radicAl rEactivity in thiazoles. i. comparison of the reactivity of thiazole, mono- and dialkylthiazoles and mono- and diphenylthiazoles in was written by Vernin, Gaston;Dou, Henri J. M.;Metzger, Jacques. And the article was included in Bulletin de la Societe Chimique de France in 1967.SDS of cas: 1826-13-7 This article mentions the following:
The radical reactivity in thiazoles (I) was studied by examining the products formed by the decomposition of Bz2O2 in I. Thus, thiazole (85 g.) was treated with 10 g. Bz2O2 20 hrs. at 78°, according to method described by G. Vernin and J. Metzger (1963), to give the following compounds: CO2 0.5, BzOH and phenylbenzoic acid 7, basic fractions (containing phenylthiazoles 80, dithiazolyls 15, and others 5%) 1, and resins 1 g. 4-Methylthiazole and 2,4-dimethylthiazole were treated similarly and showed an increase in the formation of secondary products due to the dimerization of thiazolyl methylene radical produced. The determination of I isomers in the basic fraction at position 2, 4, and 5 was carried out by gas chromatog. using 5% diethylene glycol succinate at 200° or by Al2O3 column using C6H6 as eluant. Column chromatog. gave 4 sep. fractions: the 1st was rich in 2-phenyl- and 4-phenylthiazole (II); the 2nd contained 2,2′- and 2,5′-dithiazolyls; the 3rd contained 5-phenylthiazole (III); and the 4th (eluted by 10% MeOH in C6H6) contained polythiazolyls, polyphenylthiazoles, and hydroxythiazoles. The 3 first fraction isomers were further separated by gas chromatog. using by 10% Carbowax 20M. The effect of temperature and Bz2O2 concentration on the % of phenylthiazole isomers was studied at 80-115° and 0.01-0.1 mole Bz2O2/mole I. The results show the highest percentages of II and III were obtained at 115-20° and 0.1 mole Bz2O2. The phenylation of I was also carried out in presence of AcOH. The results showed an increased activity of position 2 of the ring. The steric effect of substituents at the 2 and 4 position of thiazole ring on % isomers and radical reactivity was examined in acidic and neutral media. Radical phenylation of thiazole-2-d was carried in acid media. No isotopic effect was shown on % of 4- and 5- isomers. The phenylation of phenylthiazoles was carried in acidic and neutral media in the presence of 0.001 mole Bz2O2. The results showed that the decomposition of Bz2O2 in both media is the same. The following are % triphenylthiazoles obtained from 2,4-diphenylthiazole 17, 2,5-diphenylthiazole 3, and 4,5-diphenylthiazole 25%. The relative rates of arylation of I were determined by the competitive Ingold method using 5% Bz2O2 solutions and PhNO2 as a reference substrate at 120° in both acidic and neutral media. The reaction products were analyzed by gas chromatog. using Silicone SE-30 and Carbowax 20M columns. The % of nitrobiphenyls and phenylthiazoles were determined by Bartlet and Smith method (1960). The results showed the exptl. reactivity of I in phenylation reactions are in the order of -5>-2>-4 positions in the ring. In the experiment, the researchers used many compounds, for example, 5-Phenylthiazole (cas: 1826-13-7SDS of cas: 1826-13-7).
5-Phenylthiazole (cas: 1826-13-7) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1). Electrophilic attack at nitrogen depends on the presence of electron density at nitrogen as well as the position and nature of substituent linked to the thiazole ring.SDS of cas: 1826-13-7
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica