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Novel Porphyrinoids, 14. – Biomimetic Syntheses of Doubly N , N ′‐Bridged [18]Porphyrinogens
Author(s) -
Franck Burchard,
Timmermann Ralf,
Sirges Wolfram
Publication year - 1993
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.1993199301173
Subject(s) - chemistry , yield (engineering) , pyrrole , stereochemistry , condensation , group (periodic table) , organic chemistry , materials science , physics , metallurgy , thermodynamics
Six N , N ′‐alkylene‐bridged bispyrroles 9a–9e and one N , N ′‐oxaalkylene‐bridged bispyrrole 16 with a reactive group at C‐1 of each pyrrole unit were synthesized in 53–78% yields. Acid‐catalyzed “biomimetic” condensations of the bispyrroles with N , N ′‐C 3 to N , N ′‐C 5 bridges yielded N , N ′: N″,N ‴doubly bridged porphyrinogens 14 , 15 , 17 , 18 , which are novel heterocyclic systems. By exchanging one CH 2 group for oxygen in the N , N ′‐alkylene chain of 9e to reduce the Prelog strain, the condensation yield was significantly increased. The N , N ′‐C 1 ‐and the N , N ′‐C 2 ‐bridged bispyrroles 9a , 9b did not cyclize to porphyrinogens, but in one case cyclized to give a N , N ′‐C 1 ‐bridged dipyrrylmethane 12 instead.