Syntheses and exploration of new biological activities in ethyl 6/7-substituted and 6, 7-disubstituted quinolin-4-one-3-carboxylates

Syntheses of a number of ethyl 1H, 4H-quinolin-4-one-3-carboxylates carrying substituted piperidinedione ring at position 6 (25 & 31–35), tetrahydrofuranone (37) or tetrahydropyridazinone ring (39) at position 7 and hydroxy and hydroxymethyl substituents at positions 6 and 7 respectively (41) of the quinolone ring, are reported here. Effect of these compounds on the heme polymerase activity of Plasmodia and on the fungal growth are described.