A-Amyrin

Partial Synthesis of a-Amyrin Acetate Proof of the Structure and Stereochemistry... 

Rhodamine 6G long-chain hydrocarbons [169] squalene, a-amyrin [170] methyl esters of fatty acids [171] glycerides [91] sterols [172, 173] isoprenoids, quinones [HI] lipoproteins [174] glycosphingolipids [175] phenolic lipids [176] phosphonolipids [177] increasing the sensitivity after exposure to iodine vapor [178,179]... 

Amylene, stabilizer for solvents 120 Amylose reagent 173 a-Amyrin 44,69 jS-Amyrin 69 a-Amyrin benzoate 63 Anabolics 303, 411, 430,432 Anacardol 288... 

Amyl nitrite reagent lb 115 Amylose la 173 a-Amyrin la 44,63,69 P-Amyiin la 69... 

Figure 3.1 Mass spectra of (a) a amyrine and (b) oleanolic acid obtained by DE MS...

Regert et al. studied [9] a series of 30 Neolithic hafting adhesives from lake dwellings at Chalain (France) using an analytical procedure based on GC/MS analysis involving solvent extraction (dichloromethane) and trimethylsilylation. In the majority of the samples a series of triterpenoid compounds with a lupane structure was clearly identified on the basis of their TMS mass spectra. In particular, the presence of betulin, betulone, lupenone, lupeol and lupa-2,20(29)-dien-28-ol allowed birch bark tar to be identified. In other samples the co-occurrence of other plant biomarkers such as a-amyrin,(3-amyrin... 

The use of HMDS as a derivatization reagent in the analysis of triterpenoid resins has been less explored. The TMS derivatives of triterpenoids bearing hydroxyl groups [a-amyrine, p-amyrine and hop-22(29)-en-3p-ol] have been identified in the triterpenic fraction of Burseraceae resins, thus demonstrating that HMDS combined with Py-GC/MS is effective in the derivatization of triterpenoid compounds [59]. However, the range of structures that can be fully derivatized and detected must be extended and, in order to get comprehensive results comparable with those coming from the well assessed off-line GC/MS procedures, general improvements in the on-line trimethylsilylation-pyrolysis method are needed. 

Fig. 5.1 Cyclization of 2,3-oxidosqualene to sterols and triterpenoids. The 2,3-oxidosqualene cyclase enzymes that catalyse the formation of the different products are indicated LS, lanosterol synthase CS, cycloartenol synthase LuS, lupeol synthase PAS, P-amyrin synthase aAS, a-amyrin synthase.

Keywords a-amyrin, diterpenoids. Salvia frigida, p-sitoserol, triterpenoids. 

In our study on the chemical constituents of Salvia frigida Boiss., we report here the isolation and identification of two oleanane type (componnd 1, 2) and two cycloartane type triterpenoids (compound 3,4) with the componnds a-amyrin 5 and P-sitoserol 6. The compounds have been characterized by UV/vix, IR, H NMR, NMR and MS spectroscopy. 

Primary products a- and 8-amyrin (60% 40%) and also other minor triterpenes [44], Synthesises mainly lupeol but also produces at least five other minor triterpenoids [46,47,49]. Primary products 8-amyrin, a-amyrin and lupeol (55 % 30 % 15 %) [47,48]. 

A quick dip of the aerial parts in ether has been used to extract the glandular trichome contents of Salvia glutinosa (194). The main component was the triterpenol, a-amyrin. Small amounts of flavones and flavonols were also Isolated. 

Licania pyrifolia Grisebach is a small tree widely cultivated in the Amazonian regions of Venezuela for their edible fruits called merecure . The chloroform extract yielded a-amyrin, P-sitosterol, lupeol, betulin,... 

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