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Rearrangements of 4‐(2‐Aminophenyl)‐1,4‐dihydro‐2,6‐dimethyl‐3,5‐pyridinedicarboxylic acid diethyl ester
Author(s) -
Kim Dong H.
Publication year - 1986
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.5570230543
Subject(s) - chemistry , yield (engineering) , pyridine , toluene , ethyl ester , dicarboxylic acid , medicinal chemistry , organic chemistry , materials science , metallurgy
The treatment of 4‐(2‐aminophenyl)‐1,4‐dihydro‐2,6‐dimethyl‐3,5‐pyridinecarboxylic acid diethyl ester (III) with refluxing toluene or pyridine afforded 1,2,3,6‐tetrahydro‐2,4‐dimethyl‐2,6‐methano‐1,3‐benzodiazocine‐5,11‐dicarboxylic acid diethyl ester (IV) as the major product. In addition, the following minor products were isolated: 2‐methyl‐3‐quinolinecarboxylic acid ethyl ester (V), 3‐(2‐aminophenyl)‐5‐methyl‐6‐azabicyclo[3,3,1]‐hept‐1‐ene‐2,4‐dicarboxylic acid diethyl ester (VI), and 5,6‐dihydro‐2,4‐dimethyl‐5‐oxobenzo[ c ][2,7]naphthyridine‐1‐carboxylic acid ethyl ester (VII). In contrast, acidic conditions caused the conversion of III into V in a 95% yield. The formation of the latter appears to involve IV as an intermediate, since IV degraded rapidly in acid to give V in a quantitative yield.