Carbohydrates carboxylic acids

The application of substrates isotopically labeled in specific positions makes it possible to follow the fate of individual atoms during the microbial degradation of xenobiotics. Under optimal conditions, both the kinetics of the degradation, and the formation of metabolites may be followed— ideally when samples of the labeled metabolites are available. Many of the classical studies on the microbial metabolism of carbohydrates, carboxylic acids, and amino acids used radioactive... 

The reaction of type i is utilized for the preparation of a variety of dicarboxylic acids. Scheme 25 shows the synthesis of a C-disaccharide (73) from a carbohydrate carboxylic acid (72) [98]. 

Scheme 25 C-disaccharides by anodic decarboxylation of carbohydrate carboxylic acids.

Caoutchouc Capronic acid Carbohydrate Carboxylic acid... 

This section includes oxidations of alkanes and cycloalkanes, alkenes and cycloalkenes, dienes, alkynes, aromatic fluorocarbons, alcohols, phenols, ethers, aldehydes, ketones and carbohydrates, carboxylic acids, nitrogen compounds, and organoelement compounds, such as boron, phosphorus, sulfur, selenium, and iodine compounds, and steroids. 

Only about 20% of the DOM in natural waters consists of identifiable compounds that include carbohydrates, carboxylic acids, amino acids, and hydrocarbons (I). The remaining 80% of DOM (generally defined as humic substances) consists of complex, environmentally altered residue of plant, bacterial, and fungal origin, of moderate molecular weight (500-5000 dal-tons). This predominantly acidic undefined DOM has been classified by... 

The obvious approach for chiral synthesis would be to find a chiral starting material, such as a natural amino acid, carbohydrates, carboxylic acids or terpene. The major source of these chiral starting materials sometimes called chirons is nature itself. The synthesis of a complex enantiopure chemical compound from a readily available enantiopure substance such as natural amino acids is known as chiral pool synthesis. For example, chiral lithium amides 1.39 that are used for several types of enantioselective asymmetric syntheses can be prepared in both enantiomeric forms starting from the corresponding optically active amino acids, and these are often available commercially. 

Tobacco leaf protein by itself contributes little to smoking quality, but it is a major precursor of hundreds of tobacco smoke components, for example, numerous nitrogenous compounds and amino acids. Similarly, other major tobacco components such as the carbohydrates, carboxylic acids, pigments, polyphenols, fatty compounds, phytosterols, and many primary or secondary compounds play a significant role in producing a myriad of tobacco smoke compounds (3972, 3973, 3974c). 

Native and microcrystalline cellulose precoated plates are used in the life sciences for the separation of polar compounds (e.g. carbohydrates, carboxylic acids, amino acids, nucleic acid derivatives, phosphates, etc) [85]. These layers are unsuitable for the separation of compounds of low water solubility unless first modified, for example, by acetylation. Several chemically bonded layers have been described for the separation of enantiomers (section 10.5.3). Polyamide and polymeric ion-exchange resins are available in a low performance grade only for the preparation of laboratory-made layers [82]. Polyamide layers are useful for the reversed-phase separation and qualitative analysis of phenols, amino acid derivatives, heterocyclic nitrogen compounds, and carboxylic and sulfonic acids. Ion-exchange layers prepared from poly(ethyleneimine), functionalized poly(styrene-divinylbenzene) and diethylaminoethyl cellulose resins and powders and are used primarily for the separation of inorganic ions and biopolymers. 

Shieh et al. [20] have reported esterification of carbohydrate carboxylic acid 35 to form the corresponding ester 36. Dimethyl carbonate was used both as solvent and reagent, in the presence of l,8-diazabicydo[5,4,0]undec-7-ene (DBU), under the action of microwave irradiation for 24 min (Scheme 12.14). 

The enzyme-catalyzed aldol condensation of ca-functionalized C5- and 06-aldehydes with Dhap (dihydroxacetone phosphate) has been used to synthesize unusual Cg- and C9-sugars. An example is given in Scheme 4. Coupling of carbohydrate carboxylic acids such as 21 and 23 with alkanoic acids by mixed... 

Various aquatic plants, such as reed manna grass Glyceria maxima), rice-plant, Arundodonax and Anisogrammaanomala, have been used for PMFCs. Water-soluble root exudates of these plants, including carbohydrates, carboxylic acids and amino acids serve as the most important electron donors for electricity production. In addition, soil (if present) can also act as an electron source via chemical or anaerobic respiration processes, such as chemical oxidation of humic acids, iron(ll), and sulphur compounds, and microbial oxidation of sulphur and ammonia by specific microbes. 

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