Alicyclic Substances

The concept of a group is especially important in organic chemistry. A functional group represents a set of atoms that is closely linked with chemical reactivity and defined classes of substances. For instance, the functional group hydroxyl, -OH, is characteristic of the classes alcohol, phenol and enol. Alcohols are often represented by the general formula R-OH, in which R- represents a hydrocarbon group typical of aliphatic and alicyclic substances. 

I object to the use of the term alicyclicity in this connection. The methods used by Peover, Wender, and Fuks are selective for that group of alicyclic substances capable of yielding aromatic structures on dehydrogenation—i.e., for hydroaromatic rings. If the sulfur method really dehydrogenates any alicyclic structures (e.g. cyclooctane or camphene), then it would yield olefins rather than aromatics and could probably also convert saturated chains to olefins. On the other hand, if it attacks only hydroaromatic structures, then alicyclicity is an incorrect and misleading expression, and hydroaromaticity should be used. 

Adams, T.B., Hallagan, J.B., Putman, J.M., Gierke, T.L., Doull, J., Munro, I.C., Newberne, P.M. et al. (1996) The FEMA GRAS assessment of alicyclic substances used as avor ingredients. FoodCjwmJTmacol. 

Flavor and Extract Manufacturers Association (FEMA). (1975) Scienti c literature review of alicyclic substances used as avor ingredients. U.S. National Technical Information Services, PB86-1558351/LL, FEMA, Wahington, DC. 

B. K. Mazumdar. Low rank coals like lignites and natural humic acid derived from such coals are known to contain alicyclic structures in their constitution. How does the author envisage the formation of such structures in the transformation of lignin to humic acid-like substances ... 

H NMR data from these seven sites are presented by spectral peak-height ratios in Table III. The sites were listed in order of increasing aromatic plus olefinic carbon percentages. Fulvic acids from all the lake samples are much lower in aromatic plus oleflnic carbon content than those from river samples. These results confirm the hypothesis that autothonous inputs result in dissolved humic substances that have a low aromatic plus oleflnic carbon content. The lake samples also are lower in the ratios of peak 2 (carboxylated chains and aliphatic ketones), peak 3 (carbohydrates), and peak 4 (phenolic tannins and lignins) to peak 1 (branched methyl groups and alicyclic ali-phatics) than are the river samples. 

The aliphatic alicyclic hydrocarbon precursor is not well recognized as the major aliphatic component in dissolved humic substances, although it was previously postulated to occur (II). This precursor might arise from terpenoid hydrocarbon lipids, but the data presented in this chapter favor polyunsaturated lipid precursors that are oxidatively coupled and cyclized by free-radical mechanisms (20). Degradative studies have not identified this aliphatic component in recognizable fragments. The quantitative, structural-model approach presented here combines the results of 13C NMR, NMR,... 

Whereas a number of 5-aryl thiatriazoles have been reported, the only previously known true aliphatic and alicyclic representatives were 5-tert-butyl31 and cyclohexyl thiatriazole.32 These are unstable oils that decompose at 0° with nitrogen evolution and formation of sulfur. They are prepared from the corresponding thioacylhydrazides and nitrous acid, but the method is not generally applicable because of difficulties in obtaining the required aliphatic thioacylhydrazides.1 Wijers et o/.17 have found that aliphatic thiatriazoles can be prepared from 1-acetylthio-l-alkynes. Thus a substance believed to be 5-pentylthiatriazole was isolated from the reaction between 1-acetylthio-l-hexyne and ammonium azide. It is an oil that solidifies at about —16° and could not be analyzed because of its explosive character and poor stability at room temperature. Its formation is explained by the following scheme [Eq. 

The presence of acid substances in petroleum first appears to have been reported in 1874 and it was established nine years later that these substances contained carboxyl groups and were carboxylic acids. These were termed naphthenic acids. Although alicyclic (naphthenic) acids appear to be the more prevalent, it is now well known that aliphatic acids are also present. In addition to the carboxylic acids, alkaline extracts from petroleum contain phenols. 

A wide variety of unsaturated substance can be hydroformylated by cobalt or rhodium catalysts but conjugated alkenes (e.g., butadiene) may give a number of products including hydrogenated monoaldehydes. The mechanism is different, since addition of M H to dienes leads to alicyclic species which may be present as a-bonded intermediate or as h3allyls. 

Various colours characteristic for the group of compounds Steroids, alicyclic vitamins, many other substances... 

The major analytes in this category are the alicyclic compounds (alkaloids and terpenes) heterocyclic compounds (barbiturates, benzodiazapams, indole alkaloids, quinolines, nucleic acids, and nucleotides) aminoacids and peptides oligopeptides and proteins (globular, nucleo-, and lipo-) saccharides and polysaccharides and condensation products of saccharides with all the other analytes, e.g., glucuronides and gly-coproteins. Thus far, most analyses have been done on solid and solution forms of the drug substances. A few illustrations are reported in which CD was used in the direct analysis of biological extracts. 

A broad variety of substrates were efficiently glycosylated by glycosidases such as aliphatic and alicyclic alcohols [14], phenols, oximes, steroids and terpenes [15], amino acids [16], alkaloids [17] and many other substances. 

Ammonolysis of alicyclic anhydrides followed by Hofmann degradation is one of the most frequently used methods for the synthesis of alicyclic P-amino acids, since many anhydrides are commercially available cheap substances produced by Diels-Alder addition of maleic anhydride and the corresponding dienes [44], By this method, cis- and frans,-2-aminocyclohexane- and -cyclohexenecarboxylic acids, cis-2-aminocycloheptanecarboxylic acid [45], 3-ewtffo-aminobicyclo [2.2.1 ]heptane-2-ew/o-carboxylic acid, 3-e ifo-aminobicyclo[2.2.1 ]hept-5-ene-2-ertcarboxylic acid and some analogue P-amino acids have been prepared [44, 46-48], For partially unsaturated alicyclic compounds, a modified Hofmann degradation is used, sodium hypochlorite being applied to avoid bromine addition to the double bond [48,49]. 

Alicyclic amino alcohols 111, obtained in a facile way from amino acids by lithium aluminium hydride reduction, are also useful starting substances for different heterocycles [117]. 

Lower hydrocarbons are highly flammable substances. Compounds containing one to four carbon atoms are gases at room temperature and 760 torr pressure. Aliphatic and alicyclic hydrocarbons containing five to... 

ALIPHATIC ACYCLIC AND ALICYCLIC TERPENOID TERTIARY ALCOHOLS AND STRUCTURALLY RELATED SUBSTANCES (addendum)... 

Table 1. Summary of the results of safety evaluations of aliphatic acyclic and alicyclic terpenoid tertiary alcohols and structurally related substances used as flavouring agents ... 

---