- Isoform-selective inhibition of the human UDP-glucuronosyltransferase 2B7 by isolongifolol derivatives
-
A set of 48 derivatives of the tricyclic sesquiterpenol alcohol isolongifolol was synthesized. The set comprised homochiral and diastereomeric alcohols, amines, chlorohydrins, as well as carboxylic acids, phosphonic acids, and their corresponding esters. The absolute configuration of the epimeric compounds was assigned by 2D NMR experiments [gradient heteronuclear single quantum correlation (gHSQC) and gradient nuclear Overhauser enhancement spectroscopy (gNOESY)] in agreement with crystallographic data. The tricyclic derivatives were assessed as inhibitors of the human UDP-glucuronosyltransferase (UGT) 2B7. The phenyl-substituted secondary alcohol 26b was the best inhibitor in this series and its competitive inhibition constant was 18 nM. Compound 26b was not glucuronidated by UGT2B7 and other hepatic UGT enzymes, presumably due to the high steric hindrance exerted by its bulky phenyl substituent. Its inhibitory activity toward 14 other UGT isoforms of subfamily 1A and 2B was determined, and the data indicated that the tricyclic secondary alcohol 26b was highly selective for UGT2B7 (true selectivity > 1000).
- Bichlmaier, Ingo,Kurkela, Mika,Joshi, Tanmaya,Siiskonen, Antti,Rüffer, Tobias,Lang, Heinrich,Suchanová, Bohumila,Vahermo, Mikko,Finel, Moshe,Yli-Kauhaluoma, Jari
-
p. 2655 - 2664
(2008/02/02)
-
- Preparation of Chiral 1-Deuteriobenzenemethanethiols by Using α',β Elimination of Carbanions Derived from Benzylic Thioethers
-
The α',β elimination of the carbanion derived from benzyl isolongifolyl thioether and benzyl camphyl thioether gives the chiral benzyl mercaptan, the S isomer with 38 +/- 6percent ee and the R isomer with 49 +/- 7percent ee.The chirality of the benzyl mercaptan was determined by optical rotation of benzyl methyl thioether and thiosulfone.The enantiomeric excess was evaluated from 1H NMR measurement of ethyl (benzylthio)phenylacetate prepared from (-)-mandelic acid.The enantiomeric excess at carbon C-2 of ethyl (benzylthio)phenylacetate wasdetermined with the chiral europium chelate and was about 60percent.These results are discussed with reference to the transition state of the α,β elimination and to related processes.
- Biellmann, Jean-Francois,d'Orchymont, Hugues
-
p. 2882 - 2886
(2007/10/02)
-
- STUDIES IN SESQUITERPENES-LV ISOLONGIFOLENE(PART 6): MECHANISM OF REARRANGEMENT OF LONGIFOLENE TO ISOLONGIFOLENE-I
-
The gross mechanism of rearrangement of longifolene to isolongifolene has been elucidated by using site-specifically labelled longifolene-4,4,5,5-d4 and shown to follow the pathway proposed by Berson et al., which involves an exo, exo Me shift, in preference to the endo, endo Me migration route proposed earlier.An efficient synthesis of longifolene-4,4,5,5-d4, the key compound in the present investigation, is described.
- Yadav, J. S.,Nayak, U. R.,Dev, Sukh
-
p. 309 - 315
(2007/10/02)
-