Nano ceria catalyzed synthesis of substituted benzimidazole, benzothiazole, and benzoxazole in aqueous media

Mechanistic Study on the Formation of Compounds from Thioureas

“…This shows that the position of substitution plays a bigger role than the type of substituent in determining the pathway to give carbodiimide. It may be mentioned that earlier in our work for iodide intermediate [49], the relative energy of the deprotonated product from N4 atom was slightly less than that obtained from N2 atom. However, the energy difference between the two in the previous work was appreciably small with maximum of 3.0 kcal/mole.…”

“…Various methods have been reported in the literature for the synthesis of benzoxazoles starting from 2-aminophenol precursors with carboxylic acid derivatives, such as carboxylic acids, acid chlorides, acid anhydrides, and amides (Scheme 20), or by reacting 2-aminophenols with aldehydes followed by oxidation (Scheme 21) [48][49][50][51].…”

A comprehensive review in current developments of benzothiazole-based molecules in medicinal chemistry

“…Other general methods include the microwave mediated reaction of o-aminothiophenol with bchlorocinnamaldehydes, the reaction of dibenzyl disulfides with oaminothiophenol, reduction of o,o 0 -dinitrodiphenyl disulfide, the reaction of S-aryl thiobenzoate with arylhaloamines, from 1,2,3-benzodithiazole-2-oxides, radical cyclization of benzyne intermediates, and Grignard reactions of arylisothiocyanates [45]. A number of catalysts, namely, (pmIm)Br [46], I 2 [47], ZrOCl 2 .8H 2 O [48], TMSCl [49], H 2 O [50], PCC [51], CAN [52], nano ceria (CeO 2 ) [53], cyanide [54], boron trifluoride etherate [55], mesoporous CdS nanospheres [56], silica supported nano-copper(II) oxide [57] and many more can also be used effictly used as catalysts to prepare BTA derivatives Fig. 3.…”

Amberlyst‐15 as a Green and Efficient Reusable Catalyst for Friedel‐Crafts Alkylation of Activated Arenes with N‐Sulfonyl Aldimines and Synthesis of Bis‐triarylmethanes

“…The recovered Amberlyst-15 can be reused several times without significant loss of activity. [22][23][24] The triarylmethanes, bis-arylmethanes and bis-heteroarylmethanes have displayed various biological activities such as antiviral, [24][25][26][27] antitumor, [28] antitubercular, [29] antifungal, and anti-inflammatory agents. [30] Moreover, these compounds have been also found to possess widespread application in synthetic, medicinal and industrial chemistry.…”