Hydroxycarboxylic acids, aliphatic

Miltenberger K (2000) Hydroxycarboxylic acids, aliphatic. In Ulbnann s encyclopedia of industrial chemistry. Wiley-VCH, Weinheim... 

Carbon dioxide itself can accept e. during radiolysis of water, giving rise to the carbon dioxide anion-radical. This anion-radical can add to carboradicals. Thus, aliphatic alcohols react with the radiolytically generated hydroxyl radicals, rupturing their C—H bonds RCHjOH + OH HjO + RCH OH. These radicals accept the radiolytically generated COj" forming a-hydroxycarboxylic acids RCHjOH + CO2 RCH(OH)COO (Morkovnik and Okhlobystin 1979). 

Cyclic esters of oo-hydroxycarboxylic acids can be polymerized by ring-opening to give linear aliphatic polyesters. According to the type of initiator and monomer the polymerization occurs either by alkyl or by acyl cleavage ... 

Similar polyacetals were prepared by BASF scientists from CO-aldehydic aliphatic carboxylic acids (189,190) and by the addition of poly(hydroxycarboxylic acid)s such as tartaric acid to divinyl ethers (191) as biodegradable detergent polymers. 

Apart from fluoro ligands at hypervalent silicon complexes, also oxo and aza ligands are known to support penta- and hexacoordination in silicon compounds1-8. Among the various pentacoordinate oxo complexes, those with bidentate ligands (1,2-diols, aliphatic or aromatic, as well as a-hydroxycarboxylic acids) are most readily prepared, and are... 

Portanova, R. Lajunen, L.H.J. Tolazzi, M. Piispanen, J. Critical evaluation of stability constants for alpha-hydroxycarboxylic acid complexes with protons and metal ions and the accompanying enthalpy changes. Part II. Aliphatic 2-hydroxycarboxylic acids. Pure Appl. Chem. 2003, 75 (4), 495-540. 

In the polycondensation of aliphatic dicarboxylic acids with diols, DCC is used to mediate the reaction. In this manner biodegradable and surface active aliphatic polyesters are obtained. Also, hydroxycarboxylic acids derived from maleic or succinic acid are ho-mopolymerized in the presence of EDCCl in DMF at room temperature. In this manner... 

Further examples of reactions of aliphatic and alicyclic polycarboxylic acids with sulfur ictra-fluoride or sulfur tetrafluoride/hydrogen fluoride are known.The reaction of aliphatic hydroxycarboxylic acids with sulfur tetrafluoride can give different products depending on the reaction conditions, the position of the hydroxy group, and the presence of other substituents. The main products from a-hydroxycarboxylic acids are trifluoroalkyl fluorosulfites, e.g. 19, which can be hydrolyzed quantitatively to the corresponding alcohols. ... 

Seven a-hydroxycarboxylic acids (Cj to Cj) and 17 aliphatic dicarboxylic acids (Cj to Cg) have been found in Murchison (Peltzer et al, 1978 Lawless et al, 1974). Eight of the latter also were produced in a Miller-Urey synthesis (Zeitman et al, 1974). None have been looked for in the FTT synthesis thus far. 

The catalytic amidation of optically active aliphatic a-hydroxycarboxylic acids with benzylamine proceeds with no measurable loss (< 2 %) of enantiomeric purity under reflux conditions in toluene (Eq. 115). 

Fig. 3-88. Separation of aliphatic hydroxycarboxylic acids. — Chromatographic conditions see Fig. 3-86 solute concentrations 20 ppm each of succinic acid, malic acid, tartaric acid, and tartronic acid.

Many hydroxycarboxylic acids are naturally occurring, and their coordination chemistry is of importance in biological processes.These complexes also have uses in many other areas such as analytical chemistry, electroplating processes, and pharmacology. The most widely studied aliphatic hydroxy acids are the lower members of the 2-hydroxyalkanoic acids, while studies of aromatic hydroxy acids have often centered on salicylic acid. A number of these acids contain one or more chiral carbon centers, and hence complexes of these acids have been useful in studying chiroptical properties such as the Cotton Effect see Cotton Effect). 

Camauba wax (also called Brazil wax or palm wax) is isolated from the leaves of the palm Copernicia prunifera (camauba palm), a plant native to northeastern part of Brazil. It has an appearance of yellow flakes. Camauba consists mostly of aliphatic esters (40.0 wt%), diesters of 4-hydroxycinnamic acid (21.0 wt%), ra-hydroxycarboxylic acids (13.0 wt%), and fatty acid alcohols (12.0 wt%). These compounds are mainly derived from acids and alcohols in the C26-C30 range. Distinctive for camauba wax is the high content of methoxycinnamic acid as well as diesters. This type of wax is one of the hardest natural waxes with the highest melting point between 78°C and 86°C, but most often the melting-point range is 82°C-85°C. Like all other waxes, it is insoluble in water, but soluble on heating in ethyl acetate and in xylene, and practically insoluble in ethyl alcohol (European Pharmacopeia 6.0). 

Glueck SM, Pirker M, Nest BM, Ueberbacher BT, Larissegger-Schnell B, Csar K, Hauer B, Stuermer R. Biocatalytic reaction of aliphatic, arylaliphatic, and aromatic a-hydroxycarboxylic acids. J Org Chem 2005 70 4028-4232. 

Similar polyacetal structures were prepared by BASF scientists from general dialdehydes and aliphatic hydroxycarboxylic acids derived from sugars [156, 157], shown in Scheme 15. Alternatively, carboxypolyacetals are available by the addition of polyhydroxy carboxylic acids, tartaric acid, for example, to divinyl ethers [158]. 

The lonPac ICE-AS6 separator column has proved to be best suited for the separation of aliphatic hydroxycarboxylic acids. See Figure 5.3 for the example chromatogram of a standard solution containing various organic acids. Perfluorobutyric acid is employed as the eluent. In this stationary phase, the acid concentration in the eluent is one of the most important parameters determining retention. Furthermore, the selectivity of lonPac ICE-AS6 is affected by the column temperature. 

These catalysts are useful in the reactions of both primary and secondary amines with various carboxylic acids (Equation 10). Catalytic amidation of optically active aliphatic a-hydroxycarboxylic acids with benzylamine proceeds with no measurable loss (<2%) of enantiomeric purity under reflux conditions in toluene. Most amino acids are barely soluble in non-aqueous solvents. Nevertheless, their lactams can be prepared by the present technique under heterogeneous conditions. For example, when 6-aminocaproic acid and 1 mol% of the boron catalyst 3.4,5-FjC5H2B OH)2 are suspended in refluxing xylene, the solid slowly dissolves and caprolactam is formed in 93% yield. 

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