The synthesis of 5-substituted 3-benzoylamino-6-(2-substituted amino-1-ethenyl)-2H-pyran-2-ones and their transformations into 2H-pyrano[3,2-c]pyridine derivatives

Article abstract of DOI:10.1002/jhet.5570330338

A new approach to the 2H-pyrano[3,2-c]pyridine system is described, 5,6-Disubstituted 3-benzoylamino-2H-pyran-2-ones 3a,b, prepared from the corresponding 1,3-dicarbonyl compounds 1a,b and methyl (Z)-2-benzoylamino-3-dimethylaminopropenoate (2), were converted into 3-benzoylamino-6-(2-dimethylamino-1-ethenyl)-5-ethoxycarbonyl-2H-pyran-2-one (4a) and 5-acetyl derivative 4b. The exchange of the dimethylamino group in 4a,b with aromatic amines 5a-f,m, heteroaromatic amines 5g-i, and benzylamines 5j-1 produced 5-ethoxycarbonyl-3-benzoylamino-6-(2-arylamino- or heteroarylamino-or benzylamino-1-ethenyl)-2H-pyran-2-ones 6a-1, and its 5-acetyl analog 6m. The compounds 6 were cyclized in basic media into 2H-pyrano[3,2-c]pyridine derivatives 7a-h. Analogously react also α-amino acid derivatives 8a-c and 11 as nitrogen nucleophiles producing 9a-c, 10 and 12.