Reference

Chalcones as potent tyrosinase inhibitors: the importance of a 2,4-substituted resorcinol moiety

Chalcones as potent tyrosinase inhibitors: the importance of a 2,4-substituted resorcinol moiety. Khatib, Soliman; Nerya, Ohad; Musa, Ramadan; Shmuel, Maayan; Tamir, Snait; Vaya, Jacob (Laboratory of Natural Medicinal Compounds, Migal-Galilee Technological Center, Kiryat Shmona 11016, Israel). Bioorganic & Medicinal Chemistry, Volume Date 2005, 13(2), 433-441 (English) 2004 Elsevier Ltd. CODEN: BMECEP. ISSN: 0968-0896. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 26, 62 Compds., which inhibit tyrosinase, could be effective as depigmenting agents. We have introduced a group of mono-, di-, tri- and tetra-substituted hydroxychalcones as effective tyrosinase inhibitors, showing that the most important factor detg. tyrosinase inhibition efficiency is the position of the hydroxyl group(s) rather their no. The aim of the present study was to investigate the contribution of the different functional groups of the tetrahydroxychalcones to their inhibitory potency, with a view to optimizing the design of whitening agents. Four tetrahydroxychalcones were evaluated, the com. available Butein and other three were synthesized, and their inhibitory effect on tyrosinase was tested. Results showed that a 2,4-substituted resorcinol subunit on ring B contributed the most to inhibitory potency. Changing the resorcinol substitute to position 3,5- or placing it on ring A significantly diminished the inhibitory effect of the compds. A catechol subunit on ring A acted as a metal chelator (in the presence of copper ions) and as a competitive inhibitor (in the presence of tyrosinase), while a catechol on ring B oxidized to o-quinone (in the presence of both copper ions and tyrosinase). Three of the compds. also demonstrated antioxidant activity, which may contribute to the prevention of pigmentation. An examn. of correlations between inhibitory activity and phys. 1197-09-7 and 26153-38-8 are also in the experiment. properties of the chalcones tested (such as dissocn. energy and mol. planarity) showed pos. correlation with the moment dipole value in the Y-axis, which may be used as an indicator of the inhibitory potential of new mols. The present study revealed two very active tyrosinase inhibitors, 2,4,3',4'-hydroxychalcone and 2,4,2',4'-hydroxychalcone (with IC50 of 0.2 and 0.02 mM, resp.). Structure-related activity studies added some understanding of the role and contribution of different functional groups assocd. with tyrosinase inhibitors. .

A general synthesis of side chain derivatives of D9-THC

A general synthesis of side chain derivatives of D9-THC. Pitt, Colin G.; Seltzman, Herbert H.; Sayed, Yousry; Twine, Charles E., Jr.; Williams, David L. (Chem. Life Sci. Div., Res. Triangle Inst.Several reagents such as 26153-38-8 is used here., Research Triangle Park, N. C., USA). 26153-38-8 is just another one chemical used in this study. Tetrahedron Lett., (1), 37-40 (English) 1978. CODEN: TELEAY. ISSN: 0040-4039. DOCUMENT TYPE: Journal CA Section: 30 (Terpenoids) The silyl ether I, prepd. (50% yield based on 42% recovered starting material) by condensation of p-mentha-2,8-dien-1-ol with the dithiane II, on treatment with 1% BF3.Et2O in CH2Cl2 at -20° for 48 h gave 54-66% of a 3:1 mixt. of the dibenzopyran III and the alternative cyclization product IV. III was converted to 1'-, 2'-, 3'-, and 4'-hydroxy-D9-tetrahydrocannabinol and 3-carboxy-6,9,9-trimethyl-6H-dibenzo[b,d]pyran-1-ol. ..