541-58-2Relevant articles and documents
Synthesis of trisubstituted thiazoles by ligand-free palladium-catalyzed direct 5-arylation of 2,4-disubstituted thiazoles under conventional and microwave-assisted heating
Kim, Su Kang,Kim, Ji-Hyun,Park, Young Chul,Kim, Jae Won,Yum, Eul Kgun
, p. 10990 - 10995 (2014/01/06)
Trisubstituted thiazoles were synthesized with excellent yields using ligand-free, palladium-catalyzed, direct 5-arylation of 2,4-disubstituted thiazole and conventional or microwave-assisted heating. The palladium-catalyzed reaction yields were significantly influenced by LiCl additive, solvent, and heating method. The reaction times were reduced dramatically by employing microwave radiation instead of conventional heating. The synthetic methods can be applied to diverse 2,4,5-trisubstituted thiazoles by varying the aryl bromide and disubstituted thiazole reactants.
Reactivity of Heterocyclic Nitrogen Donors in Systems containing the Tetrachloroaurate(III) Anion
Canovese, Luciano,Cattalini, Lucio,Tomaselli, Michele,Tobe, Martin L.
, p. 307 - 314 (2007/10/02)
A series of gold(III) complexes of the type has been prepared and characterized (L = oxazole, benzoxazole, thiazole, their benzo and methyl-substituted derivatives, or 2-methylbenzoselenazole).The five-membered N.O-, N,S- and N,Se-heterocyclic bases are all bound to Au(III) through nitrogen.The kinetics of the displacement of L by chloride to give (1-) has been studied in methanol-water (95:5. v/v) at 25.0 deg C and I = 0.20 mol dm-3 (LiClO4).The equilibrium constants for the reversible processes have also been determined.The reactions of the corresponding pyridine, 4-chloro-, 4-cyano- and 2,6-bis(chloromethyl)-pyridine complexes have also been reexamined under the same conditions.The equlibrium constants, K2, depend upon the basicity of the nitrogen in the ligands and points for all ligands, irrespective of ring size and composition, lie roughly on the same log K2 versus pKa curve.There is no significant systematic steric effect on the equilibrium constants of the sort found for the more basic methyl pyridines.The complexes of the five-membered heterocyclic ligands are approximately ten times less reactive than those of the six-membered N-heterocycles of comparable basicity and exhibit steric retardation from ortho-methyl substituents.The nucleophilicities of these ligands have been calculated and five-membered N,O- and N,S-heterocycles are considerably less reactive than six-membered N-heterocycles of similar basicity.
Isolation and Reaction of New Aromatic Dications. 4-Thioniapyridinium Dications: 2-Aryl-(or 2-Alkyl-)4-methyl-3-oxo-2H-1,4-thiazin-2-ylium Tetrafluoroborates
Hojo, Masaru,Ichi, Tadaaki,Masuda, Ryoichi,Kobayashi, Makoto,Shibano, Hiroshi
, p. 2209 - 2213 (2007/10/02)
2-Hydroxy-4-methyl-2-aryl(or -2-tert-butyl)-2H-1,4-thiazin-3-ones (5) generate carbocations 6 in trifluoroacetic acid solution at room temperature.These ions are sufficiently stable to be observed spectroscopically in this solution.Reaction of 6 with some nucleophiles are described.Stable crystalline tetrafluoroborates of 6 were isolated.From 1H NMR, 13C NMR, and UV-vis spectral data it was concluded that these cations are aromatic in nature and should be depicted as 9 and called 4-thioniapyridinium dications.
Novel skin-whitening agent
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, (2008/06/13)
A novel skin-whitening composition comprising as an active ingredient a compound of the formula: STR1 useful for the prophylaxis and treatment of skin troubles due to melanin metabolism disorder.
Spectral studies on the interaction of iodine with thiazoles
Abdel-Hamid, Refat,El-Samahy, Ahmed A.,El-Taher, Abdel-Hafiz,El-Sagher, Hussein
, p. 468 - 472 (2007/10/02)
The electron donor-acceptor molecular complexes between thiazole and some of its derivatives and iodine in several solvents have been investigated spectrophotometrically at different temperatures.Spectral characteristics, equilibrium constants, K, extinction coefficients, ε, and thermodynamic functions of formation, ΔH0, ΔG0, and ΔS0 have been determined.It was found that the data fit satisfactorily the 1:1 stoichiometric equilibrium: D + I2 = DI2 "outer complex".The EDA complexes obtained are of "n - ?*" type in which the nitrogen atom of thiazole is the donor center.Moreover, the effect of solvents on the K values is discussed in terms of the solute-solute and solute-solvent competing equilibria.
