Letters in Organic Chemistry - Volume 9, Issue 2, 2012

Optically active oxetane and cis-but-2-ene-1,4-diol derivatives were used as starting materials in the synthesis of novel five membered heteorcyclic compounds as dihydrofuran and pyrroline derivatives. In addition, new 2,4- disubstituted dioxolane was synthesized diastereoselectively from the diol and the structure of the product was confirmed by NOESY (Nuclear Overhauser Effect Spectroscopy) experiments. Reductive ring o Read More

New, optically active ligands derived from imidazole were tested in the cyclopropanation reaction of styrene using ethyl diazoacetate and copper(I) triflate as a catalyst.

The A ring-expanded derivative of ursolic acid and the corresponding fragmentation product were obtained through the Beckmann rearrangement under optimized reaction conditions. A mechanistic approach was taken in order to explain both the specificity of the rearrangement and the fragmentation of the cycle. The intermediates and the final products of the route were evaluated for antimalarial activity.

1,3-Dipolar cycloadditions of aryl nitrile oxides 2d-f to various racemic 3-hydroxy- and 3-acyloxy-but-1-enes 1a-c proceeded with complete regioselectivity to afford the corresponding 3,5-disubstituted isoxazolines in good yields. The steric and/or electronic effect of an acyloxy group at the allylic position on the stereoselectivity has been studied.

Multicomponent reaction involving isatin (1), malononitrile (2), and dimedone (3), in the presence of triphenylphosphine as an efficient catalyst in the eco-friendly solvent ethanol, results in the formation of spirooxindole derivatives 4 i.e 2-Amino-5-oxo-7,7-dimethyl spiro[(4H)-5,6,7,8-tetrahydrochromene-4,3-(3H)-indol]-(10H)-2-onecarbonitrile. The reaction proceeds smoothly under mild conditions and the products ar Read More

Oligonucleotide analogs with L- and D-lysine residues incorporated in internucleotide linkages were synthesized and their affinity toward complementary DNA was studied. Stability of the duplexes formed by the modified oligonucleotides and their wild-type complements appeared to be close to that of the isosequential unmodified duplex, oligonucleotides carrying D-lysine residues forming generally more stable duple Read More

The new simple method of synthesis of tripodal esters, building blocks for monomacrocyclic pendant macrocycles and bicyclic cryptands is reported. Six new tripodal esters, derivatives of hydroxybenzoic acids were prepared and characterized, and their reaction with tris(2-aminoethyl)amine carried under high pressure conditions was studied using Electrospray Ion Mass Spectrometry

Microwave assisted solid phase synthesis of imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrimidines by the treatment of polymer-bound α-bromoketone with various 2-aminopyridines or 2-aminopyrimidines was achieved. Functionalizations of the 3-positions were realized by the treatment of polymer-bound 3-iodoimidazo[1,2-a]pyridine or polymer-bound 3-iodoimidazo[1,2-a]pyrimidine with various boronic acids u Read More

Tetrakis(acetonitrile)copper(I) hexafluorophosphate, [Cu(CH3CN)4]PF6, was explored as an efficient catalyst to promote the three-component reaction of aryl aldehydes, dimedone and urazole or phthalhydrazide to afford the corresponding triazolo[1,2-a]indazole-1,3,8-trione and 2H-indazolo[2,1-b]phthalazine-trione derivatives respectively in high yields. The reactions were conducted at 80-100 °C under solvent-free c Read More

Copper-catalyzed nitration of arylboronic acids has been developed with nitrite salts as nitrating agent under mild conditions. This process provides an efficient and practical method for the synthesis of nitro aromatics, due to its simple experimental procedure and its use of convenient and inexpensive copper catalyst.

In the present study, we introduce two nonconventional ionic liquids [MIMPS]3PW12O40 (a) and [TEAPS]3PW12O40 (b) as green solid acid catalysts for the efficient synthesis of bis(indolyl)methanes. The reaction of indole with aldehydes or ketones in water afforded the corresponding bis(indolyl)methanes in excellent yields. This reaction has been carried out in the presence of 1 mol% of catalysts at room temperature. Read More

An efficient synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one derivatives via the three-component condensation of aromatic aldehyde, 2-naphthol and 5,5-dimethyl-1,3-cyclohexanedione was carried out in 72- 85% yields at 80 °C under solvent free condition using silica sulfuric acid (SSA) as catalyst.

The 1:1 reactive intermediates generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates were trapped by 4-hydroxy quinoline to yield highly functionalized 1-azabuta-1,3-dienes