Synthesis and antibacterial activity of crossed aldol products
A number of [alpha], [beta]-unsaturated carbonyl compounds were prepared by condensing of 2-formylfuran, 2-formylpyridine and 2-formylthiophene with acetone, acetophenone, 3-methyl-acetophenone, [alpha]-chloroacetophenone and ethyl methyl ketone in ethanolic NaOH solutions. These compounds were tested for antibacterial activity against Escherichia coli. (E. coli). It was found that the mesomeric and the hyperconjugation effects have a strong influence on the antibacterial activity.
Crossed aldol (Claisen-Schmidt) type reaction of 2-formylpyrrole, 2-formylfuran or 2-formyl thiophene with active methylene compounds gave [alpha], [beta]-unsaturated carbonyl compounds in high yields . [alpha], [beta]-Unsaturated carbonyl compound derivatives were reported to be active as antibacterial, antifungal, antimutagenic, anticancer, antioxidant, anticoagulant, antiangiogenesis, antitumor and anticarcinogen activity [2-11]. In continuation of this interested work, [alpha], [beta]-unsaturated carbonyl compounds have been synthesis from condensation of 2-formylfuran, 2-formylpyridine and 2-formylthiophene with different a-hydrogen carbonyl compounds. These compounds were characterized by spectroscopic data, also tested for their antibacterial activity against E. coli bacteria.
Melting points were determined in open capillaries and are uncorrected. IR spectra were recorded in KBr on perkin-Elmer 883 spectrometer and UV spectra (MeOH) on Perkin-Elmer 15 spectrophotometer. 2-Formylfuran, 2-Formylpyridine and 2-Formylthiophene were obtained from Sigma-Aldrich ltd. and used without further purification. All compounds were tested for their antibacterial activity against negative bacteria E-coli at concentration of 10 and 50 pg/disc using cup-plate method .
General method for synthesis of 4-(furan-2-yl)-3-buten-2-one 1, 3-(furan-2-yl)-2-chloro-1-phenyl-2-propen-1-one 4, 1-(furan-2-yl)-1-penten-3-one 5, 4-(pyridin-2-yl)-3-buten-2-one 6, 3-(pyridin-2-yl)-2-chloro-1-phenyl-2-propen-1-one 9, 1-(pyridin-2-yl)-1-penten-3-one 10, 4-(thiophen-2-yl)-3-buten-2-one 11, 3-(thiophen-2-yl)-2-chloro-l-phenyl-2-propen-l-one 14 and 1-(thiophen-2-yl)-1-penten-3-one 15 was carried out
Aldehyde (0.013 mol) was dissolved in 15 ml ethanol. Then added to a solution of acetone or [??]-chloroacetophenone or ethyl methyl ketone (0.021 mol) and sodium hydroxide (95%, 8 mL). The mixture was heated under reflux for 15 min. and allowed to cool. The crude mixture was extracted with chloroform (3x30 ml). The organic layer was dried over calcium chloride, the solvent was removed. Then the product was...
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