Synthesis of novel amide functionalized 2H-chromene derivatives by Ritter amidation of primary alcohol using HBF4·OEt2 as a mild and versatile reagent and evaluation of their antimicrobial and anti-biofilm activities.

Abstract A series of novel amide functionalized 2 H -chromene derivatives 3 were prepared starting from ethyl-2-hydroxy-2-(trifluoromethyl)-2 H -chromene-3-carboxylate 1 via sodium borohydride reduction followed by Ritter amidation using HBF 4 ·OEt 2 as a mild and versatile reagent. All the products 3 were screened for antimicrobial activity against various Gram-positive, Gram-negative bacteria and fungal strain. The promising derivatives such as 3f , 3g , 3k , 3l , 3m , 3n and 3o were further screened for minimum bactericidal concentration and bio-film inhibition activity and identified the potential ones. Among all the promising, compound 3g was more potent for antimicrobial, MBC and anti bio-film activities. The structure verses activity relationship of 3g revealed that the presence of two bromine atoms at sixth and R position promotes high activity.