Hydrogenated triesters

Unsaturated fats seem to be more healthful than saturated ones, especially in reducing the buildup of deposits in the arteries. Do not expect to reap the benefits of unsaturated fats, however, by eating fully hydrogenated triesters. 

Pyridinium salt 422, prepared from nicotinaldehyde, was alkylated with dimethyl sodiomalonate and subsequently cyclized with hydrogen bromide to triester 423. Lithium iodide-induced demethylation, followed by decarboxylation... 

The reaction depended upon the marked difference in reactivity between the chlorine atoms and the fluorine atom in phosphorus oxydichlorofluoride. In general, the reaction with alcohols waa clear-cut, and most of the phosphorofluoridic esters were obtained in excellent yield and uncontaminated with the phosphoric triester. For example, when ethyl alcohol and phosphorus oxydichlorofluoride were allowed to react in the odd, diethyl phosphorofluoridate (VII, R = Et) was obtained in 93 per cent yield. No tertiary base was necessary to remove the hydrogen chloride produced in the reaction. The general process was patented during the war.1... 

From phosphorus trichloride, benzyl alcohol and 2 mol. of a tertiary base, dibenzyl hydrogen phosphite (XIV), is obtained which on treatment with chlorine or a chlorinating agent (e.g. sulphuryl chloride)4 gives the phosphorochloridate (XV). Although not isolated, (XV) is almost certainly obtained by treatment of (XIV) with a polyhalogen hydrocarbon because reaction in the presence of an alcohol or of a primary or secondary amine gives a triester (XVI) or a phosphoramidate. 

Figure 1. (Top) the chemical structure of 3-aminopropyltriethoxysilane or APS. (Bottom) the hydrolysis of the triester to the trisilanol in water at room temperature. ALPH1, ALPH2, ALPH3, ETCH2 and ETCH3 designate hydrogen environments discussed in the text.

Lipids are constituents of plants and animals that are characteristically insoluble in water. Fats and oils are lipids that are triesters formed by reaction of the triol glycerol with long-chain saturated or unsaturated acids called fatty acids. The common acids in fats and oils have an even number of carbons (for example, stearic acid has 18 carbons), and, if unsaturated (for example, oleic acid), they have the Z configuration (Table 15.1 lists the fatty acids, with their common names). Hydrogenation of oils, which have a high percentage of unsaturated acids, converts them to solid fats in a process called hardening. 

Fatty acid triesters of glycerol containing the unnatural trans isomers of fatty acids. Trans fats are often formed as by-products in the partial hydrogenation of vegetable oils to produce margarine and vegetable shortening, (p. 1205)... 

This acid, PH(0)(0H)2, is obtained by treating PC13 or P406 with water when pure, it is a deliquescent colorless solid (mp 70.1°C, pK = 1.3). It can be oxidized to orthophosphate by various agents, but the reactions are slow and complex. The mono-, di-, and triesters can be obtained from reactions of alcohols or phenols with PC13 alone or in the presence of an organic base as hydrogen chloride acceptor. They can also be obtained directly from white phosphorus by the reaction... 

If triesters are made with unsaturated fatty acids—ones with double bonds in their hydrocarbon-like parts—oils are produced. If only single bonds are in the fatty acids, fats are produced. Because consumers seem to prefer solid fats (such as butter) to liquid oils, some food manufacturers hydrogenate the unsaturated oils to reduce the number of double bonds in the molecules and produce a more solid product ... 

Other HTPs have been synthesized in the presence of hydrogen peroxide in combination with phosphoric acid triesters (i.e., tricresyl phosphate) or halogen-containing Ni, Pt, Pd compounds, Ag salts (e.g., AgNOs, AgjPOj at 118 °C. The yield was 60% and the functionality varied between 2.2 and 2.5 105 107)... 

Hydroxyalkyl)phosphonic acids, and also the related phosphinic acids, are normally obtained from hydrogen phosphonates and aldehydes or ketones. The reactions between perfluoroacetone and mixed dialkyl hydrogen phosphonates are noteworthy in that the expected products (129) may be accompanied by the phosphoric triesters (130). Trimethylsilyl alkylene P(III) triesters (131) are also useful starting materials when acted upon by aromatic aldehydes or by (1-oxoalkyl)phosphonic acid esters, the initial... 

In view of their extreme sensitivity to hydrogen chloride, the synthesis of aliphatic phosphorous acid triesters from phosphorus(V) oxychloride and alcohols can only be carried out in the presence of a molar mixture with inorganic or organic bases ... 

In the case of enterobactin, the complete reduction of the complex in a 1 3 Fe2SC>3 monomer solution, was achieved at a hydrogen (calomel) electrode potential of — 0.6 V, which should be contrasted with the irreducibility of the corresponding cyclic triester complex down to electrode potentials approaching hydrogen discharge ( — 1.8 V) (63). A plausible explanation is that the reducible species is a partially dissociated (i.e. hydrated) complex, present in equilibrium with the tricatechol chelate, which itself is practically irreducible. This is consistent with the observation that the potential for full reduction decreases as the concentration of monomeric ligand is increased beyond the stoichiometric requirement. 

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