Facile and versatile procedures have been explored for the synthesis of tetrahydropyridines and 2,3-dihydroquinazolin-4(1H)-ones. These protocols employ the one-pot multi-component condensation of arylaldehydes and aromatic amines with β-keto esters and isatoic anhydride in chloroacetic acid, respectively. The reactions proceeded smoothly to generate the corresponding products in high yield. We have found that the use of chloroacetic acid as catalyst results in a remarkable beneficial effect on the reaction, allowing it to be performed without the need of any co-catalyst, which is the case in other similar reported methodologies. In addition, the preparation of 2,3-dihydro-4(1H)-quinazolinones derivatives from the reaction of arylaldehydes and anthranilamide in the presence of mentioned catalyst is reported. پرونده مقاله

FeCl3.6H2O was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in EtOH at room temperature. The remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. The structures of all compounds were characterized by comparison of their IR and NMR spectra with authentic samples. Also, the relative stereochemistry of these piperidines has been confirmed by single X-ray crystallography analysis in previously reported literature. Starting materials with electron-deficient or electron-releasing groups were reacted efficiently. پرونده مقاله

Na2SO4 as an inexpensive and effective catalyst has provided a green protocol for the synthesis of tetrahydrobenzo[b]pyran, pyrano[2,3-d]pyrimidinone and dihydropyrano[3,2c]chromene derivatives from the three-component domino reaction of aromatic aldehydes and malononitrile with 4-hydroxycoumarin/ dimedone/ barbituric acid in ethanol/water as a mixture of solvent that, this mixture entirely is green solvent. Products could simply be separated from the catalyst. Using neutral and mild conditions, short reaction time, environmentally benign procedure, high to excellent yields of the products and easy work-up without using column chromatography are the advantages of this method. By virtue of these advantages, sodium sulfate can be used as catalyst in the organic transformations. پرونده مقاله

Acetic acid has been applied as an efficient catalyst and a green solvent for the two–component condensation reaction consisting of benzaldehyde, 2-amino-benzamide. The advantages of this protocol was excellent yield, short reaction time, mild reaction conditions, higher availability, low costs, more environmentally friendly, lack of need for column chromatography and simple work-up procedure. In addition, based on the spectral data, the partial order with respect to each reactant was one. Furthermore, useful information regarding the mechanism of the reaction was obtained from studies of the effect of solvent, concentration and catalyst on the rate of the reaction. The results showed that the first step of the mechanism was a rate-determining step. In the studied temperature range, the second order rate constant (lnk1, lnk1/T) depended on reciprocal temperature was in good agreement with the Arrhenius and Eyring equations. These data provided the suitable plots for calculating the activation energy (Ea = 52.80 kJmol-1) and the related kinetic parameters (ΔG‡ = 63.74 kJmol-1, ΔS‡ = -54.22 Jmol-1 and ΔH‡ = 50.28 kJmol-1) of the reaction. پرونده مقاله