Nucleophilic reactivity of 2-chlorobenzothiazole was written by Todesco, Paolo Edgardo;Vivarelli, Piero. And the article was included in Gazzetta Chimica Italiana in 1962.Category: thiazole This article mentions the following:
The reaction of MeONa with 5- or 6-substituted derivatives of 2-chlorobenzothiazole has been studied. 2-Chlorobenzothiazole (I), b21 133-4°, was prepared according to Moon (CA 43, 6670c). The 6-nitro derivative (II) of I, pale yellow needles, m. 191-2°, was prepared by nitrating I with KNO3 and H2SO4 (U.S. 2,659,730, CA 49, 2519a; Katz, CA 46, 3044b). The 5-nitro derivative (III) of I, m. 112°, was prepared by adding an excess of SO2Cl2, in the cold, to 0.003 mole of 2-mercapto-5-nitrobenzothiazole, crude m. 223-5°, prepared in turn in 60% yield, by adding a KSH solution (0.01 mole KOH in little water and 30 ml. alc., saturated with H2S) to a boiling alc. solution of 2-bromo-5-nitroaniline, cooling, adding 0.3 ml. CS2, stirring 4 hrs. at 80°, steam distilling, cooling, making ammoniacal, filtering off S, and precipitating the product by making acid with HCl. The 4-nitro derivative (IV) of I, yellow needles, m. 169-70°, was prepared by diazotizing 2-amino-4-nitrobenzothiazole (Erlenmeyer and Ueberwasser, CA 34, 28446), m. 254°, and decomposing the diazonium salt with cold Cu2Cl2-HCl. The 6-methyl derivative (V) of I, m. 49-50°, resulted from 2-amino-6-methylbenzothiazole, m. 135-6°, according to Metzger and Plank (CA 50, 15512a). The 5-methyl derivative (VI) of I, m. 41-2° (cold pentane) was made by treating 2-mercapto-4-methylbenzothiazole with SO2Cl2, the intermediate being prepd, according to Teppema and Sebrell (CA 21, 2688). The 6-chloro derivative (VII) of I, m. 98-9°, was prepared by diazotizing 2-amino-6-chlorobenzothiazole, m. 200°, in a mixture of HCO2H, AcOH, and HCl, and decomposing the diazo salt with Cu2Cl2-HCl (Stuckwisch, CA 44, 2514a). The intermediate was obtained according to Kaufmann and Kuchler (CA 28, 50666). The 5-chloro derivative (VIII) of I, m. 70-1°, was prepared by treating 2-mercapto-5-chlorobenzothiazole, m. 196-7°, with SO2Cl2. The 6-methoxy derivative (IX) of I, m. 53-4°, was prepared according to Stuckwisch (loc. cit.). For the reaction with Me-ONa, MeOH solutions of the reagents, previously brought to reaction temperature, were mixed and kept at const, temperature, taking samples at intervals and pouring them into an excess of aqueous HNO3, followed by AgNO3, and determining Cl– by the Volhard method. The resulting data were plotted and used to calculate the rate constant and energy of activation of the reactions. The second-order rate const, k (103 sec.-1 mole–1) for 0°, 13°, 25°, 35°, and 45°, followed by the activation energy E (kcal. mole-1) for the various derivatives of I: I, -, -, 0.55, 1.43, 3.39, 16.9; IV, -, 42.8, 132.0, 335.0, -, 16.3; III, 8.09, -, 87.8, 205.0, -, 15.4; VIII,-, 2.53, 6.37, 15.20, -, 15.8; VI, -, 0.116, 0.374, 1.05, -, 17.8; II, -, 97.0, 280.0, 647.0, -, 14.2; VII, -, 1.01, 3.25, 7.79, -, 16.0; V, -, 0.057, 0.197, 0.578, -, 18.3; and IX, -, 0.0244, 0.0893, 0.255, -, 18.7. Electron-attracting substituents (Cl, NO2) speed up the reaction, while electron-donor substituents (Me, MeO) slow it down. The log k of the reaction gave a straight line function of Hammett’s σ (of. Jaffe, Chem. Rev. 53, 191(1953)), except in the case of II. In the experiment, the researchers used many compounds, for example, 5-Nitrobenzothiazole-2-thiol (cas: 58759-63-0Category: thiazole).
5-Nitrobenzothiazole-2-thiol (cas: 58759-63-0) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1). Thiazole is a versatile building block for the construction and lead generation of new drug discoveries. Numerous diazole-based compounds are in clinical use as anticancer, antileukemic, antiinflammatory, antiviral, antifungal, antirheumatic, immunomodulator, and antiparasitic agents.Category: thiazole
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica