Production phosphorylation

A peculiai- case of phosphoryl radical addition to difluoroalkenes involves the reaction of trialkyl phosphites with l-bromo-2-iodo-l,l,2,2-tetfafluoroethane under ultraviolet irradiation (254 nm). Surprisingly, the corresponding 2-iodo-l,l,2,2-tetrafluoroethylphosphonates are formed in 42 8% yields with no detectable amount of the bromo derivative (Scheme 3.39). The proposed mechanism involves a halide-induced dealkylation of the trialkyl phosphite radical cation followed by addition of the product phosphoryl radical to tetrafluoroethene (generated by halide anion elimination) and iodide radical abstraction from the starting haloalkane. s... 

An essential feature of Sox-containing sensors is the differential binding affinity for Mg " " between the substrate and product (phosphorylated) peptides. A 10-to 25-fold enhancement of binding affinity for Mg " " (as measured by dissociation constant, /Cp) is observed upon phosphorylation. Therefore, substrate peptides manifest low background fluorescence, while phosphorylation results in robust fluorescence increases (three- to eightfold) in the presence of Mg " ". In the presence of Mg and ATP, these sensors accurately report kinase activity, while providing kinetic detail. The kinetic parameters (/C, and sensors are... 

In keeping with its biogenetic origin m three molecules of acetic acid mevalonic acid has six carbon atoms The conversion of mevalonate to isopentenyl pyrophosphate involves loss of the extra carbon as carbon dioxide First the alcohol hydroxyl groups of mevalonate are converted to phosphate ester functions—they are enzymatically phosphorylated with introduction of a simple phosphate at the tertiary site and a pyrophosphate at the primary site Decarboxylation m concert with loss of the terti ary phosphate introduces a carbon-carbon double bond and gives isopentenyl pyrophos phate the fundamental building block for formation of isoprenoid natural products... 

Phosphoric Acid-Based Systems for Cellulosics. Semidurable flame-retardant treatments for cotton (qv) or wood (qv) can be attained by phosphorylation of cellulose, preferably in the presence of a nitrogenous compound. Commercial leach-resistant flame-retardant treatments for wood have been developed based on a reaction product of phosphoric acid with urea—formaldehyde and dicyandiamide resins (59,60). 

The principal steps in the mechanism of polyisoprene formation in plants are known and should help to improve the natural production of hydrocarbons. Mevalonic acid, a key intermediate derived from plant carbohydrate via acetylcoen2yme A, is transformed into isopentenyl pyrophosphate (IPP) via phosphorylation, dehydration, and decarboxylation (see Alkaloids). IPP then rearranges to dimethylaHyl pyrophosphate (DMAPP). DMAPP and... 

In the normal process ( ), step (J) occurs very rapidly and step (/) is the rate-determining step, whereas in the inhibition process (B), step (3) occurs very slowly, generally over a matter of days, so that it is rate determining. Thus it has been demonstrated with AChE that insecticides, eg, tetraethyl pyrophosphate and mevinphos, engage in first-order reactions with the enzyme the inhibited enzyme is a relatively stable phosphorylated compound containing one mole of phosphoms per mole of enzyme and as a result of the reaction, an equimolar quantity of alcohoHc or acidic product HX is hberated. 

Finally, the importance of quinolinium salts to dye chemistry accounts for the long, productive history of their synthesis. The reaction of A/-methylformanihde with ketones, aldehydes, ketone enamines, or enol acetates in phosphoryl chloride leads to high yields of /V-methylquinolinium salts (60). 

Phosphate Esters. The phosphorylation of sucrose using sodium metaphosphate has been reported (78). Lyoptulization of a sodium metaphosphate solution of sucrose at pH 5 for 20 hours followed by storage at 80°C for five days produced a mixture of sucrose monophosphates. These products were isolated by preparative hplc, with a calculated yield of 27% based on all organic phosphate as sucrose monoesters. Small proportions of glucose and fmctose were also formed. 

Polyphosphoric acid, P2O5, POCl, and PCl are suitable phosphorylatiag agents. Reaction of an alkyl sulfate with sodium pyrophosphate has also been reported for preparation of alkyl pyrophosphates (77). In general, phosphorylation leads to a mixture of reaction products that are sold without further separation. Thus, when lauryltri(ethyleneoxy)ethanol reacts with 0.3 mol of P2O5 at 50°C and is neutralized with 50% aqueous NaOH, the reaction mixture contains the foUowiag products ... 

Direct chlorination of 3,6-dichloropyridazine with phosphorus pentachloride affords 3,4,5,6-tetrachloropyridazine. The halogen is usually introduced next to the activating oxo group. Thus, 1,3-disubstituted pyridazin-6(l//)-ones give the corresponding 5-chloro derivatives, frequently accompanied by 4,5-dichloro compounds as by-products on treatment with chlorine, phosphorus pentachloride or phosphoryl chloride-phosphorus pentachloride. 

Figure 6.24 The function of the enzyme phosphofructokinase. (a) Phosphofructokinase is a key enzyme in the gycolytic pathway, the breakdown of glucose to pyruvate. One of the end products in this pathway, phosphoenolpyruvate, is an allosteric feedback inhibitor to this enzyme and ADP is an activator, (b) Phosphofructokinase catalyzes the phosphorylation by ATP of fructose-6-phosphate to give fructose-1,6-bisphosphate. (c) Phosphoglycolate, which has a structure similar to phosphoenolpyruvate, is also an inhibitor of the enzyme.

In an effort to prepare 1 2-dihydropapaverine, Buck dehydrated with phosphoryl chloride, and subjected the product (V) to catalytic reduction, followed by the action of phosphorus pentachloride in the cold. The final product was assumed to be 1 2-dihydropapaverine but Young and Robinson interpret this synthesis differently, and their formulae (V) and (VI) are given above, the final product being 3 4-dihydropapaverine (VII), which Buck thus prepared for the first time in a crystalline condition, m.p. 97-8° picrate, m.p. 151° perchlorate, m.p. 238° dec.). 

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