Showing papers by "Rajendra P. Pawar published in 2013"
TL;DR: In this paper, an efficient synthesis of 2-amino-4H-chromene derivatives is achieved via one pot three component coupling reaction of aromatic aldehyde, active methylene compound and activated phenol in presence of silica gel supported polyamine heterogeneous catalyst.
Abstract: An efficient synthesis of 2-amino-4H-chromene derivatives is achieved via one pot three component coupling reaction of aromatic aldehyde, active methylene compound and activated phenol in presence of silica gel supported polyamine heterogeneous catalyst. The catalyst is easily prepared, highly stable, simple to handle and recycled for several times without significant loss of activity.
36 citations
TL;DR: An efficient zinc oxide nanoparticle catalyzed one-pot, four-component synthesis of 6-amino-3-methyl-5-cyano-4-aryl-1,4-dihydropyrano[2,3-c]pyrazoles from aromatic aldehyde, malononitrile, ethyl acetoacetate, and hydrazine hydrate in aqueous medium is described in this article.
Abstract: An efficient zinc oxide nanoparticle catalyzed one-pot, four-component synthesis of 6-amino-3-methyl-5-cyano-4-aryl-1,4-dihydropyrano[2,3-c]pyrazoles from aromatic aldehyde, malononitrile, ethyl acetoacetate, and hydrazine hydrate in aqueous medium is described. Since water was employed as the reaction medium, it serves as a green route for the synthesis of pyrano[2,3-c]pyrazoles. The advantages associated with the present protocol include nonchromatographic purification technique, use of recyclable heterogeneous nano-ZnO catalyst in aqueous medium, and short reaction time. It combines successfully the synergistic effect of green chemistry with nanocatalysis.
35 citations
TL;DR: An efficient and high-yielding protocol using nano-ZnO (50-100nm) as an efficient heterogeneous catalyst for one-pot three-component synthesis of pharmacologically significant furanone derivatives by the condensation of aromatic aldehyde, amine and dimethylacetylenedicarboxylate has been developed as mentioned in this paper.
Abstract: An efficient and high-yielding protocol using nano-ZnO (50–100 nm) as an efficient heterogeneous catalyst for one-pot three-component synthesis of pharmacologically significant furanone derivatives by the condensation of aromatic aldehyde, amine and dimethylacetylenedicarboxylate has been developed. Since the catalyst is heterogeneous, it can be easily separated and recycled several times without much loss of its catalytic activity. Use of aqueous medium, recyclable nanocatalyst, operational simplicity, non-chromatographic purification technique, excellent yield and short reaction time makes this approach an attractive protocol for the synthesis of 3,4,5-trisubstituted furan-2(5H)-ones.
19 citations
TL;DR: The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5- d ]pyrimidine-2,7(1 H,3 H )-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst.
13 citations
TL;DR: In this paper, a novel route for the synthesis of tetrahydroimidazo [1,2-a] pyrimidine-6-carboxylate derivatives in presence of 1-ethyl-3-methyl imidazolium hydrogen sulphate ionic liquid at room temperature has been reported via Biginelli reaction.
Abstract: A novel route for the synthesis of tetrahydroimidazo [1,2-a] pyrimidine-6-carboxylate derivatives in presence of 1-ethyl-3-methyl imidazolium hydrogen sulphate ionic liquid at room temperature has been reported via Biginelli reac-tion. The process offer several advantages such as short reaction time, excellent yield of products, simple work up proce-dure etc. 1-ethyl-3-methyl imidazolium hydrogen sulphate ionic liquid is utilized as solvent system and catalyst to en-hance the rate of reactions. Keywords: Aromatic aldehydes, Biginelli reaction, Catalyst, Ionic liquid, 5-amino-4,5-dihydro-1 H -pyrazole-4-carbonitrile. INTRODUCTION 3, 4-Dihydropyrimidine-2-(1 H )-ones and their deriva-tives are pharmacologically important because of having several potential biological activities including, antiviral, antibacterial, antitumor and antihypertensive agents. Fur-thermore, these compounds have emerged as the integral backbone of certain calcium channel blockers [1 - 6]. Recently to improve and modify the process, various syn-thetic methodologies for the preparation of such compounds have been developed using microwave irradiation [7-11], by using Lewis and Bronsted acids FeCl
9 citations
TL;DR: In this article, the catalytic utility of micron particulate aluminium nitride (AlN/Al) as a reusable heterogeneous catalyst for the synthesis of bis(indolyl)methanes involving the electrophilic substitution of indoles on aldehydes was investigated.
8 citations
TL;DR: In this article, a facile and green one pot four component synthesis of polyhydroquinoline derivatives from aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of ferrite composite catalyst has been reported under microwave irradiation.
Abstract: A facile and green one pot four component synthesis of polyhydroquinoline derivatives from aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of ferrite composite catalyst has been reported under microwave irradiation. The method offers excellent yield of products in short reaction time.
7 citations
TL;DR: In this article, the application of micron-particulate crystalline hexagonal aluminium nitride/aluminium as a novel, mild acidic and reusable solid heterogeneous catalyst in organic synthesis was reported.
Abstract: The present work reports the application of micron-particulate crystalline hexagonal aluminium nitride/aluminium as a novel, mild acidic and reusable solid heterogeneous catalyst in organic synthesis. The catalyst was synthesized by thermal plasma technique and characterized using X-ray diffractometer and scanning electron microscopy. It catalyzes efficiently many organic transformations such as the synthesis of heterocyclic compounds 2,4,5-triaryl-substituted imidazoles and 2-aryl benzimidazoles.
6 citations
TL;DR: In this article, an efficient, environmentally benign, highly facile and convenient synthetic protocol for the selective t-butyl carboxylation of aliphatic, aromatic and heterocyclic amines using AmberlystR A 21 catalyst; a mild basic solid resin under solvent free conditions is reported.
Abstract: An efficient, environmentally benign, highly facile and convenient synthetic protocol for the selective t-butyl carboxylation of aliphatic, aromatic and heterocyclic amines using AmberlystR A 21 catalyst; a mild basic solid resin under solvent free conditions is reported. This method explores several advantages such as reusability of the heterogeneous catalyst, cleaner reaction profile, mild and solvent free system, short reaction time, operational simplicity, high conversions , excellent product yields and low cost of the catalyst. Furthermore since the catalyst is mild basic, decomposition of the carbamate formed is not observed if the reaction is continued for prolonged time as in the case of Lewis acid catalyzed N-Boc protection. This makes the present protocol a useful and attractive for N-Boc protection of amines.
2 citations
01 Jan 2013
TL;DR: In this paper, the authors have synthesized some novel Isoxazoline with help of chalcones and hydroxylamine hydrochloride in glacial acetic acid by conventional method.
Abstract: Over the past 20 years, Isoxazoline have seen a vast increase in their use, both as intermediates in the synthesis of natural and unnatural products and as bioisosteric functionalities in medicinal compounds. Here we have synthesized some novel Isoxazoline with help of chalcones and hydroxylamine hydrochloride in glacial acetic acid by conventional method. The synthesized compounds were characterized by IR, 1 H NMR and Mass spectra.
1 citations
TL;DR: Eaton's reagent efficiently catalyzed the Claisen-Schmidt condensation reaction of aryl aldehydes with aromatic as well as cyclic ketones under solvent-free microwave irradiation conditions as discussed by the authors.
Abstract: Eaton′s reagent efficiently catalyzed the Claisen—Schmidt condensation reaction of aryl aldehydes with aromatic as well as cyclic ketones under solvent-free microwave irradiation conditions.