Novel molecular iodine catalyzed cyclization reactions of 2-amino anilines with aryl alkyl ketones under oxidant and metal-free conditions are described. The reaction likely involves sequential C–N bond formation followed by C(CO)–C(alkyl) bondcleavage. Various 2-substituted benzimidazoles are obtained in moderate to good yields in a single step from readily available acetophenones, propiophenones
Synthesis and diverse general oxidative cyclization catalysis of high-valent Mo<sup>VI</sup>O<sub>2</sub>(HL) to ubiquitous heterocycles and their chiral analogues with high selectivity
作者:Nabyendu Pramanik、Satinath Sarkar、Dipanwita Roy、Sudipto Debnath、Sukla Ghosh、Saikat Khamarui、Dilip K. Maiti
DOI:10.1039/c5ra21825j
日期:——
The first synthesis and diverse oxidative cyclization catalysis properties of high-valent MoVI–triazole are demonstrated towards highly selective construction of benzimidazoles, benzothiazoles, isoxazolines, isoxazoles and their chiral analogues.
Synthesis of Glycal-Based Chiral Benzimidazoles by VO(acac)<sub>2</sub>−CeCl<sub>3</sub> Combo Catalyst and Their Self-Aggregated Nanostructured Materials
作者:Dilip K. Maiti、Samiran Halder、Palash Pandit、Nirbhik Chatterjee、Dripta De Joarder、Nabyendu Pramanik、Yasmin Saima、Amarendra Patra、Prabir K. Maiti
DOI:10.1021/jo901458k
日期:2009.11.6
combo catalyst has been developed for chemoselective cyclocondensation cum oxidation undermild reaction conditions toward synthesis of a new class of optically pure compounds, 2-(2′-C-3′,4′,6′-tri-O-benzyl/methyl-glycal)-1H-benzimidazoles. It involves an operationally simple synthetic protocol efficient for the syntheses of a wide range of chiral benzimidazoles in high yields without formation of undesired
Vanadyl Acetylacetonate-Copper (II) Trifluoro Methane Sulfonate Catalyzed Eco-friendly Synthesis of Substituted Benzimidazoles in Aqueous Media
作者:Samiran Halder
DOI:10.13005/ojc/360413
日期:2020.8.28
Various substituted benzimidazoles have been successfully synthesized in aqueous medium by developing VO(acac)(2)-Cu(OTf)(2) catalytic system. A green synthetic protocol has been created in presence of water and cetyltrimethyl ammonium bromide (CTAB) system in an organic solvent free condition. This chemoselective cyclocondensation cumoxidation process occurred in aqueous media. In this suitable method easily synthesized 2-Substituted benzimidazoles with good yields and no 1,2-disubstituted by-products were noticed. Excellent yields, environmentally benign and mild reaction condition, easy purification of the desired products are the main attractive features of this newly devised method.[GRAPHICS]