silica-bonded n-propyltriethylene-tetramine (sbnptt) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4h-chromenes. chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oc under solvent-free conditions. the heterogeneous solid base showed much the same efficiency when u...

silica-bonded n-propyldiethylenetriamine sulfamic acid (spdtsa) is employed as a recyclable heterogeneous solid acid catalyst for the synthesis of benzopyrano[2,3-d]pyrimidines  through one-pot condensation reaction of salicylaldehydes, malononitrile and secondary amines  at room temperature under solvent-free conditions. spdtsa showed much the same efficiency when used in consecutive reaction ...

Waste cooking oil (WCO) was used as a potential feedstock for biodiesel production. High levels of free fatty acids (9.85% w/w) in WCO made it an undesirable substrate for direct transesterification reaction. To solve this issue, a two-step process was implemented in this research. Firstly, esterification reaction was performed in presence of sulfuric acid as a common acid catalyst to reduce th...

In this study, synthesis of copper nanoparticles and effect of the reaction conditions on the particle size were investigated. The copper nanoparticles were synthesized and stabilized in a narrow temperature range in the presence of polyvinylpyrrolidone under nitrogen atmosphere. Reaction temperature and concentration ratio of the reducing agent to the precursor (R/P) as two main conditions i...

Quinazolinone derivatives are nowadays well recognized as valuable scaffold in drug discovery. In this manuscript an improved multicomponent process for the chemical synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives is described. Isatoic anhydride and aromatic aldehydes with ammonium acetate have been subjected to a three-component reaction under solvent-free conditions and catalysis of ...

We consider a reaction-diffusion system of activator-inhibitor or substratedepletion type which is subject to diffusion-driven instability if supplemented by pure Neumann boundary conditions. We show by a degree-theoretic approach that an obstacle (e.g. a unilateral membrane) modeled in terms of inequalities, introduces new bifurcation of spatial patterns in a parameter domain where the trivial...

the cross-coupling reaction between phenylboronic acid and various types of aryl halides (suzuki reaction) was carried out using a catalytic amount of a new palladium catalyst (1-benzyl-3-(1-benzyl-1-methylpyrrolidin-1-ium-2-yl) pyridin-1-ium palladium chloride [dbnt][pdcl4]) in poly (ethylene glycol) (peg-200) in the presence of koh as the base. this new catalyst was synthesized and characteri...

3,4-dihydropyrimidinones and their derivatives are synthesized via biginelli routes involving an aromatic aldehydes, ethylacetoacetates and urea in one-pot procedure by using cds nanoparticles as efficient heterogeneous catalyst in solvent-free conditions. compared with classical biginelli reaction reported in 1893, this new method provides much improved modification in terms of simplicity. the...

Sufficient conditions for destabilizing effects of certain unilateral boundary conditions and for the existence of bifurcation points for spatial patterns to reaction-diffusion systems of the activator-inhibitor type are proved. The conditions are related with the mollification method employed to overcome difficulties connected with empty interiors of appropriate convex cones.