| Abstrakt: |
Cyclization of 2-(N-acetyl-N-arylamino)nicotinonitriles in the presence of dry HCl gave 1-aryl-2-methyl-4-oxo-1,4-dihydropyrido[2,3-d]pyrimidines. It was shown that they are acylated by acetic anhydride, aroyl chlorides, and phenyl isocyanate at the methyl group and that with benzaldehyde they give styryl derivatives. It was determined by UV, IR, and NMR spectra that 2-acetonyl, 2-phenacyl, and 2-(N-phenylcarbamoylmethyl) derivatives of 1-aryl-4-oxo-1,4-dihydropyrido[2,3-d]pyrimidines exist in enaminocarbonyl and imino enol forms with strong chelate-type intramolecular hydrogen bonding. |
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