers from Unrearranged Aminomethylpyrromethane: Separation of Isomeric Coproporphyrin Esters
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The unrearranged pyrromethane (1) is transformed chemically mainly into uro'gen-I with a smaller amount of uro'gen-IV but only traces of uro'gen-III are formed.Uro'gen-I is produced via a tetrapyrrolic (bilane) intermediate and when the diaminase-cosynthetase enzyme system from Euglena gracilis is present, this intermediate is converted into uro'gen-III.The rearrangement step for this conversion has the same characteristics found earlier for the natural biosynthetic process from porphobilinogen.Pyrromethane (1) is not a direct biosynthetic precursor of uro'gen-III and reasons are advanced why this is understandable.Methods are developed based on high pressure liquid chromatography for the separation of all four isomeric coproporphyrin esters.
- Battersby, Alan R.,Buckley, Dennis G.,Johnson, Dawid W.,Mander, Lewis N.,McDonald, Edward,Williams, D. Clive
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p. 2779 - 2785
(2007/10/02)
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