31769-45-6Relevant articles and documents
Photochromism of the complex between 4′-(2-hydroxyethoxy)-7- hydroxyflavylium and β-cyclodextrin, studied by 1H NMR, UV-Vis, continuous irradiation and circular dichroism
Gago, Sandra,Basílio, Nuno,Fernandes, Ana,Freitas, Victor,Quintas, Alexandre,Pina, Fernando
, p. 106 - 112 (2014)
The network of chemical reactions of the compound 4′-(2- hydroxyethoxy)-7-hydroxyflavylium and its photochromic properties were studied in the absence and presence of β-cyclodextrin. The system was characterized by 1H NMR, UV-Vis, continuous irradiation and circular dichroism. In the presence of β-cyclodextrin 4.8 mM the pK′a is reduced to 2.2. The association constants with β-cyclodextrin, follow the order trans-chalcone > quinoidal base > flavylium cation, respectively 1.7 × 103 M-1; 5.6 × 102 M -1; ≈0. The rate of inter-conversion of the network species increases in the presence of β-cyclodextrin circa 2.6 times. The appearance of an induced circular dichroism signal of trans-chalcone inside the β-cyclodextrin is described for the first time. It gives information about the position of the guest inside the host and allows the calculation of the respective association constant.
Design, synthesis, biological evaluation and inhibition mechanism of 3-/4-alkoxy phenylethylidenethiosemicarbazides as new, potent and safe tyrosinase inhibitors
Liao, Bing,Mai, Yuliang,Shi, Huahong,Song, Senchuan,Wang, Fei
, p. 369 - 379 (2020/05/14)
Tyrosinase plays important roles in many different disease related processes, and the development of its inhibitors is particularly important in biotechnology. In this study, thirty-nine 3-/4-alkoxyphenylethyli-denethiosemicarbazides were synthesized as novel tyrosinase inhibitors based on structure-based molecular design. Our experimental results demonstrated that thirty-one of them possess remarkable tyrosinase inhibitory activities with IC50 value below 1μM, and 5a, 6e, 6g and 6t did not display any toxicity to 293T cell line at the concentration of 1000μmol/L. According to the inhibitory activities, several compounds were selected for detail investigation on the structure–activity relationships (SARs), mechanisms of enzyme inhibition, inhibitory kinetics and cytotoxicity. In particular, the interaction between the selected inhibitors and the active center of tyrosinase was considered and discussed in detail based on their structural characteristics. Taken together, the results presented here demonstrated that the newly designed compounds are promising candidates for the treatment of tyrosinase-related disorders and further development of them may have significant contribution in biomedical science.
A molybdenum based metallomicellar catalyst for controlled and chemoselective oxidation of activated alcohols in aqueous medium
Thiruvengetam, Prabaharan,Chakravarthy, Rajan Deepan,Chand, Dillip Kumar
, p. 123 - 133 (2019/07/19)
A surfactant based oxodiperoxo molybdenum complex, which could activate molecular oxygen, has been employed as a catalyst for controlled oxidation of benzylic alcohols to corresponding carbonyls. The oxidation reactions were carried out under aqueous environment, however, in the absence of any extraneous base or co-catalyst. Sensitive/oxidizable functional groups like cyano, sulfide, hydroxyl, aryl-hydroxyl, alkene (internal/terminal), alkyne (internal/terminal), and acetal were tolerated during the transformations. Such selectivity is attributed to the mild nature of the catalyst. The methodology could also be scaled-up for multi-gram synthesis and the protocol is likely to find practical use since it requires an inexpensive recyclable-catalyst and easily available oxidant (under green conditions). A plausible mechanism is proposed with the help of preliminary computational study.
