Rishanlang Nongkhlaw

Reaction of selenium dioxide with aromatic ketones in the presence of boron triflouride etherate: a protocol for the synthesis of triarylethanones.

An efficient regioselective protocol for the C-C bond formation by the unexpected α,α-diarylation of aromatic ketones with unactivated arenes in the presence of selenium dioxide and boron trifluoride etherate has been developed. The generality and functional tolerance of this protocol is demonstrated by the synthesis of a series of triarylethanones.

Synthetic, mechanistic and kinetic studies on the organo-nanocatalyzed synthesis of oxygen and nitrogen containing spiro compounds under ultrasonic conditions

A novel class of organo-nanocatalysts was fabricated by encapsulating magnetic Fe2O3@SiO2 nanoparticles with thiamine hydrochloride. Its catalytic application in the synthesis of oxygen and nitrogen containing spiro heterocycles via ultrasonication was thoroughly investigated. The synthetic protocol was found to be efficient, economical and green. The prepared catalyst was characterised by TEM, SEM, EDS, powder XRD, VSM, FT-IR, TGA, DTA, etc. Mechanistic and kinetic studies for the organic transformations were also carried out to determine the catalytic role of thiamine hydrochloride using a computational method viz. DFT: B3LYP.

KHSO4-Assisted Michael Addition–Elimination Reactions of Indole with 3-Dimethylamino-1-phenylprop-2-en-1-ones in Water: An Environmentally Friendly Synthesis of Novel 3-Indolylchalcones

Abstract KHSO4-assisted Michael addition–elimination reactions of 2-methylindoles and 1,2-dimethylindoles with 3-dimethylamino-1-phenylprop-2-en-1-ones (2) in water, leading to the formation of 3-(2-methyl-1H-indol-3-yl)-1-arylpropenones (3a–e) and 3-(1,2-dimethy-1H-lindol-3-yl)-1-arylpropenones (3f–j) respectively in good to excellent yields have been reported. However, cyclodehydration of adducts 3a–f to give carbazoles 4 failed to take place under the reaction conditions. Supplemental materials are available for this article. Go to the publishers online edition of Synthetic Communications® to view the free supplemental file. GRAPHICAL ABSTRACT

Nickel nanoparticles assisted regioselective synthesis of pyrazoloquinolinone and triazoloquinazolinone derivatives

Biologically important pyrazoloquinolinone and triazoloquinazolinone derivatives were synthesized by the condensation reaction of 3-amino-1H-1,2,4-triazole/3-amino-5-methyl-1H-pyrazole, dimedone and aryl aldehydes using catalytic amount of magnetically retrievable nickel nanoparticles under reflux condition. This protocol eliminates the usage of toxic reagents, complex work-up conditions, etc., with the added benefit of reusability of the catalyst without compromising the yield or purity of the product.

A nano-organo catalyzed route towards the efficient synthesis of benzo[b]pyran derivatives under ultrasonic irradiation

An efficient, one-pot synthesis of benzo[b]pyrans catalyzed by vitamin B1 functionalized Fe2O3@SiO2 NPs under ultrasonic conditions is reported herein. The nano-organocatalyst was synthesized and characterized by FT-IR, TEM, EDS, powder XRD, etc. Several benzo[b]pyran derivatives were prepared with satisfactory yields and the nanocatalyst was magnetically retrieved and recycled. The salient features of this protocol include convenient work-up procedure, mild reaction conditions, easy catalyst recovery, shorter reaction time and use of green solvents. Ultrasound energy has been meticulously exploited for the synthesis of a nano-organocatalyst as well as for the preparation of several benzo[b]pyran derivatives. The biological activity of the synthesized benzo[b]pyrans were investigated and one of the derivatives was found to demonstrate profound activity in suppressing the side-effects of chlorpyrifos, an insecticide on the morphology of the external gills of the Duttaphrynus melanostictus tadpoles.

Experimental and theoretical studies on SPION@glutathione catalyzed synthesis of indolyl chromene, indolo xanthene, and pyrimido[4,5-b]quinoline

ABSTRACT The potential of glutathione as a catalyst for carbon–oxygen ring cyclization was investigated experimentally as well as computationally. The glutathione molecules were immobilized on superparamagnetic iron-oxide nanoparticle so as to improve the efficiency of the catalyst and to augment magnetically aided recyclability. Ultrasound was also exploited for thorough dispersion of the nanoparticles in the aqueous medium so that contact between the catalyst and the reactants are enhanced. This nano-organocatalyst was synthesized and characterized by the following analytical techniques: TEM, scanning electron microscope, EDS, powder X-ray diffraction, vibrating sample magnetometry, FTIR, TGA, DTA. Its catalytic prowess in the synthesis of several indolyl chromenes, pyrrolyl chromenes, and indoloxanthenes were meticulously investigated. The synthetic protocol was found to be efficient, economical, and environment benign. Quantum chemical studies were performed to study the effect of the catalyst on C–O ring cyclization using Gaussian program viz. B3LYP. GRAPHICAL ABSTRACT

UV365 light promoted catalyst-free synthesis of pyrimido[4,5-b]quinoline-2,4-diones in aqueous-glycerol medium

Herein, a highly efficient and environmentally benign protocol for the synthesis of biologically important pyrimido[4,5-b]quinolinone-2,4-diones from aromatic amines, barbituric acid and aryl aldehyde is reported. This process takes place at room temperature under direct irradiation from a UV365 light source in the absence of a photocatalyst. The reported approach has several advantages such as high yield, clean reaction conditions, chromatography-free synthesis and the use of a cheap water–glycerol solvent system, which is also an environmentally friendly solvent. The applicability of this protocol for the large-scale synthesis of pyrimido[4,5-b]quinolinone-2,4-diones without wasting any expensive chemicals is an added advantage.