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Synthesis of chlorophyll‐ a skeleton homologs using grignard reaction with methyl pyropheophorbide‐ a
Author(s) -
Wang JinJun,
Shim Young Key,
Jiang GuiJi,
Imafuku Kimiaki
Publication year - 2004
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.5570410105
Subject(s) - chemistry , ethylenedioxy , grignard reaction , alcohol , chlorin , ketone , medicinal chemistry , stereochemistry , organic chemistry , reagent , photodynamic therapy , alkyl
From methyl pyropheophorbide‐ a (MPPa) (1), methyl 2‐formylmethyl‐2‐devinyl‐9‐ethylenedioxy‐9‐deoxopyropheophorbide‐ a (2) and methyl 3‐acetyl‐9‐ethylenedioxy‐2‐devinyl‐9‐deoxopyropheophorbide‐ a (3) were prepared. The Grignard reactions of 2 and 3 were performed using cycloalkyl magnesium bromides to afford cycloalkyl‐substituted sec ‐alcohol 4 and tert ‐alcohols 9a‐c, respectively. By the deprotection of the ethylenedioxy group, these alcohols were respectively converted to exocyclic ketones 5 and 10a‐c, which were dehydrated to give chlorins 6 and 11a‐c having an alkenyl function at the 2‐position. On the other hand, the oxidation and deprotection of the alcohol 4 gave a diketo chlorin 8.