Pinenes borneol from

The most straightforward method involves the conversion of pinene [l] into pinene hydrochloride [2], bornylchloride [3] and hence into borneol [6] (or iso-borneol) from which camphor [7] is obtained by oxidation. Also bornylchloride [3] is converted to isobro-nylacetate [5] upon heating with sodium acetate and glacial acetic acid. Alternatively, c-amphene [U] is oxidatively hydrated to camphor [7]-... 

FIGURE 11.5 Terpenoids, (a) The basic five-carbon units isopentane and isoprene. (b) The monoterpenes borneol and a-pinene. (c) A monoterpene lactone, nepetalactone. (d) A sesquiterpene, germacrone. (e) A triterpene, papyriferic acid, from paper birch. 

Detailed study of the coriander spice oil composition showed that the d-linalool content ranged from 60 to 70% and the hydrocarbon content was about 20%. a- and (3-pinenes, dipentene (limonene), p-cymene, a- and y-terpinenes, n-decanal, geraniol and 1-borneol were also identified as constituents of the spice oil. 

During acid sulfite pulping a-pinene and some monocyclic terpenes are partially converted to p-cymene (Fig. 7-18). Crude cymene can be separated from the digester gas relief condensates and purified by distillation. With spruce and fir the distilled product is 99% p-cymene and only minor quantities of other products, such as borneol and sesquiterpenes, are present. Pine wood contains 3-carene, which affords appreciable quantities of m-cymene besides p-cymene. The crude cymene can be used within the mill as a resin-cleaning solvent. The distilled p-cymene finds use in the paint and varnish industry. 

Borneol, camphene, and a-pinene are made in nature from geranyl pyrophosphate. The biosynthesis of a-pinene and the related camphor is described in the chapter. In the laboratory bornyl chloride and camphene can be made from a-pinene by the reactions described below. Give mechanisms for these reactions and say whether you consider them to be biomimetic. 

The main products are monolitic terpenes such as alpha-terpineol 32. Minor amounts of bicyclic compounds (34), e.g. borneol 31, can be observed. Some of these products are of commercial importance as fragrances with lilac and nutmeg odor (monocyclic alcohols like alpha-terpineol or 1-terpinene-4-ol) or with campher-like and extremely delicate pepper odor (bicyclic compounds). In current industrial practice, the bicyclic alcohol borneol 31 is synthesized by a multi-step procedure. Much research has been done to develop clean processes which have high selectivity towards one of the products starting directly from alpha-pinene 30. 

Camphene is a solid terpene. The dextro variety d-camphene is found in camphor, ginger and spike oils, and the levo variety, 1-camphene is in citrondla and valerian oil and in French and American turpentine. Bornylene does not occur in nature but has been prepared from the alcohol corresponding to it known as Borneol or Borneo camphor. This, as previously stated, may be prepared from pinene so that Bornylene itself may be made from pinene. Fenchene, also, is not found in nature but is obtained by reduction of fenchone a terpene ketone found in fennel oil and in Thuja oil. 

Borneol is oxidized to camphor with chromic or nitric acid dehydration with dilute acids yields camphene. Borneol is readily esterified with acids, but on an industrial scale bornyl esters are prepared by other routes. For example, levorotatory borneol is synthesized industrially from levorotatory pinenes by Wagner-Meerwein rearrangement with dilute acid, followed by hydrolysis of the resulting esters [86],... 

It was found that the rate of the reaction and selectivity towards formation of 4 could both be increased by dealumination of the outer surface of the zeolite with Na2H2EDTA. When the solvent was changed to pure acetone a new compound (5) was formed. In this study, the coupling of ketones (acetone, butanone, and cyclohexanone) with 1 was found to be catalyzed solely by zeolite beta. The reaction also seems to be exclusive to a-pinene, because no reaction occurred when other terpenes such as 3, 4, and borneol (6) were used in place of a-pinene. It is also worth noting that borneol (6) has also been prepared from 1 by use of a high-silica zeolite [14],... 

Thymus sp. (thyme) is a common spice that has been extensively studied [116-123]. Thyme is one of the earliest medicinal plants in western herbal medicine. The essential oil isolated from this spice is active in the inhibition of Gram positive and Gram negative bacteria as well as yeast and fdamentous fungi. A major constituent of thyme oil is thymol (91), which has been implicated as the molecule responsible for the activity of this essential oil. Other materials isolated from thyme oil that possess biological activity include carvacrol (92), bomeol (93), p-cymene (37), a-pinene (13) and camphene (94). Thymol (91) was shown to be the most active, followed by carvacrol (92), borneol (93), / -cymene (37), a-pinene (13), and camphene (94) [121]. 

Oil of Rosemary. Volatile oil from fresh flowering cops of Rosmarinus officinalis L., Labiatae. Constit Not less than 10% total borneol not less than 2,5% esters calculated horny] acetate camphor, eucalyptol, pinene, cam phene. 

Definition Essential oil obtained from steam distillation of Saivia iavandulaefolia, contg. essential oil thujone, a-pinene, cineol, borneol, and d-camphor... 

In the elimination of HOTs from exo-2-norbornyl tosylate using the sodium salt of 2-cyclohexylcyclohexanol in triglyme at 80 °C, syn-exo elimination is at least 100 times faster than anti elimination. If 18-crown-6 is added, the rate ratio falls to ca. 15 1, indicating that the presence of the sodium cation is important in the complex transition state of the syn process. Pyrolysis of urethanes of borneol and isoborneol has been re-examined and found to give mixtures including a-pinene, tricyclene, camphene, and alcohols. Pyrolysis of nitrobenzoates gives no alcohols but camph-ene, tricyclene, and bornene. ... 

Plants especially from the Lamiaceae family can inhibit the growth of several weeds by releasing phytotoxic monoterpenes (a-pinene, P pinene, camphene, limonene, a-phellandrene, p-cymene, 1,8-cineole, borneol, pulegone, and camphor) (Angelini et al., 2003). The herbicide effect of 1,4-cineole and 1,8-cineole is also described by Dayan et al. (2012). Plants that are exposed to essential oils often metabolize them, and when citral was added geraniol, nerol and their acids appeared. When citronellal metabolization was tested, citronellol and citronellic acid were formed, and with pulegone (iso)-menthone, isopulegol and menthofuran were found (Dudai et al., 2000). 

---