An efficient synthesis of polyhydroquinoline derivatives was reported via four-component coupling reactions of aldehydes, 1,3-dicarbonyl ketones (dimedone or 1,3-cyclohexanedione), ethyl acetoacetate or methyl acetoacetate and ammonium acetate in the presence of a catalytic amount of nanocrystalline TiO2 under solvent free conditions. The reported method is mild, rapid and has the advantages su...

An efficient synthesis of polyhydroquinoline derivatives is achieved via Hantzsch condensation reaction between aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of catalytic amount of SFHS in ethanol. This method gives remarkable advantages such as shorter reaction time, simple workup procedure and good to excellent yields. Furthermore the catalyst can be recovered c...

In the present work, we have developed a mild, efficient, and environmentally benign method for the synthesis of tetrahydrobenzo[b]pyran derivatives via a three-component cyclocondensation of aldehydes, malononitrile and dimedone utilizing ammonium chloride as a simple, easily available and cost effective catalyst under microwave irradiation. This method has several attracting features such as ...

an efficient one pot multi component synthesis of 1, 4-polyhydroquinoline derivatives through unsymmetrical hantzsch reaction using lanthanum chloride heptahydrate (lacl3.7h2o) from an aromatic aldehyde, ethyl acetoacetate, dimedone and ammonium acetate as a nitrogen precursor in ethanol at room temperature is described. in the present work we report lanthanum chloride heptahydrate remarkably n...

a rapid and efficient one-pot, four-component protocol towards the synthesis of polyhydroquinoline derivatives has been developed. the condensation of aldehyde, dimedone, ethyl acetoacetate and ammonium acetate in presence of stannous chloride was carried out under solvent free condition to synthesize a variety of polyhydroquinoline derivatives in good to excellent yields. stannous chloride was...

sulfonic acid functionalized sba-15 (sba-pr-so3h) as a new nanoporous acid catalyst was used in the one-pot synthesis of polyhydroquinolines derivatives via the hantzsch four component condensation reaction of aldehydes, b-ketoesters, dimedone and ammonium acetate under solvent free conditions with short reaction time in excellent yields. sba-pr-so3h was proved to be an efficient heterogeneous ...

Cysteine sulfenic acid formation in proteins results from the oxidative modification of susceptible cysteine residues by hydrogen peroxide, alkyl hydroperoxides, and peroxynitrite. This species represents a biologically significant modification occurring during oxidant signaling or oxidative stress, and it can modulate protein function. Most methods to identify such oxidatively modified protein...

Protein sulfenic acids are formed by the reaction of biologically relevant reactive oxygen species with protein thiols. Sulfenic acid formation modulates the function of enzymes and transcription factors either directly or through the subsequent formation of protein disulfide bonds. Identifying the site, timing, and conditions of protein sulfenic acid formation remains crucial to understanding ...