Letters in Organic Chemistry - Volume 10, Issue 7, 2013

An efficient one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones via a three-component Biginelli condensation of aldehyde, ethyl acetoacetate, and urea or thiourea in the presence of a catalytic amount of ascorbic acid (5 mol %) is described. The reaction proceeded efficiently under solvent-free conditions at 80 °C to afford the desired products in moderate to good yields.

Coumarin derivatives were synthesized using magnetically recoverable iron oxide nanoparticles supported amino acids as heterogeneous catalysts via one-pot multi component reaction using MW irradiation. Easy recovery of the catalyst using an external magnet, efficient recycling, and reusable without significant loss of their catalytic efficiency makes the protocol greener and sustainable.

Nucleophilic addition of hydrazines and thiosemicarbazide to the 2-(2-oxoindolin-3-ylidene) malononitrile derivatives 1, followed by elimination of malononitrile, lead to 3-(2-arylhydrazono)indolin-2-ones and 1-(2-oxoindolin-3- ylidene)thiosemicarbzides respectively. Also the reaction of compounds 1 with 4-substituted thiosemicarbazides, followed by elimination and cyclization, afforded spiro(indolone-3,2´-[1,3,4]thiadiaz Read More

The reaction of 5,5-dimethylcyclohexane-1,3-dione with an acyclic nitrone in DMF or acetone affords a 1:1 mixture of dimer 2,2´-(arylmethylene)-bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) and tetramer 2,2','','''-(1,2- diarylethane-1,1,2,2-tetrayl)tetrakis(3-hydroxy-5,5-dimethyl-cyclohex-2-enone). This unprecedented type of metal-free homocoupling of two molecules of the dimer to furnish the tetramer is believed to proce Read More

One-pot three-component synthesis of benzimidazo[2,1-b]-quinazolin-1-ones was efficiently performed under microwave irradiation and solvent-free condition. The method provides some advantages such as low cost, experimental simplicity, high yields, and short reaction times. The structure of newly synthesized compounds is characterized by IR, 1H-NMR, MS and elemental analysis.

Simvastatin is used in the treatment of hypercholesterolemia as β hydroxy acid of simvastatin (BHA) which inhibits 3-hydroxy methyl glutaryl coenzyme A involved in cholesterol synthesis. The present communication deals with the development of colorimetric method for estimation of BHA through rational design of colorimetric reagent for sensitivity and selectivity enhancement. BHA is an active metabolite as well as i Read More

Three regioisomers of lactose fatty acid monoesters at positions 3', 6' and 3 and other related compounds have been chemically synthesized. The 3'- and 6'-O-palmitoyl-D-lactose derivatives were prepared via the regioselective esterification at O-3' and O-6' of the dibutylstannylene derivatives obtained from benzyl 2,3,6-tri-O-benzyl-4-O-(2,6-di-Obenzyl-β-D-galactopyranosyl)-β-D-glucopyranoside (1) and benzyl 2,3,6-tri-O-benzyl Read More

A series of novel tetrazoles (4a-k) and thiazolidinones (6a-k) appended to 2-aryl-1,2,4-triazolin-3-ones were efficiently synthesized from 3-arylsydnones (1a-k) in excellent yields using Zinc triflate as catalyst.

A robust approach for the synthesis of five and six member sultam is achieved employing commercially available starting materials and reagents. The use of simplest reactions without any critical parameter is the key strength of this route applicable on large scale synthesis.

A new method for the synthesis of aryl nitriles has been developed by the cyanation of aryl bromides in the presence of the Pd(0) nanoparticles stabilized by collagen fibers as a highly active, air-stable and recyclable heterogeneous catalyst. This method has the advantages of high yields, simple methodology and easy work-up. The catalyst was recovered and reused several times without the significant loss of its catalytic p Read More

Nano CoFe2O4 is found to be efficient catalyst for synthesis of 1-substituted 1H-1,2,3,4-tetrazoles under solvent- free conditions. The significant advantages of this methodology are high yields, elimination of dangerous and harmful hydrazoic acid and simple work-up procedure. The catalyst was easily isolated from the reaction mixture by magnetic decantation using an external magnet and reused with no significant loss in its reactivity.

Formamides were efficiently synthesized from N-formylation of amines using CoFe2O4 nanoparticles as a magnetically recoverable and reusable catalyst under ultrasound irradiation. The main advantages allocated to this method are chemoselectivity, reduced reaction times, high yields, magnetically recyclable catalyst, non-solvent green conditions and simple work-up procedure.

The fluorescent D-glucose derivative, 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-β-Dglucopyranose (2-NBDG) is synthesized by reacting D-glucosamine with inexpensive 7-nitro-2,1,3-benzoxadiazol-4-yl chloride (NBD-Cl). A series of reaction conditions such as reaction time, bases, the loading of bases, solvents and reaction temperature has been investigated. The yield of 2-NBDG can be enhanced to 83.0% under the o Read More