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[4+2]‐Cycloadditionen von α,β‐ungesättigten Hydrazonen. Teil 2. Pyridin‐2,3‐dicarboximide aus 1,4‐Dihydropyridin‐Derivaten
Author(s) -
Waldner Adrian
Publication year - 1988
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19880710223
Subject(s) - chemistry , cycloaddition , pyridine , dimethylamine , medicinal chemistry , dihydropyridine , lactam , stereochemistry , organic chemistry , catalysis , calcium
[4+2] Cycloaddition of α,β‐Unsaturated Hydrazones to Pyridine‐2,3‐dicarboximides via 1,4‐Dihydropyridine Derivatives The [4 + 2] cycloaddition of α,β‐unsaturated hydrazones of type 1 (1‐aza‐1,2‐butadienes) with maleimides ( e.g. 2b ) affords the tetrahydropyridines of type 8. Elimination of dimethylamine to 9 is easily achieved by treatment of 8 with silica gel at elevated temperature. Oxidation of the dihydropyridines 9 leads to highly substituted pyridine‐2,3‐dicarboxylic‐acid dervatives 4 .