Diisopropyl Phosphite Research Articles

Ultrasensitive quantification of trace amines based on N-phosphorylation labeling chip 2D LC-QQQ/MS

Trace amines (TAs) are metabolically related to catecholamine and associated with cancer and neurological disorders. Comprehensive measurement of TAs is essential for understanding pathological processes and providing proper drug intervention. However, the trace amounts and chemical instability of TAs challenge quantification. Here, diisopropyl phosphite coupled with chip two-dimensional (2D) liquid chromatography tandem triple-quadrupole mass spectrometry (LC-QQQ/MS) was developed to simultaneously determine TAs and associated metabolites. The results showed that the sensitivities of TAs increased up to 5520 times compared with those using nonderivatized LC-QQQ/MS. This sensitive method was utilized to investigate their alterations in hepatoma cells after treatment with sorafenib. The significantly altered TAs and associated metabolites suggested that phenylalanine and tyrosine metabolic pathways were related to sorafenib treatment in Hep3B cells. This sensitive method has great potential to elucidate the mechanism and diagnose diseases considering that an increasing number of physiological functions of TAs have been discovered in recent decades.

Stand out from matrix: Ultra-sensitive LC−MS/MS method for determination of histamine in complex biological samples using derivatization and solid phase extraction

The determination of low abundant endogenous components is a challenge for the clinical samples. Histamine, a crucial endogenous component, fulfils various regulatory and mediatory functions in human, and the change of content is a critical index for the diagnosis of some diseases, especially allergy, asthma, and anaphylactic shock. However, it is challenging to detect histamine because of the low stability and concentration in complex biological samples. Here we developed an ultra-sensitive and accurate LC−MS/MS quantification method based on derivatization, isotope dilution, and solid phase extraction. The derivatization of histamine with diisopropyl phosphite (DIPP) not only enhanced the retention on the LC column but also improved the ionization efficiency. Next, solid phase extraction was applied to remove the interference, which finally resulted in standing out of the trace histamine from the high contents of the matrix. The lowest limit of quantification (LLOQ) was 0.1 pg/mL that is enough low to determine the histamine in one cell and low nano-liter of serum. This approach was successfully applied for the quantification of histamine in clinical serum samples of asthma patients and mast cell treated with chemicals modulating histamine release.

Michael Addition of P-Nucleophiles to Conjugated Nitrosoalkenes.

A general approach to various α-phosphorus-substituted oximes (β-oximinoalkyl-substituted phosphonates, phosphine oxides, phosphine-borane complexes, and phosphonium salts) was developed. The strategy exploits hitherto unknown Michael addition of PH-containing compounds (diphenylphosphine oxide, diisopropyl phosphite, phosphine-borane complexes, and triphenylphosphonium bromide) to unstable conjugated nitrosoalkenes, which are generated in situ from corresponding nitrosoacetals. The resulting α-phosphorus-substituted oximes can be considered as useful P-, N-, and O-ligands for catalysis and precursors to valuable β-aminophosphonates.

Multistep Wavelength Switching of Near-Infrared Photoluminescence Driven by Chemical Reactions at Local Doped Sites of Single-Walled Carbon Nanotubes.

Local chemical functionalization is used for defect doping of single-walled carbon nanotubes (SWNTs), to develop near-infrared photoluminescence (NIR PL) properties. We report the multistep wavelength shifting of the NIR PL of SWNTs through chemical reactions at local doped sites tethered to an arylaldehyde group. The PL wavelength of the doped SWNTs is modulated based on imine chemistry. This involves the imine formation of aldehyde groups with added arylamines, imine dissociation reaction, exchange reaction of bound arylamines in the imine, and the Kabachnik-Fields reaction of imine groups using diisopropyl phosphite. Using doped sites as a localized chemical reaction platform can exploit the versatile molecularly driven functionality of carbon nanotubes and related nanomaterials.

Optimization of Phosphoramidates Synthetic Conditions

An optimized catalytic oxidative cost effective process of dehydrogenative coupling of diisopropyl phosphite with arylamines led to formation of the corresponding phosphoramidates. Structures of products were elucidated from NMR and ESI-MS data.

Conversion of nitriles to 1-aminophosphonic acids and preparation of phosphahomocysteines of high enantiomeric excess

GRAPHICAL ABSTRACT

The synthesis of new pyrrolo[2,3-d]pyrimidine-containing α-hydroxyphosphonic acids

The work is devoted to the synthesis of new pyrrolo[2,3-d]pyrimidine-containing α-hydroxyphosphonic acids as precursors for the synthesis of potential biologically active compounds. The reaction between methyl 7-allyl-1,3dimethyl-2,4-dioxo-2,3,4,7-tetrahydro-1Н-pyrrolo[2,3-d]pyrimidine-6-carboxylate and iodine has resulted in 8-iodomethylpyrimido[5’,4’:4,5]pyrrolo[2,1-c][1,4]oxazine. The composition and structure of the compound has been confirmed by elemental analysis, NMR-spectroscopy and X-ray examination, and it is a convincing evidence of the presence of the oxazine cycle. Elimination of hydrogen halide of the iodomethyl derivative occurred with formation of 1,3,8-trimethyl-2H-pyrimido[5’,4’:4,5]pyrrolo[2,1-c][1,4]oxazine-2,4,6(1H,3H)-trione. The compound obtained upon heating with methanol in the presence of potassium carbonate was subjected to the nucleophilic attack at the carbonyl group. 7-(2-Oxopropyl)-1H-pyrrolo[2,3-d]pyrimidine derivative was formed by cleavage of the lactone ring. The treatment of ketone with diisopropyl phosphite by Abramov reaction resulted in formation of pyrimido[5’,4’:4,5] pyrrolo[2,1-c][1,4]oxazin-8-ylphosphonate, its hydrolysis was carried out by boiling in dilute hydrochloric acid. The reaction proceeded by opening of the oxazine ring, with the concomitant decarboxylation giving pyrrolo[2,3-d] pyrimidine with the 1-hydroxyphosphonoethyl substituent in position 7 of the heterocycle. The structure of the compounds obtained has been proven using NMR spectroscopy, mass-spectra and elemental analysis.

ChemInform Abstract: Synthesis of Phenanthrene Derivatives by Intramolecular Cyclization Utilizing the [1,2]‐Phospha‐Brook Rearrangement Catalyzed by a Broensted Base.

AbstractBiaryl compounds bearing an α‐ketoester moiety and an alkyne moiety at positions C‐2 and C‐2′, respectively, react with diisopropyl phosphite in the presence of a catalytic amount of phosphazene base P2‐tBu.

Synthesis of phenanthrene derivatives by intramolecular cyclization utilizing the [1,2]-phospha-Brook rearrangement catalyzed by a Brønsted base.

The synthesis of functionalized phenanthrene derivatives was achieved by intramolecular cyclization utilizing the [1,2]-phospha-Brook rearrangement under Brønsted base catalysis. Treatment of biaryl compounds having an α-ketoester moiety and an alkyne moiety at the 2 and 2' positions, respectively, with diisopropyl phosphite in the presence of a catalytic amount of phosphazene base P2-tBu provides 9,10-disubstituted phenanthrene derivatives in high yields. This reaction involves the generation of an ester enolate through an umpolung process, that is, addition of diisopropyl phosphite to a keto moiety followed by the [1,2]-phospha-Brook rearrangement, the intramolecular addition to an alkyne, and the [3,3] rearrangement of the allylic phosphate moiety in a consecutive fashion.

Copper (I) Iodide-Catalyzed Solvent-Free Synthesis of α-Aminophosphonates

A method for the synthesis of α-aminophosphonates through the three-component coupling reaction of aldehydes, amines, and diisopropyl phosphite using copper (I) iodide salt catalyst is demonstrated, The reaction is highly efficient, economic, and also environment friendly. [Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Table S1, Figures S1–S9.] GRAPHICAL ABSTRACT

Synergistic effect of diisopropyl phosphite and ashless organic ammonium phosphate salt additives on tribological properties of AISI 52100 steel/Al2O3 ceramics

The friction-reducing and antiwear effects of the 500SN base oil containing diisopropyl phosphite (T451) and ashless organic ammonium phosphate salt (KT139) on AISI 52100 steel/Al2O3 ceramic were investigated with a ball-on-disc tribometer at a light load of 200 N and a high load of 400 N. The results indicate that the 500SN base oil containing T451 and KT139 appears with a synergistic effect on AISI 52100 steel/Al2O3 ceramic. Under a single additive, increasing percentage of T451 or KT139 can decrease the friction coefficient and the wear rate of the pair monotonously. However, under the compound system, the tribological behaviour of the pair is strongly dependent of the concentrations of additives. Within the experimental data, the most effective compositions for the loads 200 and 400 N are 2 wt%T451 + 2 wt%KT139 and 1 wt%T451 + 3 wt%KT139, respectively. The scanning electron microscopic images showed that plowed grooves, spalling, and corrosion are the dominant wear modes for the pair. The energy dispersive spectroscopy analysis shows that a protective tribochemical film containing both S and P forms on the steel ball worn surface. Nevertheless, the atom concentrations of P and S are too low to be referred for further analysis of the tribochemical reaction mechanism.

Synergistic effect of diisopropyl phosphite and over‐based calcium sulphonate additives on tribological properties of AISI 52100 steel/Al2O3 ceramics

ABSTRACTThe friction‐reducing and anti‐wear effect of the 500SN base oil containing diisopropyl phosphite (T451) and over‐based calcium sulphonate (KT5447) on AISI 52100 steel/Al2O3 ceramic were investigated with a ball‐on‐disc tribometer at a light load of 200 N and a high load of 400 N. The results indicate that the 500SN base oil containing T451 and KT5447 appears to have a synergistic effect on the pair. For the light load of 200 N, the effective composition is 3 wt% T451 + 2–3 wt% KT5447. For the high load of 400 N, the combination of T451 and KT5447 appears to have a synergistic friction‐reducing and anti‐wear effect. The scanning electron microscope images show that ploughed grooves, pitting, spalling and corrosion are the dominant wear modes for both 200 and 400 N. However, no evidence for the formation of the expected sulphur‐containing or phosphorus‐containing chemical compound is found according to X‐ray photoelectron spectroscopy analysis of the worn steel ball surface at both loads. Copyright © 2011 John Wiley & Sons, Ltd.

ChemInform Abstract: Copper‐Mediated Cross‐Coupling of 1,1‐Dibromo‐1‐alkenes with Dialkyl Phosphites: A Convenient Synthesis of 1‐Alkenylphosphonates.

AbstractThe Hirao reduction of 1,1‐dibromo‐1‐alkenes with diisopropyl phosphite generates intermediate 1‐alkenylbromides, which react with a second equivalent phosphite to afford desired 1‐alkenylphoshonates.

Potential transition state phosphoramidate inhibitors of beta-tubulin as antifilarial agents.

Transition state phosphoramidate inhibitors of beta-tubulin were designed as potential antifilarial agents. The reaction of 2-aminobenzimidazole with diisopropyl phosphite and carbon tetrachloride at a low temperature gave the unexpected 1-diisopropoxyphosphoryl-2-aminobenzimidazole, which on heating gave the novel benzimidazole derivative, 2-(diisopropoxyphosphoryl)aminobenzimidazole. Both products were fully characterized and the synthetic procedure to both compounds was optimized. The procedure was used to prepare the related 5-benzoyl-2-(diisopropoxyphosphoryl)aminobenzimidazole and 5-benzoyl-2-(diethoxyphosphoryl)aminobenzimidazole (1d). In a preliminary trial against Brugia pahangi compound 1d was found to have no antifilarial activity. This lack of activity may be attributed to its extreme insolubility and thus low bioavailability. The synthesis of analogous, more soluble, phosphorothioate-substituted benzimidazoles using the same methods may yield compounds with greater antifilarial activity.

Synergistic effect of diisopropyl phosphite and triphenyl thiophosphate additives on tribological properties of T8 steel/Al 2O 3 ceramics

The effect of friction-reducing and antiwear of lubricant additives on T8 steel/Al 2O 3 ceramics was investigated using a pin-on-disk tribometer at a room temperature. Diisopropyl phosphite (T451) and triphenyl thiophosphate (T309 or TPPT) with various mass concentrations were blended in 500SN base oil to produce the lubricants, and their friction-reducing and antiwear were examined under the given applied normal loads of 220 N (mainly for assessment of friction-reducing) and 400 N (for antiwear), respectively. The results showed that base oil containing T451 and T309 can be more essential for improving the friction-reducing and antiwear behaviors, rather than those under the pure base oil, or the single additive. In detail, at a load of 220 N, the synergistic effect of friction-reducing increased with addition of T451 and T309 within a suitable amount. At a load of 400 N, the synergistic effect of antiwear prominently related with the content of T451, and the appropriate composition was 2%T451 + 1%T309. SEM analysis of worn surfaces and AES spectra of typical elements indicated that the synergistic friction-reducing and antiwear effect is owing to the thick sulfur-rich and phosphorus-rich protective film formed on the worn surface T8 steel pin. The wear mechanisms were characterized by fracture and scuffing under the lubricants.

Chiral Brønsted acid-catalyzed hydrophosphonylation of imines—DFT study on the effect of substituents of phosphoric acid

The enantioselective hydrophosphonylation reaction of diisopropyl phosphite with aldimine furnished α-amino phosphonates with high enantioselectivities by means of a chiral phosphoric acid. DFT calculation of the effect of 3,3′-substituents of the phosphoric acid revealed the reason for the high enantioselectivities.

Diisopropyl (hydroxyphenylmethyl)phosphonate

The title compound, C13H21O4P, was obtained by the reaction of diisopropyl phosphite and benzaldehyde. The crystal structure is stabilized by strong inter­molecular O—H⋯O hydrogen bonds.

Chiral Brønsted Acid Catalyzed Enantioselective Hydrophosphonylation of Imines: Asymmetric Synthesis of α-Amino Phosphonates

[reaction: see text] A cyclic phosphoric acid derivative, derived from (R)-BINOL, was used as a chiral Brønsted acid (10 mol %) in hydrophosphonylation of aldimines with diisopropyl phosphite at room temperature. Alpha-amino phosphonates were obtained with good to high enantioselectivities.

The Effectivity of 1H‐Triazoles and ‐Tetrazoles as Activators in Acid‐Catalyzed Phosphoramidite Alcoholysis

AbstractThe efficiency of 5‐nitro‐1,2,4‐1H‐triazole (3), 5‐(methylthio)‐1H‐tetrazole (4), and 5‐(4‐nitrophenyl)‐1H‐tetrazole (5) as activators in phosphoramidite alcoholysis has been studied relative to 1H‐tetrazole (6). Reactions of these azoles with diisopropyl (diisopropylamido)phosphite (1a) were followed in THF, and the rates were found to increase with increasing acidity of the azoles. The Brønsted α value of 0.7 determined for this dependence is in agreement with data published earlier.

Kinetics and mechanism of the pudovik reaction in the azomethine series: II.1 Hydrolysis and catalysis in the reaction of dialkyl phosphites with benzalaniline

A 31P NMR study show that diisopropyl phosphite and benzalaniline do not react with each other as individual components. Adduct formation is made possible by partial hydrolysis of the dialkyl phosphite.