Cysteine compounds represented by the following formula
wherein each symbol is as defined in the specification, and salts thereof, are superior in stability, have less odor, exhibit an eumelanin production suppressive effect, and are useful as cosmetic agents.
Coordination of six 2-substituted thiazolidine-4-carboxylic acid derivatives by the diethyltin(IV) cation was studied in aqueous solutions. The formation constants of the complexes MLH, ML and MLOH and of the hydrolysis products of diethyltin(IV) ion were determined by potentiometric equilibrium measurements. The ligands are effective complexing agents with amino acid type coordination in the pH>5 range, where the mixed hydroxo species MLOH predominates. The polyhydroxyalkyl substituents on the ligand do not show direct coordination to tin(IV), they exert only sterical effects on the process. The solid compounds with composition MLOH show, according to Mossbauer investigations based on the partial quadrupole splitting concept and according to IR spectroscopic studies, trigonal bipyramidal arrangement of the donor atoms around the tin(IV) ion with hydroxide, carboxylate and amine coordination.
Proton and zinc(II) complexes of 2-(polyhydroxyalkyl)thiazolidine-4-carboxylic acid derivatives
作者:Tam�s Gajda、L�szl� Nagy、K�lm�n Burger
DOI:10.1039/dt9900003155
日期:——
The protonation and zinc-ion co-ordination equilibria of 2-(polyhydroxyalkyl) thiazolidine-4-carboxylicacidderivatives have been studied by potentiometric titration in the range pH 1.5–8. In most cases the formation of complexes with a metal-to-ligand ratio of 1 : 2 was demonstrated, but at above pH 6 mixed-ligand complexes involving hydroxide-ion co-ordination were also observed. The protonation
Synthesis of new 2-galactosylthiazolidine-4-carboxylic acid amides. Antitumor evaluation against melanoma and breast cancer cells
作者:Arménio C. Serra、António M. d'A. Rocha Gonsalves、Mafalda Laranjo、Ana M. Abrantes、Ana C. Gonçalves、Ana B. Sarmento-Ribeiro、M. Filomena Botelho
DOI:10.1016/j.ejmech.2012.04.003
日期:2012.7
different length for the carbon chain amide moiety. The cytotoxicity of the molecules was evaluated against A375 melanoma and MCF7 breastcancercell lines. For the derivatives tested, the one that contains a C16 amide carbon chain is the most active with an IC50 of 17.0 μM for A375 and 5.8 μM for MCF7. This compound also showscytotoxicity in the triplenegativecancercell line HCC1806. The selectivity of