Diethyl Phosphite Research Articles

ChemInform Abstract: An Eco‐Friendly Three Component Manifold for the Synthesis of α‐Aminophosphonates under Catalyst and Solvent‐Free Conditions, X‐Ray Characterization and Their Evaluation as Anticancer Agents.

A series of α-aminophosphonates were synthesized through one-pot condensation of aryl aldehydes, aryl amines and diethyl phosphite in the absence of any catalyst and organic solvents. All the synthesized α-aminophosphonates were characterized by spectral and elemental analysis and in the case of compound 4j by X-ray crystallography. Some of these new α-aminophosphonate derivatives were found to have cytotoxic activity on the cancer cell line DU145 in vitro by the MTT method.

Synthesis of α-aminophosphonates using carbon nanotube supported imidazolium salt-based ionic liquid as a novel and environmentally benign catalyst

A supported acidic catalyst was easily prepared via anchoring imidazolium salt-based ionic liquid onto multiwalled carbon nanotube by covalent bonds. This novel immobilized acidic ionic liquid effectively catalyzed the one-pot synthesis of α-aminophosphonates from the reaction of amines and aldehydes with diethyl phosphite. The catalyst can be easily recovered and reused without appreciable change in its efficiency.

Diethyl Phosphite Initiated Coupling of α-Ketoesters with Imines for Synthesis of α-Phosphonyloxy-β-amino Acid Derivatives and Aziridine-2-carboxylates.

Coupling of α-ketoesters with imines initiated by diethyl phosphite in the presence of alkaline metal hexamethyldisilazides is reported. Base-promoted addition of diethyl phosphite to α-ketoesters, followed by [1,2]-phosphonate/phosphate rearrangement, generates α-phosphonyloxy enolates that are subsequently intercepted by imines. The use of suitable azomethine coupling partners allows selective construction of syn-α-hydroxy-β-amino acid derivatives or trans-aziridine-2-carboxylates in high yields with excellent diastereoselectivities.

Bis(β-diketiminato) Lanthanide(Ⅱ) Complexes-Catalyzed Hydro-phosphonylation of Aldehydes/Ketones and Diethyl Phosphite

The hydrophosphonylation of aldehydes/ketones was explored by use of seven bis(β-diketiminato) lanthanide(II) complexes: (Eu(L 2,6-ipr2 )2·CH3C6H5 , L 2,6-ipr2 = [N(2,6i Pr2C6H3)C(Me)]2CH − ) (1); Eu(L 2,6-Me2 )2(THF), L 2,6-Me2 = [N(2,6-Me2C6H3)C(Me)]2CH − ) (2); Eu(L 2,4,6-Me3 )2(THF), L 2,4,6-Me3 = [N(2,4,6-Me3C6H2)C(Me)]2CH − ) (3); Eu(L 2,6-ipr2 Ph)2, L 2,6-ipr2 Ph = [(2,6i Pr2C6H3)NC(Me)CHC(Me)N(C6H5)] – ) (4); Sm(L 2,6-ipr2 )2·CH3C6H5 (5); Yb(L 2,6-ipr2 Ph)2 (6); Yb(L 2-Me )2(THF), (L 2-Me = [N(2-MeC6H4)C(Me)]2CH – (7)) as the catalysts. All complexes were found to be able to catalyze the hydrophosphonylation between aromatic or heterecycle aldehyde and diethyl phosphite with high activity under wild conditions. All the reactions gave the products in 90-99% yields using 0.08 mol% of complex 7 at 25 °C under solvent-free. The catalyst activity was found to depend on the β-diketiminato ligands, with the sequences of L 2,6-Me2 < L < L ~ L2,6-ipr2Ph. This catalyst system showed a wide scope of aldehydes. Besides, bis(β-diketiminato) lanthanide(II) complexes could also efficiently catalyze the hydrophosphonylation of unactive ketones with diethyl phosphite and showed a good substrate scope.

Surface thermodynamic parameters of modified wood

Energy characteristics of modified wood are studied in the paper. Application of this approach during the study of wooden materials allows forecasting the efficiency of modifiers for surface layer of wood. Phosphites, the efficient fire-retarders, were applied as modifiers. Using the example of a number of ethers with various alkoxy substituents of phosphorus atom, we have made an attempt to associate surface thermodynamic properties of modified wood and formation of properties for fire-, bio- and smoke protection. The dependence of change of energy characteristics and surface structure of wood on the nature of modifiers is determined. To study energy characteristics of wood, modified by various compounds, the following characteristics were used: σ surface tension and ΔG free enthalpy gradient. Easy Drop setting and the corresponding software were used to determine these values. According to the obtained data, the conclusion is made about the influence of modifiers on energy characteristics of wood. The high degree of modification (% P) causes bigger change of Gibbs energy, which determines formation of high-level fire-, bio- and smoke protection. Diethyl phosphite is the most efficient modifier. Formation of fire-protective properties stipulates long-term operation of wood and wood-based materials.

Synthesis of ethyl 4,5-bis(diethoxyphosphorylmethyl)-3-furoate

Preparative procedure for 4,5-bis(diethoxyphosphorylmethyl)-3-furoate from 4-chloromethyl-3-furoate is developed. It includes substitution of chlorine with iodine, phosphorylation by means of the Arbuzov reaction, chloromethylation of 4-(diethoxyphosphorylmethyl)-3-furoate in the position 5 of the furan ring, substitution of chlorine with iodine in the obtained chloromethyl derivative, and repeated phosphorylation with triethyl phosphite. It was found that ethyl 4-(diethoxyphosphorylmethyl)-5(chloromethyl)-3-furoate reacts with sodium diethyl phosphite by two pathways. Besides usual nucleophilic substitution leading to phosphonate, transfer of the reaction center in the position 2 of the furan ring takes place. The ambident diethylphosphite anion in this case reacts at the oxygen to give tertiary phosphite. The latter is oxidized with the air oxygen to form ethyl 2-(diethoxyphosphoryloxy)-4-(diethoxyphosphorylmethyl)-5-methyl-3-furoate. Unlike that analogous iodomethyl phosphonate is phosphorylated selectively under the conditions of the Arbuzov reaction.

Brønsted base-catalyzed three-component coupling reaction of α-ketoesters, imines, and diethyl phosphite utilizing [1,2]-phospha-Brook rearrangement.

A three-component coupling reaction of α-ketoesters, imines, and diethyl phosphite under Brønsted base catalysis was developed by utilizing the [1,2]-phospha-Brook rearrangement. The reaction involves the generation of ester enolates via the umpolung process, i.e., the chemoselective addition of diethyl phosphite to α-ketoesters followed by the [1,2]-phospha-Brook rearrangement, and the trapping of the resulting enolates by imines preferentially over α-ketoesters and protons. This operationally simple reaction can provide densely functionalized β-amino acid derivatives including an oxygen functionality at the α-position in good yields. The diastereoselectivity is highly dependent on the substrates and reaction temperature, which is attributed to the reversibility of the addition of the ester enolates to the imines. The methodology was further extended to the reaction of α-ketoesters, β-nitrostyrenes, and diethyl phosphite.

Bifunctional Iminophosphorane Catalyzed Enantioselective Ketimine Phospha-Mannich Reaction

The enantioselective phospha-Mannich reaction of diethyl phosphite to unactivated N-DPP-protected ketimines catalyzed by a bifunctional iminophosphorane (BIMP) superbase organocatalyst is described. The reaction is applicable to ketimines bearing electron-rich and electron-poor aryl substituents and occurs with excellent yields and moderate enantioselectivities under mild reaction conditions.

An Eco‐friendly Three Component Manifold for the Synthesis of α‐Aminophosphonates under Catalyst and Solvent‐free Conditions, X‐ray Characterization and Their Evaluation as Anticancer Agents

AbstractA series of α‐aminophosphonates were synthesized through one‐pot condensation of aryl aldehydes, aryl amines and diethyl phosphite in the absence of any catalyst and organic solvents. All the synthesized α‐aminophosphonates were characterized by spectral and elemental analysis and in the case of compound 4j by X‐ray crystallography. Some of these new α‐aminophosphonate derivatives were found to have cytotoxic activity on the cancer cell line DU145 in vitro by the MTT method.

An unexpected reaction of diethyl phosphite with electron-deficient dialkyl dicyanofumarates

GRAPHICAL ABSTRACT

Synthesis, mechanical properties and fire behaviors of rigid polyurethane foam with a reactive flame retardant containing phosphazene and phosphate

Reactive flame retardant hexa-(phosphite-hydroxyl-methyl-phenoxyl)-cyclotriphosphazene (HPHPCP) was synthesized by hexachlorocyclotriphosphazene, diethyl phosphite and p-hydroxybenzaldehyd. Flame retardant rigid polyurethane foams (FR-RPUFs) were prepared by free foaming with incorporating HPHPCP with polyether polyol, polyester polyol and polymethylene polyphenyl isocyanate. The chemical structure of HPHPCP was characterized by proton and 31P nuclear magnetic resonance. The morphology, physical–mechanical properties, thermal stability and flame-retardant performance of rigid polyurethane foam (RPUF) and FR-RPUFs were investigated. Results suggested that the incorporation of HPHPCP into RPUF enhance the density, comprehensive strength and thermal stability as a result of higher crosslink concentration resulting from the multifunctional group of HPHPCP. Furthermore, with the increase of HPHPCP content, the limiting oxygen index (LOI) increased along with the gradually decreased values of the second peak heat release rate (PHRR2). In addition, when the additive of HPHPCP was higher than 10 wt%, FR-RPUFs pass UL-94 HF-1 rating and the flame spread limited simultaneously, indicating the reinforced and flame-retardant RPUFs could be obtained.

ChemInform Abstract: BuLi‐Triggered phospha‐Brook Rearrangement: Efficient Synthesis of Organophosphates from Ketones and Aldehydes.

AbstractBuLi promoted mild reactions of activated/unactivated ketones and aldehydes with diethyl phosphite give aromatic and allylic phosphates in good yields.

ChemInform Abstract: Glycosylation with 2‐Acetamido‐2‐deoxyglycosyl Donors at a Low Temperature: Scope of the Non‐oxazoline Method.

A direct construction of 1,2-trans-β-linked 2-acetamido-2-deoxyglycosides was investigated. The 3,4,6-tri-O-benzyl- and 3,4,6-tri-O-acetyl-protected glycosyl diethyl phosphites and 4,6-O-benzylidene-protected galactosyl diethyl phosphite each reacted with a variety of acceptor alcohols in the presence of a stoichiometric amount of Tf2NH in CH2Cl2 at −78 °C to afford the corresponding β-glycosides in good to high yields with complete stereoselectivity. Some experiments provided strong evidence that the corresponding oxazolinium ions are not responsible for the reaction. We demonstrated that glycosylations with the corresponding glycosyl imidate and thioglycoside also proceeded at a low temperature, indicating the possibility of these donors being attractive alternatives to the phosphite. A plausible reaction mechanism, which features glycosyl triflimide and contact ion pair as reactive intermediates, is proposed on the basis of the results obtained with 2-acetamido-2-deoxymannosyl donors.

Spiro- and substituted tetrahydrobenzo[b]thiophene-triazaphospholes and phosphoramidates as potent antineoplastic agents: synthesis, biological evaluation, and SAR studies

New and efficient conjugate addition reaction of trimethyl, triethyl, and triisopropyl phosphites with 2-azido-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile was developed and furnished spiro-triazaphosphole-oxide derivatives in ≈70 % yield. Contrary to these results, linear substituted phosphoramidates were obtained from the reaction of the azide with dimethyl, diethyl, and diisopropyl phosphites. N-Alkylamino- or 2-aminotetrahydrobenzo[b]thiophene-3-carbonitrile was also isolated in ~10 % yield from the previous two reactions. In the context of this work, hexaalkylphosphorus triamides were caused to react with the same substrate afforded the corresponding phosphoric triamides only in the presence of a protonating agent (dil. alcohol). The three reactions proceeded smoothly, cleanly, and were completed within ~6 h at r.t. Pharmacological evaluation results of antibreast, anticolon, and antiprostate carcinoma cell lines properties for the products were discussed in terms of structure–activity relationship to define a chromophore for lead compounds.

New method of metal-induced oxidative phosphorylation of benzene

A new approach to phosphorylation of benzene with diethyl phosphite is suggested, which is based on the electrocatalytic oxidation of a mixture of benzene and diethyl phosphite (1 : 1) under mild conditions (room temperature, normal pressure) in the presence of bimetallic catalytic systems MnII/CoIIL (MnSO4/CoCl2dmphen or MnCl2/CoCl2bipy). This method gives diethyl phenylphosphonate in high yield (up to 90%) and practically 100% conversion of the phosphite.

A convenient synthesis and biological evaluation of some novel linear and cyclic α-aminophosphonic acid derivatives containing a quinazolinone ring

Synthesis of some novel linear and cyclic α-aminophosphonic acids and their esters bearing a quinazolin-4(3H)-one ring was achieved. The methodology depends on Pudovik reaction conditions in which using 3-(benzylideneamino)-2-phenyl-quinazolin-4(3H)-one (2) with phosphorous acid, diethyl phosphite and tris(2-chloroethyl) phosphite gives the corresponding linear α-aminophosphonic acid derivatives 3, 5 and 7, respectively, in good yields. Heterocyclization of the linear compounds to 1,4,2-oxazaphosphinanes as cyclic α-aminophosphonic acid derivatives 4, 6 and 8, respectively, was carried out. The synthesized compounds were evaluated for their antimicrobial and antioxidant activities. The cyclic α-aminophosphonic acids and their esters showed better antimicrobial and antioxidant activities than the corresponding linear α-aminophosphonic acids and their esters. Synthesis of some novel linear and cyclic α-aminophosphonic acids and their esters bearing a quinazolin-4(3H)-one ring as antimicrobial and antioxidant agents from 3-(benzylideneamino)-2-phenyl-quinazolin-4(3H)-one was achieved.

Synthesis of gem-bisphosphonates with (3-aryl-4,5-dihydroisoxazol-5-yl)methylamino moiety

Three-component reaction between N-allyl-N-methylamine, triethyl orthoformate and diethyl phosphite affords N-[bis(diethoxyphosphoryl)methyl]-N-methyl-3-arylprop-3-en-1-amine whose cycloaddition with nitrile N-oxides gives 5-{N-[bis(diethoxyphosphoryl)methyl]-N-methylamino}methyl-4,5-dihydroisoxazoles.

BuLi-triggered phospha-Brook rearrangement: efficient synthesis of organophosphates from ketones and aldehydes

A variety of organophosphates are synthesized from n-BuLi-triggered, (additional) solvent-free reactions of diethyl phosphite with both activated/unactivated ketones and aldehydes preferably at room temperature via phospha-Brook rearrangement. We could successfully synthesize the naphthylic/allylic phosphates using this approach.

Glycosylation with 2-Acetamido-2-deoxyglycosyl Donors at a Low Temperature: Scope of the Non-Oxazoline Method.

A direct construction of 1,2-trans-β-linked 2-acetamido-2-deoxyglycosides was investigated. The 3,4,6-tri-O-benzyl- and 3,4,6-tri-O-acetyl-protected glycosyl diethyl phosphites and 4,6-O-benzylidene-protected galactosyl diethyl phosphite each reacted with a variety of acceptor alcohols in the presence of a stoichiometric amount of Tf2NH in CH2Cl2 at -78 °C to afford the corresponding β-glycosides in good to high yields with complete stereoselectivity. Some experiments provided strong evidence that the corresponding oxazolinium ions are not responsible for the reaction. We demonstrated that glycosylations with the corresponding glycosyl imidate and thioglycoside also proceeded at a low temperature, indicating the possibility of these donors being attractive alternatives to the phosphite. A plausible reaction mechanism, which features glycosyl triflimide and contact ion pair as reactive intermediates, is proposed on the basis of the results obtained with 2-acetamido-2-deoxymannosyl donors.

Synthesis of the Tetrasaccharide Repeating Unit from Acinetobacter baumannii Serogroup O18 Capitalizing on Phosphorus-Containing Leaving Groups.

The first convergent synthesis of the tetrasaccharide repeating unit of the polymeric O antigen isolated from Acinetobacter baumannii serogroup O18 has been achieved. The ManNAcβ1→4Gal and GalNAcβ1→3Gal units were successfully obtained through β-selective glycosylation with 2-azido-4,6-O-benzylidene-2-deoxymannosyl diphenyl phosphate and Tf2NH-promoted glycosylation with 2-acetamido-2-deoxygalactosyl diethyl phosphite, respectively. The disaccharide units could be coupled with the aid of TMSClO4 as an activator of the diphenyl phosphate leaving group, and global deprotection completed the synthesis of the tetrasaccharide.