scholarly journals Palladium(II)-Catalyzed Efficient Synthesis of Wedelolactone and Evaluation as Potential Tyrosinase Inhibitor

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4130
Author(s):  
Huidan Huang ◽  
Jianqiu Chen ◽  
Jie Ren ◽  
Chaofeng Zhang ◽  
Fei Ji
Keyword(s):  
Natural Product ◽  
Raw Material ◽  
Coupling Reactions ◽  
Biosynthesis Pathway ◽  
Tyrosinase Inhibitor ◽  
Efficient Synthesis ◽  
Melanin Biosynthesis ◽  
Methodological Research ◽  
Palladium Catalyzed ◽  
Tyrosinase Inhibitors

Tyrosinase is an enzyme widely distributed in nature, which has multiple functions, especially in the melanin biosynthesis pathway. Despite the few clinically available tyrosinase inhibitors for whitening, a great demand remains for novel compounds with low side effects in terms of potential carcinogenicity and improved clinical efficacy. A natural product, wedelolactone (WEL), with a polyhydroxyl moiety, attracted our attention as a potential tyrosinase inhibitor. Before we studied the biological activity of the natural product, a synthetic methodological research was firstly carried to obtain enough raw material. WEL could be obtained efficiently through palladium-catalyzed boronation/coupling reactions and 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ)-involved oxidative deprotection/annulation reactions. Immediately after, the natural product was proven to be an efficient tyrosinase inhibitor. In conclusion, we developed a mild and efficient approach for the preparation of WEL, and the natural product was disclosed to have anti-tyrosinase activity, which could be widely used in multiple fields.

Phlorotannins Derived From the Brown Alga Colpomenia bullosa as Tyrosinase Inhibitors

2021 ◽  
Vol 16 (7) ◽  
pp. 1934578X2110213
Author(s):  
Hideyuki Kurihara ◽  
Kazuki Kujira
Keyword(s):  
Inhibitory Activity ◽  
Brown Alga ◽  
Molecular Structures ◽  
Free Form ◽  
Biosynthesis Pathway ◽  
Tyrosinase Inhibitor ◽  
Melanin Biosynthesis ◽  
Tyrosinase Inhibitory Activity ◽  
Tyrosinase Inhibitors ◽  
Potential Use

Tyrosinase catalyzes hydroxylation of L-tyrosine and dehydrogenation of L-DOPA in the melanin biosynthesis pathway. Tyrosinase inhibitors have potential use as cosmetic whitening agents and for preventing seafood deterioration. In this report, tyrosinase inhibitors extracted from brown alga Colpomenia bullosa (Scytosiphonaceae, Scytosiphonales) were investigated. Inhibitory principles were isolated from the extract and identified as phlorotannins, phloroglucinol (1), diphlorethol (2), triphlorethol C (3), which have not been isolated in a free form previously, and fucophlorethol C (4). Compounds 3 and 4 have not been reported previously as tyrosinase inhibitors. Triphlorethol C (3) was the most potent tyrosinase inhibitor among the phlorotannins isolated, whereas isomeric fucophlorethol C (4) displayed the weakest inhibitory activity. The results suggest that molecular structures of phlorotannins strongly affect their tyrosinase inhibitory activity.

Efficient synthesis of 2-phenyl-3-substituted furo/thieno[2,3-b]quinoxalines via Sonogashira coupling reaction followed by iodocyclization and subsequent palladium-catalyzed cross-coupling reactions

RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 83901-83908 ◽  
Author(s):  
Tayebeh Besharati-Seidani ◽  
Ali Keivanloo ◽  
Babak Kaboudin ◽  
Tsutomu Yokomatsu
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Sonogashira Coupling ◽  
Efficient Synthesis ◽  
Cross Coupling Reactions ◽  
Sonogashira Coupling Reaction ◽  
Quinoxaline Derivatives ◽  
Palladium Catalyzed

In this paper, we report the successful synthesis of new 2-phenyl-3-substituted furo/thieno[2,3-b]quinoxaline derivatives from 2-chloro-3-methoxyquinoxaline and 2-chloro-3-(methylthio)quinoxaline by a three-step approach.

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