A CONVENIENT SYNTHESIS OF PYRANDIONE DERIVATIVES USING P-TOLUENESULFONIC ACID AS CATALYST UNDER ULTRASOUND IRRADIATION

A new series of 3,3'-{alkane-alpha,omega-diylbis[imino-eth-1-yl-1-ylidene]} bis(6-methyl-2H-pyran2,4(3H)-dione) derivatives (3c-e) has been synthesized by the convenient ultrasound-mediated condensation of a diamine with dehydroacetic acid in the presence of a catalytic amount of p-toluenesulfonic acid. The structure of all synthesized compounds was elucidated by IR spectroscopy, H-1 NMR spectroscopic spectra, elemental analysis, and mass spectroscopy. A tautomeric form for the derivatives species is also proposed.