2- benzothiazole synthesis, 2-methylbenzothiazole

Trying to prepare precursors for the synthesis of 3-substituted [l,2,4]triazolo[5,l- ]benzothiazoles, 2-hydrazino-4-methylbenzothiazole 393 was submitted to reaction with formic acid, urea, carbon disulfide, and acetic anhydride to give compounds 230, 238, 89, and 394 (Scheme 45) <1998IJC(B)921>. 

An industrial process for the preparation of 2-p-aminophenyl-6-methylbenzothiazole (562) (dehydrothiotoluidine) is based on the high temperature reaction of sulfur with p-toluidine (561 Scheme 297). A similar process involves the simultaneous action of sulfur and carbon disulfide on a primary arylamine. Benzothiazole-2-thione (564) (2-mercaptobenzothiazole) is synthesized industrially by reaction of aniline (563) with sulfur and carbon disulfide (Scheme 298). In this synthesis, sulfur plays the role of a dehydrogenating reagent and may be replaced by nitrobenzene. 

Calo, V., Del Sole, R., Nacci, A. et al. (2000) Synthesis and crystal structure of bis(2,3-dihydro-3-methylbenzothiazole-2-ylidene)palladium(II) diiodide the first palladium complex with benzothiazole carbene ligands suitable for homogeneous catalysis. Eur. J. Org. Chem., 869-71. 

The required pyridinium salts can be obtained by the King-Ortoleva reaction ((het-ero)benzylation of pyridine with a methyl(hetero)arene mediated by I2), as shown by the synthesis of benzothiazole-2-carbaldehyde (241) from 2-methylbenzothiazol [139] ... 

Benzothiazolium salts have great use in the synthesis of different types of cyanine dyes while on the other hand the benzothiazolium salts have also been studied for their activity in different biological systems. In 1959 Pianka and Hall studied the fungi toxicity of 3-ethylbenzothiazolium iodide and 3-ethylbenzoxazolium ethyl sulfate derivatives and activity was found to reside only in the cation (Pianka Hall 1959). In the same year (1959) Leslie and co-workers patented a method for the preparation of quaternary salts of benzothiazole for making the thiacarbocyanine dyes. In 1961 Horwitz and co-workers prepared a benzothiazolium salt (76) from 6-(2-aminocarbonyl)ethoxy-2-methylbenzothiazole (75, Scheme-22) for the use in preparation of different dyes. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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