Synthesis and Antimicrobial Activity of Some New Coumarin and Dicoumarol Derivatives

Phase transfer catalysis reaction of 4-hydroxy-6-methyl-2H-chromen-2-one with alkyl halides afforded C4 oxygen alkylation products of 2H-chromen-2-one derivatives in appreciative yield, whereas with phenyl isothiocyanate gives the C3 addition product of 4-hydroxy-6-methyl-2-oxo-N-phenyl-2H-chromene-3-carbothioamide, also one pot three component phase transfer reaction was investigated. Treatment of 4-hydroxy-6-methyl-2H-chromen-2-one with aromatic aldehydes in different molar ratios gives 3‑arylidine and the dicoumarol derivatives. However pyrano chromene and pyrano pyridine were obtained by reaction of arylidine with ethyl acetoacetate through Michael cycloaddition reaction. The stability of pyrone ring in 3-arylidine and dicoumarol towards different nucleophilic reagents under reflux and/or fusion conditions has been studied by the action of, hydrazine hydrate, ammonium acetate, methyl amine and p-toluidine afforded compounds 1,2-bis(benzo[d][1,3]dioxol-5-ylmethylene)hydrazine, 1,2-bis(4-methoxybenzylidene)hydrazine and 2,6-bis((2,6-dihydroxy-3-methylphenyl)(hydroxy)methylene)-1-(4-methoxyphenyl)-4-(p-tolyl) piperidine-3,5-dione derivatives. The antimicrobial activity of some synthesized compounds has been investigated.