Phosphate diesters alkali

The resulting cyclic phosphate diester is hydrolyzed readily in acid or alkali to the phosphate monoester. 

In these electrodes, the active material is a large organic molecule capable of interacting specifically with an anion or cation. Typical of these materials are the phosphate diesters (R0)2P02, used for calcium ion electrodes, metal complexes used for anion electrodes and the neutral macrocyclic crown ethers which are suitable for alkali-electrodes. The active organic molecule is adsorbed onto an inert porous support or dissolved in an organic solvent, and indeed their selectivity can be aflected by the choice of medium. Some typical electrodes are shown in Table 12.4. 

The jS-cyanoethyl group has been employed for the protection of phosphate diesters in the synthesis of deoxyribo- [34] and ribo-oligonucleotides [35]. It is introduced using a procedure similar to Fig. 6.11b, and is selectively removed on treatment wdth sodium hydroxide. In the synthesis of ribo-oligonucleotides protection by the phenyl group, also alkali-labile, has been described [36] (Fig. 6.14). It is introduced as in Fig. 6.11a. 

Phosphoric acid diesters are prepared by treating a liquid slurry of phosphate monoester with epoxides in the presence of alkali compounds. Thus a mixture of monolauryl phosphate sodium salt and triethyl amine in water was treated with glycidol at 80°C for 8 h to give 98% lauryl(2,3-dihydroxypropyl)phosphate sodium salt [13]. 

E.P. (ethylene propylene) Water, dilute acids and alkalies, ketones, alcohols, phosphate ester base fluids, and silicone oils Petroleum oils or diester base lubricants Typical color purple. Temperature range -54 to 149°C. Easily compressed. Density 0.86. 0.85... 

Alkyl phosphates, also coco based, are formed by the reaction of fatty alcohol with phosphorous pentoxide. The product is a mixture of monoesters and diesters. Its sodium salt (MAP) is reportedly mild and is used in facial wash, such as Kao s Biore. Other uses are as antistatics in textile auxiliaries, corrosion inhibitors, surfactant additives for extreme pressure (EP) lubricants, and surfactant components in alkali and acid cleaners. Coco-based alkyl polyglycosides (APG) have been successfully produced and marketed by Henkel in the United States. The alkyl polyglycoside fuUy satisfies the demand for a mild surfactant and is completely biodegradable. 

An elegant explanation was provided by Brown and Todd, - who likened the alkaline lability of ribonucleic acid to that of the phospho-diester, glycerol methyl phosphate, which, in alkali, is converted into glycerol 1-phosphate and 2-phosphate. The phospho-diester bonds of ribonucleic acid (14) imdergo an 8 2 attack on phosphorus by the cis-... 

Uridine 3 -phosphate (147) was prepared by Hall and Thedford by the phosphorylation of 2, 5 -di-0-trityluridine with 2-cyanoethyl phosphate and iVjiV -dicyclohexylcarbodiiinide to give the diester (146). This diester was de-esterified with alkali, and then hydrolyzed with 80% acetic acid at 100° for 90 minutes, to give (147). The structure of (14S) had been rigorously established by Yung and Fox, who methanesulfonated (145) to obtain (148). Treatment of (148) with sodium benzoate in N,N-di-methylformamide gave the 2,3 -anhydronucleoside (149). The anhydro... 

Ribonucleoside 2 3 -cyclic phosphate are far more liable toward alkali and acid than are the noncyclic phospho-diesters. Hydrolysis of ribonucleoside 2 3 -cyclic phosphate produces a mixture of 2 - and 3 -phos-phates in approximately equal amoimts. Acid- and alkali-catalyzed alcoholysis of these cyclic phosphates also produces a mixture of the 2 -and 3 -alkyl phosphates, - - and the reactions are apparently reversible. " This behavior is a rather general characteristic of five-mem-bered, cyclic phosphates. [[Six-membered, cyclic phosphates, namely (25), (28), and (28a), are relatively more stable. Phosphodiesterases have been employed for the convenient preparation of specific nucleoside 2 - or 3 -phosphates by selective cleavage of a particular 0-P linkage in nucleoside 2 3 -cyclic phosphates. ... 

Commercial phosphate esters are usually mixtures of the free acids, although they may be sodium or triethanolamine salts. Monoesters nearly always contain some diester, and diesters both mono- and triester, with the nominal product predominating. They cannot be hydrolysed by either acids or alkalis at normal temperatures, but acid hydrolysis with strong acid at high temperature may be effective. 

The phosphate esters are converted to the free acid form, if they are present as salts, and determined by alkali titration. Monoesters have one weakly acidic and one strongly acidic proton. Diesters are strongly acidic. 

Sokolov et al. [26] have reported successful analysis of a mixture of pure sodium dodecyl sulphate and pure sodium dodecyl phosphate (mono- or diester not specified) by this method, and Ivanov et al. [27] analysed alkyl phosphates by titration of the column effluent with alkali to bromocresol green. 

Monoalkyl phosphates are very stable to alkali. The dianion R—0 —PO3 " is predominant in alkaline solution and the stability appears to be due to electrostatic repulsion to attack by 0H . The neutral triesters (R0)3 P0 are readily hydrolyzed by alkali to the diesters (R0)2 = P02 . No inversion or migration has been detected during alkaline hydrolysis so that the affected bond is probably P-0. Neighboring groups such as OH (as in glycol phosphate or glycerolphosphate) increase stability while NH2 (as in aminoethyl phosphate) decreases it ° ° . 

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