efficient and chemoselective protection of aldehydes to the corresponding dimethyl acetals have been carried out by mixture of trimethyl orthoformate and methanol in the presence of a catalytic amount of tmscl or alcl3 under microwave irradiation. under these conditions, acetalization of ketones does not take place and they remain intact under reaction conditions. the results are compared with ...

the direct three component modified mannich reaction via condensation of aldehydes, 2-naphthol or 2,7-naphthalendiol and piperidine to generate betti bases has been carried out over l-proline (20 mol%) with high efficiency under solvent free conditions at 70 oc. also, the reaction of aromatic aldehyde and 4-hydroxycoumarin in the presence of l-proline (20 mol%) in the ethanol under reflux condi...

one-pot preparation of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles has been conducted in the presence of poly(4-vinylpyridinium butane sulfonic acid) hydrogen sulfate, p(4vpbsa)hso4, as an efficient dual acidic catalyst under solvent-free conditions. reusability of the catalyst, easy work-up procedure, eco-friendly reaction conditions, short reaction times and high yields of th...

The three components one pot synthesis of 2-amino-4H-benzo-[b] -pyran derivatives were obtained in good to excellent yields within short reaction time by condensing dimedone, aldehydes and malanonitrile or ethylcyanoacetate using a catalytic amount of (diacetoxyiodo)benzene as hypervalent iodine in aqueous ethanol under reflux conditions have been discussed. This aqua mediated Knoevenagel-cyclo...

An efficient and simple one-pot approach for the synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives using antimony trichloride (SbCl3) as a mild catalyst by means of three-component Biginelli reaction between β-keto esters, aldehyde derivatives and urea/thiourea under thermal and solvent-free conditions with excellent yields and short reaction times is reported. This m...

The condensation of benzylamine with glyoxal leads to Hexabenzylhexaazaisowurtzitane (HBIW) in acetonitrile solvent with citric acid as a green catalyst under both conventional stirring and ultrasonic irradiation conditions. The influence of four variables, including the amount of catalyst, solvent, reaction time and ultrasonic power, on the reaction yield was investigated. The results showed t...

enzymatic acidolysis of canola oil through caprylic and capric acids was investigated for making structured lipids. lipozyme tl im, an sn-1,3 specific thermomyce slanuginosa lipase, was utilized as the biocatalyst in the batch reactor. reaction conditions were designed according to taguchi’s method considering fatty acid to oil ratio, at three levels (1:1, 2:1, 3:1) , enzyme load (4, 8 and, 12%...

The purpose of this research work was to investigate the optimum operating conditions for biodiesel production from castor oil using a microwave. The Box–Behnken design of experiment was carried out using the Design Expert 7. A response surface methodology (RSM) was used to analyze the influence of the process variables (molar ratio of methanol to castor oil, catalyst concentration, reaction ti...