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Syntheses of protoporphyrin‐IX regioselectively carbon‐13 labelled at the alpha‐vinyl carbons
Author(s) -
Smith Kevin M.,
Fujinari Eugene M.
Publication year - 1986
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580230110
Subject(s) - chemistry , carbon fibers , thallium , vinyl alcohol , organic chemistry , medicinal chemistry , polymer chemistry , materials science , composite number , composite material , polymer
A method for transformation of readily available beta‐vinyl 99% carbon‐13 enriched derivatives of protoporphyrin‐IX dimethyl ester ( 3 ‐ 5 ) into the less accessible alpha‐vinyl labelled isomers ( 6 ‐ 8 ) is described. The procedure involves thallium(III) promoted vinyl carbon rearrangement, and proceeds through 2,2‐dimethoxyethyl (e.g. 10 ), formylmethyl (e.g. 11 ), 2‐hydroxyethyl (e.g. 12 ) and 2‐chloroethyl (e.g. 13 ) porphyrins; the rearranged vinyl groups are regenerated from 2‐chloroethyl in the last step by treatment with base. No evidence of vinyl carbon scrambling in the sequence is observed, and spectroscopie data of the products are given.