Alternative synthesis of 3-acetyl, 3-epoxy, and 3-formyl chlorins from a 3-vinyl chlorin, methyl pyropheophorbide-a, via iodination

摘要

We developed novel methods to convert the C3-vinyl group of a chlorophyll derivative, methyl pyropheophorbide-a, into an acetyl group, an epoxy group, and a formyl group via iodination with I-2 and phenyliodine(III) bis(trifluoroacetate). Reaction of the iodinated intermediate with ethylene glycol and subsequent treatment with base led to formation of the C3-acetyl chlorin. Reaction of the iodinated intermediate with ethylenediamine afforded the C3-oxiranyl chlorin. The C3-formyl chlorin was readily derived from the epoxide without hazardous reagents such as OsO4. These reactions were facile and useful alternatives to the previous methods. (C) 2015 Elsevier Ltd. All rights reserved.