Benzo thiazole, arylation

H,8H-< Azeto[2, l-b]-l,3-benzothia-zine) 2a-Aryl-2-chIor-5,6-dimethoxy-1 -oxo-2,2a-dihydro-E14a/3, 537 (2-Ar-4H-l,3-benzo-thiazol + Cl - CH2 - CO - Cl)... 

Structures comprising Two Five-Membered Rings and One Six-Membered Ring (5,5,6).—l,2,4-Triazolo[3,4-h]benzothiazole [C2N3-C3NS-C6]. The 3-aryl derivatives (157) were prepared by oxidation of 2-arylhydrazones of benzo-thiazole, using lead tetra-acetate. ... 

The first example of C—H arylation of (benz)oxazoles (20 examples 23—92% yield) and (benzo)thiazoles (3 examples 43—97% yield) with easily accessible aryltrimethylammonium triflates was recendy reported by Wang and coworkers (2015OL4926). The researchers evaluated a catalyst system... 

The thermal stabilities of thiazole and of some aryl and benzo derivatives have been determined (66BSF2857) and the pyrolysis temperatures are reported in Table 14. They have been correlated with the energy of the LUMO whereas there is no correlation with calculated... 

As can be seen in the scheme below, a series of substituted 2-(2-aminothiazol-4-yl)-benzo[ ]furans with inhibitory activity for leukotriene B4 were made from benzofurans via acylation, followed by Hantzsch thiazole formation <070BC3083>. 2-Substituted benzo[ ]furans could also be generated via an aerobic oxidative coupling of 2-unsubstituted benzo[ ]furans with arenes through the palladium-catalyzed double C-H activation <07OL3137>. In addition, 2,3-diarylbenzo h I uran could be constructed by a palladium-catalyzed arylation of benzo[6]furan with an aryl chloride in the presence of a bulky, and electron-rich phosphine <07OL1449>. 

A mild and efficient a-heteroarylation of simple esters and amides via nucleophilic aromatic substitution has been described <06OL1447>. Treatment of 2-chloro-benzo[<5(]thiazole 99 with tert-butyl propionate in the presence of NaHMDS under nitrogen furnishes tert-butyl 2-(benzo[c/]thiazol-2-yl)propanoate 100. When the same reaction is preformed initially under nitrogen and then exposed to air, the hydroxylation product 101 is obtained. This method offers two desirable features that are either complementary or improvements to the palladium-catalyzed a-arylation reactions. First, heteroaryl chlorides... 

Ohta and co-workers carried out extensive studies on intermolecular arylation of various heterocycles (furan, thiophene, pyrrole, oxazole, thiazole, A-methylimi-dazole, benz[fe]oxazole, benzo[i>]furan, and benzo[ ]thiophene) with mainly chlo-ropyrazines as heteroaryl halides using Pd(PPh3)4 and AcOK [3]. 

Most reactive sites in thiazoles, oxazoles, and imidazoles are electron-rich C-5 positions. If C-5 positions are blocked, less reactive C-2 positions are arylated. Also arylation of their benzo derivatives occurs at C-2. 

Habermann, J., Ley, S.V., Scicinski, J.S., Scott, J.S., Smits, R., and Thomas, A.W., Clean synthesis of a-bromo ketones and their utilization in the synthesis of 2-alkoxy-2,3-dihydro-2-aryl-l,4-benzo-dioxanes, 2-amino-4-aryl-l,3-thiazoles and piperidino-2-amino-l,3-thiazoles using polymer-supported reagents, J. Chem. Soc., Perkin Trans. 1, 2425, 1999. 

S. M. H. Khorassani, N. A. Torbati, A. Hosseinian, S. Garcla-Granda, L. Torre-Femindez, Heteroat. Chem. 2013, 24, 58—65. Synthesis and crystal structure study of diethyl aryl(benzo[d]thiazol-2-ylamino)methyl phosphonates. (u) C. B. Reddy, K. S. Kumar, M. A. Kumar, M. V. N. Reddy, B. S. Krishna, M. Naveen, M. K. Arunasree, C. S. Reddy, C. N. Raju, C. D. Reddy, Eur. J. Med Chem. 2012, 47, 553-559. PEG-SO3H catalyzed synthesis and cytotoxicity of a-aminophosphonates. 

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