One-pot tandem approach for the synthesis of benzimidazoles and benzothiazoles from alcohols

Synthesis of 2-aryl substituted 2,3-dihydroquinazoline-4(1H)-ones under solvent free conditions using ionic liquid as a mild and efficient catalyst

“…In continuation numbers of our efforts in the development of novel, environ-friendly and synthetic methodologies [26][27][28][29][30][31][32][33], we report here a mild and efficient one-pot protocol for the synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives by two component reactions catalysed by ionic liquid under mild condition (Scheme 1). The reaction when tried with different aldehydes, diverse functional groups played significant roles in achieving the product yield.…”

Synthesis, Biological Activity and Recent Advancement of Benzothiazoles: A Classical Review

“…Onepot tandem approach was reported by Rangappa and co-workers for synthesis of benzothiazole in excellent yields, using variety of alcohols and o-aminothiophenol without any oxidant (Fig 42). [60] This process includes oxidation of alcohols to aldehydes followed by cyclization with o-aminothiophenol and finally propylphosphonic anhydride (T 3 P) mediated dehydrogenationunder mild reaction conditions (0-25°C). Closer look to the scope of reaction depicts that the reaction of o-aminothiophenol with variety of aromatic, aliphatic and heterocyclic substituents reacts well under these optimized reaction conditions and provides access to high yield of the product.…”

An Efficient and Green Synthesis of Benzimidazole Derivatives Using SBA-15 Supported Cobalt Nanocatalysts

“…nitrobenzene, 1,4-benzoquinone, air, heteropoly acids, MnO 2 , Pb(OAc) 4 , H 2 O 2 /HCl etc.). An alternative protocol for the synthesis of benzimidazoles is the one-pot tandem synthesis from alcohols in the presence of bifunctional catalysts, where alcohols are in situ oxidized to aldehydes followed by cyclocondensation with amine compounds [12][13][14]. However, multistep processes, drastic reaction conditions, tedious work-up procedures and low yields are among major drawbacks of these methods.…”