Dimethyl phosphinic acid

G.S. Denisov, K.G. Tokhadze, Ultrastrong hydrogen bond in gas phase. Dimer of dimethyl -phosphinic acid. Dokl. Phys. Chem. 337, 117-119 (1994)... 

Both methylphosphine (this synthesis) and dimethylphosphine (the following synthesis) are considerably stronger Lewis bases than phosphine, and their reactions with various Lewis acids, including boranes, have been the subject of recent studies. Both methylphosphine and dimethylphosphine are readily oxidized by air, and thus can serve as sources of methylphos-phonous (methylphosphinic) acid, CH3PHO(OH), and dimethyl-phosphinic acid, (CH3)2PO(OH). ... 

C4H11O2P dimethyl-phosphinic acid ethyl ester 2511-19-5... 

Phosphabicyclo[3.3.1]nonanes 146a and 146b were converted into the phosphinic acid, 4,8-dimethyl-2-phospha-bicyclo[3.3.1]nonan-2-ol 2-oxide 147, upon treatment with hydrogen peroxide under acidic catalysis. The structure of phosphinic acid 147 was accomplished by an X-ray analysis. Additionally, it was shown that if phosphines 146a and 146b were exposed to air, they underwent a rapid oxidation to yield the ammonium salt of 2-(4-methylcyclohexyljpropylphosphonic acid 148, whose structure was also confirmed by the X-ray analysis <2001TL2609>. 

SYNS BIS(HYDROXYMETHYL)PHOSPHINE OXIDE DIMETHOXYPHOSPHINE OXIDE DIMETHYL ACID PHOSPHITE DIMETHYLESTER KYSEUNY FOSFORITE (CZECH) DIMETHYLFOSFIT DIMETHYLFOSFONAT DLMETHYLHYDRO-GENPHOSPHITE DLMETHYL PHOSPHITE DIMETHYL PHOSPHONATE DIMETHYL PHOSPHOROUS ACID HYDROGEN DIMETHYL PHOSPHITE METHYL PHOSPHONATE NCI-C54773 PHOSPHOROUS ACID DIMETHYL ESTER... 

The second objective of this study is to determine the feasibility of using diphenyl phosphinic acid as a catalyst for synthesis of dimethyl 4-methyl-1, 3-phenylene dicarbamate (DMPD) from 2, 4-diaminotoluene and DMC (step 6) as follows ... 

The dynamics of mixtures of surfactants with proteins is of great importance for many practical processes, such as coating of photographic films, where gelatine in mixtures with surfactants and surface active dyes adsorb at the interface. Hempt et al. (1985) studied the relaxation behaviour of gelatine solutions in presence and absence of surfactants (SDS, tetradecyl dimethyl phosphine oxide, cetyltrimethyl ammonium bromide, n-decanoic acid, perfluoro octanoic acid tetraethyl ammonium salt). 

Esters and other derivatives of alkenyl- and alkynyl-phosphonic acids, and of the correspondingly unsaturated phosphinic acids, undergo a wide range of addition and cycloaddition reactions which will be considered more fully in Chapter 6. These reactions include applications of the Diels-Alder reaction to yield carbocyclic phosphonic acids based on mono- and poly-cyclic ring systems, some of which are precursors to other aromatic phosphonic acids. A typical example of this procedure is the addition of dimethyl (bromoethynyl)phosphonate to 2,3-dimethylbutadiene elimination of HBr from the 1 1 cycloadduct, using Et3N, affords dimethyl (2,3-dimethylphenyl)phosphonate. The addition of carbenes to alkenylphosphonic derivatives yields those of cyclopropylphos-phonic acids. ... 

The use of trichloroacetaldehyde is also to be particularly noted. Although reactions between this aldehyde and various dialkyl hydrogenphosphonates have been report- 269,274,294,295 it is the dimethyl ester of (l-hydroxy-2,2,2-trichloroethyl)phosphonic acid which has received particular attention, and which has been studied widely from the structural point of view in the light of its commercial importance as the powerful insecticide dipterex (also known as trichlorphon and chlorophos). Polyfluoroalkyl esters of the related alkyl(l-hydroxy-2,2,2-trichloroethyl)phosphinic acids have been prepared by the unusual combination of chloral hydrate and the bis(polyfluoroalkyl) alkylphosphonite ester ... 

In Section VILA, the 1,2-addition of a hydrogenphosphonic diester or related compound to an a,j5-unsaturated aldehyde or analogous ketone " " was discussed in relation to the synthesis of (l-hydroxyalkyl)phosphonic diesters. The latter are formed under condition of kinetic control whereas 1,4-addition (the so-called Pudovik reaction), which leads to the (2-oxoalkyl)phosphonic diester occur under thermodynamic controP" ". In general, reactions which involve ethylenic aldehydes, or acetylenic aldehydes or ketones, tend to result in adduct formation across the carbonyl group, whilst ethylenic ketones tend to take part in 1,4-additions and afford 3-oxoalkyl phosphonic (or phosphinic) acid systems 550 34,946-949 consistent with Markovnikov predictions. Such statements are a broad oversimplification, however, at least with regard to the formation of the oxoalkyl phosphonates. In practice, the manner of addition depends on experimental circumstances, the nature and even amount of catalyst and other factors For instance, for the additions of dimethyl hydrogenphosphonate to the ketones 561 ( = 1 or 2) and 559 (R" = H, R = 2-furyl, R = Me), carried out by the addition of a trace of saturated MeONa-MeOH solution to a mixture of reactants in diethyl ether, yielded (within 5 min) the respective 1,2-adducts (1-hydroxyalkylphosphonates) in yields of64,69 and 52% ... 

Mention might also be included here of the nature and potential importance of the choice of amino-protection and ester groupings in work on the aminophosphonic acids. The choice of groups for protection at nitrogen is obviously based on experience in conventional amino acid chemistry, and both r rr-butyloxycarbonyl (boc) and benzyloxy-carbonyl (cbz) groups are extensively employed. Most recorded syntheses of aminoalkyl-phosphonic and -phosphinic acids have relied on diethyl or dimethyl esters, largely as a consequence of the ready availability of the simple trialkyl phosphites and dialkyl hydro-genphosphonates the same esters are also preparable under mild conditions from the free acids by the action of ortho esters RC(OR )3 (R = H or Me, R = Me or Until... 

Compared with formic acid (pX = 3.77 in water, 5.75 in 95% aqueous ethanol), acetic acid (pKa = 4.76 in water), and benzoic acid (pK = 4.17 in water, 7.07 in 95% aqueous ethanol), simple symmetrical dialkylphosphinic acids (1) are moderately strong acids. Thus, for dimethylphosphinic acid (R = Me), pK = 3.08 (in water) and 6.64 in 95% aqueous ethanol, figures which rise to 3.56 for R = Pr and 4.24 for R = Bu for solutions in water for R = Ph, pK = 5.80 in 95% aqueous ethanol. These values can also be compared with those for the dialkyl phosphoric acids for dimethyl hydrogenphosphate, pK = 0.47 in water and 1.88 in 80% aqueous ethanol. Obviously the phosphorus-oxygen bonded acids are rather stronger, with the simple phosphinic acids closer to the carboxylic acids in their acidity. 

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 . ... 

PCgH,, Phosphonous acid, phenyl-, dimethyl ester, nickel complex, 28 101 OjPCijH, , Phosphinic acid, diphenyl-, tin complex, 29 25... 

Hydroxy- and cpoxyalkyl-phosphonic and phosphinic acids, and related sulphur or selenium co/npou/jt/s-Conventional reactions between 1,2-propadienylphosphinic acid and substituted benzaldehydes yield [(a-hydroxybenzyl)( 1,2-propadienyl)]phosphinic acids. Reactions between (1-oxoalkyl)pho.sphonic esters and nitromethane in the pre.sence of a base (K2CO3) yield the esters (281). The compounds (282 n = 1 or 2), and (283) are obtainable conventionally from the cyclic ketone and dimethyl... 

Aminopropylmorpholine Dimethyl terephthalate Ethylene 2-(5-Ethyl-2-pyridyl)ethyl acrylate Potassium bromide fiber mfg., polyester Diisopropylamine fiber mfg., rayon stable Carbon disulfide fiber mfg., self-extinguishing Benzene phosphinic acid fiber mfg., synthetic Caprolactam... 

---