Studies on Coumarins, I

Abstract

4-Bromomethylcoumarins, prepared by the reaction of phenols and 4-bromoethyl acetoacetate, were reacted with primary aromatic amines to yield 4-anilinomethylcoumarins. The spectral properties and antimicrobial activities against five micro-organisms are reported.

Stereoselective Synthesis of <i>cis</i>-Substituted-3’-anilino-2’, 3’-dihydro-4-2’-benzo[<i>b</i>]furanylcoumarins via Intramolecular Aldol Reactions

“…The product 7 could be obtained with decreased yield (55% -60%) by using solvents such as DMF, 1, 4-dioxane and ethanol. However, a various 4-bromomethyl coumarins 5 [37] and substituent salicylidineaniline 6 could be cyclized with increased stereoselective products and short reaction time. The reaction to yield the 3'-Anilino-2',3'-dihydro-4-2'-benzo[b]furanylcoumarins 7a-l showed a full conversion after sixteen hours at room temperature, but a much longer reaction time of more than 30 hours, probably the elimination of aromatic amines starts due to the aromatisation of product 7 to 8 was observed (Scheme 1).…”

Synthesis and antimicrobial studies on novel sulfonamides containing 4-azidomethyl coumarin

“…The required 4-bromomethyl-7-methylcoumarin [19] have been synthesized by the Pechmann cyclization of m-cresol with 4-bromoethylacetoacetate [31].…”

“…Amongst the various alkyl amines and sulfides synthesized, the 4-piperazinomethyl and imidazomethyl sulfides [18] were found to be the most active compounds. We have been studying structurally analogous, 4-arylaminomethyl [19] 4-sulphonamidomethyl [20] and 4-dichloroacetamidomethyl coumarins [21] for their anti-bacterial activity. Recent reports on the cytotoxic effects of coumarin sulfonamides [22,23], on leukemia cell lines have generated a renewed interest in such class of compounds.…”

One Pot Three Component Diastereoselective Synthesis of Tricyclic Furoquinolones and Furocoumarins

“…The required substituted 4-bromomethylcoumarins [37] 1 were prepared by the Pechmann cyclization of substituted phenols with 4-bromoethylacetoacetate [38] using sulfuric acid as the condensing agent. The three component reaction between 4-bromomethyl coumarins 1 and benzaldehyde 2 (R= H) and 4-hydroxy coumarin 3 in presence of pyridine using chloroform as solvent at room temperature resulted in the formation of a white crystalline solid corresponding to the 4-coumarinomethyl pyridinium hydrobromide.…”