Monoterpenoids from

Determination of enantiomeric distribution of monoterpenoids from geranium oil... 

NT532 Behr, D., 1. Wahlberg, T. Nishid, and C. R. Enzell. Tobacco chemistry. 45. (2E,6S) 2,6 dimethyl 2,7 Octadiene-1,6-diol, a new monoterpenoid from Greek tobacco. Acta Chem Scand Ser B 1978 32 228-234. 

Kuwahara, M., Suzuki, K. and Hiramatsu, A. (1992c). Synthesis of robinal, a highly conjugated monoterpenoid from the mite Rhizoglyphus robini. Bioscience, Biotechnology and Biochemistry 56 1510-1511. 

Sakata, T, Okabe, K. and Kuwahara, Y. (2001). Structure elucidation of twelve novel esters between five fatty acids and three branched new alcohols along with four monoterpenoids from Sancassania shanghaiensis (Acari Acaridae). Bioscience, Biotechnology and Biochemistry 65 919-927. 

Determination of enantiomeric distribution of monoterpenoids from geranium oil Fused silica Supelcowax 10 capillary column, (60 m X 0.32 mm i.d. 0.25 pjn film thickness)... 

Dimethylethylcydohexanes.—Two new halogenated monoterpenoids are violacene (150) from Plocamium violaceum,250 a 1,4-dimethyl-1-ethylcyclohexane which can be rationalized biosynthetically from the cyclization of an acyclic precursor via a bromonium ion, and plocamene B (151), again from Plocamium violaceum, which may be the first member of a series of non-isoprenoid monoterpenoids from this species.251... 

In this article the gas-chromatographic methods adequate for an analysis of chiral monoterpenoids are presented. Recent results on the enantiomeric composition of monoterpenoids from different species of plants are discussed. The bioactivity of selected chiral monoterpenoids is also described. 

A new halogenated monoterpenoid from Aplysia californica is (64) which is related to the previously reported (65) (Vol. 6, p. 20), although the latter probably has a different stereochemistry the previously reported (Vol. 6, p. 20) dibromotrichloro-monoterpenoid can now be assigned the structure (61 X = CH2Br) and a third new compound may tentatively be assigned the structure (66). ... 

New brominated monoterpenoids from Cymopolia barbata include cymopol [E-(249 X = H2)], the bromonium-ion-catalysed cyclization product, cyclocymopol (250), whose AT-ray structure has been determined, cymopolone and isocymopolone [E- and Z-(249 X = O) respectively], and cymopochromenol (251). ... 

A cell-free extract from T. vulgare has been prepared that synthesized geraniol and nerol from [2- C]MVA and [4- " C]IPP in high yield (2.4% and 11.9% respectively). Dimethylvinylcarbinol was also incorporated efficiently into monoterpenoid alcohols by the system and this raises the important issue as to its role in monoterpenoid biosynthesis. Both dimethylvinylcarbinol pyrophosphate and DMAPP inhibited the formation of monoterpenoids from (3/ )-[2- C]MVA by the cell-free preparation, and the marked change in the proportions of geraniol and nerol produced in the presence of these additives led to the conclusion that two prenyltransferases were present in the system. The cell-free extract also incorporated [9,10- C2]-a-terpineol and [7- C]terpinen-4-ol into isothujone. The cyclase activity appeared to be associated with a particulate fraction. 

Fig, 6,34 Chiral monoterpenoids from Mentha-species (from ref [94])... 

Fig, 6,35 Simultaneous enantio-MDGC analysis of chiral monoterpenoids from Mentha-species, pre column (A), main column (B) (from ref [94])... 

In Fig. 6.44 characteristic monoterpenes and monoterpenoids from lemon oils are compared. By introducing the i-IST method the individual influences of provenance are eliminated. 

A second type of analysis is undertaken to ascertain the effect of some extraneous factor on a plant. Examples are the studies made on the effect of various metabolites or inhibitors that might change the monoterpenoid production of a commercial crop such as roses. Effect of seasonal change on the composition of monoterpenoids from Rosmarinus officinalis, particularly in the spring, has been examined.The fact that the bark beetles Dendroctonus brevicomis and D. ponderosae preferentially attack Pinus ponderosa trees that have been injured by photochemical air pollution suggested study of the monoterpenoid composition... 

Fig. 7.2 Monoterpenes/monoterpenoids from floral and vegetative volatile emissions of Nicotiana spp. (Solanaceae)...

Although the three C-10 aroma components (276) to (278) are monoterpenoids from a formal point of view, they should probably be considered as degradation products of corresponding carotenoid compounds. At any rate, this assumption was made for the formation of safranal (277) (527), the main component of saffron oil (72, 727). The ketone (278) has only been detected in Burley tobacco (777, 502). P-Cyclocitral (276) and safranal (277) were also shown to be present in tea (491). 

Tange K 1981 The biosynthesis of monoterpenoids in higher plants. The biosynthetic pathway leading to the monoterpenoids from amino acids with a carbon-skeleton similar to mevalonic acid. Bull Chem Soc Jpn 54 2763-2769... 

Sampli, P Tsitsimpikou, C Vagias, C., Harvala, C and Roussis, V. (2000) Schimperiol, a new monoterpenoid from the brown alga Stypopodium schimperi. Nat. Prod. Res., 14, 365-372. 

Several other commercially available natural insect repellents also use monoterpenoids from oils of cinnamon, lemongrass, rosemary, and lemon eucalyptus. Other specific monoterpenoids used as active ingredients in repellents are phenylethyl propionate (from peanuts) and p-menthane-3,8-diol (from lemon eucalyptus) (Figure 5.1). 

Bxe enzymology of monoterpene biosynthesis has been extensively studied particularly in Salvia species. Systems have been obtained which mediate the formation of mono- and bicyclic monoterpenoids from geranyl pyrophosphate. Not unexpectedly the key enzyme systems are at their most active during maximum... 

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