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An efficient one-pot synthesis of 1,2-disubstituted benzimidazoles was developed via cyclocondensation starting from o-phenylenediamine with substituted aromatic aldehydes using catalyst vitamin B1 under ultrasound-assisted, and was characterized by HR-MS, FT-IR, 1H and 13C NMR spectroscopy. N-Ts-substituted 1,2-disubstituted benzimidazoles were formed when 2 equivalents of p-toluenesulfonic acid were added to the reaction. The reaction conditions of the method are environmentally friendly, no metal is required, the operation is simple, the substrates are extensive, the yield is high, and the catalyst is non-toxic and reusable. The crystal structure of compound 1-(2-methoxybenzyl)-2-(2-methoxyphenyl)-1H-benzoimidazole (3ab) in triclinic P21/n space group is presented. 4-(1-(2,3,4-Trihydroxybenzyl)-1H-benzoimidazol-2- yl)benzene-1,2,3-triol (3af) as a metal ion fluorescent probe, has excellent selectivity to Pb2+ and Ag+, and exhibits obvious discoloration. An efficient one-pot synthesis of 1,2-disubstituted benzimidazoles was developed via cyclocondensation starting from o-phenylenediamine with substituted aromatic aldehydes using catalyst vitamin B1 under ultrasound-assisted, and were characterized by HR-MS, FT-IR, 1H and 13C NMR spectroscopy. N-Ts-substituted 1,2-disubstituted benzimidazoles were formed when 2 equivalents of p-toluenesulfonic acid was added to the reaction. The crystal structure of compound 1-(2-methoxybenzyl)-2-(2-methoxyphenyl)-1H-benzoimidazole (3ab) in triclinic P21/n space group was presented. [ABSTRACT FROM AUTHOR]

TAIm[I] ionic liquid was used as a suitable medium for microwave- and ultrasound-assisted preparation of 1-substituted-1H-1,2,3,4-tetrazoles as well as 5-substituted 1H-tetrazoles under environmentally friendly conditions. In the presence of N3− ion, TAIm[N3] active species, were responsible for the progress of the reactions under microwave as well as ultrasonic irradiation. High to excellent yields were obtained for a variety of aldehyde and nitrile substrates toward the synthesis of 5-substituted 1H-tetazole. Also, 1-substituted 1H-1,2,3,4-tetrazoles were prepared from amine precursor under these conditions with high to excellent efficiencies. The TAIm[I] ionic liquid could be recycled from the homogenous mixture for at least six consecutive cycles without any activity loss. The present method suggests a catalyst-free, solvent-free, cost-effective and environmentally friendly protocol for the synthesis of a wide variety of tetrazole derivatives. TAIm[I] ionic liquid was utilized for the efficient preparation of 5- and 1-substituted tetrazoles under ultrasonic and microwave via a catalyst-free and solvent-free method [ABSTRACT FROM AUTHOR]

Two powerful methods for the synthesis of indole-based chalcone derivatives, namely ( E)-1-(2-chloro-1-(4-chlorobenzyl)-1 H-indol-3-yl)-3-aryl(hetaryl)prop-2-en-1-ones ( 3a- l), are described, involving the ultrasound-assisted or solvent-free Claisen-Schmidt condensation reaction of 3-acetyl-2-chloro-1-(4-chlorobenzyl)indole ( 1) and various aromatic aldehydes ( 2a- l). The ultrasound-assisted Claisen-Schmidt condensation reaction was carried out using 1,4-dioxane as solvent and KOH as base at room temperature to give the corresponding products ( 3a- l) in yields ranging from 75 to 88 %. Alternatively, the Claisen-Schmidt condensation reaction could also be conducted under solvent-free conditions to obtain the products ( 3a- l) in comparable yields. The two procedures offer easy access to indole-based chalcone derivatives in short reaction times and good yields under mild conditions. Particularly, the advantageous aspect of the solvent-free method could avoid the use of environmentally hazardous and toxic solvents, and also reduced costs. The structures of all the newly synthesized indole-based chalcones 3a- l were confirmed by spectral data and elemental analyses. [ABSTRACT FROM AUTHOR]

A facile synthesis of hitherto unreported benzofuran-2-yl(9-methyl-9 H-carbazol-3-yl)methanones ( 3a- l) is described. The synthesis mainly relies on the ultrasound-assisted Rap-Stoermer reaction of 3-chloroacetyl-9-methyl-9 H-carbazole ( 1) with a variety of salicylaldehydes, as well as 2-hydroxy-1-naphthaldehyde ( 2) in CHCN, with the presence of PEG-400 as a catalyst. This procedure offers easy access to benzofuran-2-yl(carbazolyl)methanone derivatives in a short reaction time and the products are achieved in good yields. [ABSTRACT FROM AUTHOR]