Dioxidosqualenes: characterization and activity as inhibitors of 2,3-oxidosqualene-lanosterol cyclase
作者:Jose Luis Abad、Josefina Casas、Francisco Sanchez-Baeza、Angel Messeguer
DOI:10.1021/jo00067a036
日期:1993.7
The preparation and characterization of dioxidosqualenes 4-10 is reported. Treatment of the appropriate epoxysqualene 1, 2, or 3 with NBS followed by chromatographic purification afforded the corresponding epoxybromohydrins 11-14 as diastereomeric mixtures, with the exception of compound 11, which could be separated into the respective racemates 11a and 11b. Further dehydrobromination with NaH in THF led to the respective dioxidosqualenes 4-8 in good conversion yields. Dioxides 9 and 10 were isolated from the crude reaction mixture of the treatment of epoxide 2 with dimethyldioxirane. Characterization of compounds 4-10 was carried out by combining IH and C-13 NMR spectral means with positive GC-MS-CI analysis. The GC-MS-CI analysis included the identification of the carbonyl compounds resulting from the cleavage of dioxido derivatives 4-10 with periodic acid. Finally, data on the activity of dioxidosqualenes as oxidosqualene-lanosterol cyclase (OSLC) inhibitors in rat liver microsomes are also presented. In this respect, 2,3:18,19-dioxidosqualene (7) was found to be the best inhibitor within the compounds assayed (IC50 = 0.11 muM), although dioxides 4, 5, and 9 also exhibited a potent inhibitory activity (IC50 = 21.3, 13.0, and 9.3 muM, respectively). The fact that these compounds could be potentially generated in an organism constitutes a remarkable difference relative to other OSLC inhibitors described to date.