Phosphonates dimethyl methylphosphonate

Antiblaze 19, a phosphonate ester and flame retardant used in textiles and polyurethane foam manufactured from trimethyl phosphite, dimethyl methylphosphonate, and trimethyl phosphate. 

Nolan and co-workers have extended the scope of transesterification reactions to include phosphonate esters as phosphorylating agents [137]. In this publication the authors use dimethyl methylphosphonate 273 and benzyl alcohol with a variety of imidazolylidene carbenes (Table 23). The nse of molecnlar sieves to absorb methanol leads to increased conversion however, longer reaction times lead to decreased... 

One embodiment of this general reaction led to a product which was commercially produced for several years by Stauffer as Fyrol 76 (9), a copolycondensation product of dimethyl methyl-phosphonate with bis(2-chloroethyl) vinylphosphonate. The features of Fyrol 76 were high phosphorus content (20%), water solubility, and ability to be polymerized by means of a radical initiator to a crosslinked polymer. A related polycondensation product was developed from tris(2-chloroethyl) phosphate and dimethyl methylphosphonate. By control of the reagents and procedure used for neutralization, these oligomeric products were produced with primary alcohol functional groups (7). 

Figure 2. The effect of derivatization on methylphosphonic acid (a) methyl phosphonic acid analyzed as solid KBr pellet, (b) dimethyl methylphosphonate analyzed with cryodeposition-FTIR, and (c) bis(trimethylsilyl) methylphospho-nate (CAS 18279-83-9) analyzed with cryodeposition-FTIR (Source M. Soderstrom, unpublished results)...

Preparation of the DHAP analogue, 4-hydroxy-3-oxobutylphosphonic acid, which is an effective donor substrate, is accomplished in four steps from glycidol.29 Glycidol is silyl protected then its epoxide is opened by dimethyl methylphosphonate. The secondary alcohol was oxidized under the Dess-Martin conditions. Deprotection of the alcohol followed by phosphate hydrolysis, generated the DHAP phosphonate analogue (Scheme 5.9). 

Phosphonate esters can be prepared either by the Arbuzov reaction (rearrangement) or by the alkylation of esters with DMMP (dimethyl methylphosphonate) (Scheme 4.28). Variation of the reaction conditions and reagents allows one to synthesize E- and Z-aUcenes with a high degree of stereoselectivity, as shown in Scheme 4.29. For example, 6-heptenal (4.33) on reaction with 4.34 in the presence of NaH gives -nonadienoate (4.35) on the other hand, in the presence of a base n-BuLi, Z-nonadienoate (4.36) is the major product. 

Reaction of dienoaldehyde with the stabilized Wittig reagent(s) provided a triene 88, which upon high-pressure Diels-Alder cyclization furnished bicyclo[4.3.0]nonene [78]. Alternatively the aldehyde S7-E was converted into the methyl ester 89, which reacted with the dimethyl methylphosphonate anion affording the phosphonate 90. Reaction of the latter with aldehydes under mild PTC conditions yielded a (regioisomeric to the previous one) triene 91, which cyclized spontaneously to bicyclo[4.4.0]decene (O Scheme 37) [79]. 

The preparation of methyl (carbomethoxymethyl) methyl phosphonate was conducted with methyl chloroacetate and an excess of dimethyl methylphosphonate, using sodium carbonate as a catalyst (27). 

A relatively general procedure for the preparation of dialkyl 2-oxoalkylphosphonates by direct acylation of dialkyl 1-lithioalkylphosphonates has been introduced by Corey and Kwiatkowski in 1966. The use of phosphonate carbanions as nucleophiles in reaction with carboxylic esters avoids the problems associated with the Michaelis-Arbuzov reaction. The reaction sequence is initiated by the addition at low temperature of dimethyl 1-lithiomethylphosphonate (2 eq and frequently more) to a carboxylic ester (1 eq) to give the transient lithium phosphonoenolate. The dimethyl methylphosphonate, being readily available and easy to eliminate, is the most frequently used phosphonate, but other phosphonates such as diethyl and diisopropyl methylphosphonates can be used. When the resulting enolate is treated with acid, dimethyl 2-oxoalkylphosphonate is produced in moderate to good yields (45-95%, Scheme 7.20). The reaction has been achieved with... 

A series of deprotection, reduction, and reprotection steps provided a 69% yield of silyl ether 226, which was subjected to a hydroboration-oxidation sequence to afford aldehyde 267 (87%) as a mixture of isomer at C-8. Aldehyde 267 was then converted to the Emmons reagent 268 via a sequence involving addition of lithium dimethyl methylphosphonate, oxidation to the keto phosphonate, deprotection, and oxidation in 65% overall yield. 

Dimethyl methylphosphonate 352 Trimethyl phosphite (0.1 mole) is heated with methyl iodide (10 mmoles) at 100° for 30 min. After a short induction period a violent reaction sets in which is complete in a few minutes. Distillation in a vacuum gives a 93 % yield of the phosphonate, b.p. 63°/10 mm. When only 1 mmole of methyl iodide is used, the yield of phosphonate amounts to about 80%. 

Functionalized p-keto phosphonates. Note Dimethyl methylphosphonate, which should have exactly the same reactivity, is described in the cited report.) After reaction of the a-lithio derivative with succinic anhydride and esterification of the... 

In the presence of BuLi in thf, the active methylene compounds (Et0)2P(0)CH2Z (Z = P03Et2, COOMe, S02Me or CN) add to PhCH—CMe(N02) to give the products 78 as intermediates in a synthesis of C-phosphorylated 2-isoxazoline derivatives Other reactions have been performed between 2-aryl-1-nitroethenes and the anions from dimethyl methylphosphonate " or dimethyl (difluoromethyl)phosphonate in the initial steps towards syntheses of phaclofen 80 X = H) and its difluoro analogue (80 X = F) by the reduction (H2-Raney nickel) of the initial adduct 79 (Scheme 6). 

Dimethyl methylphosphonate is said to afford dimethyl [alkyl(or aryl)thio]-methyUphosphonates when acted upon by thiolsulphinates. The anion from diethyl [(phenylthio)methyl]phosphonate may be alkylated and subsequently converted into (l-alkene)phosphonates (Scheme 5). ... 

Stereochemistry — The conformational analysis of various deuteriated ethyl-phosphine-borane adducts and dimethyl methylphosphonates were based on vibrational spectral data. The stereochemistry of diethylphosphonyl acetamide,the unusual vinyl compounds (60 X = L.E.P., O, and a number of l,3,2-dioxaphosphorinanes have been studied. It was found that the Raman-active ring vibration is related to the orientation of the phosphoryl group. Conformational data for dioxaphosphepane was compared with calculated parameters. A low-temperature study of several cyclopropyl-phosphonates (61) revealed rotational isomerization about the P-O bonds but not about the P-C bond. The variable temperature i.r. and Raman spectra of the silyl phosphates (62) also revealed rotational isomerism. ... 

The reactions of dimethyl methylphosphonate and the corresponding carbanion in the gas phase have been investigated. The carbanion displays a similar range of reactions to those encountered in solution, including olefmation with carbonyl compounds. The effect on olefin stereochemistry of a variety of conditions in reactions of a-phosphono lactones (e.g. 129) with ethanal and propanal has been studied and the results applied in syntheses of integerrinecic acid and senecic acid lactones. Yet further minor modifications of the conditions for phosphonate-olefination reactions, involving the use of lithium hydroxide as the base, have been reported. ... 

FIGURE 11.6 Plot of alpha values for protonated monomers of organophosphate compounds obtained at two fields of 80 (bottom) and 140 (top) Td as a function of moisture. DMMP, dimethyl-methylphosphonate TMP, trimethyl-phosphate DEMP, diethyl-methyl-phosphonate DEEP, diethyl-ethylphosphonate DIMP, di-iso-prophyl-methylphosphonate DEIP, diethyl-iso-prophylphosphonate TEP, triethyl phosphate TPP, tripropyl phosphate DBBP, dibutyl-butylphosphonate TBP, tri-n-butylphosphate. (From Krylova et al., Effect of moisture on high field dependence of mobility for gas phase ions at atmospheric pressure organophosphorus compounds, J. Phys. Chem. 2003. With permission.)... 

Phosphonic acid, methyl-, dimethyl ester. See Dimethyl methylphosphonate Phosphonic acid, methyl-, (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphorinan-5-yl) methyl methyl ester, p-oxide. See Methylphosphonic acid, (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphorinan-5-yl) methyl methyl ester Phosphonic acid, methyl (5-methyl-2-methyl-1,3,2-dioxaphosphorinan-5-y) ester,P,P -dioxide. See Methylphosphonic acid, bis [(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphorinan-5-yl) methyl] ester Phosphonic acid, [nitriliotris (methylene)] tris-, sodium salt. See Sodium nitrilotris (methylene phosphate)... 

Under normal conditions, dialkyl phosphonates are stable compounds. At elevated temperatures (above 160 °C), they begin to decompose. Dimethyl H-phosphonate is the most unstable homologue in that respect. At a temperature of 173 °C, it pyrolyzes to monomethyl H-phosphonate and dimethyl methylphosphonate [55,56]. 

The first step of the process is the homolysis of the P-H bond. Due to the respective volatilities of the solvent (toluene) and of the phosphonate, a thermolytic mechanism in the vaporous phase of the bubble seems unlikely (Fig. 22). Pyrolysis of dimethyl phosphonate gives methylphosphonic acid, probably via an intramolecular Arbuzov reaction. On the other hand, y-radiolysis and UV... 

The values 11.26 and 13.38 represent the acidic and alkaline limits of the P titration curve chemical shifts with respect to the a-ATP resonance. Phosphonic acid derivatives, like methylene diphosphonic acid (MDPA) or dimethyl methylphosphonate (DMMP), resonating far from physiological phosphates (ca. 20-30 ppm) can be used as an external reference for chemical shift and concentration calibrations. Sometimes these references cross the cell membrane and two different resonances are observed for the intracellular and extracellular compounds. In these cases it is possible to determine the relative cellular volume from the relative areas of the intra- and extracellular resonances (Figure 3 inset). 

Complexes of beryllium with phosphonate ligands have been extensively researched, mainly by potentiometry. The ligands investigated are as follows methylphosphonate (259, 260) chloromethyl-phosphonate (259) 2-aminopropane-l-phosphonate (259) methylene-diphosphonate (130, 260, 261) hexamethylenediphosphonate (259) l-hydroxyethane-l,l-diphosphonate (261) 1,1-dimethyl-1-amino-... 

Figure 8. LC/MS mass chromatograms, positive APCI showing the detection of four isomeric alkyl alkylphosphonic acids (1 Hg/ml) and two dialkylalkyl phosphonates (10 p,g/ml) (upper), negative APCI showing selective detection of the phosphonic acids, a. i-PrMPA and EEPA (unresolved), b. methyl n-PrPA, c. n-PrMPA, d. ethyl methyl methylphosphonate, and e. dimethyl ethylphosphonate (lower)...

METHYI- PHOSPHATE see TMD250 METHYL PHOSPHITE see TAIDSOO METHYL PHOSPHONATE see DSG600 METHYLPHOSPHONIC ACID DIMETHYL ESTER see DSR400... 

---