Thermal degradation of phytate produces all four possible inositol pentakisphosphates as determined by ion chromatography and 1H and 31P NMR spectroscopy

Abstract

Decomposition of phytate has recently been shown to occur under mild conditions in the solid state, giving rise to a complex mixture of lower inositol phosphates. In this study, the reaction products of this thermal, abiotic degradation of phytate were separated using ion chromatography and the most highly phosphorylated products subsequently identified using 1D and 2D NMR spectroscopy. Two late eluting fractions were each shown to be a mixture of two specific inositol pentakisphosphate isomers. The peak with shorter retention time contained Ins(1,2,3,4,6)P₅ and DL-Ins(1,2,3,4,5)P₅, while the later eluting fraction contained Ins(1,3,4,5,6)P₅ and DL-Ins(1,2,4,5,6)P₅. The formation of all four possible inositol pentakisphosphate isomers by thermal degradation of phytate contrasts with the selective production of unique inositol pentakisphosphate isomers during enzymatic phytate degradation and therefore suggests a method for differentiating abiotic and biotic processes in environmental samples, including soils and decomposing plant biomass.     

Enzymatic Synthesis of Inositol Phosphodiesters Using Phosphatidylinositol-Specific Phospholipase C

Abstract

Transesterication of inositol 1,2-cyclic phosphate with primary alcohols in the presence of phospholipase C produces alkyl inositol phosphates.     

Inositol Monophosphates Prepared in a Single Step from Myo-Inositol and Inorganic Phosphate

ABSTRACT

A mixture of myo-inositol and inorganic metaphosphate (prepared by freeze drying an aqueous solution at pH 4) produced, upon warming, in moderate yield every inositol monophosphate ester, thereby providing in a single step a complete library of these compounds. The individual inositol monophosphates, both meso-compounds and racemic mixtures of the two pairs of enantiomers, were isolated by ion-exchange chromatography which was facilitated by the addition of borate to the mobile phase. The phosphates were characterised using phosphorus analysis in conjunction with alkaline phosphatase, mass spectrometry and ¹H NMR spectroscopy.     

Phosha-Meerwein Reaction of Diazo Esters

Abstract

Diazo esters (la,b) react with trialkyl phosphates (2a–c) in the presence of BF₃.OEt₂ to give the corresponding phosphates (3a–e) in 42–58 % yields. The competed intra/intermolecular protonation in the reaction of la with dimethyl hydrogen phosphite leads to phosphonate. 4,and phosphite 5.     

Triethylphosphate/Phosphorus Pentoxide as an Efficient Reagent for the Phosphorylation of Phenols

Abstract

A simple, efficient, and novel method has been developed for the phosphorylation of phenols. Treatment of phenols with a mixture of triethylphosphate/phosphorus pentoxide gives the corresponding phosphate derivatives in good yields. This method is easy, rapid, and offers good yields for the phosphorylation of phenols. The reaction of triethylphosphate with phosphorus pentoxide was also studied by variable-temperature ³¹P-NMR spectroscopy.     

Organophosphorus compounds—XIX : The reaction of trialkyl phosphites with extended p-quinones

Trimethyl and triethyl phosphites react with diphenoquinone 3, yielding 4,4′-dihydroxydiphenyl 10; 4′-alkoxy-4-biphenylyl dialkyl phosphates 5, 4,4′-biphenylylene tetraalkyl bis(phosphates), 6, and 4′-hydroxy-4-biphenylyl dialkyl phosphates 9 are also isolated in minor yields. The effect of temperature on the reaction is studied. A mechanism for the reaction is presented which accounts for the experimental results. The reaction of trimethyl and triethyl phosphites with quinoneimines 12 gives the corresponding phosphoramidates 13, in quantitative yields.     

Synthesis of Substituted Phosphonates and Their Reactions with Carbonyl Compounds

Abstract

The reaction of the derivatives of 3-phenyl-3-chloro-2-oxopropionic acid with the trivalent phosphorus compounds has been studied. The esterification or amidation of this acid have been shown to influence the course of reaction with Ph₃P. In the reaction with esters enolphosphonium salts are produced, ketophosphonium salts are obtained when amides are involved. Properties of these compounds have also been studied in the Wittig reaction. 3-(α-chlorobenzyl)-2-oxoquinoxaline which reacted with trialkyl phosphates (Arbuzov reaction) has been synthesized. These phosphonates are obtained in nearly quantitative yields, in alkaline conditions (Horner-Emmons reaction) they react smoothly with aromatic aldehydes to give the substituted vinylyuinoxalines.     

Synthesis of Phosphate Esters by Using Diphenyl Ditelluride as Organocatalyst

We report a protocol for the synthesis of new dialkyl(1-(organolthio)naphthalen-2-yl)phosphates and derivatives via a dehydrogenative phosphorylation reaction between functionalized naphthols and H-phosphonates. Diphenyl ditelluride was employed as an organocatalyst and sonochemistry as an alternative energy source. The reaction conditions were defined through a factorial design approach, and the best condition provided the synthesis of dialkyl(1-(organolthio)naphthalen-2-yl)phosphates in yields that varied from 51–98 % under ultrasound irradiation after 2 h of sonication. The synthetic protocol was also effective for phenol and thiophenol starting materials. All products were characterized by state-of-the-art spectroscopic and spectrometric techniques.     

Synthesis and Stereochemistry of some New Unsymmetrical Phosphates with α-Poly-fluoroalkylbenzyl Fragments

Abstract

The methods of synthesis unsymmetrical polyfluoroalkyl phosphates (II) by catalytic phosphorylation of phenols or polyfluoroalkanols by chlorophosphates (I) were elaborated     

Synthesis of Some Specifically Deoxygenated D-Hexopyranosyl Phosphates

Abstract

A number of diphenyl α-glucopyranosyl and xylopyranosyl phosphates (4, 7, 11. 15, 19, and 25) were prepared from their respective glycosyl chlorides by reaction with silver diphenyl phosphate. These sugar phosphates are of interest as enzyme substrates in deoxy sugar biosynthesis.     

The “Other” Inositols and Their Phosphates: Synthesis,Biology, and Medicine (with Recent Advances in myo‐Inositol Chemistry)

Cell signaling via inositol phosphates, in particular via the second messenger myo‐inositol 1,4,5‐trisphosphate, and phosphoinositides comprises a huge field of biology. Of the nine 1,2,3,4,5,6‐cyclohexanehexol isomers, myo‐inositol is pre‐eminent, with “other” inositols (cis‐, epi‐, allo‐, muco‐, neo‐, l ‐chiro‐, d ‐chiro‐, and scyllo‐) and derivatives rarer or thought not to exist in nature. However, neo‐ and d ‐chiro‐inositol hexakisphosphates were recently revealed in both terrestrial and aquatic ecosystems, thus highlighting the paucity of knowledge of the origins and potential biological functions of such stereoisomers, a prevalent group of environmental organic phosphates, and their parent inositols. Some “other” inositols are medically relevant, for example, scyllo‐inositol (neurodegenerative diseases) and d ‐chiro‐inositol (diabetes). It is timely to consider exploration of the roles and applications of the “other” isomers and their derivatives, likely by exploiting techniques now well developed for the myo series.     

Conversion of Cyclic Phosphorothioates into Halophosphates and Neutral Phosphorus Esters and Amides

Abstract

Cyclic phosphorus esters and amides in the 1,3,2-dioxaphosphorinane-2-one series are usually obtained by the condensation of a diol with a suitable phosphorus oxyhalide. In the case of dissymetric diols the formation of two diastereoisomeric products, epimeric at phosphorus, can be expected. This procedure failed or proceeded with low yields when applied to the preparation of cyclic phosphates which would lead to the formation of sterically strained dioxaphosphorinane ring.¹     

Copper-catalyzed allylations of o-vinylbenzylzirconocene intermediate

Benzylzirconocene intermediate, which was readily prepared by the reaction of o-alkoxymethylstyrene with `Cp₂Zr' under mild conditions, reacted with allylic halides or phosphates in the presence of catalytic amount of CuCl to give allylated products in good yields.     

Electrode Hybride Pour la Determination de Phosphates et de Polyphosphates. Application aux Problemes Lies a l'Environnement

Abstract

The determination of phosphates and polyphosphates has been effected using an hybrid electrode, which consists of a glucose oxydase enzymic membrane and a Solanum tuberosum tissue slice. This membrane, rich in acid phosphatase, catalyses the glucose-6-phosphate hydrolysis. This reaction is quantitatively inhibited by phosphate. Several factors involved in the electrode response, like substrate concentration, pH, ionic strength and type of buffer are discussed in detail. At a 4.10^?4 M glucose-6-phosphate concentration, the linear ranges of phosphates and polyphosphates are, respectively, 6.10^?5 M to 1.6.10^?3 M and 3.10^?5 M to 1.10^?3 M. The urinary phosphate contents determinated by this biosensor are in good agrement with those obtained by usual spectrophotometric techniques.     

TRANSESTERIFICATION OF TRIS(p-NITROPHENYL) PHOSPHATE WITH SODIUM ALKOXIDES: BIS(p-NITROPHENYL) METHYL PHOSPHATE,BIS(p-NITROPHENYL) BENZYL PHOSPHATE,BIS(p-NITROPHENYL) n-BUTYL PHOSPHATE

Abstract

Transesterification of tris(p-nitrophenyl) phosphate by sodium alkoxides, in dichloromethane at 0°, provides a convenient synthetic route to diaryl alkyl phosphates which are produced in a high state of purity and in moderate to high yields. The procedure is used to prepare bis(p-nitrophenyl) methyl phosphate, bis(p-nitrophenyl) benzyl phosphate and bis(p-nitrophenyl) n-butyl phosphate.     

Diastereoselective Synthesis of Glycosyl Phosphates by Using a Phosphorylase–Phosphatase Combination Catalyst

Sugar phosphates play an important role in metabolism and signaling, but also as constituents of macromolecular structures. Selective phosphorylation of sugars is chemically difficult, particularly at the anomeric center. We report phosphatase‐catalyzed diastereoselective “anomeric” phosphorylation of various aldose substrates with α‐D ‐glucose 1‐phosphate, derived from phosphorylase‐catalyzed conversion of sucrose and inorganic phosphate, as the phosphoryl donor. Simultaneous and sequential two‐step transformations by the phosphorylase–phosphatase combination catalyst yielded glycosyl phosphates of defined anomeric configuration in yields of up to 70 % based on the phosphate applied to the reaction. An efficient enzyme‐assisted purification of the glycosyl phosphate products from reaction mixtures was established.     

Synthesis of Some Mixed Dialkyl Phosphites and their Use as Forerunners for Potential Chiral Phosphates

Abstract

Organophosphorus compounds containing a c h i d ccntrc at the P atom are of considerable interest fiom a stcreochemical point of view. Accordingly, trialkyl phosphates (RO)(RIO)(R20)P(0) (4) were synthesized starting from dialkyl phosphites. Thus: direct hydrolysis of dialkyl phosphites (ROhP(0)H (1) with tetraethylammonium hydroxide (20% aqueous solution), followed by extraction with dichloromethane affords the corresponding tetraethylammonium alkyl hydrogen phosphitcs (2). Good yields (q) of mixed dialkyl phosphites (3) were obtained on heating stoichiometric amounts of (2) and alkyl iodides in acetonitrile solution at 6O°C, for 6 hrs. Mixed dialkyl phosphites (3) were used in synthesis of some trialkyl phosphates (4) by PTC (see scheme).     

Ester Exchange Reaction of Oxyphosphorane with Thymidine

Ester exchange reaction of oxyphosphorane (1) with thymidine (2) afforded diastereomeric spirooxyphosphoranes 3 under mild conditions in good yield. After hydrolysis, thymidine phosphates monomers (5, 6) and dimer (7) were obtained.     

Mechanisms of phosphate transfer on the purine salvage pathway

Abstract

α-D-Ribofuranosyl-1,2-cyclic monophosphate and 5-phospho-α-D-ribofuranosy1-1, 2-cyclic monophosphate were synthesized in good yields. The five-membered ring cyclic phosphates have ³¹p chemical shifts similar to those found for such structures, presumably reflecting the smaller O-P-O bond angle, compared to that in six-membered ring phosphates. The rate of OH^? catalyzed ring opening was similar to that reported for ethylene phosphate, indicating relief of ring strain during hydrolysis. α-D-Ribofuranosyl-1, 2-cyclic monophosphate was found to irreversibly inactivate purine nucleoside phosphorylase (EC 2.4.2.1) at its catalytic center.     

Base-promoted O-deprotonation/alkylation reaction of P(O)–OH compounds with alkyl halides

A novel base-promoted O-deprotonation/alkylation reaction of P(O)–OH compounds with alkyl halides has been developed. The protocol is practical, representing a simple way to produce a broad spectrum of functionalized phosphinates, phosphonates, and phosphates from basic starting materials with good to excellent yields. A plausible mechanism was proposed for this reaction.