A rapid access to new coumarinyl chalcone and substituted chromeno[4,3-c]pyrazol-4(1H)-ones and their antibacterial and DPPH radical scavenging activities

A series of new coumarin derivatives 4 containing a chalcone moiety were synthesized by condensation of 3-acetyl-4-hydroxycoumarin 1 with aryl or heteroaryl aldehydes 2 in the presence of piperidine in chloroform. The interaction of 3-formyl-4-chloro-coumarin 3 with nitrogen compound nucleophiles are described and lead to the corresponding substituted chromen[4,3-c] pyrazol-4-ones 5. The structures of the obtained compounds were established on the basis of IR|1D|2D NMR, while crystal structure of 3-acetyl-4-hydroxy coumarin 1 was determined using X-ray diffraction and further were evaluated for possible antibacterial and antioxidant activities. The coumarinic chalcone 4d has been found to be the most active (IC(50) = 2.07 mu M) in this study.