Ozonolysis of 18 α -Oleanane triterpenoid with an alkenenitrile moiety in the five-membered ring A

Synthesis, Cyclization, and Cytotoxic Activity of 2,3-Secolupane Triterpenoids With an Ethylketone Fragment

“…It should be noted that direct ozonolytic cleavage of the C(20)-C(29) double bond of α,β-alkenenitrile 8 did not lead to the formation of the corresponding C(20) methyl ketone 7 . As a result of the reaction (from the Thin-layer chromatography (TLC) data), a mixture of highly polar products was formed, as was in the previously described case with C(3) unsubstituted alkenenitrile 10 13 (Figure 1).…”

“…Infrared spectroscopy (IR) spectra of the compounds dissolved in CHCl 3 were recorded on a Bruker 66/S IFS Fourier spectrometer (Bruker, Germany). The 1 H and 13 C Nuclear magnetic resonance (NMR) spectra of the compounds dissolved in CDCl 3 were recorded on a Bruker AVANCE II spectrometer (Bruker BioSpin GmbH, Germany) at 400 and 100 MHz, respectively. Chemical shifts (δ) were expressed in parts per million (ppm) relative to Tetramethylsilane (TMS) as an internal standard.…”

Diastereoselective Synthesis of Triterpenoid 1,2,4-Trioxolanes by Griesbaum Co-ozonolysis

“…1,2,4-Trioxolanes, or secondary ozonides, are well-known cyclic organic peroxides that have found a wide application in pharmacological research . The development of methods to produce 1,2,4-trioxolanes based on natural terpenoids has received scant attention in the research literature, with only a few papers having been published (Figure ). Most of these methods have relied on ozonolysis of a spatially hindered double bond, and the most preferable reaction route has turned out to be the unusual formation of oxy-functionalized derivatives …”