Synthesis of chlorophyll-a homologs by Wittig and Knoevenagel reactions with methyl pyropheophorbide-d
1997; Elsevier BV; Volume: 53; Issue: 31 Linguagem: Inglês
10.1016/s0040-4020(97)00699-6
ISSN1464-5416
AutoresHitoshi Tamiaki, Mitsuru Kouraba,
Tópico(s)Photosynthetic Processes and Mechanisms
ResumoThe formyl group at the 3-position of methyl pyropheophorbide-d reacted with phosphorous ylides and activated methylene compounds to give efficiently the corresponding 3-(2-substituted ethenyl)chlorins compounds as a product of Wittig and Knoevenagel reactions. The trans-isomers of the synthetic chlorins, methyl 32-substituted pyropheophorbide-a had visible bands absorbing longer wavelengths than the cis-isomers and the 32-unsubstituted chlorin, methyl pyropheophorbide-a. 32,32-Disubstitution strongly affected the absorption bands compared with the bands of the 32-mono-substituted chlorins. The absorption, fluorescence and circular dichroism spectra were dependent upon the 3-substituents conjugated with the chlorin chromophore.
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