Fragrant Components

Fresh wood after cutting has a characteristic odor that diminishes continuously over time. However, some species retain a fragrance for a long time, which gives them an additional value. The odor constituents of wood are formed as secondary metabolites by species-specific biosynthetic pathways, like the coloring matter described in the previous section. Therefore the odor of wood can sometimes be used for the identification of wood species. 

The fragrant components of the major conifer woods are summarized in Table 9.1.2 (11, 18). Since larger amounts of these essential oils are formed when the living tree is wounded, it is presumed that they protect the tree and preserve it from decay, repel insects, act as a waterproofing, etc. Some of these components emitted from the leaves into the atmosphere act as phytocides, the so-called green showers that are coming into popular concern. The odors of the hardwoods are more varied than those of conifer woods. Some species are used for 

Hernandia peltata Lindera umbellata Liquidambar orientalis Magnolia kobus Ocotea pretiosa Octomeles sumatrana Populus spp. 

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F.l Citral is a fragrant component of lemon oil that is used in colognes. It has the molecular structure shown. Calculate the mass percentage composition of citral (black = C, gray = H, red = O). 

Figure 1 Coexistence of the past and present techniques in F F industry classical enfleurage process (photo on the left) and a supercritical carbon dioxide extraction facility as modern factory equipment (on the right). The photo on the left shows a stock of jasmine flowers in the basket (center) that are spread upon a wooden frame (chassis) that secures a glass plate coated with fat. The chassis is then piled to allow diffusion of fragrant components (note that the fat is applied on both sides of the glass plate to gain access to the headspace volume made by the chassis underneath). Enfleurage process photo reproduced from E. Guenther, The Essential Oils with permission from Krieger Publishing Company Melbourne, FL, USA, 1948 (reprinted 2006) Vol. 1, p 192.

Zhang L, Xiang ZM, Bi LJ, Xie ZZ, Chen L. Gas chromatographic-mass spectrometric determination of fragrant components of crimson glory fresh flowers extracted by supercritical carbon dioxide. Sepu 1996 14 438-440. 

As discussed under alcohols, esters are the condensation products of alcohols and acids. They also are good organic. solvents, insoluble in water. Many found in nature arc flavorful and sweet smelling amyl acetate is the fragrant component of banana oil ( amyl is a traditional name for the 5-carbon... 

One of the fragrant components in mint plants is menthene, a compound whose lUPAC name is l-isopropyl-4-methylcyclohexene. Draw a structural formula for menthene. 

Hydroxy-4-phenylbutan-2-one is a fragrant component of wisteria flowers. 

Perillene, a monoterpenoid furan derived from p-myreene, is a eonstituent of the essential oil obtained from Perilla citridora (Labiatae) among other monoterpenes, it also occurs in the pheromones of some mites and acts as a defense pheromone of the ant Lasius fulginosus. The isomerie rose furan is a fragrant component of the oil of rose obtained from fresh flowers of Rosa damascena (Rosaceae). 3-(4-Methyl-3-pentenyl)thiophene and derived eyclic tri- and tetrasulfides (1,2,3-trithiepine and 1,2,3,4-tetrathiocine) are found in the oil of hops. 

Following are an infrared spectrum and a structural formula for methyl salicylate, the fragrant component of oil of wintergreen. On this spectrum, locate the absorption peak(s) due to (See Examples 11.2,11.3)... 

The present methods are very useful for the production of medicinal and agricultural drugs as well as fragrant components from commercially available cheap, natural, and unnatural terpenoids or a large amount of terpenoids from higher medicinal plants and spore-forming plants like liverworts and fungi. 

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