INTERMEDIATE HEXANAMIDES FROM SYNTHESIS O F 2-PYRIDONES VIA 2-PYRONES- PHYSICOCHEMICAL (AND SPECTROSCOPY) STUDY OF MOLECULAR ASSOCIATIONS

Methyl-6 hydroxy-4 pyridone-2 synthesis from methyl-6 hydroxy-4 pyrone -2 occurs through aliphatic intermediates RNHC (CH3)CHCOCH2CONHR (R=-C H3, -C6H5, -CH2C6H5, -CH2CH2C6H5). Dipole moments and spectroscopic me asurements (especially IR spectroscopy) confirm that the tautomeric fo rm observed in the solid state is also present in solution. This form is stabilized by intramolecular and intermolecular hydrogen bonds. Fun damental vibrations of hydrogen-bonded CO and NH (amido and amino) gro ups are assigned. The strength of hydrogen bond associations in variou s solvents is analysed with respect to the solid state.