nanoporous sodium montmorillonite clay (na+-mmt) was used as a support for the immobilization of 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (na+-mmt-[pmim]hso4). this catalyst showed excellent catalytic activity for the preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4h-benzopyrans via three-component reactions between aldehydes, dimedone and malononitrile. the proc...

using hartree–fock (hf) and ِِdensity functional theory (dft) calculations the thermodynamic properties such as thermal energy , , thermal enthalpy , , thermal entropy , , thermal gibbs free energy , , heat capacity ,cv, and molecular structures of several species involving in keto↔enol tautomerism related to acetaldehyde (a), 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and  acetylacetone (aa) h...

Acridinediones were synthesized by the one-pot Hantzsch condensation of an aromatic aldehyde, 5,5-dimethyl-1,3-cyclohexanedione, and aniline/4-methylaniline in refluxing water. This method has then been extended to the four-component reaction of an aromatic aldehyde, 5,5-dimethyl-1,3-cyclohexanedione, ethyl acetoacetate and ammonium acetate for the synthesis of polyhydroquinoline derivatives. Th...

a facile and efficient protocol for the synthesis of 1,8-dioxo-octahydroxanthenes has been developed by one-pot knoevenagel condensation, michael addition and cyclodehydration reaction of dimedone (active methylene carbonyl compound) with aromatic aldehydes in the presence of iron (iii) sulfate hydrate as a solid acidic catalyst under solvent-free conditions. various aromatic aldehydes were uti...

a green and convenient méthode for the synthesis of  a variety of xanthene derivatives by condensation reaction between aldehydes and β-naphthol or dimedone in an micellar solution of sodium dodecylphosphonate is described. this method offers several advantages, such as using of a cheap and environmentally benign reaction media, low loadings of sodium dodecylphosphonate as catalyst and easy wor...

The trapping of a sulfenic acid within the fully active C165S mutant of the AhpC peroxidase protein from Salmonella typhimurium was investigated. The electrophilic reagent employed in these studies, 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl), has previously been used to modify thiol, amino, and tyrosine hydroxyl groups in proteins; at neutral pH only cysteinyl residues of AhpC proteins are...

this study introduces a green and efficient method for preparation of biologically-active substituted 4h-pyrans using the one-pot three-component reaction of aromatic aldehydes, dimedone and malononitrile in the presence of cobalt oxide nanoparticles. co3o4 nanoparticles were used as an efficient catalyst for the synthesis of polyhydroquinoline derivatives by the reaction of aromatic aldehydes,...

Sulfenic acids, formed as transient intermediates during the reaction of cysteine residues with peroxides, play significant roles in enzyme catalysis and regulation, and are also involved in the redox regulation of transcription factors and other signaling proteins. Therefore, interest in the identification of protein sulfenic acids has grown substantially in the past few years. Dimedone, which...

1, 8-dioxo-octahydroxanthene derivatives have efficiently been synthesized from dimedone and aromatic aldehydes using [fe(iii)(salen)cl] complex as an efficient and homogeneous catalyst in molten tetrabutyl ammonium bromide. this methodology offers several advantages, such as good yields, short reaction times, simple procedure, and mild conditions.