Methyl phosphonates

B) The preparation of (cis-1,2-epoxypropyi)phosphonic acid [ (1 -chloroethoxy )chloro-methyl] phosphonic acid (1.0 g) is added with stirring to tetrahydrofuran (50 ml) to which has been added a crystal of iodine and a zinc-copper couple (15.0 g). The mixture is then heated under reflux for 24 hr and the resulting solution filtered to yield (cis-1,2-epoxy propyl )-phosphonic acid. 

The reaction of the aldehyde 174, prepared from D-glucose diethyl dithio-acetal by way of compounds 172 and 173, with lithium dimethyl methyl-phosphonate gave the adduct 175. Conversion of 175 into compound 176, followed by oxidation with dimethyl sulfoxide-oxalyl chloride, provided diketone 177. Cyclization of 177 with ethyldiisopropylamine gave the enone 178, which furnished compounds 179 and 180 on sodium borohydride reduction. 0-Desilylation, catalytic hydrogenation, 0-debenzyIation, and acetylation converted 179 into the pentaacetate 93 and 5a-carba-a-L-ido-pyranose pentaacetate (181). 

Plugging solution contains Portland cement, sodium sulphate, potassium ferricyanide and nitrile-tri-methyl-phosphonic acid. Patent SU 1700204-A, 1991. 

P. F. Tsytsymushkin, S. R. Khajmllin, A. P. Tamavskij, Z. N. Kudryashova, and B. V. Mikhajlov. Plugging solution contains Portland cement, sodium sulphate, potassium ferricyanide and nitrile-tri-methyl-phosphonic acid. Patent SU 1700204-A, 1991. 

Once inside the body, diisopropyl methylphosphonate is rapidly converted to isopropyl methyl-phosphonic acid (IMPA), which is rapidly cleared from the blood. Laboratory tests can determine the amount of IMP A in the blood or urine. However, because IMPA leaves the body rapidly, these tests are useful only for recent exposure. It is helpful for your doctor to know whether there are other chemicals to which you have been exposed. See Chapters 2 and 6 for more information. 

No MRL was derived for acute oral exposure to diisopropyl methyl phosphonate because the data were considered too limited to determine an appropriate threshold and derive an MRL. 

Guilbault GG, Scheide EP. 1970. Chemisorption reactions of diisopropyl methyl phosphonate with various metal salts and the effect of complex-ion formation on the phosphorus-oxygen stretching frequency. Journal of Inorganic and Nuclear Chemistry 32(9) 2959-2962. 

Hoskin FCG. 1956. Some observations concerning the biochemical inertness of methyl phosphonic and isopropyl methylphosphonic acids. Can J Biochem Physiol 34 743-746. 

An estimate of the rate enhancement associated with the intramolecular phosphorylation can be made by using isopropyl p-nitrophenyl methyl-phosphonate as a model for the covalent intermediate formed in the initial step of the reaction of cycloheptaamylose with bis (p-nitrophenyl) me thy 1-phosphonate. The first-order rate constant for the alkaline hydrolysis of isopropyl p-nitrophenyl methylphosphonate at pH 9.86 can be obtained from the data of van Hooidonk and Groos (1970) kun = 1.4 X 10-5 sec-1. This value may be compared with the maximal rate constant for the reaction of cycloheptaamylose with bis(p-nitrophenyl) methylphosphonate— k2 = 1.59 X 10-1 sec-1 at pH 9.86—which must be a minimal value for the rate of the intramolecular phosphorylation. This comparison implies a kinetic acceleration of at least 104 which is similar to rate enhancements associated with the formation of cyclic phosphates from nucleoside phosphate diesters. 

MePO2- or PME2- (Table XIX), but the open closed equilibrium lies very much on the side of the chelated form of the complex (87% for the Ca2+ complex - compare 15% for [Ca(atp)]2 and just 7% for [Ca(amp)] (695)). The availability of stability constants both for methylphosphonate and for benzimidazole (a purine model) complexes means that the chelate effect for complexes of (1H-benzimidazol-2-yl-methyl)phosphonate can be discussed without the usual complications, such as the differences between ethane-1,2-diamine and two ammonia or two methylamine ligands and disparities between units (704). 

Katritzky, A.R., Zhang, G., and Jiang, J., Convenient preparations of diethyl [(acylamino)methyl]phosphonates, 2-azabutadienes, and isoquinolines from a 1,2-monoazabisylide equivalent,. Org. Chem., 59, 4556, 1994. 

D-Ribonolactone is a convenient source of chiral cyclopentenones, acyclic structures, and oxacyclic systems, useful intermediates for the synthesis of biologically important molecules. Cyclopentenones derived from ribono-lactone have been employed for the synthesis of prostanoids and carbocyclic nucleosides. The cyclopentenone 280 was synthesized (265) from 2,3-0-cyclohexylidene-D-ribono-1,4-lactone (16b) by a threestep synthesis that involves successive periodate oxidation, glycosylation of the lactol with 2-propanol to give 279, and treatment of 279 with lithium dimethyl methyl-phosphonate. The enantiomer of 280 was prepared from D-mannose by converting it to the corresponding lactone, which was selectively protected at HO-2, HO-3 by acetalization. Likewise, the isopropylidene derivative 282 was obtained (266) via the intermediate unsaturated lactone 281, prepared from 16a. Reduction of 281 with di-tert-butoxy lithium aluminum hydride, followed by mesylation, gave 282. 

Orthophosphoric and benzylphosphonic acids have been selectively alkylated with triethyl phosphite in a new synthesis of mono-, di-, and triethyl phosphates and of mono- and di-methyl phosphonates.62 A-Methylol carboxamides and sulphonamides react with trialkyl phosphites to give the phosphonate derivatives (78) and (80), respectively.63 However, the mechanism appears to be quite different in each case while the carboamides react by a transesterification-rearrange-ment pathway, the sulphonamides undergo elimination-addition via the imine (79). 

Tetraphenylcyclopent-3-enone and dimethyl phosphonate are the major products from the base-catalysed reaction of methyl phosphonate with tetra-cyclone.75 A mechanism involving initial hydride transfer from dimethyl phosphinate anion to the ketone followed by kinetically controlled protonation to give (98) is suggested. 

Dimethyl ether, 31 41, 244 formation in zeolites, 42 95-98 Dimethylethylbenzenes, 20 281 Dimethylindan, cyclization, 28 298, 299 Dimethylindene, cyclization, 28 298, 299 Dimethyl methyl phosphonate, catalytic decomposition, 35 159-160 Dimethylnaphthalenes, hydrogenation of, 18 64-102... 

Synonyms DMHP dimethoxyphosphine oxide dimethyl phosphite methyl phosphonate... 

Weeks MH Acute vapor toxicity of phosphorus oxychloride, phosphorus trichloride and methyl phosphonic dichloride. Am Ind Hyg Arrowy 25 470-475, 1964... 

In related studies, it has been shown that a-fluorobenzylphosphonates ArCHFPO(OEt)2 (38) will undergo Wadsworth-Emmons-type olefination reactions with aldehydes and ketones [57]. 39 was prepared from benzaldehydes and HP(0) (OEt)2, which was fluorinated using diethylaminosulfur tiifluoride for example, diethyl [(3,5-dimethylphenyl)(fluoro)methyl]phosphonate (38) was formed in 91%. An 82% yield of Me 2-[(fluoro)(4-fluorophenyl)methylene]butanoate (1 1 E Z) (40) was obtained from 38 and methyl 2-oxobutanoate (Scheme 13). 

Diisopropyl Methyl Phosphonate DIMP Organophosphonates Organophosphorus Compounds... 

Dihydric and Polyhydric Phenols under Dihydric, Polyhydric Phenols Dusopropyl Methyl Phosphonate DIMP under Organophosphonates Dimethyl Acetamide under Amides Dimethyl Disulfide under Sulfides, Disulfides... 

Dialkyl methyl phosphonate derivatives 37a-c of mannopyranosides may be prepared from cyclic sulfate 36 by reaction with the appropriate lithiated methylphosphonate, prepared by titration of the corresponding methyl-phosphonate with butyllithium in the presence of 1,1-diphenylethylene as indicator (Equation 4) <2002TL4017>. 

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