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.     

MICROWAVE SYNTHESIS OF TRICHLORFON AND ITS ANALOGUES

The synthesis of dialkyl-(2,2,2-trichloro-1-Hydroxyethyl) phosphonates using dialkyl hydrogen phosphite and chloral hydrate under solvent-free condition by microwave irradiation is reported. The products were chrachetrized using ¹ H NMR, ¹³ C NMR, and ³¹ P NMR spectroscopy.     

水杨酸与二烷基亚磷酸酯反应历程31P NMR与电喷雾质谱跟踪研究

The reaction between salicylic acid and dialkyl phosphite was traced by electrospray ionization mass spectrometry and ^31P NMR. All reactants, unstable intermediates and products were detected. The mechanism was proposed based on ESI-MS results and ^31P NMR profiles.     

Microwave-assisted synthesis of α-aminophosphonates with sterically demanding α-aryl substituents

Abstract

A series of N-benzhydryl protected α-aminophosphonates with α-phenyl, α-(1-naphtyl), α-(9-anthryl) or α-(1-pyrenyl) substituents was synthesized by the Kabachnik–Fields condensation of diphenylmethylamine (benzhydrylamine), the corresponding aryl aldehyde and a dialkyl phosphite under MW irradiation. X-ray studies performed at low temperatures for a few of these α-aminophosphonates confirmed the presence of unusually short intramolecular C_α–H^δ+ ··· ^δ+H–C_peri contacts.     

Synthesis and biological activities of novel dialkyl (4-trifluoromethylphenylamino)-(4-trifluoromethyl or 3-fluorophenyl) methylphosphonates

A series of novel dialkyl (4-trifluoromethylphenylamino)-(4-trifluoromethyl or 3-fluorophenyl) methylphosphonates 3 were synthesized through the reaction of 3-fluorobenzaldehyde or 4-trifluoromethylbenzaldehyde and 4-trifluoromethylaniline with dialkyl phosphite by microwave irradiation using boron trifluoride-ether catalyst and their structures were clearly verified by spectroscopic data (IR, ¹H NMR and elemental analysis). The results of bioassay showed that these title compounds possess potential anticancer activities in vitro by MTT method. At the same time, we found these title compounds exhibit moderate antiviral activity against tobacco mosaic virus.     

New type of ring-chain tautomerism. Direct evidence from 1H NMR spectroscopy

A new type of ring-chain tautomerism consisting in the reversible transformation of 4-(5-)haloalkanecarboxylic acid dialkylamides into dialkyl(tetrahydrofuran-2-ylidene)- and dialkyl(tetrahydropyran-2-ylidene)ammonium halides, respectively, was found and studied by ¹H NMR spectroscopy.     

An efficient synthesis of dialkyl 2-(diphenoxyphosphoryl)-3-(alkylthio)succinates from alkylthiols, triphenyl phosphite and dialkyl acetylenedicarboxylates

An efficient synthesis of dialkyl 2-(diphenoxyphosphoryl)-3-(alkylthio)succinates, as a mixture of two diastereomers, in 78–90% yields, is described via reaction between alkylthiols, dialkyl acetylenedicarboxylates, and triphenyl phosphite. The structures of products were deduced from their high-field ¹H, ¹³C, and ³¹P NMR spectra, and IR spectral data. Since these hosphonate esters possess two stereogenic centers, two diastereomers with gauche HCCH arrangements are possible. Observation of ³ J _HH = 3.5-4.6 Hz for the vicinal methine protons confirmed the dominance of the gauche arrangement. A mechanism is proposed for the formation of products.     

Synthesis and Fungicidal Activity of O,O'-Dimethyl α-[(5-Ethoxycarbonyl-4- Methyl-1,3-Thiazol-2-YL-Amino)Arylmethane] Phosphonates

A series of dialkyl [(5-ethoxycarbonyl-4-methyl-1,3-thiazol-2-ylamino)arylmethane] phosphonates was synthesized by the reaction of ethyl 2-amino-4-methylthiazole-5-carboxylate, with dialkyl phosphite and aromatic aldehydes using Mg(ClO₄)₂ as the catalyst. All new compounds were identified by elemental analysis, IR, ¹H NMR, and ¹³C NMR spectra. O,O'-Dimethyl α-[(5-Ethoxycarbonyl-4-methyl-1,3-thiazol-2-ylamino)arylmethane] phosphonate was further analyzed by a single-crystal X-ray diffraction analysis. The result of a preliminary bioassay indicated that some compounds exhibit inhibition activities against Rhizoctonia solani and Botrytis cinereapers at a dosage of 100 mg/L.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

An Efficient One-Pot Synthesis of 2,3-Dialkyl-1,1-Diethyl-1-(Acetylamino)-3-(1,1,1-Triphenylphosphanilidene)-1,1,2,3-Propanetetracarboxylates and Their Temperature-Dependent NMR Spectra

Abstract

Stable crystalline phosphorus ylides of 1,1-diethyl 2,3-dimethyl 1-(acetylamino)-3-(1,1,1-triphenylphosphanilidine)-1,1,2,3-propanetetracarboxylates were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of diethyl acetamidomalonate as a CH-acid. These stable ylides exist in solution as a mixture of two geometrical isomers (E and Z) as a result of restricted rotation around the carbon–carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group on the nuclear magnetic resonance (NMR) time scale at ambient temperature. The dynamic effects in the ylide moieties were investigated by ¹H NMR spectra.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

SYNTHESIS OF THE FIRST BENZODISELENAGERMOLES AND ONE SPIROBISDISELENAGERMOLE

Abstract

The first examples of compounds R¹R²GeSe₂C₆H₄R³ (R¹,R²=CH³ C₂H₅, C₃H₂, n-C₄H₉, i-C₅H₁₁, Ph, p-CH₃Ph. R³=H, CH₃, OCH₃) were easily obtained (40–80% yield) from electrophilic cleavage of diselenophenylene zirconocenes by dialkyl or diaryl dichlorogermanes. The synthesis of a spirodi-selenagermole was achieved in the same way using germanium tetrachloride. Analytical data, ¹H and ⁷⁷Se NMR. mass spectra are perfectly consistent with the expected structures.     

Unusual behavior of o,o"-dimethylene(tri-p-cresyl) bicyclophosphite as a novel organophosphorus ligand in olefin hydrogenation and hydroformylation

A representative of the new class of organophosphorus ligands, viz., o,o"-dimethylene(tri-p-cresyl) bicyclophosphite (BCP), was studied as a promoter of Rh(acac)(CO)₂ in hydrogenation and hydroformylation. BCP enhances the activity and stability of the catalyst much more strongly than analogous organophosphorus ligands used previously (triphenylphosphine, triphenyl phosphite, and etriolphosphite). A reason for this behavior of BCP was studied using NMR spectroscopy, quantum-chemical calculations, and molecular simulation. The high sensitivity of the ¹H NMR signals of the methylene groups of BCP toward complexation appears due to the high density of the highest occupied and lowest unoccupied MO of protons of the CH₂ groups, especially those directed toward the P atom. The ¹H and ³¹P NMR spectra indicate the formation of hydrides of two types (HRh(BCP)₃ and HRh(BCP)₄) directly upon the addition of BCP in amounts exceeding that corresponding to the BCP/Rh = 2 ratio to a solution of Rh((acac)(CO)₂. The most probable source of the hydride ion is the BCP molecule itself, namely, the bridging CH₂ groups. The molecular mechanics simulation showed that in the [Rh(BCP)₃]⁺ complexes the aromatic rings of BCP formed two molecular cavities. These cavities can alternatively open and close, thus providing flexible screening of the catalytic site. This explains the unusual behavior of the Rh complexes with BCP in hydrogenation and hydroformylation.     

An NMR study of sequential intermediates and collateral products in the conversion of 1,3,6,8-tetraazatricyclo[4.4.1.1]dodecane (TATD) to 1,3,6,8-tetraazatricyclo[4.3.1.1]undecane (TATU)

In situ ¹H nuclear magnetic resonance spectroscopy was used to investigate the processes that occur during the synthesis of 1,3,6,8-tetraazatricyclo[4.3.1.1^3,8]undecane (TATU). NMR analysis showed a reaction mixture containing more than one compound. The production of these intermediates and collateral products was rationally supported by a careful ¹H NMR monitoring study. We characterized 1,3,5-triazabicyclo[3.2.1]octane (TABO, 4) and 3-(2-aminoethyl)-1,3,5-triazabicyclo[3.2.1]octane (AETABO, 7) by ¹H and ¹³C NMR in D₂O solution inside the NMR sample tube, as an intermediate and collateral product of the reaction, respectively. Further, a reaction of 1,3,6,8-tetraazatricyclo[4.4.1.1^3,8]dodecane (TATD) with ¹⁵N-labeled ammonium chloride was carried out. The ¹⁵N NMR and GC-MS experiments indicated that ¹⁵N was incorporated into TATU, TABO, and urotropine.     

Addition of Dialkyl Hydrogen Phosphites to Alkenes in the Presence of Carbonyl Complexes of Chromium Subgroup Metals and Iron

Depending on the reactant ratio and order of their mixing, reactions of dialkyl hydrogen phosphite with alkenes in the presence of catalytic amounts of homoligand carbonyl complexes of iron or chromium subgroup metals yield phosphonates by two pathways: reaction of dialkyl hydrogen phosphite with -coordinated alkene and addition to alkene of the product of reaction of dialkyl hydrogen phosphite with the transition metal carbonyl. The products of reactions of Fe(CO)₅ and W(CO)₆ with dialkyl hydrogen phosphites contain the phosphorus-metal bond.     

Magnesium and calcium surfactants Ternary phase diagrams of magnesium and calcium dodecylsulphate with decanol and water

The isothermal ternary phase diagrams for the systems magnesium dodecylsulphate-decanol-water at 40 °C and calcium dodecylsulphate-decanol-water at 50 °C are determined by water deuteron NMR and polarizing microscopic studies. In the magnesium system, three liquid crystalline phases (lamellar and normal and reverse hexagonal) and two isotropic (normal and reverse) solution phases are characterized and their ranges of existence are obtained. The calcium system yields the same liquid crystalline phases, but only the lamellar liquid crystalline phase is investigated in detail. The important observations made are: (i) The lamellar liquid crystalline phase for the magnesium and calcium systems can incorporate, respectively, a maximum of 22.5 and 14.3 mole water per mole surfactant ion against 139 mole water for the corresponding sodium system. (ii) The reverse hexagonal liquid crystalline phase is formed for both the magnesium and calcium systems while no such liquid crystalline phase exists for the corresponding sodium system. (iii) The²H NMR quadrupole splittings obtained in the liquid crystalline phases for C₈SO ₄ ^– and C₁₂SO ₄ ^– surfactant systems with different counterions (Ca²⁺,Mg²⁺,Be²⁺,Na⁺) reveal that surfactant hydration is almost independent of alkyl chain length and counterions.     

The Reactivity of Mn(II) and Ti(IV) Dialkylamides with Organophosphorus Esters

Abstract

Treatment of dialkyl (or diaryl) phosphites with titanium tetrakis-(diethylamide) at room temperature resulted in a smooth displacement of both ester functions by the diethylamino groups to give bis(diethylamino) phosphorus acid (58–65%). The same results are obtained at ?40° and no evidence of an intermediate product was detected using ¹H n.m.r. techniques. Treatment of dimethyl phosphite with titanium tetrakis(n-dibutylamide) resulted in isolation of two products which were identified as bis-(n-dibylamino) phosphorus acid (52%) and methyl-(n-dibutylamino) phosphorus acid (21%). On the other hand, trialkyl (triaryl) phosphates are inert to the titanium reagents.     

Diels-Alder reaction of 2-phosphaindolizines catalysed by organoaluminium reagent: theoretical and experimental results

Theoretical calculations at the DFT (B3LYP/6-31+G^**) level of the model Diels-Alder (DA) reactions of 1-methyl-3-(methoxycarbonyl)-2-phosphaindolizine with 1,3-butadiene in the presence of methylaluminium dichloride reveal that the co-ordination of organoaluminium reagent to the carbonyl oxygen increases the activation barrier compared to that for the uncomplexed 2-phosphaindolizine. On the other hand, co-ordination of the organoaluminium reagent to the σ², λ³ P atom lowers the activation barrier by ∼6 kcal mol⁻¹. 1-Methyl-2-phosphaindolizines having an electron-withdrawing group at the 3-position only undergo DA reaction with 2,3-dimethylbutadiene in the presence of the ethylaluminium dichloride catalyst in methylene chloride at a low temperature to afford [2+4] cycloadducts. The formation of an intermediate having the ethylaluminium reagent co-ordinated to σ², λ³ P atom has been detected by ³¹P NMR. The products have been characterized by ³¹P and ¹H NMR studies.     

ON THE NATURE OF THE NUCLEOPHILE IN THE MIXTURE OF PHOSPHITES AND AMINES

Abstract

It is now commonly accepted that in the presence of strong bases (like metal alcoholates) an equilibrium between phosphite and phosphonate forms of dialkyl phosphites exists and that the phosphite form is highly reactive in the reaction with carbonyl compounds. There is a controversy on the structure of the active form of the phosphite when the addition is catalyzed by amines. We have found that aliphatic amines and dialkyl phoshites form a complex which is a reactive species. Its stoichiometry depends on the nature of the solvent.     

[NiCl2(dppp)]‐Catalyzed Cross‐Coupling of Aryl Halides with Dialkyl Phosphite,Diphenylphosphine Oxide,and Diphenylphosphine

We present a general approach to C? P bond formation through the cross‐coupling of aryl halides with a dialkyl phosphite, diphenylphosphine oxide, and diphenylphosphane by using [NiCl₂(dppp)] as catalyst (dppp=1,3‐bis(diphenylphosphino)propane). This catalyst system displays a broad applicability that is capable of catalyzing the cross‐coupling of aryl bromides, particularly a range of unreactive aryl chlorides, with various types of phosphorus substrates, such as a dialkyl phosphite, diphenylphosphine oxide, and diphenylphosphane. Consequently, the synthesis of valuable phosphonates, phosphine oxides, and phosphanes can be achieved with one catalyst system. Moreover, the reaction proceeds not only at a much lower temperature (100–120 °C) relative to the classic Arbuzov reaction (ca. 160–220 °C), but also without the need of external reductants and supporting ligands. In addition, owing to the relatively mild reaction conditions, a range of labile groups, such as ether, ester, ketone, and cyano groups, are tolerated. Finally, a brief mechanistic study revealed that by using [NiCl₂(dppp)] as a catalyst, the Ni^II center could be readily reduced in situ to Ni⁰ by the phosphorus substrates due to the influence of the dppp ligand, thereby facilitating the oxidative addition of aryl halides to a Ni⁰ center. This step is the key to bringing the reaction into the catalytic cycle.     

Direct Aryloxylation/Alkyloxylation of Dialkyl Phosphonates for the Synthesis of Mixed Phosphonates

A strategy for the direct functionalization strategy of inertial dialkyl phosphonates with hydroxy compounds to afford diverse mixed phosphonates with good yields and functional‐group tolerance has been developed. Mechanistic investigations involving both NMR studies and DFT studies suggest that an unprecedented highly reactive P^V species (phosphoryl pyridin‐1‐ium salt), a key intermediate for this new synthetic transformation, is generated in situ from dialkyl phosphonate in the presence of Tf₂O/pyridine.     

Pyridyl phosphates from the reaction of sodium pyridinates,dialkyl phosphite and carbon tetrachloride

A convenient method for preparing pesticidal pyridyl phosphates from the reaction of sodium halopyridinales, dialkyl phosphite and carbon tetrachloride is described. The dialkyl phosphonato anion as an intermediate in this reaction is proposed.