Bekington Myrboh

Polarized ketene dithioacetals. 28. A new general highly stereoselective and regiospecific method for homologation of ketones to .alpha.,.beta.-unsaturated esters via .alpha.-oxoketene dithioacetals

A partir de cetones a methylene actif, obtention des esters methyliques des acides cinnamique, crotonique cyclopentene-1 et cyclohexene-1 carboxylique, dihydro-3,4 naphtoique-2 et thiocinnamique

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 Developments in Functionalized Pyrano[2,3-c]pyrazoles. A Review

Introduction ................................................................................. 254 I. General Types and Structure of Pyranopyrazoles .......................... 255 II. Modes of Pyrano[2,3-c]pyrazole Synthesis..................................... 255 III. Two-component Synthesis of Pyrano[2,3-c]pyrazoles..................... 256 IV. Three-component Synthesis of Pyrano[2,3-c]pyrazoles .................. 276 V. Four-component Synthesis of Pyrano[2,3-c]pyrazoles .................... 292 Acknowledgment .......................................................................... 299 References .................................................................................... 299

A facile one-step synthesis of β, γ-Unsaturated carboxylic acid esters via 1,2-carbonyl transpositions of α,β-unsaturated ketones

Abstract Reaction of α,β-unsaturated ketone, 1 , with lead(IV)acetate and borontrifluoride etherate in the presence of methanol yielded the β, γ-unsaturated esters, 2 , in a single step procedure, at room temperature.

Favorski Type Rearrangement in the Lead Tetraacetate Oxidation of Cycloalkanones

Abstract The cycloalkanones (1a-lf) have been converted into their corresponding cycloalkane carboxylates (2a-2f) by a lead (IV) acetate promoted rearrangement in presence of perchloric acid in triethyl orthoformate.

L-Proline as an efficient enantioinduction organo-catalyst in the solvent-free synthesis of pyrazolo[3,4-b]quinoline derivatives via one-pot multi-component reaction

The role of L-proline as an efficient organo-catalyst for the three-component synthesis of pyrazoloquinolinones involving dimedone, 3-methyl-1H-pyrazol-5-amine and various aryl aldehydes under mild solvent-free condition is reported. Besides the several advantages offered by this method such as its generality, simplicity, high yields and environment friendly reaction, the most notable is the ability of the catalyst to influence asymmetric induction in the reaction. Interestingly, it was observed that in addition to being an efficient catalyst, L-proline also imparted enantioselectivity in the synthesised pyrazoloquinolinones derivatives.

Synthesis of Diaryl Methanes by Friedel-Craft Condensation of Benzalazines with Aromatic Hydrocarbons

Abstract The Friedel-Craft condensation between benzalazines and aromatic hydrocarbons provide a convenient method for the preparation of unsymmetrical diaryl methanes.

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.

Potassium Hydroxide Impregnated Alumina (KOH-Alumina) as a Recyclable Catalyst for the Solvent-Free Multicomponent Synthesis of Highly Functionalized Substituted Pyridazines and/or Substituted Pyridazin-3(2H)-ones under Microwave Irradiation

The work described herein employs potassium hydroxide impregnated alumina (KOH-alumina) as a mild, efficient, and recyclable catalyst for a one-pot solvent-free and environmentally safer synthesis of 3,4,6-triarylpyridazines and some substituted pyridazines from active methylene carbonyl species, 1,2-dicarbonyls, and hydrazine hydrate by microwave (MW) irradiation. The method offers highly convergent, inexpensive, and functionality-tolerable procedure for rapid access to important pyridazine compounds in good yields.

NOVEL ONE POT SYNTHESIS OF SUBSTITUTED 1, 2, 4-TRIAZINES

Substituted-1, 2, 4-triazines were conveniently prepared in one pot by the condensat ion of amides and 1,2-diketones in presence of base, fol lowed by cyclisation with hydrazine hydrate.