Hormi Mecadon

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

Organocatalytic domino Knöevenagel–Michael reaction in water for the regioselective synthesis of benzo[4,5]imidazo[1,2-a]pyrimidines and pyrido[2,3-d]pyrimidin-2-amines

An organocatalyzed simple and general route towards the regioselective synthesis of benzo[4,5]imidazo[1,2-a]pyrimidines and pyrido[2,3-d]pyrimidin-2-amines is developed via L-proline catalyzed domino reaction of 2-aminobenzimidazole or 2,6-diaminopyrimidin-4-one with aldehydes and β-ketoesters in water. High yields within a shorter reaction time, simple purification, and environmentally benign mild reaction conditions are the key features that make the protocol significantly applicable.

Ni–Al2O3 as reusable heterogeneous catalyst for expedient one-pot synthesis of naphthopyrans

Ni–Al2O3 is an efficient and reusable heterogeneous catalyst for the synthesis of naphthopyrans by one-pot three-component reaction of naphthols, aldehydes, and malononitrile in EtOH/H2O (1:1) solvent medium. A comparative study of Ni–Al2O3 with neutral Al2O3 revealed that reactions with the former afforded better product yields, indicating higher catalytic efficacy. Ni–Al2O3 due to its low cost, good activity, ease of handling, and easy recovery, with high yields and simple purification method makes the procedure highly applicable.Graphical Abstract

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.

Synthesis of β-Amino Carbonyl Compounds via the Iodine-Alumina Catalyzed Three-Component Coupling Reaction under Microwave Irradiation

Iodine-alumina was employed as a catalyst in the coupling reactions of aldehydes, enolizable ketones, or 1,3-dicarbonyls with methyl carbamate or aromatic amines under microwave irradiation to afford β-amino carbonyl compounds in good-to-excellent yields. The key features of this environmentally friendly methodology are its operational simplicity, mild reaction conditions, and less reaction time.