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Studies of spiro‐chlorin formation using porphyrin amides
Author(s) -
Smith Kevin M.,
De Almeida José A. P. Baptista,
Lewis W. Michael
Publication year - 1980
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.5570170312
Subject(s) - chemistry , porphyrin , chlorin , imine , hydrolysis , yield (engineering) , imide , cleavage (geology) , bond cleavage , derivative (finance) , ring (chemistry) , medicinal chemistry , organic chemistry , stereochemistry , catalysis , materials science , geotechnical engineering , fracture (geology) , economics , financial economics , engineering , metallurgy
Syntheses of 7‐(3‐ethoxycarbonylpropyl)‐2,3,5‐triethyl‐1,4,6,8‐tetramethylporphyrin ( 8 ) ( via the MacDonald dipyrrylmethane route) and 2‐(2‐chloroethyl)‐4‐ethyl‐6‐methoxycarbonyl‐7‐(3‐methoxy‐carbonylpropyl)‐1,3,5,8‐tetramethylporphyrin ( 22 ) ( via the tripyrrene route) are described. The corresponding pyrrolidides of these compounds were cyclized in high yield to furnish the spiro imines ( 20 and 30 respectively), but attempts to hydrolyze these imines to the appropriate spiroketochlorins were largely unsuccessful. A small amount of the spiroketochlorin 9 (from 8 ) was obtained, and this was successfully hydrogenated to give the dihydro derivative 21 . The major problem in imine hydrolysis was observed to be reversion to the parent porphyrin through simple bond migration and spiro ring cleavage. A successful transformation of protoporphyrin‐IX dimethyl ester ( 31 ) into mesoporphyrin‐IX dimethyl ester ( 32 ) using di‐imide generated from dipotassium azodicarboxylate is described.