Fatty acids alicyclic

Table 6. Some Fatty Acids with Alicyclic Substituents...

More than 600 different carotenoids from natural sources have been isolated and characterized. Physical properties and natural functions and actions of carotenoids are determined by their chemical properties, and these properties are defined by their molecular structures. Carotenoids consist of 40 carbon atoms (tetraterpenes) with conjugated double bonds. They consist of eight isoprenoid units j oined in such a manner that the arrangement of isoprenoid units is reversed at the center of the molecule so that the two central methyl groups are in a 1,6-position and the remaining nonterminal methyl groups are in a 1,5-position relationship. They can be acyclic or cyclic (mono- or bi-, alicyclic or aryl). Whereas green leaves contain unesterified hydroxy carotenoids, most carotenoids in ripe fruit are esterified with fatty acids. However, those of a few... 

Alicyclic hydrocarbons are saturated carbon chains that form ring structures. Naturally occurring alicyclic hydrocarbons are common (Chap. 1). For example, alicyclic hydrocarbons are a major component of crude oil, comprising 20-67 vol.%. Other examples of complex, naturally occurring alicyclic hydrocarbons include camphor (a plant terpene) and cyclohexyl fatty acids (components of microbial lipids). Anthropogenic sources of alicyclic hydrocarbons to the environment include fossil-fuel processing and oil spills, as well as the use of such agrochemicals as the pyrethrin insecticides (Chap. 1, and references therein). 

The principal constituents of rosin (qv) are abietic and related acids. Tall oil (qv) is a mixture of unsaturated fatty and alicydic acids of the abietic family. Refined tall oil may be high in rosin acids or unsaturated acids, depending on the refining process. Ethoxylates of rosin acids, eg, dehydro abietic acid, are similar to fatty acid ethoxylates in surfactant properties and manufacture, except for their stability to hydrolysis. No noticeable decomposition is observed when a rosin ester of this type is boiled for 15 min in 10% sulfuric acid or 25% sodium hydroxide (90). Steric hindrance of the carboxylate group associated with the alicyclic moiety has been suggested as the cause of this unexpectedly great hydrolytic stability. 

DCA is the first bile acid whose inclusion ability was confirmed in the crystalline state. During the last century many research groups dealt with the inclusion compounds of DCA with various guest molecules, such as aliphatic, aromatic and alicyclic hydrocarbons, alcohols, ketones, fatty acids, esters, ethers, nitriles, peroxides and amines, and so on [2], In 1972, Craven and DeTitta first reported the exact crystal structure of DCA with acetic acid [3], Subsequent crystallographic studies made clear that most of DCA inclusion crystals have bilayer... 

R Dreher, K Poralla, WA Konig. Synthesis of w-alicyclic fatty acids from cyclic precursors by Bacillus subtilis. J Bacteriol 127 1136-1140, 1976. 

RC-OH, where R may be a straight-chain saturated (alkyl) or an unsaturated (alkenyl) hydrocarbon residue in the more prevalent naturally occurring fatty acids the R group may vary in chain length from Cn to C23 and may contain in addition hydroxy, keto, branched, or even alicyclic substitiuents. Inasmuch as it is not possible to consider here in depth all of the naturally occurring fatty acids, emphasis will be placed on the more commonly encountered types. 

Watkinson [1988] lists some surfactants used for their dispersing action in organic liquids. He includes amongst them organic and metal sulphonates metal phenolates metal dialkyl dithiophosphates sodium dialkyl sulphosuccinates polyoxyethylene alkyl and alicyclic amines monethanol ammonium phosphate salts co-polymers of N-substituted formamide fatty acid phosphates... 

Mass spectral analysis of the municipal refuse-derived oil ( ) identified only two long chain fatty acids with certainty however, not more than traces of aromatics were determined to be present. The manure-derived oil was found to be largely alicyclic hydrocarbon but contained heterocyclic nitrogen and alkyl phenollcs ( ). These claims of the saturated hydrocarbon nature of the oil products are at odds with the reported elemental analyses (see Table I). The low hydrogen to carbon ratios dictate that the oil products must contain a large fraction of aromatic or, at least, highly unsaturated compounds. 

Natural Product Reports consists of critical reviews of literature that has been published, during well-defined periods, on the topics of general chemistry and biosynthesis of alkaloids, terpenoids, steroids, fatty acids, and 0-heterocyclic. aliphatic, aromatic and alicyclic natural products. Occasional reviews provide details of techniques for separation and spectroscopic identification, and describe methodologies that are useful to all chemists and biologists actively engaged in the study of natural products. 

The main occurrence of cyclopentenyl fatty acids in seeds of Flacourtia-ceae suggests a function as an eneigy reserve to be utilized during germination. The degradability of these alicyclic acids by endogenous enzymes can be deduced from indirect evidence. In the course of jS-oxidation, aleprolic acid must be formed as an intermediate. It has been shown that exogenously added [l- C]aleprolic acid is readily catabolized (Cramer and Spener, 1976). 

When unsaturated fatty acids are subjected to thermolytic cleavage, dimers, polymers and cyclic compounds are produced. The dimers include alicyclic mono-, di-, and triene dehydrodimers, saturated dimers with cyclopentene structures, tetrasubstituted cyclohexanes and bicyclic and tricyclic dimers (Nawar, 1985). Cyclic mononmers exhibit toxicity in experimental animals (Van Gastel et al, 1984), therefore, generation of cyclic monomers at high temperature frying with oils containing polyunsaturated fatty acids should be carefully monitored. 

The non-polar components of waxes can be isolated also as compound classes by adsorption TLC and analysed in a subsequent gas chromatographic procedure these are long-chain hydrocarbons and esters of fatty acids with aliphatic or alicyclic alcohols [2, 149]. 

P. cyclohexanicum sp. nov. was isolated recently from spoiled orange juice (Kusano et al., 1997). The results of phylogenetic analysis of the 16S rRNA gene indicated the highest level of homology with the classical propionibacterium P. freudenreichii, to which it is also similar pheno-typically. co-Cyclohexyl undecanoic acid, an alicyclic fatty acid rarely found in bacteria, is the major cellular fatty acid in the new propionibacterium. P. cyclohexanicum produces large amounts of lactic acid, is acid-tolerant and heat-resistant, which differentiates the new species from the other propionibacteria. 

This section is mainly concerned with the non-volatile, non-nitrogen-containing organic acids. It is restricted to the aliphatic acids and alicyclic acids (except for fatty acids, which are covered in Sect. 6.4.2) the aromatic acids, except for shikimic and quinic acid, are covered in Chap. 7. Since only a limited number of acids have been reported to occur in woody tissues such as bark and heartwood, the acids present in other parts, such as leaves and fruit, are also included. Those found only in herbs are excluded. No attempt has been made to search all the woody plants for the occurrence of these compounds. In the following, a brief introductory explanation about the bioformation and function in plants is described for the respective organic acids (10, 33, 43, 61, 120, 121), and this is followed by tables listing the occurrence of the acid in woody plants, if any. 

Other saturated and unsaturated cyclic esters are more stable to gas chromatography. Methyl 11-cyclohexylundecanoate, a minor constituent of rumen microrganisms and milk fat, is eluted with 18 2(n-6) on a packed column of PEGA and with 18 0 on one of Apiezon [354]. In addition, retention data have been published for some synthetic and natural (o-alicyclic fatty acids on polar and non-polar phases [215,458]. 

Homolipids, which consist of fatty acids linked to various alcohols, are now categorised exclusively by the structure of the bound alcohol. The most common alcohol in natural lipids is glycerol. Rarely occurring alcohols are glycols, higher monohydric aliphatic alcohols, aliphatic and alicyclic terpenoid hydroxy compounds, such as xanthophylls (see Section 9.9.1.2), and various steroid compounds (see Section 3.7.4). 

Aliphatic framework molecules most common in organic acids include alkanes (saturated hydrocarbons) and alkenes (unsaturated hydrocarbons). These saturated and unsaturated aliphatic carboxylic acids may be acyclic (straight or branched chains) or alicyclic (aliphatic rings). Acyclic aliphatic monocarboxylic acids are also referred to as fatty acids (Table 1). The first five saturated acids (formic to valeric) of this type are sometimes referred to as short-chain, low-molecular-weight, or volatile fatty acids. Although a nomenclature for these acids has been established by the International Union of Pure and Applied Chemistry (lUPAC), the convention of using the trivial names for the first five saturated acids has remained. Similarly, trivial names are used for the aliphatic dicarboxylic acids (Table 2) that are saturated with two to four carbon atoms (C2-C4) and unsaturated with four carbon atoms (C4). Alicyclic carboxylic acids contain one or more saturated or partially unsaturated rings. These acids most commonly occur... 

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