Synthesis of 2-aryl-benzothiazoles via Ni-catalyzed coupling of benzothiazoles and aryl sulfamates

2-Aryl-benzothiazoles have been successfully synthesized via a simple coupling reaction between benzothiazoles and aryl sulfamates using a nickel catalyst. The nickel catalyst is inexpensive, reusable and commercially available. In addition, the use of highly expensive palladium catalysts and unstable raw materials has been avoided. 2-Aryl-benzothiazoles bearing various substituents on the aryl groups were obtained in good yield.

An efficient synthesis of 2-substituted benzothiazoles in the presence of FeCl3/Montmorillonite K-10 under ultrasound irradiation

2-Substituted benzothiazoles have been synthesized via one-pot reaction from aromatic aldehydes and o-aminothiophenol in the presence of FeCl(3)/Montmorillonite K-10 in absolute methanol at 25-30°C under ultrasound irradiation. The remarkable advantages are an inexpensive and easily available reagent, a simple procedure, mild conditions, short reaction times and moderate to good yields.

1,3-Dibromo-5,5-dimethylhydantoin catalyzed one-pot synthesis of 2-arylbenzothiazoles

A one-pot synthesis of 2-arylbenzothiazoles from the reaction of 2-aminothiophenol and aromatic aldehydes catalyzed by 1,3-dibromo-5,5-dimethylhydantoin is reported.

Solvent-free, one-pot synthesis of 2,4,6-triarylpyridines using trichloroisocyanuric acid or N-bromosuccinimide as a novel and neutral catalyst

A simple and benign protocol has been explored for the preparation of 2,4,6-triarylpyridines by a one-pot reaction between aryl aldehydes, enolizable ketones and ammonium acetate in the presence of N-bromosuccinimide or trichloroisocyanuric acid as green and neutral catalysts. The reactions proceed smoothly at 130 °C under solvent-free conditions to provide 2,4,6-triarylpyridines in good yields.

An efficient synthesis of 2-arylbenzothiazoles using silica sulfuric acid, oxalic acid and aluminum chloride hydrate as heterogeneous and homogeneous catalyst systems

A convenient method for the synthesis of 2-arylbenzothiazoles from condensation of aromatic/heteroaromatic aldehydes with 2-aminothiophenol has been developed using inexpensive, green and reusable solid acids – silica sulfuric acid (SSA), oxalic acid or AlCl3·6H2O as efficient catalysts. The reactions occurred under mild conditions to afford the corresponding 2-arylbenzothiazoles in good to excellent yields.

Solvent-Free Synthesis of 3,5-di(Hetero)Aryl-1,2,4-Thiadiazoles by Grinding of Thioamides under Oxidative Conditions

An efficient and facile synthesis of 3,5-di(hetero)aryl-1,2,4-thiadiazoles by oxidative dimerisation of thioamides by grinding with NBS under solvent-free conditions at room temperature has been developed. The efficiency of this reaction was demonstrated by the compatibility with trifluoromethyl, methyl, methoxy, chloro, pyridyl and thienyl groups. This method has notable advantages in terms of short reaction times, high yields and is a more practical alternative to the existing methods to access these compounds.

Synthesis of quinoxalines catalysed by cetyltrimethyl ammonium bromide (CTAB) in aqueous media

A facile and simple method has been developed for the condensation of 1,2-diaminobenzenes with α-bromoketones to form quinoxalines with good yields using cetyltrimethyl ammonium bromide (CTAB) in aqueous media. The efficiency of this reaction was demonstrated by the compatibility with nitro, methyl, methoxy, fluoro chloro bromo and furanyl groups. The important features of the methodology are broad substrate scope, simple workup, and no requirement for metal catalysts.

Sodium dithionite-promoted synthesis of 2-arylbenzothiazoles by reaction of 2,2'-disulfanediyldianiline with aldehydes in water

Sodium dithionite-promoted synthesis of 2-arylbenzothiazoles by reaction of 2,2'-disulfanediyldianiline with aldehydes in the presence of sodium dodecyl sulfate in water has been developed. Possible reaction pathways are discussed and the effects of different promoter on the reaction are investigated. The important features of this methodology are simple work-up, environmentally benign, high yields, metal-free, and inexpensive reagents.