One-pot four-component synthesis of some novel octahydroquinolindiones using ZnO as an efficient catalyst in water

ZnO has been shown to be an inexpensive, efficient, readily available, and mild catalyst for a one-pot fourcomponent synthesis of some novel octahydroquinolindione-3-carboxylic acid ethyl esters using diethylmalonate, dimedone, ammonium acetate, and appropriate aromatic aldehydes in water at reflux. ZnO acts as a recyclable heterogeneous catalyst to afford the products in excellent yield in short reaction duration. © 2012 Elsevier Ltd. All rights reserved

An efficient and simple approach for the synthesis of pyranopyrazoles using imidazole (catalytic) in aqueous medium, and the vibrational spectroscopic studies on 6-amino-4-(4′-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazole using density functional theory

We describe a one-pot four component synthesis of pyranopyroles from aryl aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of catalytic amounts of an organocatalyst imidazole in water as medium. A plausible mechanism for the formation of imidazole catalyzed pyranopyrazoles has been envisaged. This method is rapid, simple, provides products in good yield, and is eco-friendly. In addition, based on the optimized geometry, the frequency and intensity of the vibrational bands of 6-amino-4-(4′-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazole were obtained by the density functional theory (DFT) calculations using 6-31G(d,p) basis set. The vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement

An efficient sonochemical oxidation of benzyl alcohols into benzaldehydes by FeCl3/HNO3 in acetone

Sonochemical oxidation of benzyl alcohols into corresponding aldehydes by FeCl3/HNO3 in acetone at room temperature has been reported. All substrates give good yield of the products within 10-25 min. The reaction of selected substrates were also studied under reflux and at the room temperature. Further, various Lewis acids were used to evaluate their catalytic efficacy. © 2011 Elsevier B.V. All rights reserved

Nuclear magnetic resonance, vibrational spectroscopic studies, physico-chemical properties and computational calculations on (nitrophenyl) octahydroquinolindiones by DFT method

In the present study, 2′-nitrophenyloctahydroquinolinedione and its 3′-nitrophenyl isomer were synthesized and characterized by FT-IR, FT-Raman, 1H NMR and 13C NMR spectroscopy. The molecular geometry, vibrational frequencies, 1H and 13C NMR chemical shift values of the synthesized compounds in the ground state have been calculated by using the density functional theory (DFT) method with the 6-311++G (d,p) basis set and compared with the experimental data. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution using GAR2PED programme. Isotropic chemical shifts for 1H and 13C NMR were calculated using gauge-invariant atomic orbital (GIAO) method. The experimental vibrational frequencies, 1H and 13C NMR chemical shift values were found to be in good agreement with the theoretical values. On the basis of vibrational analysis, molecular electrostatic potential and the standard thermodynamic functions have been investigated

Ultrasound-assisted, one-pot, four-component synthesis of 1,4,6,8-tetrahydroquinolines in aqueous medium

A series of 2-amino-3-cyano-4-aryl-5-oxo-7,7-dimethyl-1,4,6,8- tetrahydroquinolines were prepared by a one-pot, four-component condensation of aromatic aldehydes, dimedone, malononitrile, and ammonium acetate using K 2CO3 as a catalyst in aqueous medium under sonic conditions. This protocol, being a single-step reaction, has the advantages of operational simplicity and minimal environmental impact. The synthesized compounds were confirmed through spectral characterization using infrared, 1H NMR, 13C NMR, and CHN analysis. Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details. © 2014 Copyright Taylor and Francis Group, LLC

SiO 2-NaHSO 4 as an efficient reusable heterogeneous catalyst for the one-pot three-component synthesis of octahydro-quinazolin-2, 5-diones in water

An environmentally benign method for the synthesis of octahydro-quinazolin-2, 5-diones by the reaction of aromatic aldehydes, dimedone, and urea in the presence of SiO 2-NaHSO 4 is reported. SiO 2-NaHSO 4 acts as an efficient, mild, and recyclable heterogeneous catalyst to give excellent yields within a short reaction time in water at 60-80°C