Triterpenes chemistry

Triterpenes are C30 compounds, produced from two molecules of famesyl pyrophosphate (FPP) condensed head-to-head. Representative structures are shown in Fig. 20. The compounds shown represent only a few of the many triterpenes found in plants. They are chosen to suggest the great variety of structures and to illustrate specifically some of the compounds that have played, or are playing, key roles in studies of triterpene chemistry and biochemistry. For a detailed survey of triterpene structures the reader is referred to Connolly and Overton (1972) and Ourisson et al. (1964), as well as Devon and Scott (1972). Analytical techniques for triterpenoids, and the distribution of triterpenoids in plants, have been reviewed by Rastogi and co-workers (Kulsh-reshtha et al., 1972 Pant and Rastogi, 1979). Chandler and Hooper (1979) have recently reviewed the literature on fiiedelin and associated triterpenes. 

R.S. Pardhy, S.C. Bhattacharyya, P Boswellic acid, acetyl P boswellic acid, acetyl 11 keto P boswellic acid and 11 keto P boswellic acid, four pentacyclic triterpene acids from the resin of Boswellia serrata Roxb, Indian Journal of Chemistry, 16B, 176 178 (1978). 

A good example of the simplicity and power of the chemistry to rapidly construct complex systems is provided by the Kolbe dimerization of (55) as the key step of a total synthesis of the triterpene (+)-Q -onocerin (57 Scheme 14) [33], Thus, oxidation of (+)-hydroxy keto acid (55) in methanol containing a trace of sodium methoxide and at a temperature of 50 C, followed by acylation and chromatography, provided (+)-diacetoxydione (56) in a 40% yield. 

Triterpenes, structural chemistry, 136 Tropopause, emissions model, 605 Troposphere ozone analysis, 605 trifluoromethyl peroxynitrate, 743 Tryptophan... 

Nishibe, S., H. Tsukamoto, I. Agata, S. Hisada, K. Shima, and T. Takemoto. Isolation of phenolic compounds from stems of Olea europaea. Shokugaku Zasshil981 35 251-254. Tsukamoto, H., S. Hisada, and S. Nishibe. Studies on the lignans from Oleaceae plants. Proc 26th Symposium on the Chemistry of Natural Products, Kyoto, Japan 1983 26 181—188. Paganuzzi, V. Use of silver nitrate TLC in the analysis of olive oil triterpene alcohols. I. Oils obtained from various anatomical parts of the olives. Riv Ital Sostanze Grasse 1981 58(8) 285-393. 

Limonoids are a group of chemically related triterpene derivatives found in the Rutaceae and Meliaceae. Limonin, a bitter member of the group, occurs widely in citrus juices. It has commercial significance because bitterness (excessive bitterness in the case of grapefruit) reduces juice quality. Dreyer (1) and Connolly et al. (2) have reviewed the chemistry and biochemistry of limonoids. 

Poralla K (1999) Cycloartenol and other triterpene cyclases. Comprehensive Natural Products Chemistry, Vol 2. Elsevier, Amsterdam, pp 299-319. 

Chemistry of Cytochrome P450 Monooxygenases, Glycosyl Transferases and Methyl Transferases Metabolic Engineering Steroid and Triterpene Biosynthesis Terpenoid Biosynthesis... 

Triterpenes forms an important group of natural products widely distributed in the plant kingdom. The chemistry and distribution of triterpenoids have been reviewed [75,208] and many studies have been stimulated by a variety of biological properties exhibited by triterpenes and triterpene glycosides. 

G. R. Mallavarapu "Recent Advances in Oleanane Triterpenes in A.U. Rahman Studies in Natural Product Chemistry. Elsevier Science Publ. B.V., Amsterdam, 7 (1990), 131. 

The Beilstein-Institut also took over the publication of Elsevier s Encyclopaedia of Organic Chemistry. Following the publication of four parts of Supplement V of the fourteenth volume of Elsevier on steroids and triterpenes (in English, but under the auspices of the Beilstein-Institut), further volumes will appear in the Beilstein Handbuch series. 

The chemistry of echinoderms, particularly the Holothuroidea (sea cucumbers) is characterized by the presence of saponins (triterpene glycosides) and sterol sulfates. Saponins are released by the sea cucumber s Cuvier gland when the organism is threatened. A number of biosynthetic investigations have addressed the origins of saponins and have yielded conflicting results. 

---