O-Pinene

The oil contains f-o-pinene, and a sesquiterpene ( ) of specific gravity 0 9340, speciHc rotation - 21 24, and refractive index I 49fi0 at 16°. 

It is obtained from American turpentine as dextro-o-pinene, or from French turpentine as laevo-a-pinene. It is also obtained in a very pure form as dextro-a-pinene from Greek oil of turpentine. Optically inactive o-pinene can be obtained by regeneration from the nitrosochloride. The purest specimens of a-pinene yet obtained have the following characters —... 

Sometimes, on account of the difiiculty in preparing the nitroso-chloride from a highly active o-pinene, it is necessary to examine the oxidation products before it is possible to come definitely to a conclusion as to the presence or absence of the hydrocarbon. Pinene yields numerous acids as the result of oxidising processes, so that the method of preparing the product to be examined must be rigidly adhei ed to if useful results are to be obtained. The terpene is transformed into pinonic acid, CjoHj Og, in the following manner A solution of 233... 

An alkene, sometimes caJled an olefin, is a hydrocarbon that contains a carbon-carbon double bond. Alkenes occur abundantly in nature. Ethylene, for instance, is a plant hormone that induces ripening in fruit, and o-pinene is the major component of turpentine. Life itself would be impossible without such alkenes as /3-carotene, a compound that contains 11 double bonds. An orange pigment responsible for the color of carrots, /3-carotene is a valuable dietary source of vitamin A and is thought to offer some protection against certain types of cancer. 

The same author,3 .s and also Ritter and Ruaeel,1448 reported that o-pinene oxide, on the other haud, undergoes a deop-seated skeletal rearrangement under the same conditions, as shown in Eq. <446). 

C4H7Br02 Ethyl bromo- 158.2 CeHsBr Bromobenzene 156.1 CioHn o-Pinene 155.8 <152.3 243... 

Gas-phase ozonolyses of ethene, cis- and trans-but-2-ene, isoprene, as well as several monoterpenes such as o-pinene, /3-pinene, 3-carene, limonene, and /3-myrcene have been performed by trapping the reaction products in C>2-doped argon matrices and recording the IR spectra <2000SAA2605>. Bands characteristic for the secondary ozonides were identified after bleaching by broad-band UV-Vis photolysis. In the case of isoprene 34, a secondary ozonide appears to be formed more likely at the more substituted double bond however, the two possible carbonyl compounds 35 and 36 could not be put into evidence by infrared (IR) in the reaction condensate as these reacted further with O3 (Scheme 6). 

Epoxidation. The two reagents (premixed in CHC13) can serve as a catalyst for epoxidation of alkenes in H20 by H202 (60% yield). In some cases (hexene, o-pinene) addition of trimethylamine is essential for high yields, 57-87%. Surprisingly, addition of a phase-transfer catalyst depresses the yield. 

H. C. Brown, P. V Ramachandran, Asymmetric Reduction with Chiral Organoboranes Based on o-Pinene, Acc. Chem. Res. 1992, 25, 16-24. 

Fig. S. Run numbei of poly(i o-butylene o-/ -pinene) vs. copolymer composition...

Regardless of their apparent structural differences, all terpenoids are related. According to a formalism called the isoprene rule, they can be thought of as arising from head-to-tail joining of 5-carbon isoprene units (2-methyl-1,3-butadiene). Carbon 1 is the head of the isoprene unit, and carbon 4 is the tail. For example, myrcene contains two isoprene units joined head to tail, forming an 8-carbon chain with two 1-carbon branches. cv-Pinene similarly contains two isoprene units assembled into a more complex cyclic structure, and humulene contains three isoprene units. See if you can identify the isoprene units in o-pinene and humulene. 

Radiation-Induced Cationic Polymerization of Limonene Oxide, o-Pinene Oxide, and - ene Oxide... 

In comparison with the catalytic cationic polymerization of these monomers (14), It Is remarkable that the radiation-induced polymerization gives high conversions at room temperature to a preclpltatable polymer. Although the catalytic polymerizations (14) were carried out in solution between -78 and -130°C under conditions which should minimize the formation of dimer oils and monomer rearrangement products, the highest reported conversion of a-pinene oxide to polymer was only 28%, and In this case the material was described as a viscous oil. Conversions to polymer In the form of a white powder varied from 1 to 20% although 76-100% of the o-pinene oxide... 

Oil of Cedar Leaf. Cedar leaf oil. Obtained by steam distillation from the fresh leaves of Thuja occidentalis L, Cupressaceae. Although this oil is known commercially as cedar leaf oil, the tree from whose leaves it is obtained is not a true cedar it is a coniferous tree popularly known as "arbor vitae, sometimes erroneously called white cedar. Habit. Canada and Northern U.S. Constit. o-pinene, d-ikujone, a -fenchone. 

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