Hexamethylphosphorus Triamide Research Articles

Water as a key ingredient in the synthesis of platinum H‐phosphonate complexes and catalytic cascade reactions involving the hydration of alkynes and hydrogen/deuterium exchange reaction

Several platinum (II) complexes bearing heteroatom‐substituted phosphine oxides ligand H(O)P(OCMe2CMe2O) were obtained. The H‐phosphonate was synthesized in an alternative, one‐pot procedure with the use of water from hexamethylphosphorus triamide and pinacol. In the presence of H(O)P (OCMe2CMe2O) ligand, [PtCl2(cod)] was converted into three new complexes: [PtCl2{P(OH)(OCMe2CMe2O)}2] [Pt1], [PtCl{P(O)(OCMe2CMe2O)}{P(OH)(OCMe2CMe2O)}2] [Pt2], and [Pt{P(OH)(OCMe2CMe2O)}4]Cl2 [Pt3]. When [PtCl2(PPh3)2] was utilized as the substrate, [PtCl(PPh3)2{P(OH)(OCMe2CMe2O)}]Cl [Pt4] and [PtCl(PPh3)2{P(O)(OCMe2CMe2O)}] [Pt5] complexes were obtained, as the results of reaction with H(O)P(OCMe2CMe2O) and HP(OCMe2CMe2O)(OCH2CMe2NH) ligands. The structural features of all complexes were characterized by physicochemical and spectroscopic methods as well as single X‐ray diffraction studies. Complex [Pt1] was found to promote cascade reaction, the addition of water to triple bond, and hydrogen/deuterium exchange reaction. The hydration reaction of substituted terminal aryl alkynes gave exclusively Markovnikov products and tolerated different functional groups. Various aryl ketones were synthesized in good to excellent yield. H/D exchange reaction was exemplified by the model reaction of acetophenone in deuterium containing methanol. Factors influencing the effectiveness of the hydrogen/deuterium exchange reaction of the methyl group were determined. The cascade procedure bears the potential to overcome the limitations of conventional synthesis and unlocks practical use in the synthesis of deuterium‐labeled pharmaceuticals.

Synthesis, X-ray, DFT Studies and Antimicrobial Properties of New Quinolinylphosphonates

The phosphorus atom in hexamethyl phosphorus triamide 5 attacks the carbonyl function in 2-chloroquinoline-3-carbaldehyde 4a to give the bis-quinolinyl ethanone product 6. On the other hand, quinoline ring-attack proceeds by the same phosphorus reagent upon reaction with 2-chloroquinoline- 3-aldoxime 4b yielding phosphonate 7. Meanwhile, the reaction of the tris-aminophosphine reagent 5 with 2-chloroquinoline- 3-(p-chlorophenyl)imine 4c affords the respective α-aminophosphonate 8. Moreover, the attack by phosphine 5 on 2-chloroquinoline-3-imines 4d and 4e produces the respective cyclic azophosphole derivatives 9a and 9b. [(2-chloroquinolin-3-yl)methylidene]propane dinitrile 4f reacts with phosphine 5 to yield [(2-chloroquinolinen-3-yl) 2,2-dicyanoethyl]tetramethylphosphonic diamide 10. Structural elucidations for the new products were based on compatible analytical and spectroscopic data. Moreover, the structures assigned for compounds 7 and 9a were unambiguously confirmed by X-ray crystallographic measurements. Biological evaluations indicated that compounds 4a,c exhibit antibacterial potency against Gram-positive bacteria and 4a,c and 9a show activity against Candida albicans strain.

Thioether macrocycles of the microbisporicins via reductive desulfurization

The microbisporicins are the most potent lantibiotics isolated to-date. Cyclic tetra-, hexa- and octapeptides, inspired by this family of antimicrobial agents, have been synthesized from linear peptides. Generalized reaction conditions are reported for the two-step conversion of linear peptides to thioether macrocycles: formation of a disulfide followed by reductive desulfurization. 1H NMR analysis of the reduction reaction mixture indicated the intermediacy of a dehydroalanine when excess hexamethylphosphorus triamide (HMPT) was employed for the reduction. Maintaining a stoichiometric amount of HMPT, in dilute methanolic solution, gave the corresponding thioethers, retaining stereochemical integrity.

Comparative Study on the Reaction of Organophosphorus Reagents with Vanillin from Moringa Oleifera Plant. Synthesis of Phosphoranylidenepyranone, Dioxaphospholane and Butenethione Derivatives of Anticipated Antitumor Agents

Vanillin which can be isolated from Moringa oleifera plant was allowed to react with different nucleophilic organophosphorus reagents. Treatment of 4-hydroxy-3-methoxybenzaldehyde (vanillin) with the active phosphacumulene ylides (N-phenyliminovinylidene)- and (2-oxovinylidene)-triphenylphosphorane afforded the homocyclic phosphoranylidene-cyclobutylidenes. On the other hand, its reaction with the satabilized phosphoniumylide, acetylmethylenetriphenylphosphorane gave the corresponding butenone, which reacted with the active phosphacumulene to give finally the pyran derivative. Next, the phenyliminophenol derivative was obtained from the reaction of vanillin with the iminophosphorane. Moreover, dioxaphospholane oxide was isolated from the reaction of vanillin with hexamethylphosphorus triamide. Finally, the butenethione was generated from the reaction of Japanese reagent with vanillin.

ChemInform Abstract: Phosphorus Compounds of Polyols. Unusual Equilibria Connecting Bicyclic Phosphites and Polycyclic Phosphoranes.

Abstract Threitol or (and) xylitol react with hexamethylphosphorus triamide giving bicyclic phosphites 1, 2, whose structure has been established by NMR spectroscopy. These compounds undergo, at 60°C, fast oligornerisation leading, particularly, to polycyclic phosphoranes 3,4. In presence of diethylamine 3, 4 give again phosphites 1,2.

The Enthalpies of Solution of Tetraethyl- and Tetrabutylammonium Bromides in Aqueous Solutions of Hexamethylphosphorus Triamide at 328.15 K

The heats of solution of Et4NBr and Bu4NBr in water and aqueous solutions of hexamethylphosphorus triamide (HMPT) at 328.15 K were measured in a variable-temperature isothermic-shell calorimeter. The standard enthalpies of solution were calculated using the Debye-Huckel second-order theory. The enthalpy parameter of electrolyte—amide pair interactions was determined in terms of the McMillan-Mayer formalism. The processing of the data obtained in this work and previously led us to conclude that heat capacity changes caused by pair interactions of Et4NBr and Bu4NBr with HMPT were negative and independent of temperature over a wide temperature range. The methyl and methylene groups interacted with HMPT without heat capacity changes and, consequently, the enthalpies and entropies of their interactions with HMPT were constant over a wide temperature range.

Organophosphorus Chemistry 34 1 . The Reaction of Alkyl Phosphites and Hexamethylphosphorus Triamide with 1-Phenyl-3-methyl-4-ylidene-5-pyrazolones

1-Phenyl-3-methyl-4-ylidene-5-pyrazolones ( 1a-c ) produce the respective 1:1 phosphonate adducts ( 4a-i ) upon reaction with the appropriate dialkyl phosphites ( 2a-c ). The reaction of 1a-c with trialkyl phosphites ( 3a-c ) proceeds only in presence of water, also to give phosphonates 4a-c almost exclusively. Hexamethylphosphorus triamide ( 3d ) was successfully utilized to introduce the bis(dimethylamino)-phosphoryl function in the f , g -unsaturated carbonyl moiety in 1a-c , producing phosphoramidates 15a-c . Possible reaction mechanisms were discussed. Compatible elemental and spectroscopic results were recorded for the new products.

Case Study of a γ-Butyrolactone Alkylation with 1,3-Dimethyl-2-imidazolidinone as a Promoter

1,3-Dimethyl 2-imidazolidinone (DMI) is of lower toxicological risk than 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), hexamethyl-phosphorus triamide (HMPT), and hexamethylphosphoramid...

Palmitoyl diol S- and O-phosphoroamidates of some sterols

The hexamethylphosphorus triamide activated by the addition of iodine at the optimum molar ratio 1.05:0.05 was used as a phosphorylating reagent to synthesize 1-palmitoyloxyethyl-2- O-, 1-palmitoyloxypropyl-3- O- and 1-palmitoyloxybutyl-4- O-( N, N-dimethylamido)thiophosphate and -phosphate derivatives of β-sitosterol, cholesterol and stigmasterol in a one-pot procedure with overall yields of 80–87%. 1-Palmitoyloxypropyl-3- O-(cholesteryl-3- O-)-( N, N-dimethylamido) phosphite was used as a model synthon for the preparation of transamidated morpholido-thiophosphate and -phosphate analogues with final yields of 82–86%.

Thermogravimetry of wood reacted with hexamethylphosphorus triamide as a flame retardant treatment

Specimens of pine were reacted with hexamethylphosphorus triamide (HMPT) in dimethylformamide solutions. The specimens were evaluated using thermogravimetry for their potential fire resistance. Specimens reacted with HMPT had a temperature at maximum pyrolysis rate 113°C lower than that of unreacted wood. There was 45.4% residual char after pyrolysis of reacted specimens that were water extracted, compared to 17.6% residual char from unreacted specimens. The amount of residual char and peak temperatures of HMPT-reacted specimens were indicative of an effective flame retardant and were essentially unchanged when specimens were extracted with water. Reacted specimens would not burn in a simple flame test.

Phosphorus Compounds of Polyols. Unusual Equilibria Connecting Bicyclic Phosphites and Polycyclic Phosphoranes

Abstract Threitol or (and) xylitol react with hexamethylphosphorus triamide giving bicyclic phosphites 1, 2, whose structure has been established by NMR spectroscopy. These compounds undergo, at 60°C, fast oligornerisation leading, particularly, to polycyclic phosphoranes 3,4. In presence of diethylamine 3, 4 give again phosphites 1,2.

Phosphorus Compounds of Polyols. Unusual Equilibria Connecting Bicyclic Phosphites and Polycyclic Phosphoranes

Abstract Threitol or (and) xylitol react with hexamethylphosphorus triamide giving bicyclic phosphites 1, 2, whose structure has been established by NMR spectroscopy. These compounds undergo, at 60°C, fast oligornerisation leading, particularly, to polycyclic phosphoranes 3,4. In presence of diethylamine 3, 4 give again phosphites 1,2.

Stereospecific cyclization of β-hydroxy aryl amides to β-lactams

N-Aryl-β-lactams can be prepared conveniently by an intramolecular reaction of β-hydroxyarylamides under the influence of diethyl azodicarboxylate (DEAD) and triphenylphosphine (TPP). Optically active 3-amino-2-azetidinone derivatives can be prepared by this method starting with a suitably protected α-amino-β-hydroxy carboxylic acid amide. This cyclization involves the retention of configuration at C2 and complete inversion at C3 of the starting acid. In some cases diamides of azodicarboxylic acid have been used by replacing TPP with the more reactive tributyl phosphine. Other phosphorus reagents such as phosphite esters and hexamethyl phosphorus triamide could also be used.

The behaviour of N-t-butyl-2,2′-iminodiethanol towards some trivalent phosphorus compounds

Phosphorus trichloride and hexamethylphosphorus triamide react with N-t-butyl-2,2′-iminodiethanol (4) forming the 2 : 3 adduct N,N-bis[2-(6-t-butyl-1,3,6,2-dioxazaphosphoran-2-yloxy)ethyl-t-butyl-amine (5) which, on treatment with water (2 mol equiv.) is hydrolysed to give 6-t-butyl-1,3,6,2-dioxazaphosphocane 2-oxide (8) and N-t-butyl-2,2′-iminodiethanol (4). Compound (8) reacts with o-chloranil to produce a crystalline product which in solution gives an equilibrium mixture of six-co-ordinated phosphorus with a P–OH bond (9) and the phosphate ester (10). Phenylphosphonous dichloride and N,N,N′,N′-tetramethyl-P-phenylphosphonous diamide react with (4) to give 2-phenyl-6-t-butyl-1,3,6,2-dioxazaphosphocane (11) which adds to o-chloranil to form a tautomeric equilibrium mixture of the four-co-ordinate and six-co-ordinate phosphorus compounds (13)⇌(14). Phenyl azide reacts with (11) to give 2-phenyl-2-phenylimino-6-t-butyl-1,3,6,2-dioxazaphosphocane (15). The structural assignments are based on analytical, chemical, and spectroscopic results.

STRUCTURES IN SOLUTION OF ADDUCTS OF HEXAMETHYLPHOSPHORUS TRIAMIDE AND SUBSTITUTED BENZILS

Abstract Hexamethylphosphorus triamide has been allowed to react with p,p′-dinitrobenzil, p-chlorobenzil, p,p′-difluorobenzil, p,p′-dimethylbenzil and p,p′-dimethoxybenzil. All of these materials in benzene-d6 had negative δ 31P chemical shifts except for the p,p′-dinitro adduct whose resonance was found at δ + 17.6. In dichloromethane-d2 the resonances ranged from δ + 38.2 for the p,p′-dinitro adduct to δ − 22.5 for the p,p′-dimethoxy adduct. The 13C NMR spectra of these compounds all showed coupling J POCC to the ipso carbons except for the p,p′-dinitro adduct. These data indicate that the p,p′-dinitro adduct is ionizing rapidly and that the others are phosphoranes. On cooling the coupling was lost for the p,p′-difluoro adduct and for the p-chloro adduct. These spectral changes are attributed to rapid ionization which occurs because of the change of the dielectric constant with change in temperature.

Synthesis of [2.2]cyclophanes by photodeselenative ringcontraction

Several cyclophanes were prepared by photodeselenation of diselena[3.3]cyclophanes with hexamethylphosphorus triamide in excellent yields, compared with the other chalcogen-atom extrusion methods.

Anionic polymerization. VI. Effect of polar modifiers on alkylsodium and alkylpotassium polymerization of butadiene

AbstractIt was found that N,N,N′,N′‐tetramethylethylene diamine and hexamethyl phosphorus triamide minimize chain transfer reactions in the polymerization of 1,3‐butadiene in hydrocarbon solvent with alkylsodium or alkylpotassium initiators. The polymers obtained with alkylsodium initiators had a high molecular weight and high vinyl content at 90–95% conversion. The molecular weight of the polybutadiene made by alkylsodium and alkylpotassium initiators was dependent on the polymerization temperatures and modifier ratios, but the vinyl contents were independent of the modifier ratios. Vinyl contents of alkylpotassium‐initiated polymers showed a slight dependency on polymerization temperature; the vinyl contents of alkylsodium‐initiated polymers were independent of temperature. Addition of lithium tert‐butoxide and potassium tert‐amylate to these initiators in the presence of the modifiers affected the molecular weight but not the microstructure.

14N pure quadrupole resonance in some five-membered heterocyclic compounds and in three acyclic compounds

The 14N nuclear quadrupole coupling constants of 2,1,3-benzothiadiazole, 2,1,3-benzoselenadiazole, 2,5-dimethyl-1,3,4-thiadiazole, 2-imidazolinenone and guanidine hydrochloride at 298 K, and of hexamethylphosphorus triamide and hexamethylphosphoric triamide at 77 K, are reported. The coupling constants and asymmetry parameters are interpreted within the Townes and Dailey theory.

Reaction of hexamethylphosphorous triamide with cotton cellulose

The reactivity of hexamethylphosphorus triamide, (P[N(CH3)2]3) (HPT), with cotton cellulose was examined under various conditions. HPT was found to react readily with the cellulose to produce a cellulose phosphite and/or phosphate ester having approximately one acidic hydrogen atom per phosphorus atom. The reaction of HPT with cotton cellulose was efficiently catalyzed by dimethylamine hydrochloride (1%). The phosphorus content imparted by the catalyzed reaction on cotton fabrics was approximately twice that imparted by the uncatalyzed reaction. Flame resistance of the treated fabrics ranged from fair to excellent. The treated fabrics also exhibited ion exchange properties and some crosslinking.

The temperature dependence of the14N nuclear quadrupole resonance of hexamethylphosphorus triamide and hexamethylphosphoric triamide

The temperature dependence of the 14N nuclear quadrupole resonance frequency in hexamethylphosphorus traimide, P[N(CH3)2]3, and hexamethylphosphoric triamide, O=P[N(CH3)2]3, has been studied between 77 K and the melting points. Values for the torsional oscillation frequencies v t and the empirical parameter b, a function of v t and the associated moment of inertia I, and of the volume-dependence parameter α, are reported. The values are consistent with previously reported values for thiourea, S=C(NH2)2.