21a-H-Hopanes

FIGURE 30.9 Partial m/z 191 and 205 mass chromatograms for fluid inclusions oils and crude oil, South Pepper-1, showing the distribution of hopanes and methylhopanes. Peak assignments define the stereochemistry at C-22 (S and R) a 3 and 3a denote 17a(H),2ip(H) and 17 3(H),21a(H)-hopanes, respectively.Ts = C2718a(H)-22,29,30-trisnorneohopane Tm = C2717a(H)-22,29,30-trisnorhopane = diahopane and 2a(Me) = methylhopane. Numbers in italics refer to the relative abundance of chromatograms (modified from Reference [34]). 

Deriv. 2.4-Dinitrophenylhydrazone of 30-nor-21a-H-hopan-22-one, mp 247-248 °C, from 30-nor-21a-H-hopan-22-one with 2.4-dinitro-phenylhydrazine... 

Triterpenoids of, or related to, the hopane skeleton (135) are ubiquitous components of sediments. They occur as three stereochemical series (17/3-H,21/S-H 17a-H,21/8-H 17/3-H,21a-H). A variety of functional classes is found as a range of extended (> 30) and degraded (< 30) compounds.The presence in various sediments of a series of extended hopanes with an aldehyde/ketone or an alcohol function in the side-chain has been reported. The survival of the aldehydes (136) and (137) in an Eocene shale (ca. 5 x 10 years) is remark-able. " The acid (138) has been isolated from Sphagnum peat in sufficient quantity to allow its configuration at C-22 (/ ) to be determined directly by n.m.r. spectroscopy. The presence in sediments of a series of triterpenoids [e.g. (139)—(141)] derivable in vitro by the photolysis of the corresponding... 

Hveding-Bergseth N, Bruun T, Kjosen H (1983) Isolation of 30-nor-21a-hopan-22-one (isoadiantone). Phytochemistry 22 1826-1827... 

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