Methyl phosphinic acid, ethyl ester

Isopropyl titanium triisostearate Methacrylic acid 2-Methylacrylic acid 2-(2-oxo-imidazolidin-1-yl) ethyl ester Methyltrimethoxysilane Oleic aminoethylimidazoline PEG-3 dimethacrylate PEG-6 trimethylolpropane Pentaerythrityl-tris-(B-(N-aziridinyl) propionate Polyethylenimine Propylene/MA copolymer PVPA/A copolymer Rosin, polymerized Styrene/allyl alcohol copolymer Styrene/MA copolymer Tallowaminopropylamine Tetraisopropyl di (dioctylphosphito) titanate Triallylcyanurate Tricaprylyl methyl ammonium chloride Trimethylolpropane tris-(B-(N-aziridinyl) propionate) Tris [1-(2-methyl-aziridinyl) phosphine oxide] adhesion promoter, acrylic resins... 

Phosphonic acid amide esters. A soln. of ethyl [l-[[(phenylmethoxy)carbonyl]amino]-2-methylpropyl]phosphinate in acetonitrile under argon treated with bis(trimethyl-silyl)acetamide, followed after 1 min by L-alanine hydrochloride methyl ester, CCI4, and Et3N, the soln. stirred at room temp, for 30 min, cooled to 0°, and quenched with methanol N-[ethoxy[ 1 -[[(phenylmethoxy)carbonyl]am no]-2-methylpropyl]-... 

Deprotection of Phosphates, Phosphonates, and Phosphi-nates. BSA has been used in removal of alkyl groups from phosphate, phosphonate, and phosphinate esters to generate the corresponding acids. Conversion of phosphinate ester 99 into phosphinic acid 100 was carried out by treatment with BSA and trimethylsilyl iodide (TMSI), which caused simultaneous removal of the carbobenzyloxy group from the terminal proline residue and of the methyl group from the phosphinate ester (eq 63). Same reaction condition can also allow effective removal of ethyl groups from phosphonate diethylesters. ... 

Barabanov VI, Abramov VS (1965) Esters of ethyl (methyl) a-hydroxy-p, p, p-trichloroethyl phosphinic acid analogs of chlorophos. Zh Obsh Khim 35 2225-2229... 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

Many communications have concentrated on specific amino phosphonic acids or derivative types. Thus, esters of phosphonoaminoacetic add were obtained by the reactions between trialkyl (ethyl) phosphite and (218) and which are thought to proceed via the phosphorane (219). A sequence has been presented for the preparation of the mono- and di-benzyl esters of N-chz protected (a-aminoben-zyl)phosphonic acid. A synthesis of (aminomethylene)bisphosphonic acid from dibenzylamine, dibenzyl hydrogenphosphonate and triethyl orthoformate has been noted and the asymmetric hydrogenation of (220) in the presence of chiral phosphine catalysts yields samples of (221) with e.e.s of 63-96%. The pyrrolidine-based compound (222) has been prepared from methyl S)-N-methoxycarbonyl-4-oxo-2-pyrrolidinecarboxylate and iV-coupled 4-amino-butanal diethyl acetals were the starting materials in syntheses of the pyrrolidine-2-phosphonic add derivatives (223) in which Z represents the iV-protected amino add or peptide moiety. ... 

This route is especially convenient because no over-alkylation of the anion of acetonitrile occurs. Over-alkylation can be a problem in attempts to methylate the anion of diethyl cyano-methylphosphonate (4) directly a mixture of unalkylated, monoalkylated and dialkylated products in a ratio of 1 2 1 is formed. The same problem arises with the alkylation of triethyl phosphonoacetate (11). For the preparation of a Ca-ester synthon, an alternative method to the propionitrile route is used (Scheme 7). This method has been used in the synthesis of labelled Cio-central units, described in the next Section. The starting material is acetic acid (9) which is converted into ethyl bromoacetate (10) as described above (Scheme 3). The ethyl bromoacetate (10) is reacted with triphenyl phosphine in a nucleophilic substitution reaction the phosphonium salt is formed (yield 97%). The phosphonium salt is deprotonated in a two-layer system of dichloromethane and an aqueous solution of NaOH. After isolation, the phosphorane 22 is reacted at room temperature with one equivalent of methyl iodide (19) the product consists mainly of the monomethylated phosphonium salt (>90%) which is deprotonated with NaOH, to give the phosphorane 23 in quantitative yield relative to phosphorane 22, and 23 is reacted with the aldehyde in dichloromethane. The ester product 12 can subsequently be reduced to the corresponding alcohol and reoxidized to the aldehyde 8. An alternative two-step sequence for this has also been used. First, the ester 12 is converted into the A -methyl-iV-methoxyamide (16) quantitatively by allowing it to react with the anion of A, 0-dimethylhydroxylamine as described above (Scheme 5). This amide 16 is converted, in one step, into the aldehyde 8 by reacting it with DIB AH in THF at -40°C [46]. 

Concerning the first approach, methyl or alkyl protection of the phosphinic group requires suitable masking of the carboxylic terminus of the main pseudodi-peptidic unit which could be selectively removed prior to C-elongation. Selective deprotection of carboxylic esters in the presence of alkyl phosphinates include enzymatic hydrolysis of methyl carboxylates [18, 58], controlled alkaline hydrolysis of ethyl carboxylates [59, 60], acidic cleavage of 3,4-dimethoxybenzyl... 

Of particular note, A[,A[-dimethylbenzylamines 5.4 are the most popular with 350 articles reported, followed by such other popular compounds as benzyl methyl derivatives 5.30 with 168,2-phenhylpyridines 5.14 with 135, dimethylantinopropyl (or propenyl) compounds 5.22 with 159, alkyl (or aryl) ethyl (or ethenyl) ketones 5.19 with 108, diallyl (or diaryl or propenyl) phosphines 5.25 with 206, and alkyl (or aryl) propionic acid esters 526 with 164. 

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