Triethyl Phosphite Research Articles

Unusual Reactivity of Aryl Aldehydes with Triethyl Phosphite and Zinc Bromide: A Facile Preparation of Epoxides, Benzisoxazoles, and α‐Hydroxy Phosphonate Esters

AbstractA facile preparation of trans‐epoxides was achieved by a (EtO)3P–ZnBr2‐mediated deoxygenation reaction of the corresponding 2‐nitrobenzaldehydes. The sterically hindered analogues of 2‐nitrobenzaldehyde underwent a reaction with triethyl phosphite in the presence of ZnBr2 as the catalyst to form benzisoxazoles as the sole product. Under identical conditions, the reactions of electron‐rich as well as moderately electron‐deficient aryl aldehydes furnished the corresponding α‐hydroxy phosphonate esters.

A Simple and Green Procedure for the One-Pot Synthesis of α-Aminophosphonates with Quaternary Ammonium Salts as Efficient and Recyclable Reaction Media

A simple and highly efficient approach has been developed for a multicomponent one-pot reaction of aldehydes or ketones with amines and diethyl or triethyl phosphite to give the corresponding α-aminophosphonates. In the presence of quaternary ammonium salts, which are environmental friendly, inexpensive, and recyclable, α-aminophosphonates were obtained in excellent yields at room temperature within short times.

One-pot synthesis of novel oxazaphosphinanes under ultrasound irradiation and solvent-free conditions

A rapid and efficient solvent-free one-pot synthesis of novel oxazaphosphinane is described under ultrasound irradiation. This reaction was carried out through a three-component condensation reaction of amino alcohol, aromatic aldehyde, and triethyl phosphite. Ultrasonic effects were established with many advantages, including high yields, shorter reaction times, easy and quick isolation of the products. The newly synthesized compounds were systematically characterized by IR, 1H NMR, 13C NMR, 31P NMR, MS, and elemental analysis.

Synthesis and biological evaluation of aminomethylidenebisphosphonic derivatives of β-arylethylamines

Addition of two equivalents of triethyl phosphite to β-arylethylisocyanides to synthesize tetraethyl aminomethylidenebisphosphonates in the presence of a stoichiometric amount of hydrogen chloride is reported. Acid hydrolysis of the tetraethyl esters gave the 2-arylethylaminomethylidenebisphosphonic acids in good yields. Additionally, the obtained bisphosphonates were evaluated for their antiproliferative effect against MCF-7 human breast cancer cells, J774E mouse macrophages and HL-60 human promyelocytic leukemia cells. β-Phenylphenethylamine derivative showed a selective activity towards J774E cells with IC50 values three times lower than Incadronate and twice as high as Zoledronate.

Microwave-promoted syntheses of fluoren-9-ones and benzisoxazoles

Synthesis of some new fluoren-9-ones and benzisoxazoles under both thermal and microwave conditions is reported. The prepared products under microwave conditions are obtained with high yields and within shorter reaction times. Reaction of lithiated bromobenzene with aromatic aldehydes 2a,b delivered diarylmethanols 3a,b that were oxidized to 4a,b. Compound 4a was cyclized to give methoxyfluoren-9-one 5, which was demethylated affording hydroxyfluoren-9-one 6. Compound 4b was reacted with triethyl phosphite to produce benzisoxazole 10. On the other hand, reaction of triethyl phosphite with 13a,b afforded a mixture of phosphoramidates 14a,b and benzisoxazoles 15a,b. The structures of the synthesized compounds have been elucidated unambiguously by NMR-spectroscopic methods including HH COSY, HSQC, and HMBC experiments.

A derivatization strategy for the detection and identification of volatile trialkylphosphites using liquid chromatography-online solid phase extraction and offline nuclear magnetic resonance spectroscopy

We demonstrate herein the application of selective derivatization method that converts volatile and labile trialkylphosphites (TAPs) into virtually non-volatile, thermally stable, and UV absorbing derivatives. After simple sample preparation, purification/enrichment of the derivatives was achieved by using high performance liquid chromatography (HPLC) coupled to on-line post column solid phase extraction (SPE) system. These derivatives were subjected to 31P{1H} NMR and 1D-selTOCSY experiments. Conclusive identification was achieved on the basis of their HPLC retention time and NMR spectral signatures (δH1,δpE1, nJH–H, and 3JP–H). This method was tested for the unambiguous identification of a mixture containing low concentrations (∼10μgmL−1) of trimethylphosphite (TMP), triethylphosphite (TEP), triisopropylphosphite (TIP), and tributylphosphite (TBP) along with a high concentration of irrelevant background chemicals. It offered a high dynamic range and good detection limit and recovery (>75%) without the need for special NMR probe heads or exotic NMR experiments.

Reaction of benzolactams with triethyl phosphite prompted by phosphoryl chloride affords benzoannulated monophosphonates instead of expected bisphoshonates

In contrast to aliphatic lactams, which gave cyclic aminomethylene-gem-bisphosphonates in reaction with triethyl phosphite and phosphoryl chloride, the corresponding benzoannulated lactams usually provide monophosphonates of variable structures, which depend on size of the substrate aliphatic ring. Most likely they are obtained by dephosphonylation of bisphosphonates, which form as initial products of this reaction. These phosphonate esters appeared to be unstable upon acid hydrolysis and upon storage. Mechanism of acid catalyzed degradation of these compounds has been proposed.

Efficient one-pot protocol for diverse pyrazolylphosphonates by multi-component reactions: their antioxidant and antibacterial activities.

Efficient one-pot three-component reactions of pyrazolones with arylaldehydes and triethyl phosphite were carried out in the presence of ethylenediammonium diacetate as catalyst to synthesize biologically interesting pyrazolylphosphonate derivatives. This methodology offers several significant advantages such as environmentally benign character, the use of a mild catalyst, high yields, and ease of handling. The synthesized compounds were screened for their antioxidant and antibacterial activities. The result showed that compound 4d [Formula: see text] exhibited a strong free radical scavenger toward DPPH free radicals compared with standard BHT [Formula: see text]. In addition, compounds 4e and 4p showed potent antibacterial activities against Gram-negative bacteria of E. coli and compound 4o exhibited a potent activity against Gram-positive bacteria of S. aureus compared with standard Ampicillin.

Synthesis of Functionalized Oxaphosphaphenanthrenes and Chromenes via Multicomponent Reactions of Trivalent Phosphorus Nucleophiles

 Abstract—Stable derivatives of oxaphosphaphenanthrenes were prepared using multicomponent reactions of dialkyl acetylenedicarboxylate with 3-bromo-2-naphthol in the presence of trimethyl or triphenyl phosphite in good yields. Chromene derivatives were produced by using triethyl phosphite and dialkyl acetylenedicarboxylate in the presence of OH-acids in excellent yields.

N-(R-cyclopropyl)fluorobenzimidoyl phosphonates

Reaction of N-(R-cyclopropyl)benzimidoyl chloride with triethyl phosphite has yielded the corresponding N-(R-cyclopropyl)-substituted benzimidoyl phosphonates existing predominantly in the E-configuration [E : Z ≈ (8–10) : 1] at room temperature. 19F NMR spectroscopy allowed determination of inductive and resonance σ-constants of N-(R-cyclopropyl)-substituted imidoyl chloride and imidoyl phosphonate groups for the first time.

Structural characterization of some sol–gel derived phosphosilicate glasses

A comparative study of three phosphosilicate gels of the 90SiO2–10P2O5 composition obtained from tetraethoxysilane and three phosphorous precursors: triethylphosphate (TEP), triethylphosphite (TEPI) and H3PO4 is performed. 29Si and 31P Magic Angle Spining NMR, X-ray Photoelectron, X-ray Fluorescence and Raman spectroscopies as well as TG analysis are used in order to establish phosphorous precursors and annealing influence on composition and structure of the outcome materials. Unlike the three dimensional silicate network made of Si(OSi)x(OH)4−x species, unreacted TEP (100% Q1 condensed phosphorous units) from TEP derived gel and a large amount of isolated phosphorous species (39.7% Q0) in the H3PO4 derived gel are identified. Annealing at 700°C of the three gels give similar structure with the 90SiO2–10P2O5 glass, excepting the triethylphosphate derived glass that has a much lower P content. Thus, the H3PO4 derived glass at 700 and 1000°C shows 1.89 and 1.94 times higher P2O5/SiO2 ratios than in the case of the TEP derived one.

Synthesis of Substituted 6-(1H-1,2,3-Triazol-1-Yl)- 4,7-Dihydro-1,3,5-Dioxazepine

A convenient method was developed for the synthesis of 6-(1H-1,2,3-triazol-1-yl)-4,7-dihydro-1,3,5-dioxazepines, using deoxygenation of 1-(5-nitro-1,3-dioxan-5-yl)-1H-1,2,3-triazoles with triethyl phosphite.

ChemInform Abstract: Synthesis of Diethyl Pyridin‐2‐ylphosphonates and Quinolin‐2‐ylphosphonates by Deoxygenative Phosphorylation of the Corresponding N‐Oxides.

E-mail: cmyoon@korea.ac.krReceived November 4, 2013, Accepted March 7, 2014Key Words : Pyridine N-oxide, Ethyl chloroformate, Triethyl phosphite, Diethyl pyridin-2-ylphosphonateDialkyl pyridin-2-ylphosphonates widely used as corro-sion inhibitors, dispersing and emulsifying agents, antistaticsand lubricant additives in various technological fields

Expeditious synthesis of (±)-diethyl 2-alkyl- and 2-aryl-(3-oxoisoindolin-1-yl)phosphonates catalysed by OSU-6

An efficient synthesis of (±)-diethyl 2-alkyl- and 2-aryl-(3-oxoisoindolin-1-yl)phosphonates is reportedviacondensation of 2-carboxybenzaldehyde with an amine and triethyl phosphite using OSU-6 as the catalyst.

Synthesis and photophysical characterization of dimethylamine-derived Zn(ii)phthalocyanines: exploring their potential as selective chemosensors for trinitrophenol

We report a novel synthetic approach, with good yields, for the synthesis of selective dimethylamine-substituted phthalonitriles (1–3) in the presence of triethyl phosphite and dimethylformamide at 160 °C.

2D ultrafast HMBC 1H,31P: obtaining mechanistic details on the Michaelis–Arbuzov reaction.

Ultrafast NMR spectroscopy (UF-NMR) can be used to monitor chemical reactions in real time and to provide insights into their mechanisms and the nature of the intermediates formed. Here, we have developed a 2D 1H,31P UF-HMBC method and the corresponding NMR experimental setup to enable the study of a Michaelis–Arbuzov reaction at two different temperatures, 25 and 70 °C. The specific reaction studied was between triethyl phosphite and benzyl bromide to produce diethylbenzyl phosphonate. Our results show that at 70 °C the reaction takes place directly, without the detection of an intermediate by 1H,31P UF-HMBC. In contrast, at 25 °C, using zinc bromide as a catalyst, our results show the formation of benzyltriethoxy phosphonium bromide as an intermediate. The experiments again show the power of UF-NMR in mechanistic studies of reactions involving various phosphorus chemical species.

ChemInform Abstract: Phospha‐Michael Addition to in situ Prepared 5‐Arylmethylidene Meldrum′s Acids.

AbstractTrimethyl phosphite (III) can be substituted by triethyl phosphite.

CyanobenzeneTTF-type donors; synthesis and characterization

Two cyanobenzeneTTF-type electron donors, which are also dithiolene ligand precursors, cyanobenzenedicyanoethylthiotetrathiafulvalene, (cbdc-TTF) and dicyanobenzenedicyanoethylthiotetrathiafulvalene, (dcbdc-TTF), were obtained through cross-coupling reactions with triethyl phosphite between 4,5-bis(2-cyanoethylthio)-1,3-dithiole-2-one and 4,cyanobenzene-1,3-dithiole-2-thione or dicyanobenzene-1,3-dithiole-2-thione, respectively. These reactions also yield 2,3,6,7-tetrakis(2-cyanoethylthio)-TTF and the corresponding symmetric cyanobenzene TTF derivatives dicyanodibenzenetetrathiafulvalene (dcdb-TTF) and tetracyanodibenzotetrathiafulvalene (TCN-DBTTF) resulting from the self-coupling reactions of the ketone and the thiones. Compound dcdb-TTF was also synthesized by homo-coupling reaction of the cyanobenzene-1,3-dithiole-2-ketone with triethyl phosphite. These compounds were characterized namely by single crystal X-ray diffraction and cyclic voltammetry.

ChemInform Abstract: Simple Method for the Synthesis of Aryl(furfuryl)glyoxals.

Furan derivatives containing reactive functional groups are useful structural units for the synthesis of different classes of chemical compounds [1-6]. Even such simple furans as phenacylfurans [7] containing one carbonyl group can be used in the preparation of cyclopentenones [8] which are the basic structural fragments in prostaglandins. In this connection, the development of methods for the synthesis of novel, functionalized furan compounds is a current problem. To our surprise aryl(furfuryl)glyoxals (which might be expected to have interesting reactivity) have proved to be unknown compounds. In this work we report the synthesis of these aryl(furfuryl)glyoxals. A Knoevenagel condensation of the readily available phenacylazides 1a-d [9, 10] with the furfurals 2a,b gives the azidochalcones 3a-e [11]. Subsequent treatment with triethyl phosphite and hydrochloric acid gives the target compounds 4a-e.

N-(R-Cyclopropyl) Trifluoroacetimidoyl Phosphonates

A convenient synthetic approach for previously unknown N-(R-cyclopropyl)trifluoroacetimidoyl phosphonates 5a,b (R˭H, CF3) was developed on the basis of the reaction of respective trifluoroacetimidoyl chlorides with triethyl phosphite. It was shown that imidoyl phosphonates 5a,b exist as equilibrium mixture of Z/E isomers (Z:E ∼92:8). Activation parameters of Z–E isomerization were evaluated by 19F NMR spectroscopy. Catalytic hydrogenation of 5a,b can serve as a convenient method for the synthesis of trifluoroethylaminophosphonates with a rigid N-cyclopropyl group.