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Microwave‐Assisted C‐2 Direct Alkenylation of Imidazo[4,5‐ b ]pyridines: Access to Fluorescent Purine Isosteres with Remarkably Large Stokes Shifts
Author(s) -
Baladi Tom,
Granzhan Anton,
Piguel Sandrine
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201600166
Subject(s) - chemistry , pyridine , fluorescence , purine , catalysis , combinatorial chemistry , ring (chemistry) , microwave , stereochemistry , medicinal chemistry , organic chemistry , enzyme , physics , quantum mechanics
We describe herein the first C‐2 direct alkenylation of the valuable 3 H ‐imidazo[4,5‐ b ]pyridine promoted by microwave‐assisted Pd/Cu co‐catalysis. The reaction is rapid and compatible with a wide range of functional groups either on the imidazo[4,5‐ b ]pyridine ring or on the styryl bromides thereby leading to the isolation of 23 compounds with moderate to good yields. The relevance of this method is demonstrated by its application to the synthesis of new cross‐conjuguated push–pull 2‐vinyl‐ and 2‐alkynylimidazo[4,5‐ b ]pyridines characterized by satisfactory fluorescence quantum yields and remarkable solvatofluorochromic properties.