Phosphorous esters

Phosphoric esters, not common as bases, but used as additives. 

Anti-wear and extreme pressure additives phosphoric esters, dithiophosphates, sulfur-containing products such as fatty esters and sulfided terpenes or chlorinated products such as chlorinated paraffins. 

A pletliora of different SA systems have been reported in tire literature. Examples include organosilanes on hydroxylated surfaces, alkanetliiols on gold, silver, copper and platinum, dialkyl disulphides on gold, alcohols and amines on platinum and carboxyl acids on aluminium oxide and silver. Some examples and references can be found in [123]. More recently also phosphonic and phosphoric esters on aluminium oxides have been reported [124, 125]. Only a small selection out of tliis number of SA systems can be presented here and properties such as kinetics, tliennal, chemical and mechanical stability are briefly presented for alkanetliiols on gold as an example. 

In peptide syntheses, where partial racemization of the chiral a-carbon centers is a serious problem, the application of 1-hydroxy-1 H-benzotriazole ( HBT") and DCC has been very successful in increasing yields and decreasing racemization (W. Kdnig, 1970 G.C. Windridge, 1971 H.R. Bosshard, 1973), l-(Acyloxy)-lif-benzotriazoles or l-acyl-17f-benzo-triazole 3-oxides are formed as reactive intermediates. If carboxylic or phosphoric esters are to be formed from the acids and alcohols using DCC, 4-(pyrrolidin-l -yl)pyridine ( PPY A. Hassner, 1978 K.M. Patel, 1979) and HBT are efficient catalysts even with tert-alkyl, choles-teryl, aryl, and other unreactive alcohols as well as with highly bulky or labile acids. 

R. D. O Brien, Toxic Phosphorous Esters, Academic Press, Inc., New York, 1960. 

Sahcyhc acid can be converted to sahcyloyl chloride [1441 -87-8] hy reaction with thionyl chloride in boiling ben2ene. The formation of acyl haUde may also extend to reaction with the phenoHc hydroxyl. The reaction with phosphoms tri- and pentachlorides is not restricted to the formation of the acid chloride. Further interaction of the phosphoms haUde and the phenoHc hydroxyl results in the formation of the phosphoric or phosphorous esters. 

Amongst synthetic quinoxalines, numerous types of biological activity have been reported. 5,6,7,8-Tetrachloroquinoxaline (132) and related halogenated derivatives have found use in fungicidal formulations. Phosphoric esters of 6-hydroxyquinoxaline (133) have found use in insecticidal preparations, and phosphoric ester derivatives of 2-hydroxyquinoxalines, such as (134), function as anthelmintics. 

Ironically, the reactor was used to produce Antiblaze 19, a flame retardant used in textiles and polyurethane foam. Antiblaze 19 is a cyclic phosphorate ester produced from a mixture of trimethyl phosphite, dimethyl methylphosphonate (DMMP), and trimethyl phosphate (TMOP). The final product is not considered flammable, but trimethyl phosphite is moisture sensitive and flammable, with a flash point of about 27 C. 

Thus 297 kg of the phosphoric ester of the creatinoi are obtained having these characteristics MP240°C to243°C. 

Fig. 32. Stepwise preparative desorption chromatography of phosphoric esters of thiamine on CS-KU-2 cellosorbent /) highly phosphoric thiamine esters, 2) thiamine diphosphate, 3) thiamine monophosphate, 4) thiamine, 5) impurities...

Fig. 33. Stepwise preparative desorption chromatography of phosphoric esters of adenosine on CS-AV-17 cellosorbent 1) adenine, 2) adenosine, 3) adenosine monophosphate, 4) adenosine diphosphate, 5) adenosine triphosphate...

Flavin Mononucleotide (FMN) (C17H21N409P) is a phosphoric ester of riboflavin that constitutes the cofactor of various flavoproteins. 

These compds are also formed during the prepn of nitriles, by heating aryl or arylalkyl halides, or alkyl sulfuric or phosphoric esters, or arylsulfonic esters with K or Na cyanide in ale... 

The acyclic nucleoside phosphonates (ANPs) can be considered as nucleotide rather than nucleoside analogues, in that, besides the purine or pyrimidine base, they contain an (acyclic) sugar moiety to which a phosphonate is attached. In these nucleotide analogues (Fig. 2), the phosphoric ester grouping (= P-O---C-----) is... 

Many bacterial polysaccharides contain phosphoric ester groups. There is a limited number of examples of monoesters. More common are phosphoric diesters, connecting an amino alcohol or an alditol to the polysaccharide chain. Another possibility is that oligosaccharide or oligosaccharide-alditol repeating units are connected to a polymer by phosphoric diester linkages. In addition to the intracellular teichoic acids, several bacteria, for example, different types of Streptococcus pneumoniae, elaborate extracellular polymers of this type. These polymers are generally discussed in connection with the bacterial polysaccharides. 

With the experimental results accumulated during his stay in Berlin, Garcia Gonzalez prepared two doctoral dissertations, entitled New Crystalline Phosphoric Esters of o-Fructose and Tests on Some Assumed Phases of Alcoholic Fermentation, which he presented in order to receive his doctorates in Chemistry and in Pharmacy, respectively, at the University of Madrid in 1932. Armed with these two degrees, he decided to pursue an academic career in his own country. His early training in a provincial... 

The use of f.a.b.-m.s. to monitor hydrolysis and acetolysis reactions is illustrated by studies on a yeast high-mannose oligosaccharide containing two phosphoric esters (19). The molecular-ion region of the negative f.a.b. 

In the reaction of a phosphoric ester diimidazolide (for preparation see Section 2.2) with an alcohol it is possible to substitute either one or two of the imidazole groups. 

This method is superior to that involving the phosphoric ester (treatment first with (C2HsO)2POC1 and then with KNH2). 

Fig 39a and b. Stereoviews of the crystalline environment around the phosphoric ester guest (+)-27a in its complexes with a (— )-26, and b +)-26. For clarity, the positions of the two adjacent guest moieties are shown schematically (taken from Ref.53>)... 

The monomeric metaphosphate ion itself commands a fair amount of attention in discussions of metaphosphates. It is postulated as an intermediate of numerous hydrolysis reactions of phosphoric esters 52 S4,S5) and also of phosphorylation reactions S6> kinetic and mechanistic studies demonstrate the plausibility of such an assumption. In addition, the transient formation of ester derivatives of meta-phosphoric acid — in which the double-bonded oxygen can also be replaced by thio and imino — has also been observed they were detected mainly on the basis of the electrophilic nature of the phosphorus. 

All arguments for the metaphosphate mechanism appear persuasive only when considered together since individual arguments could also apply to other hydrolysis mechanisms of phosphoric esters. 

The pronounced proclivity of phosphoric monoester monoanions to eliminate POf is not always recognizable from the characteristic pH profile of Fig. 1. The hydrolysis rate maximum at pH w 4 may be masked by a faster reaction of the neutral phosphoric ester, as in the case of a-D-glucose 1-phosphate63) or on hydrolysis of monobenzyl phosphate 64). In the latter case, the known ability of benzyl esters to undergo SN1 and SN2 reactions permits fast hydrolysis of the neutral ester with C/O bond breakage. The fact that the monoanion 107 of the monobenzyl ester is hydrolyzed some 40 times faster than the monoanion 108 of the dibenzyl ester at the same pH again evidences the special hydrolysis pathway of 107, rationalized by means of the metaphosphate hypothesis. 

The highly electrophilic character of the POf ion would suggest a very unselective phosphorylation behavior. For example, the ratio of alkyl phosphate to inorganic phosphate obtained in hydrolyses of phosphoric esters in water/alcohol mixtures should reflect the molar ratio of water and alcohol. This is indeed found in numerous cases, e.g. in the hydrolysis of phenyl and 4-nitrophenyl phosphate monoanions 97) or of 4-nitrophenyl phosphate dianions 65) at 100 °C in methanol/ water mixtures of various compositions, as also in the solvolysis of the acetyl phosphate dianion at 37 °C 97) or of phosphoenol pyruvate monoanions 82). Calculations of the free energy of the addition reactions of water and ethanol to the POf ion support the energetic similarity of the two reactions 98) (Table 4). 

The reaction of 151 with methanol to give dimethyl phosphate (154) or with N-methylaniline to form the phosphoramidate 155 and (presumably) the pyrophosphate 156 complies with expectations. The formation of dimethyl phosphate does not constitute, however, reliable evidence for the formation of intermediate 151 since methanol can also react with polymeric metaphosphates to give dimethyl phosphate. On the other hand, reaction of polyphosphates with N-methylaniline to give 156 can be ruled out (control experiments). The formation of 156 might encourage speculations whether the reaction with N,N-diethylaniline might involve initial preferential reaction of monomeric methyl metaphosphate via interaction with the nitrogen lone pair to form a phosphoric ester amide which is cleaved to phosphates or pyrophosphates on subsequent work-up (water, methanol). Such a reaction route would at least explain the low extent of electrophilic aromatic substitution by methyl metaphosphate. 

Haley, F., and H. A. Lardy Phosphoric Esters of Biological Importance. VI. The Synthesis of D-Glucosamine 6-Phosphate and N-Acetyl-D-glucos-amine 6-Phosphate. J. Amer. chem. Soc. 78, 1393 (1956). 

Treatment of the phosphoric ester 224 with triethylamine breaks the intramolecular hydrogen bonding in the solution structure and promotes cyclization to give spirophosphorane 43 (Equation 44) <2003PS2117>. 

Substrate-ligase EC6.5 Forming Phosphoric Ester Bonds (DNA ligase (ATP), RNA ligase (ATP), etc.) ... 

These observations, as yet incomplete, are now being extended by studies with D-glycerose and its phosphoric esters, particularly because of the biological importance of these compounds.16... 

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