Phosphoric diesters, mixed

An intramolecular phosphoric-carboxylic mixed anhydride has been proposed to explain the specific behavior of AT-(dialkylphosphoryl)amino acids 15 that spontaneously give oligopeptides upon standing in various solvents [115]. Peptide formation was accompanied by diester exchange on the phosphoryl group via a reaction that may have been useful for nucleotide ligation. 

Two reports are available on the rearrangement of mixed vinyl phosphite esters to produce phosphonate diesters in moderate yield.94 95 In both instances, the vinyl phosphite esters were prepared by reaction of the dialkyl phosphorous chloride with highly enolized carbonyl compounds. The mixed ester products undergo thermal rearrangement to the phosphonate diesters (Figure 6.25). 

The use of the triphenylphosphine-di(2-pyridyl) disulphide reagent for effecting condensation reactions has been reviewed.84 Combination of triphenylphosphine with bis(O-thiocarbonyl) disulphide gives a superior reagent compared to that mentioned above for the preparation of mixed diesters of phosphoric acid from monophosphate esters.86... 

In the second area of interest, the high reactivity of compounds that stems from inherent ring strain in five-membered ring systems has been exploited in the synthesis of mixed diesters of phosphoric acid. These, for example (15), may be obtained by... 

Mixed diesters of phosphoric acid (5) can be prepared in high yield by treating (2) with an alcohol in dry pyridine, presumably through an intermediate inner salt of l-(2 -alkylhydrogen phosphoroxy-5 -nitrobenzyl)pyridinium hydroxide (4).3... 

Nucleotides are generally defined as phosphoric esters (of the carbohydrate moiety) of nucleosides. In polymerized forms (involving phospho-diester linkages), the nucleotides constitute the nucleic acids, which are fundamental components of all cells and viruses. Nucleotides also occur as mixed anhydrides, such as adenosine 5 -triphosphate and uridine 5 -(q -d-glucopyranosyl pyrophosphate), which comprise an important class of... 

Included in a general method for the preparation of mono- and mixed diesters of phosphorous acid are some examples of carbohydrate... 

Mixed phosphoric acid diesters via pyridinium phosphate betaines... 

Dicyclohexylcarbodiimide Mixed phosphoric acid diesters from phosphoric acid monoesters... 

Methyl dichlorophosphatelpyridine Mixed phosphoric acid diesters... 

In the biosphere, triesters of orthophosphoric acid are unknown, however, this does not exclude the possibility that this binding may be present in certain macromolecules. The diesters of orthophosphoric acid which exist in the biosphere are often mixed esters. Acid or alkaline hydrolysis slowly transforms them into monoesters. Most of the complex lipides are diesters and vitamin also falls into this category. The mono-phosphoric esters of alcohols form a very important biochemical group. The two free acid groups are more strongly acidic than when they were... 

Methyl dichlorophosphate I pyridine Mixed phosphoric acid diesters One-flask process... 

In an adaptation of these concentrated acid methods, Pron et al. [246] used dialkyl esters of phosphoric acid to protonate P(ANi), either in solution (solvents such as toluene, THF, m-cresol), or by mechanical mixing with neat diester. The resulting protonated P(ANi) was soluble in the protonated form in solvents such as decaline (up to 12 w/w%). Such solutions could then be used for solubilizing poly(methyl methacrylate), poly(acrylonitrile butadiene-styrene) (ABS) or other thermoplastics, and films or fibers could be cast or spun therefrom. Curiously again, however, practical applications of these promising conductive thermoplastic blends have so far not been seen. 

Pron et al. [246] used novel phosphoric acid diesters to protonate the emeraldine base form of P(ANi) in solvents such as toluene, decaline or m-cresol, yielding solutions of the conductive form of the CP. Solutions of the highly versatile thermoplastic Acrylonitrile-Butadiene-Styrene (ABS) were then mixed with these... 

The compound (3) is a useful intermediate for the synthesis of mixed diesters of phosphoric acid (4). There are several methods of cleaving the N-P bond, of which the method of Ikehara is the most convenient. Reaction of (3) with a 40 molar excess of 3-methylbutyl nitrite in acetic acid-pyridine (1 1 v/v) is successful in removing the aniline protecting group from the phosphoryl moiety in almost quantitative yields, giving the O-alkyl/aryl-O-phenyl hydrogen phosphate. 

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