Young, Claire M. et al. published their research in Organic & Biomolecular Chemistry in 2019 | CAS: 16595-80-5

(S)-6-Phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole hydrochloride (cas: 16595-80-5) belongs to thiazole derivatives. The higher aromaticity of thiazole is due to delocalization of a lone pair of sulfur electrons across the ring, which is evidenced by chemical shifts of ring hydrogen at δ 7.27 and 8.77 ppm (C2 and C4), indicating diamagnetic ring current. Thiazole sulfonation occurs only under forcing conditions: the action of oleum at 250 °C for 3 hours in the presence of mercury(II) sulfate leads to 65% formation of 5-thiazole sulfonic acid.Reference of 16595-80-5

Evaluating aryl esters as bench-stable C(1)-ammonium enolate precursors in catalytic, enantioselective Michael addition-lactonizations was written by Young, Claire M.;Taylor, James E.;Smith, Andrew D.. And the article was included in Organic & Biomolecular Chemistry in 2019.Reference of 16595-80-5 This article mentions the following:

An evaluation of a range of aryl, alkyl and vinyl esters as prospective C(1)-ammonium enolate precursors in enantioselective Michael addition-lactonization processes with (E)-trifluoromethylenones using isothiourea catalysis was reported. Electron deficient aryl esters were required for reactivity, with 2,4,6-trichlorophenyl esters providing optimal product yields. Catalyst screening showed that tetramisole was the most effective isothiourea catalyst, giving the desired dihydropyranone products I [Ar = Ph, 4-MeC6H4, 4-F3CC6H4; Ar1 = Ph] in excellent yield and stereoselectivity (up to 90 : 10 dr and 98 : 2 er). The scope and limitations of this process were evaluated, with a range of keto ester products II [Ar1 = Ph, 2-furyl, 4-MeC6H4, 3-MeOC6H4, 4-BrC6H4] being generated after ring-opening with MeOH to give stereodefined dihydropyranones with excellent stereocontrol (10 examples, typically ∼90 : 10 dr and >95 : 5 er). In the experiment, the researchers used many compounds, for example, (S)-6-Phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole hydrochloride (cas: 16595-80-5Reference of 16595-80-5).

(S)-6-Phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole hydrochloride (cas: 16595-80-5) belongs to thiazole derivatives. The higher aromaticity of thiazole is due to delocalization of a lone pair of sulfur electrons across the ring, which is evidenced by chemical shifts of ring hydrogen at δ 7.27 and 8.77 ppm (C2 and C4), indicating diamagnetic ring current. Thiazole sulfonation occurs only under forcing conditions: the action of oleum at 250 °C for 3 hours in the presence of mercury(II) sulfate leads to 65% formation of 5-thiazole sulfonic acid.Reference of 16595-80-5

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica