Triaryl Phosphites Research Articles

Synthesis and properties of 4‐hydroxy‐2,3,5,6‐tetrabromobenzyl phosphonates and effects of their flame retardance on impact polystyrene

Abstractp‐Cresol was converted into 2,3,5,6‐tetrabromocresol by AlCl3 catalyst bromination, and then further brominated to 4‐hydroxy‐2,3,5,6‐tetrabromobenzyl bromide (HTBBB) in benzene by light. HTBBB reacted easily with trialkyl phosphite to produce 4‐hydroxy‐2,3,5,6‐tetrabromobenzyl phosphonates (HTBBPs) in solvents. Although the reaction of HTBBB with triaryl phosphite was slower than that with trialkyl phosphite, it does produce corresponding phosphonate with ease. Except for DMF, DMAc, chloroform, and tetrahydrofuran, HTBBP was difficult to dissolve in ordinary organic solvents. Of all the synthesized HTBBP, dimethyl hydroxy‐2,3,5,6‐tetrabromobenzyl phosphonate showed the poorest solubility. With the addition of these new compounds containing bromine and phosphorus atoms to HIPS as flame retardants, the results of oxygen index measurement showed that the flame resistance of these compounds was greater than the additive effect of the two corresponding individual brominated compound and phosphorus‐containing compound. It means that these new compounds seem to act synergistically as flame retardants in HIPS. Simultaneous addition of bominated compound and phosphorus‐containing compound to HIPS ends up with a similar effect as mentioned above, but the new compounds can prevent the exclusion of phosphorus‐containing compound from polymer matrix.

Nickel-catalyzed synthesis of cyclooctatetraenes from substituted dipropargylamines

The nickel(0) catalyst is a complex containing olefins and trialkyl or triaryl phosphite or phosphine ligands. Subsequently, we showed that cobalt(0) complexes are even more specific catalysts for this dimerization (2). We now find that if the nickel-catalyzed dimerization is carried out in an excess of an olefin such as methyl acrylate or styrene, another type of dimer is produced, containing a cyclooctatetraene structure. Cyclohexene is also effective, although to a lesser extent, whereas simple olefins are relatively unreactive. Cobalt catalysts do not appear to be susceptible to this olefin effect. The reaction is specific for substituted dipropargylamines containing substituents on the a-carbons (Equation 2):

ChemInform Abstract: SYNTHESIS OF SUBSTITUTED N‐((PHOSPHONYL)METHYL)‐2‐IMIDAZOLIDINONES AND N‐((PHOSPHONYL)METHYL)‐2‐PYRROLIDINONE

AbstractDie Umsetzung der Irnidazolidinone (I) mit den Aldehyden (II) und den Phosphorigsäureestern (III) liefert je nach Molverhältnis die Monophosphonsäureester (IV) oder die Bisphosphonsäureester (V); analog wird aus Pyrrolidon (VI) der Phosphonsäureester (VII) erhalten.

New reactions involving phosphorus-phosphorus bond cleavage in tetraalkyldiphosphine disulfides

1. Alkylation of tetraalkyldiphosphine disulfides with alkyl halides and alkylene dihalides gives the corresponding trialkylphosphine sulfides and tetraalkylalkylenediphosphine disulfides, and also dialkylthiophosphinyl halides. 2. Reaction of tetraalkyldiphosphine disulfides with organic disulfides and triaryl phosphites gives dialkyldithiophosphinite and -monothiophosphinite esters respectively. 3. Tetraalkyldiphosphine disulfides are cleaved by PCl3, PBr3, and POCl3 to form dialkylthiophosphinyl halides. 4. Phosphonic acid dichlorides are reduced by tetraalkyldiphosphine disulfides to form dichlorophosphines, and at the same time react with the oxidation products of the tetraalkyldiphosphine disulfides to form dialkylthiophosphinyl chlorides.

The photolysis and subsequent reactions of bis(triaryl phosphite) complexes of iron(0), trans-[Fe(CO)3{P(OAr)3}2

On photolysis in solution,trans-[Fe(CO)3{P(OAr)3}2] complexes (Ar = Ph and o- and p-MeC6H4) lose CO to give red products. These cannot be isolated, but react in situ with various ligands, L (e.g. CO, phosphines, phosphites, isocyanides, CS2, SO2, tetracyanoethylene, and acetylenes) to give [Fe(CO)2{P(OAr)3}2(L)] derivatives, and with various compounds X–Y (e.g. H–H, D–D, H–Cl, and Cl–SnCl3) to form [FeII(CO)2{P(OAr)3}2(X)(Y)] compounds. These reactions are often not simple and complicated mixtures of products may be obtained. Carbon tetrachloride and N-bromosuccinimide convert the red intermediate to a mixture of [Fe(CO)2{P(OAr)3}2(X)(Y)] and [Fe(CO)2-{P(OAr)3}2X](X = Y = Cl or Br). It is suggested that the latter contain o-metallated phosphite ligands and that the red intermediate compound is related to them and is best formulated as [Fe{P(OC6H3Z)(OAr)2}{P(OAr)3}-(CO)2H] rather than [Fe(CO)2{P(OAr)3}2](Z = H or Me).

Kinetics and mechanism of cyclo- and decyclo-metallation of some iridium triaryl phosphite complexes. Evidence for the electrophilic displacement mechanism

The formation of [IrH(P–C)(cod)L]X [P–C = P(OC6H3Me-o)(OC6H4Me-o)2, cod = cyclo-octa-1,5-diene, L = P(OC6H4Me-o)3 or PMe2Ph] from [Ir(P–C)(cod) L] and HX (X = ClO4, PF6, or BF4) is proposed to occur by a mechanism involving direct proton attack at the metallated carbon for ring opening, followed by electrophilic displacement of a proton from an ortho-C–H by a preformed iridium(III) hydride in the ring closing step; a similar mechanism is proposed for the ring opening in the reaction of [Ir(P–C)(cod)L] with halogen acids HX (X = Cl, Br, or I) to give [IrHX2(cod)L].

Multiple chlorinations of the cyclometallated ring in iridium triaryl phosphite complexes: the crystal and molecular structure of [IrCl2{P(OC6Cl3Me-o)(OC6H4Me-o)2}(pyridine)(PMe3)

Complete aromatic substitution of cyclometallated aromatic rings in a series of iridium triaryl phosphite complexes is found to occur rapidly with Cl2 in benzene: the structure of [IrCl2{P(OC6Cl3Me-o)(OC6H4Me-o)2}(pyridine)(PMe3)] has been elucidated by X-ray crystallography.

ChemInform Abstract: STUDIES ON REACTIONS OF THE N‐PHOSPHONIUM SALTS OF PYRIDINES. XIX. CARBONYLATION OF AMINES WITH CARBON DIOXIDE BY MEANS OF PHOSPHORUS CHLORIDES IN TERTIARY AMINES

AbstractDie Reaktionen von Kohlenstoffdioxid und ‐disulfid (II) mit den prim. Aminen (I) fuhren in Gegenwart von P‐chloriden zu den entsprechenden symm. disubstituierten Hanrstoffen und Thioharnstoffen (III) in hohen Ausbeuten unter atmosphärischen Bedingungen.

Studies on Reactions of the N-Phosphonium Salts of Pyridines. XIX. Carbonylation of Amines with Carbon Dioxide by Means of Phosphorus Chlorides in Tertiary Amines

Abstract Reactions of carbon dioxide and disulfide with primary amines in the presence of phosphorus chlorides gave the corresponding symmetrically disubstituted ureas and thioureas in high yields under atmospheric conditions. Phosphorus trichloride and di- and mono-chlorophosphites were remarkably effective for the reactions, whereas phosphorus pentachloride and phosphoryl chloride were ineffective. The presence of tertiary amines such as pyridine satisfactorily favored the reactions. The reaction seems to proceed via the N-phosphonium salts of pyridines as those obtained from diphenyl and triaryl phosphites, on the basis of their IR spectroscopic analyses, stoichiometric relationship between reactants and the steric effect of tertiary amines.

Synthesis and properties of cobalt(I) compounds. 3. Hydridoacetonitriletris(triaryl phosphite)cobalt complexes

Synthesis and properties of cobalt(I) compounds. 3. Hydridoacetonitriletris(triaryl phosphite)cobalt complexes

High-Energy Phosphonium Compounds and Their Application to Polymer Synthesis

Abstract High-energy phosphonium compounds, the N-phosphonium salts of pyridines, were prepared by the oxidation of phosphorous acid and its esters with mercuric salts or halogens in pyridines, or by a hydrolysis-dehydration reaction of diphenyl and triaryl phosphites or phosphonites. These salts are very reactive to nucleophiles, activating carboxyl, amino, or hydroxyl compounds via the corresponding N-phosphonium salts to yield carboxylic amides and esters in high yields on further aminolysis, alcoholysis, and acidolysis. These reactions, especially the hydrolysis-dehydration reactions with phosphites, were successfully extended to the direct polycondensation reaction of dicarboxylic acids with diamines, of free α-amino acids or dipeptides, and of carbon dioxide and disulfide with diamines under mild conditions, yielding linear polymers of high molecular weight (polyamides, polypeptides, polyureas, and polythioureas).

Studies on reactions of the N‐phosphonium salts of pyridines. XIV. Wholly aromatic polyamides by the direct polycondensation reaction by using phosphites in the presence of metal salts

AbstractPoly‐p‐benzamide of high molecular weight (ηinh = ∼ in H2SO4) was obtained by the direct polycondensation reaction of p‐aminobenzoic acid (p‐ABA) by means of diphenyl and triaryl phosphites in N‐methylpyrrolidone (NMP)‐pyridine solution containing lithium and calcium chlorides. Molecular weight of polymer varied with the amount of these salts, showing maximum values at the concentration of about 4 wt‐% of LiCl or about 8 wt‐% of CaCl2 in the reaction mixture. The reaction temperature at around 80°C gave a polymer of the highest viscosity. The polycondensation reaction was also affected by monomer concentration, solvents, and tertiary amines like pyridine. Similarly, aromatic polyamides with high molecular weight (ηinh values up to 1.34 in H2SO4) were prepared from isophthalic acid and aromatic diamines, whereas terephthalic acid gave only low‐viscosity polymers.

Studies on reactions of the N‐phosphonium salts of pyridines. XIII. Direct polycondensation reaction of carbon dioxide or disulfide with diamines under mild conditions

AbstractPolyureas of high molecular weight were obtained by the direct polycondensation reaction of carbon dioxide with diamines at 40°C for several hours under a pressure of carbon dioxide (below 30 atm) by use of diphenyl phosphite in pyridine. Optimal temperature and pressure were 40°C and 20 atm of carbon dioxide. The polycondensation reaction was also affected by solvents and type and amounts of tertiary amines. Pyridine was most effective as tertiary amine and solvent as well. Of the phosphorous compounds used, triaryl phosphites and diphenyl phosphite were most effective, but trialkyl phosphites failed to give polymer. The reaction was assumed to proceed via a carbamyl N‐phosphonium salt of pyridine formed by dephenoxylation of phosphites. Similarly, polythioureas were prepared by heating a mixture of carbon disulfide, diamines, and diphenyl phosphite in pyridine at 40°C for 6 hr under nitrogen.

The Reaction Mechanism of Polyamide Synthesis by Phosphorylation

The reaction mechanism of the polyamide synthesis by phosphorylation with triaryl phosphite and imidazole was investigated in terms of the amidation reaction of model compounds and the polycondensation of various nylon salts. Triphenyl phosphite formed a complex with imidazole which reacted easily either with amine or carboxylic acid to form acyloxy phosphite or phosphoramide complexes. The electron-donating substituent of phenol of aryl phosphites retarded the amidation and polycondensation reactions, and, among various tertiary amines, only imidazole had a cocatalytic effect. The low molecular weight of the resulting polyamide was ascribed to the many competitive reactions of the phosphite—imidazole complex between amine and carboxylic acid, which resulted in the molar balance loss of amine or carboxylic acid. The reaction mechanism for the polycondensation of nylon salt by phosphorylation was again discussed in this paper.

Studies on reactions of the N‐phosphonium salts of pyridines. XI. Preparation of polypeptides and polyamides by means of triaryl phosphites in pyridine

Studies on reactions of the <i>N</i>‐phosphonium salts of pyridines. XI. Preparation of polypeptides and polyamides by means of triaryl phosphites in pyridine

ChemInform Abstract: PEPTIDE SYNTHESIS BY OXIDATION‐REDUCTION CONDENSATION BY USE OF TRIARYL PHOSPHITE AS REDUCING REAGENT

AbstractBenzoylleucin (I), Glycinäthylester (II), Triphenylphosphit (III) und das Disulfid (IV) werden in Dimethylformamid bei 30°C zu BenzoyLL‐leucylglycinäthylester (V) umgesetzt, wobei der Anteil des L‐Isomeren 94% beträgt.

Reaction of thiobenzophenone with trialkyl and triaryl phosphites

Thiobenzophenone reacts with trimethyl and triethyl phosphites at 100° to give trialkyl thiophosphate, tetraphenylethylene, O,O-dialkyl S-benzhydryl thiophosphate, and dialkyl benzhydrylphosphonate, while triaryl phosphites do not react with thiobenzophenone even at elevated temperature. Probable courses of these reactions are discussed on the basis of the products and effect of additives.

Transition-metal complexes containing phosphorus ligands. Part XIV. ortho-Metallation reactions involving some triaryl phosphite derivatives of osmium

Osmium triphenylphosphine complexes, [OsH4(PPh3)3], [OsH2(CO)(PPh3)3], and [OsHCl(CO)(PPh3)3] react with triphenyl phosphite in boiling organic solvents to yield triphenyl phosphite derivatives which subsequently undergo ortho-metallation. Products isolated and characterised include the substituted derivatives [OsHCl(CO)(PPh3)2(p)] and [OsHCl(CO)(PPh3)(p)2], the metallated species [OsCl(pc)(CO)(PPh3)(p)], [OsCl(pc)(CO)(p)2], [OsH(PC)(CO)(PPh3)(p)], and [OsH(pc)(CO)(p)2], and the dimetallated complexes [Os(pc)2(p)2] and [Os(pc)2(CO)(p)][(P)= P(OPh)3; (pc)=(PhO)2P(OC6H4)].

31P CIDNP in the reactions of phosphoranyl radicals

AbstractThe polarisation of phosphorus nuclei (31P CIDNP) during the free radical reactions of triakyl and triaryl phosphites proceeding via intermediate phosphoranyl radicals is discussed.

PEPTIDE SYNTHESIS BY OXIDATION-REDUCTION CONDENSATION BY USE OF TRIARYL PHOSPHITE AS REDUCING REAGENT

Abstract Use of triaryl phosphite as reducing reagent in peptide synthesis by oxidation-reduction condensation was studied. Aryl esters having electron-withdrawing substituents gave optically pure peptides in good yields by reacting in N,N-dimethylformamide solution.