Alcohol natural occurrence

The oxidative cyclization of the alcohol (214) with ceric ammonium nitrate gave a mixture of the two naphthopyrans (215) and (216) in a ratio of 3 1 (81CC534). The reaction is of interest because of the natural occurrence of quinones containing the naphtho[2,3-c]pyran ring system. 

The general term oxypyrazine is used here to include derivatives such as the cy-cloamidic tautomeric pyrazinones (1), the alcoholic hydroxyalkylpyrazines (2), the etherial alkoxypyrazines (3-5), the cycloamidic nontautomeric pyrazinones (6), and pyrazine A-oxides (7, 8) in addition, related types like diketopiperazines, acy-loxypyrazines, pyrazine quinones, and endoperoxypyrazines are covered as appropriate. Some brief ancillary information on trivial names, natural occurrence, and biological activities of pyrazines (mainly oxy derivatives) is collected in a final Appendix section. 

Cyclohexane monoterpenes are a chemically diverse group of monoterpenoids that occur in the plant kingdom mainly as hydrocarbons, alcohols, ketones, aromatic hydrocarbons, and phenols (Fig. 5). The saturated hydrocarbon trans-p-menthme (El) is a constituent of the oil of turpentine and the resin of pine (Pinaceae) trees. Its unsaturated analogs, namely (i )-(- -)-limonene (E2) [present in oil of orange (Citrus aurantium) and mandarin (Citrus reticulata, Rutaceae) peel oil] a-terpinene (E3) and terpinolene (E4) in some Citrus, Juniperus, Mentha and Pinus species (i )-(-)-a-phellandrene (E5) in Eucalyptus phellandra (Myrtaceae) and (5)-(- -)-3-phellandrene (E6) in water feimel (Phel-landrium aquaticum, Umbelliferae), are components of many plant volatile oils. The rich chemical diversity of cyclohexane monoterpene alcohols is apparent from the natural occurrence of all four pairs of / -menthan-3-ol enantiomers, for... 

Starch.- —While many fermented liquors obtain sugar for conversion into alcohol from sources indicated above by far the largest single source of sugar, especially for distilled liquors, is the poly-saccharide, starch. Its importance arises from the fact that by suitable treatment almost 100% conversion of starch into fermentable sugars, dextrose, maltose, etc. can be obtained. Hence the general nature, occurrence and physical and chemical properties of starch are of major interest in the fermented liquor industry. 

Further on, a wide variety of esters were detected containing specific molecular moieties characterizing man made chemicals. E.g. the 2-ethylhexyl group represents a molecular substructure frequently used in the technosphere dominantly as the corresponding alcohol or acid, but the natural occurrence of this molecular moiety is very scarce. Thus, the detected 2-hydroxypropylester of 2-ethylhexanoic acid represents a specific anthropogenic contaminant. The fro-propyl and butyl esters identified also reflect mainly the emission of technical contaminants chiefly derived from migration processes of polymer additives. 

R = CH3, C10H12O2, Mr 164.20, 101.3 kPa 232.6 °C, dg 1.0883, ng 1.5171, occurs in a number of essential oils and is a volatile aroma component of many fruits and alcoholic beverages. Phenethyl acetate is a colorless liquid with a fine rose scent and a secondary, sweet, honey note. It is used in perfumery as a modifier of phenethyl alcohol, e.g., in rose and lilac compositions. In addition, it is used in a large number of aromas, in keeping with its natural occurrence. 

Rendstrom, B., Borch, G., and Liaaen-Jensen, S. 1981b. Natural occurrence of enantiomeric and meso-astaxanthin. 4. Ex-shrimp (Pandalus borealis). Comp. Biochem. Physiol. 69 B, 621-624. Renaud, S. and Lorgeril, M. 1992. Wine, alcohol, platelets and the French paradox for coronary heart... 

The first known natural occurrence of a 2,6-naphthyridine has been reported. Thin-layer chromatography of an alcoholic extract of the plant above gave a base (CgHgNg mp 78°) whose spectral examination indicated that it is 4-methyl-2,6-naphthyridine (19). Other possible isomers were excluded on the basis of the NMR spectral data 14, 15). The same base was also isolated from A. orontium L. 16). 

In this chapter are tabulated 56 compounds accepted as bile acids and alcohols of natural occurrence. This does not include several that occur as isomers but are listed as a single compound. The list presented here could easily be modified by reexamination of the literature, particularly in the direction of compounds which have been identified as metabolites under conditions that promise their natural occurrence if only in trace amounts. Furthermore, the list will grow in subsequent years as new compounds are identified. 

The term terpene is used to describe a compound, which is a constituent of an essential oil containing carbon and hydrogen or carbon atoms, hydrogen, and oxygen atoms, and is not aromatic in character [24, 25]. This definition is usually extended to include other compounds called terpenoids, which are not of natural occurrence but are very closely related to the natural terpenes. Most terpenes, which include terpenoids, are invariably hydrocarbons, alcohols, aldehydes, ketones, or oxides, and they may be solids or liquids. Terpene hydrocarbons are usually liquids, while terpenes of higher molecular weights, mostly obtained from the natural gums and resins of plants and trees, are not steam volatile. 

Terpene compounds have natural occurrence in plants found as major components of most of the plant essential oils. Based on their structural and functional properties, terpene compounds have been classified according to their basic structural unit isoprene containing five carbons, fii the formation of terpenes, prenyldi-phosphate serves as a precursor. The terpene compounds exist in the form of mono-, sesqui-, hemi-, di-, tri-, and tetraterpenes. The mmioterpenes containing two isoprene units are responsible to cmistruct the major portion of all the essential oils. These compounds work as carbure, alcohol, aldehyde, ketone, ester, ether, peroxyde, and phenols [58]. The sesquiterpene compounds contain three isoprene units, and the functional properties are very close to monoterpene compounds. 

Together with (H-)-pulegone (78%) [derived from alcohol (49)], two new /7-menthene ketones, viz. (+)-4-hydroxypiperitone (92) 410) and ( —)-8-hydroxy-4-/7-menthen-3-one (93) 411), were isolated from Seto-mint grown in the Tokai area. Both hydroxyketones (92) and (93) develop a strong minty odor impression 443). A detailed report on the natural occurrence, the methods of preparation and the chemistry of piperitone [carbonyl derivative of (48)] and related compounds was published recently 422). 

In our poster presentation earlier in this conference we reported finding dodecenyl alcohol and tetradecenyl alcohol in four varieties of untreated apples at concentrations ranging from 70-130 ppb. The natural occurrence of these compounds in apples had been reported in 1976, but not quantitated (5). The irony is that they are two of the five components in an experimental lepidopteran insect sex pheromone for which residue determinations were made of all components on treated apples. This full season application included 52 g/ha and 10 g/ha of dodecenyl alcohol and tetradecenyl alcohol, respectively. These were minor constituents, the major component was 106 g/ha of E,E-8,10-dodecadien-l-ol. No increased levels of the saturated alcohols were detected in fruit from treated orchards, and none of the latter, major component, was detectable above 10 ppb, our level of sensitivity (Spittler, T. D., Leichtweis, H. C. and Kirsch, P. Manuscript in preparation). 

Phenyl-2-propen-l-ol [104-54-1], commonly referred to as cinnamyl alcohol, is a colorless crystalline soHd with a sweet balsamic odor that is reminiscent of hyacinth. Its occurrence in nature is widespread as, for example, in Hyacinth absolute (Hyacinthus orientalis) (42), the leaf and bark oils of cinnamon Cinnamomum cassia, Cinnamomum lancium, etc), and Guava fmit [Psidiumguajava L.) (43). In many cases it is also encountered as the ester or in a bound form as the glucoside. 

Although the biosynthetic cascade hypothesis predicts the co-occurrence of endiandric acids D (4) and A (1) in nature, the former compound was not isolated until after its total synthesis was completed in the laboratory (see Scheme 6). Our journey to endiandric acid D (4) commences with the desilylation of key intermediate 22 to give alcohol 31 in 95% yield. The endo side chain is then converted to a methyl ester by hydrolysis of the nitrile to the corresponding acid with basic hydrogen peroxide, followed by esterification with diazomethane to afford intermediate 32 in 92% overall yield. The exo side chain is then constructed by sequential bromination, cyanide displacement, ester hydrolysis (33), reduction, and olefination (4) in a straight-... 

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