Methylphenyl phosphinic acid

To a stirred solution of 11.09 gm (71.0 mmole) of methylphenyl phosphinic acid in 600 ml of ethanol is added 7.72 gm (35.5 mmole) of finely divided zinc acetate dihydrate. A white precipitate results and the mixture is stirred for another 2 hr at room temperature. The precipitate is filtered and washed twice with ethanol to give 11.8 gm (95%) after drying at 60°C in a vacuum oven. The TGA of the polymer indicates it is stable to about 400°C in nittogen without weight loss. Weight loss starts at 425°C. The polymer softens below 1(X)°C and is soluble in benzene and chloroform. The molecular weight of the polymer varies between 2500 and 10,000 (colligative methods). 

EINECS 209-391-4 Foston Phosphinic acid, (4-(di-methylamino)-2-methylphenyl)-, sodium salt Sodium (4-(dimethylamino)-2-methylphenyOphosphinate Toldimfos sodium Tonofosfan. A proprietary preparation of lol-dimibs sodium a source of phosphorus used for vet-erinary purposes. Soluble in H2O and EtOH. 

Studies on the alkaline hydrolysis of various phosphonic and phosphinic esters have provided information on the electronic or steric effects of substituents and the effects of changes in reaction conditions amongst the substrates so extensively examined are the O-aryl esters of dimethylphosphinothioic acid (552) esters of diphenylphosphinic acid and O-aryfand S -aryf esters of diphenylphosphinothioic acid (553 Z, Y = O or S). Other studies have concentrated on aryl esters of diaryIphosphinic acids (554) , and the effects of the stepwise replacement of P-Me by P-Ph in esters of dimethyl-, methylphenyl- and diphenyl-phosphinic acids The esters 555 (R = EtO, R = Me or Ph, R = R = Ph X = SEt or hydrolyse under alkaline conditions faster than do the comparable 5 -(4-substituted-butyl) esters. Comparable steric and electronic influences on the hydrolyses of phosphonic and phosphinic fluorides phosphinic chlo-rides the phosphonothioic chlorides 556 and other phosphonic and phosphinic esters have been noted. Phosphonic and phosphinic halides are prone to undergo halo-gen-exchange reactions, a process which, in general, is faster for derivatives of phosphonic than for those of phosphonothioic and phosphonoselenoic acids, and to be particularly important for acid fluorides . ... 

Iridium complexes have been shown to catalyse intermolecular additions of acid chlorides R COCl to terminal alkynes R C=CH producing (Z)- -chloro-a, -unsaturated ketones R C(Cl)=CHCOR. Ligands play a key role in this reaction NHC is efficient for the addition of aroyl chlorides, whereas dicyclohexyl(2-methylphenyl)phosphine (PCy2(o-Tol) is indispensable for the reaction of aliphatic acid chlorides. Among the salient features of these transformations is the suppression of decarbonylation and j6-hydrogen elimination. Some mechanistic insight has been obtained from stoichiometric experiments. ... 

Phenylenebis(methylene)]bis[bis(4-methylphenyl)]phosphine oxide, P-00119 2-Phenylethenylphosphonic acid, P-00129 Phenylphosphinic acid, P-00163... 

C. By Oxidation.—This year s literature has been notable for attempts to study the details of certain phosphine oxidation reactions. In one such investigation nitric acid was found to oxidize phosphines, or phosphine sulphides, to phosphine oxides with inversion of configuration at phosphorus, whereas dinitrogen tetroxide, in the absence of acid, was found to oxidize the same compounds with predominant retention. The partial racemization observed with the latter reagent was probably due to the racemization of the oxides, since methylphenyl-n-propylphosphine oxide... 

Wilkinson s (I) discovery that the soluble rhodium(I) phosphine complex, [Rh(PPh3)3Cl], was capable of homogeneous catalytic hydrogenation of olefins immediately set off efforts at modifying the system for asymmetric synthesis. This was made possible by the parallel development of synthetic methods for obtaining chiral tertiary phosphines by Horner (2) and Mislow (3,4, 5). Almost simultaneously, Knowles (6) and Horner (7) published their results on the reduction of atropic acid (6), itaconic acid (6), a-ethylstyrene (7) and a-methoxystyrene (7). Both used chiral methylphenyl-n-propyl-phosphine coordinated to rhodium(I) as the catalyst. The optical yields were modest, ranging from 3 to 15%. 

The first examples of asymmetric hydrogenation based on this principle were reported by Knowles and co-workers (the Monsanto group) in 1968 (12). Rhodium complexes of the type RhL3Cl3 (where L was a chiral phosphine) were used in the hydrogenation of a-phenylacrylic acid (atropic acid) and itaconic acid under the conditions indicated in Fig. 3. When L was (R)-( )-methylphenyl-n-propylphosphine,3 15% optically pure (S)-(+)-a-phenyl-pro-pionic acid and 3% optically pure methylsuccinic acid (configuration unreported) were obtained. 

It is interesting to note that benzeneseleninic acid (92) was found [48] to behave as a very stereoselective oxidant of optically active methylphenyl-n-propylphosphine sulfide (97a) and methylphenyl-n-propylphosphine selenide (97b). The corresponding phosphine oxide 98 was formed with almost full inversion of configuration at the stereogenic phosphorus atom (Scheme 11). 

Solvent effects on the oxidation of triphenylphosphine by perbenzoic acid have been reported. The second-order rate constants are directly proportional to the dielectric constant of the solvent. Oxidation of methylphenyl-propylphosphine with 3-chloroperbenzoic acid or ozone proceeds with retention of configuration. The reaction of alkyl- or aryl-phosphines with dialkyl peroxides or polyperoxides in aqueous solvents leads to the formation of alcohols or glycols, respectively. ... 

Earlier, reference was made to the potential third mechanism associated with nucleophilic displacements at phosphoryl phosphorus, namely that which might involve the participation of a phosphaacylium cation. Mixed sulphonic-phosphonic or sulphonic-phosphinic anhydrides 645 (Z = O, R = Me or 4-methylphenyl) have been obtained from the free phosphorus(V) acid and the 1,2,4-triazole 646 in the presence of trifluoromethanesulphonic acid, or 645 (Z = O, R = CF3) from the imidazolides 647 and trifluoromethanesulphonic acid and / r/-butylphenylphosphinothioic acid with trifluoromethanesulphonic anhydride yield the mixed 0-anhydride 648 (R = CF3), some reactions of which are illustrated in Scheme 76 ". Of those reactions, the formation of the iodide 649, albeit in low yield when the reaction is carried out in MeOH, with stereochemical retention of configuration at phosphorus, contrasts with the inversion of configuration observed for the remainder, and which is normally encountered for Sn2(P) displacements. The reaction of648 with methoxybenzene to yield the phosphine sulphide 650 in a solvent of high ionizing power (1,1,1,3,3,3-hexafluoropropan-2-ol a lower yield was obtained in a... 

Synonyms Cresyl phosphate Phosphoric acid, tris (methylphenyl) ester Phosphoric acid, tritolyl ester TCP Tricresyl phosphate, with > 3% ortho isomer Tris (methylphenyl) phosphate Tris (tolyloxy) phosphine oxide Tritolyl phosphate Classification Aromatic phosphorus compd. 

Formation.—A convenient and rapid synthesis of thiirans (yields 35— 90%) consists of treatment of epoxides with triphenyl- or tri-n-butyl-phosphine sulphide in the presence of acid. cis-Stilbene oxide gave exclusively cis-stilbene sulphide. (S)-(-)-Methylphenyl-n-propylphosphine sulphide gave, with a twofold excess of cyclohexene oxide, the (S)-(-)-oxide, indicating that this reaction proceeds with retention of configuration at phosphorus. " A mechanism involving two inversions was suggested for the conversion of 2a,3a-epoxycholestane into the 2, 3 3-epithio-isomer, as shown in Scheme 1. Epithiochlorohydrin is obtained by treatment of epichlorohydrin with di-(0-ethyl)dithiophosphoric acid and triethylamine. "... 

---