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Synthesis, spectroscopic properties, and tautomerism of mono‐ meso ‐substituted octamethylporphyrins
Author(s) -
Li Ming,
Yao YiMing,
Zou JianZhong,
Xu Zheng,
You XiaoZeng
Publication year - 1994
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19940120307
Subject(s) - tautomer , chemistry , salicylaldehyde , steric effects , aldehyde , medicinal chemistry , stereochemistry , computational chemistry , organic chemistry , catalysis , schiff base
The synthesis spectroscopic properties and tautomerism of four novel mono ‐meso substituted(R)‐octamethylporphyrins (R= o ‐hydroxybenzyl, p ‐aminobenzyl, 4‐pyridinyl, and ferrocenyl) were investigated. It was found that the porphyrins 2 , 3 could be directly prepared in good yields via the coupling reaction of salicylaldehyde and p ‐aminobenzyl aldehyde with octamethyl‐1′,8′‐dideoxy‐ac‐biladiene dihydrobromide, respectively. The free energy of activation (ΔG ≠ ) of the tautomerism of the porphyrins was calculated and interpreted in terms of electronic and steric nature. In contrast with 2‐substituted‐5,10,15,20‐tetraphenylporphyrins, the substituents in meso position do not change the relative amount of two tautomers a and b .