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

A new approach to the 2H-pyrano[3,2-c]pyridine system is described. 5, 6-Disubstituted 3-benzoyl-amino-2H-pyran-2-ones 3a,b, prepared from th e corresponding 1,3-dicarbonyl compounds la,b and methyl (Z)-2-benzoyl amino-3-dimethylaminopropenoate (2), were converted into ylamino-1-eth enyl)-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-e thoxycarbonyl-3-benzoylamino-6-(2-arylamino- or heteroarylamino- or be nzylamino-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]pyr idine derivatives 7a-h. Analogously react also cl-amino acid derivativ es 8a-c and 11 as nitrogen nucleophiles producing 9a-c, 10 and 12.