Solid-Phase Synthesis of 4(1<i>H</i>)-Quinolone and Pyrimidine Derivatives Based on a New ScaffoldPolymer-Bound Cyclic Malonic Acid Ester

Abstract

An efficient method for the preparation of polymer-bound cyclic malonic acid ester starting from Merrifield resin has been developed. Reaction of the resin-bound cyclic malonic acid ester with triethyl orthoformate and subsequent double substitution with nucleophilic reagents, such as arylamine, urea, thiourea, 2-aminobenzothiazoles, or isothiosemicarbazones, afforded the corresponding polymer-bound substituted aminomethylene cyclic malonic acid esters, which upon thermal treament led to 4(1H)-quinolones, 3-substituted uracils and thiouracils, 4H-pyrimido[2,1-b]benzothiazol-4-ones, and 1-(N-alkylidene or benzylideneamino)-1,6-dihydro-2-methylthio-6-oxo-pyrimidines, depending on the structures of the nucleophilic reagents.