Phosphoryl compounds

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. 

Uncouplers of oxidative phosphorylation Compounds that uncouple oxidative phosphorylatiou from electron transport in the inner mitochondrial membrane. Most are weak lipophilic acids that can run down the proton gradient across this membrane. 

Solvent effects on the magnitude of spin-spin coupling constants in phosphoryl compounds have been reported, as have the solvent effects on the relative strengths of phosphoric acid and some of its partially esterified derivatives.The variation of i.r. frequencies of (122) and (123)... 

The use of t.l.c. for separating organophosphorus compounds has been reviewed. In a study of phosphoryl compounds it was shown that / m values i.e. log [(1 - Rv)lRy on silica gel using hexane-acetone as eluant, depend upon the polarity of the P=0 group.The migration order found was... 

However, the most common and important method of synthesis of chiral non-racemic hydroxy phosphoryl compounds has been the resolution of racemic substrates via a hydrolytic enzyme-promoted acylation of the hydroxy group or hydrolysis of the 0-acyl derivatives, both carried out under kinetic resolution conditions. The first attempts date from the early 1990s and have since been followed by a number of papers describing the use of a variety of enzymes and various types of organophosphorus substrates, differing both by the substituents at phosphorus and by the kind of hydroxy (acetoxy)-containing side chain. 

The first P-chiral hydroxy phosphoryl compounds that were enzymatically resolved into enantiomers were o-hydroxyaryl phosphines and their oxides 75. The resolution was achieved via enzyme-assisted hydrolysis of their O-acetyl derivatives 74, the most effective enzymes being CE and Upase from C. rugosa (CRL) (Equation 35). The highest enanfioselectivity was observed in the case of naphthyl derivatives (Equation 36), having a P=0 moiety. ... 

A method for determining the basicities of phosphoryl compounds has been decribed which is based on 31P n.m.r. chemical shift measurement and a two phase system consisting of an organic solvent and 12H sulphuric acid.245 The gas-phase protonation of aliphatic phosphine oxides have been determined by cyclotron resonance. There was a good correlation of pK4 with Kabachnik constants and HO... 

Keywords Heterophene Phosphorus Phosphoryl compounds Quinoid compounds Thiophene... 

In recent years, the use of a-substituted phosphoryl compounds has mushroomed as they have become recognized as useful analogues of a-substituted carboxyl compounds (including the a-amino acids), as well as materials with their own applications. We will begin here by reviewing the well-established approaches toward such materials, specifically the Abramov and Pudovik reactions, including the associated conjugate addition reactions, and then consider the newer approaches toward such compounds. 

Block, H., Aryl Phosphoryl Compounds, European Patent 43,482, 1982. 

Determination of electrochemical oxidation potentials and electrochemical reduction of 13 p-phosphorylated acyclic nitrones shows that phosphorylated compounds have a clear anodic shift of potentials of both, oxidation (Ep 1.40 to 2.00 V versus SCE in CH3CN) and reduction (Ep—0.94 to —2.06 V). This is caused by a strong electron-acceptor influence of the diethoxyphosphoryl group (430). In contrast, a reversible one-electron oxidation of azulene nitrones (233) (Scheme 2.80) occurs 0.6 V below the Ep potential of PBN, that is at the value one observes the oxidation of AH -imidazole-1,3-dioxides (219) (428, 429). In other words, the corresponding RC (234) is 14 kcal more stable than the RC of PBN. Although the EPR spectrum of RC (234) was not recorded, RC (236) from dinitrone (235) turned out to be rather stable and gave an EPR spectrum (170). 

Holmstead, B. and Larson, L. (1951). Infra-red spectra of some organic phosphoryl compounds. Acta Chem. Scand. 5, 1179. 

Benzoic acid (271) when reacted with PCI3 yielded an adduct (272) which underwent an Arbuzov rearrangement to the phosphoryl compound (273), which eliminated 3HC1 to give benzoylphosphonic anhydride (274). Addition of water to the reaction mixture converted the anhydride (274) into benzoylphosphonic acid (275), which underwent... 

In P-O-C and P-O-H groups the values of the P-O couplings appear in the ranges 150 to 160 and 100 to 120 Hz respectively. For phosphoryl compounds the value is more variable from 90 to 200 Hz. Clearly more data are required for a deeper understanding of the underlying effects. 

The primary metabolites Include such compounds as simple sugars, amino acids, common lipids, the common nitrogen compounds and many phosphorylated compounds. 

Telbivudine is a thymidine nucleoside analog with activity against HBV DNA polymerase. It is phosphorylated by cellular kinases to the active triphosphate form, which has an intracellular half-life of 14 hours. The phosphorylated compound competitively inhibits HBV DNA polymerase, resulting in incorporation into viral DNA and chain termination. It is not active in vitro against HIV-1. 

Amine A-oxides, phosphine oxides and other phosphoryl compounds and analogous arsenic derivatives, and sulfoxides all give well-defined complexes with scandium. In many cases, authors deal with several of these classes of ligand in the same paper, so it will be most convenient to consider them together here. 

Other Phosphorylated Compounds and Thioesters Also Have Large Free Energies of Hydrolysis... 

In all these phosphate-releasing reactions, the several resonance forms available to Pi (Fig. 13-1) stabilize this product relative to the reactant, contributing to an already negative free-energy change. Table 13-6 lists the standard free energies of hydrolysis for a number of phosphorylated compounds. 

TABLE 13-6 Standard Free Energies of Hydrolysis of Some Phosphorylated Compounds and Acetyl-CoA (a Thioester)... 

Explains the distinction between biochemical and chemical equations, and the calculation and meaning of transformed thermodynamic properties for ATP and other phosphorylated compounds. 

The development of methods of enzyme purification, the discoveiy and recognition of the importance of coenzymes such as NAD, and the discoveiy of the pivotal metabolic role of ATP and other phosphorylated compounds ail came out of studies of glycolysis. The glycolytic enzymes of many species have long since been purified and thoroughly studied. 

All ten glycolytic enzymes are in the cytosol, and all ten intermediates are phosphorylated compounds of three or six carbons. 

---