Eucalyptus dives

The method has been criticised by H. G. Harding, who states that a pure white oil from Eucalyptus dives, which contained no cineol, showed an absorption of 32 per cent, by the resorcinol test. Rectifying the oil and applying the test to the portion distilling between 170° and 190° does not entirely remove the difficulty, as the results are always slightly high. 

Separation of terpinen-4-ol enantiomers performed by a chiral GC columnand a chiral lanthanide shift reagent Eu(hfc)3, showed that the enantiomeric composition of an isolated compound from sweet marjoram oil was 73% (5)(- -) 27% R) —). The (4f )(—)-enantiomer was found in the oil of Eucalyptus dives Terpinen-4-ol was also found in several bark beetle species and is the main component in the aggregation pheromone of Polygraphuspoligraphus ... 

Mentholfrom (—)-Fiperitone or Piperitol. (—)-Menthol can also be prepared from (-)-piperitone, the main component of Eucalyptus dives Typus oils. Hydrogenation in the presence of Raney nickel yields a mixture of menthols, from which (—)-menthol can be separated by crystallization and saponification of its chloroacetate. 

Eucalyptus dives oil is obtained by steam distillation of fresh leaves of Eucalyptus dives, Schau, piperitone-type, grown in Australia and South Africa. 

The main essential oil-producing species of Eucalyptus include Eucalyptus globulus, also called blue gum eucalyptus Eucalyptus dives, known as broadleaved peppermint eucalyptus Eucalyptus citriodora, known as lemon-scented eucalyptus Eucalyptus radiata, known as narrow-leaved peppermint gum Eucalyptus smithii, known as gully gum and Eucalyptus polybractea, known as blue mallee. Within each species there are many subspecies and chemo-types. This illustrates a very complex situation, producing essential oils with varying compositions and properties. 

Piperitone Mentha spp. (Lamiaceae), Eucalyptus dives OD-R (camphor- ... 

Eucalyptus dives, but the (+ )-(S)-isomer has been isolated from Mentha ... 

All the stereoisomers of the 5-menthene-l,2-diols (646A-D) are naturally occurring. The first one, 646A, has been known for some time to occur in Eucalyptus dives,the three other diols were identified from the most polar fraction of Chenopodium multifldum oil. The isomer 646A can be obtained by microbial hydroxylation of (+ )-(S)-phellandrene (512) with Corynespora... 

The essential oil of Eucalyptus dives contains L-piperitone and this provides a starting material for L-menthol using the process shown in Scheme 4.25. The L-piperitone is reduced to a mixture of piperitols, which are separated, and the major isomer, D-/ra j-piperitol, hydrogenated to give D-isomenthol containing a small amount of D-menthol. After purification, the former can be isomerized into L-menthol using aluminium isopropoxide as catalyst. About 30 tonnes per annum of l-menthol are produced by Keith Harris Co. in Australia using this route. 

The last synthesis of menthol which we will discuss, starts from /-piperitone which occurs in various species, especially peppermint. However, it is also a major component of Eucalyptus dives which made it an item of commerce in Australia. The Australian company, Keith Harris and Co, used to prepare /-menthol from this indigenous feedstock. The overall scheme is shown in Figure 4.27. 

Isopinocamphone is the main constituent of oil of hyssop, Hyssopus officinalis (Lamiaceae), imparting the typical mucolytic properties of ketones, while muscle relaxant activity has been demonstrated in vivo (Lu et al. 2002). Piperitone is the main constituent of the leaf oils of the so-called peppermint group of the genus Eucalyptus. An example is the broad-leaf peppermint. Eucalyptus dives, an excellent, non-irritant mucolytic agent for sinus congestion and bronchitis (Schnaubelt 1995). 

Myrcene (70) is very widespread in nature. Some sources, such as hops, contain high levels and it is found in most of the common herbs and spices. All isomers of a-ocimene (84), b-ocimene (85), and alio ocimene (86) are found in essential oils, the isomers of b-ocimene (85) being the most frequently encountered. Limonene (73) is present in many essential oils, but the major occurrence is in the citrus oils that contain levels up to 90%. These oils contain the dextrorotatory (/ ) -enantiomer, and its antipode is much less common. Both a phellandrene (87) and b phellandrene (88) occur widely in essential oils. For example, ( ) a phellandrene is found in Eucalyptus dives and (5)-(-)-b-phellandrene in the lodge-pole pine, Pinus contorta. p Cymene (83) has been identi ed in many essential oils and plant extracts and thyme and oregano oils are particularly rich in it. a-Pinene (65), b-pinene (7, and 3-carene (77) are all major constituents of turpentine from a wide range of pines, spruces, and rs. The pinenes are often found in other oils, 3 carene less so. Like the pinenes, camphene (89) is widespread in nature. 

A ketone has also been isolated from the oil of Eucalyptus dives Which Smith has termed piperitone. This body, of the formula OK HigO, has the following characters —... 

Wales form of Eucalyptus amygdalina is almost twice that obtained with the Tasmanian trees, and even Eucalyptus dives appears to yield a greater quantity of oil than does the Eucalyptus amygdalina of Tasmania. The oil of the Tasmanian Eucalyptus amygdalina differs from that of the New South Wales form in that it contains much less eucalyptol, has a very high laevo-rotation, contains more phellandrene, and is much less isoluble in alcohol. The odour of the oil is also much less aromatic. The oil has the followii characters —... 

Phellandrenes Both a-phellandrene [99-83-2] (106) and 3-phellandrene [555-10-2] (107) occur widely in essential oils. (—)-a-Phellandrene can be isolated from Eucalyptus dives oil. A particularly rich source of (S)-(—)- 3-phellandrene is the lodgepole pine, Pinus contorta. (5)-(—)-(3-Phellandrene [6153-17-9] (110) is found at a level of 2% in the southeastern United States turpentine and processing the turpentine gives a fraction containing 28% (—)-(3-phellandrene and 62% (—)-limonene [5989-54-8] (111). The (—)- (3-phellandrene in the fraction can be selectively hydrochlorinated to piperityl chloride (116) as the first step in an 1-menthol synthesis, details are given below in the entry on menthol. 

Piperitone (194) can be extracted commercially form Eucalyptus dives. Reduction with lithium aluminium hydride gives a mixture of (—)-c -piperitol (190) (36%) and (-l-)-/ra 5-piperitol (191) (64%), which are then separated (237). The (-l-)-/ra/Js-piperitol is then hydrogenated over Raney-nickel to give Keith Harris Co. once produced 30 tpa of /-menthol using it (154). 

Other materials used similarly include piperitone (194) and pulegone (187). The former is usually isolated from the oil of Eucalyptus dives, but some is also synthesized from limonene (82). It has a fresh minty, camphoraceous note, and finds some use in perfumes (largely for masking), but more in flavors, such as caraway and tarragon. It is also used as a mint flavor ingredient in oral care products. 

Eremophila mitchelH Eucalyptus dives Eucalyptus dumosa False sandalwood Broad-leaved peppermint White mallee <20 <20 20-A0 <20... 

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