- Wet and dry processes for the selective transformation of phosphonates to phosphonic acids catalyzed by br?nsted acids
-
A "wet"process and two "dry"processes for converting phosphonate esters to phosphonic acids catalyzed by a Bronsted acid have been developed. Thus, in the presence of water, a range of alkyl-, alkenyl-, and aryl-substituted phosphonates can be generally hydrolyzed to the corresponding phosphonic acids in good yields catalyzed by trifluoromethyl sulfonic acid (TfOH) at 140 °C (the wet process). On the other hand, with specific substituents of the phosphonate esters, the conversion to the corresponding phosphonic acids can be achieved under milder conditions in the absence of water (the dry process). Thus, the conversion of dibenzyl phosphonates to the corresponding phosphonic acids took place smoothly at 80 °C in toluene or benzene in high yields. Moreover, selective conversion of benzyl phosphonates RP(O)(OR′)(OBn) to the corresponding mono phosphonic acids RP(O)(OR′)(OH) can also be achieved under the reaction conditions. The dealkylation via the generation of isobutene of ditert- butyl phosphonate, and the related catalysis by TfOH took place even at room temperature to give the corresponding phosphonic acids in good to high yields. Nafion also shows high catalytic activity for these reactions. By using Nafion as the catalyst, phosphonic acids could be easily prepared on a large scale via a simple process.
- Li, Chunya,Saga, Yuta,Onozawa, Shun-Ya,Kobayashi, Shu,Sato, Kazuhiko,Fukaya, Norihisa,Han, Li-Biao
-
-
Read Online
- Regioselective formation of a 2,3-oxaphosphabicyclo[2.2.2] octene 3-oxide in baeyer-villiger type oxidation; a dual pathway for its fragmentation
-
The O-insertion reaction of a 7-phosphanorbornene (3) unsubstituted on the double-bond gave the corresponding 2,3-oxaphosphabicyclo-[2.2.2]octene oxide (4a) in a regioselective manner that was useful in the fragmentation-related phosphonylation of alcohol
- Jankowski, Stefan,Kovacs, Janos,Huben, Krzysztof,Blaszczyk, Michal,Glowka, Marek,Keglevich, Gyoergy
-
-
Read Online
- Competition of methanol and tert-butanol in nucleophilic substitution at phosphorus atom
-
2,3-Oxaphosphabicyclo[2.2.2]octene 1 reacts with alcohols simultaneously according to two competitive mechanisms: bimolecular addition-elimination and unimolecular elimination-addition with the intermediacy of metaphosphonate Ph-PO2 (2). In 1,2-dichloroet
- Cieplucha, Agnieszka,Jankowski, Stefan
-
-
Read Online
- METHOD FOR PRODUCING PHOSPHONIC ACID DERIVATIVE
-
PROBLEM TO BE SOLVED: To provide a method for producing a phosphonic acid derivative, in which the reaction proceeds under relatively mild reaction conditions without using hydrogen halide or a metal catalyst. SOLUTION: Provided is a method for producing a phosphonic acid derivative represented by formula (1), comprising a step in which an ester group-containing phosphonic acid derivative is reacted in a solvent or without a solvent in the presence of a superacid catalyst. (In formula (1), R1 and R2 are each independently a substituted or unsubstituted hydrocarbon group that may contain a heteroatom, n is a natural number of 1 to 3, m is a natural number of 0 to 2, o is a natural number of 0 to 1, and n + m + o = 3.). SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
- -
-
Paragraph 0053-0055
(2020/10/27)
-
- Double role of the hydroxy group of phosphoryl in palladium(II)-catalyzed ortho -olefination: A combined experimental and theoretical investigation
-
Density functional theory calculations have been carried out on Pd-catalyzed phosphoryl-directed ortho-olefination to probe the origin of the significant reactivity difference between methyl hydrogen benzylphosphonates and dimethyl benzylphosphonates. The overall catalytic cycle is found to include four basic steps: C-H bond activation, transmetalation, reductive elimination, and recycling of catalyst, each of which is constituted from different steps. Our calculations reveal that the hydroxy group of phosphoryl plays a crucial role almost in all steps, which can not only stabilize the intermediates and transition states by intramolecular hydrogen bonds but also act as a proton donor so that the η1-CH3COO- ligand could be protonated to form a neutral acetic acid for easy removal. These findings explain why only the methyl hydrogen benzylphosphonates and methyl hydrogen phenylphosphates were found to be suitable reaction partners. Our mechanistic findings are further supported by theoretical prediction of Pd-catalyzed ortho-olefination using methyl hydrogen phenylphosphonate, which is verified by experimental observations that the desired product was formed in a moderate yield.
- Liu, Liu Leo,Yuan, Hang,Fu, Tingting,Wang, Tao,Gao, Xiang,Zeng, Zhiping,Zhu, Jun,Zhao, Yufen
-
-
- PHOSPHOTHIOPHENE AND PHOSPHOTHIAZOLE HCV POLYMERASE INHIBITORS
-
Provided herein are phosphothiophene and phosphothiazole compounds, for example, of any of Formulae I, IA, HA, IIIA, IVA, VA, VIA, VIIA, IB, HB, IIIB, IVB, VB, VIB and VIIB disclosed herein, pharmaceutical compositions comprising the compounds, and proces
- -
-
Page/Page column 150
(2010/09/18)
-
- Resolution of chiral phosphate, phosphonate, and phosphinate esters by an enantioselective enzyme library
-
An array of 16 enantiomeric pairs of chiral phosphate, phosphonate, and phosphinate esters was used to establish the breadth of the stereoselective discrimination inherent within the bacterial phosphotriesterase and 15 mutant enzymes. For each substrate,
- Nowlan, Charity,Li, Yingchun,Hermann, Johannes C.,Evans, Timothy,Carpenter, Joseph,Ghanem, Eman,Shoichet, Brian K.,Raushel, Frank M.
-
p. 15892 - 15902
(2007/10/03)
-
- Enantiopure O-substituted phenylphosphonothioic acids: Chiral recognition ability during salt crystallization and chiral recognition mechanism
-
The chiral recognition ability of enantiopure O-methyl, O-ethyl, O-propyl, and O-phenyl phenylphosphonothioic acids (1a-d) for various kinds of racemic amines during salt crystallization and the chiral recognition mechanism were thoroughly investigated. T
- Kobayashi, Yuka,Morisawa, Fumi,Saigo, Kazuhiko
-
p. 606 - 615
(2007/10/03)
-
- (1H-Benzotriazol-1-yloxy)tris(dimethylamino)phosphonium Hexafluorophosphate- and (1H-Benzotriazol-1-yloxy)tripyrrolidinophosphonium Hexafluorophosphate-Mediated Activation of Monophosphonate Esters: Synthesis of Mixed Phosphonate Diesters, the Reactivity of the Benzotriazolyl Phosphon...
-
A general method for synthesizing mixed phosphonate diesters from monoesters using (1H-benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate or (1H-benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate reagents is described.The reaction proceeded through a benzotriazolyl ester as shown by comparison with other reagents such as DCC, DCC/DMAP, DCC/1-hydroxybenzotriazole, bromotris(dimethylamino)phosphonium hexafluorophosphate, or O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate and by 31P NMR analysis.This benzotriazolyl phosphonic ester intermediate was more reactive toward alcohols than toward amines, contrary to its carboxylic analogue.
- Campagne, Jean-Marc,Coste, Jacques,Jouin, Patrick
-
p. 5214 - 5223
(2007/10/02)
-
- TETRAZOLE CATALYZED SYNTHESIS OF PHOSPHONATE ESTERS
-
1H-tetrazole selectively catalyzed mono addition of alcohols to phosphonic dichlorides such that mixed phosphonate diesters could be synthesized in high yields and under mild conditions.
- Zhao, Kang,Landry, Donald W.
-
p. 363 - 368
(2007/10/02)
-
- The Mechanistic Diversity of the Thermal and Photochemical Decomposition of Bis(phenylphosphonoyl)Peroxides: Concerted Polar, Homolytic and Electron-Transfer Processes. On the Reactivity of (Phenylphosponoyl)oxyl Radicals
-
The thermal and photochemical decomposition of the first bis(phenylphosphonoyl)peroxides, dioxybis (5), and dioxybis (6) has been studied in various solvents by 1H-, 13C-, and 31P-NMR spectroscopy, laser flash photolysis (LFP), and ESR spin-trapping experiments.Kinetic studies reveal at 20 deg C a ca. 270 times slower thermal decay for 5 than for 6, which primarily results from a lower A factor rather than differences in the activation energies.The thermal decay of 5 occurs predominantly by a novel, presumably concerted polar rearrangement with formation of a thermally unstable, mixed phosphonoyl-phosphoryl anhydride.Photolysis of 5 induces homolytical cleavage of the peroxy bond with release of oxyl radicals 7.Radical 7 is characterized by a broad, transient UV/Vis absorption spectrum in the 400 to >700 nm range (λmax ca. 580 nm), as has been demonstrated by 248-nm LFP of 5 in acetonitrile solution.The short lifetime of this absorption indicates an extremely high reactivity (in hydrogen abstraction and addition) of this electrophilic radical.The thermal and photochemical decomposition of peroxide 6 leads to a virtually identical product distribution, suggesting O-O bond cleavage to be the major initial reaction under both conditions.LFP at 248 and 308 nm of a solution of 6 in acetonitrile initially produces a weak, broad absorption at ca. 500 nm and stronger bands at 280 and 400 nm.The highly transient 500-nm absorption is assigned to the oxyl radical 8, the other bands are attributed to the phosphonoyloxy-substituted benzene radical cation 8Z.The formation of this species can be explained in terms of electron transfer in the first-formed oxyl radical 8 and/or the intact peroxide 6, followed by cleavage of the peroxy bond.The decay of 8Z is accompanied by the build-up of the absorption spectrum of a 1,4-dioxy-substituted biphenyl radical cation.Key Words: Oxyl radicals / Phosphonoyl peroxides / Laser flash photolysis /ESR-Spin trapping / Electron transfer
- Korth, Hans-Gert,Lommes, Petra
-
p. 2419 - 2438
(2007/10/02)
-
- Differential binding energy: A detailed evaluation of the influence of hydrogen-bonding and hydrophobic groups on the inhibition of thermolysin by phosphorus-containing inhibitors
-
Two series of phosphorus-containing peptide analogues, 3 (CbZ-Gly-ψ(PO2-CH2)Leu-Xaa) and 4 (Cbz-Gly-ψ-(PO2-NH)Leuψ[CO2]Xaa), have been synthesized and evaluated as inhibitors of the zinc en
- Morgan, Bradley P.,Scholtz, John M.,Ballinger, Marcus D.,Zipkin, Ilan D.,Bartlett, Paul A.
-
p. 297 - 307
(2007/10/02)
-
- Stereoselectivity in Fragmentation and Rearrangement of α-Hydroxyiminophosphinates and -phosphonates. A Synthetic Approach to Acylphosphon- and phosphor-amidates. Crystal Structures of Methyl (E)-α-Hydroxyiminobenzylphenylphosphinate and Methyl Benzoylphenylphosphonamidate
-
Reaction of methyl benzoylphenylphosphinate 1 with hydroxylamine gave methyl α-hydroxyiminobenzylphenylphosphinate 2 as a mixture of E and Z isomers with the E isomer predominating.Pure (E)-2 when heated gave methyl N-benzoylphenylphosphonamidate 3 as the sole product.In contrast, (Z)-2 when heated gave, as a result of fragmentation, mainly methyl hydrogen phenylphosphonate 4 and benzonitrile, together with methyl N-phenylcarbamoylphenylphosphinate 5 as the minor product; the latter results from Beckmann rearrangement of (Z)-2.Analogous behaviour is exhibited by the two geometrical isomers of dimethyl α-hydroxyiminobenzylphenylphosphinate (E)-2 and methyl benzoylphenylphosphonamidate 3 are reported.
- Breuer, Eli,Schlossman, Ada,Safadi, Muhammad,Gibson, Dan,Chorev, Michael,Leader, Haim
-
p. 3263 - 3269
(2007/10/02)
-
- The Selective Dealkylation of Mixed Esters of Phosphoric Acid and Phenylphosphonic Acid Using Cation Exchange Resin
-
Cation exchange resin (SO3H) is a highly selective dealkylation reagent for mixed esters of phosphorus oxyacids bearing primary and secondary alkyl groups.The desired products which were produced by dealkylation of the secondary alkyl group were obtained in high yields under anhydrous and mild conditions.Keywords - dealkylation; cation exchange resin; carbonium ion; phosphorus oxyacid ester; trialkyl phosphate; dialkyl phenylphosphonate; p-toluenesulfonic acid
- Nitta, Yoshihiro,Arakawa, Yasushi
-
p. 3121 - 3129
(2007/10/02)
-
- Azolides, 7. - Phosphonate and Phosphate Group Transfer with Pyrazolides
-
The tert-butylammonium α-diazophosphinates 7 add onto acceptor-substituted acetylenes 8 with formation of N-phosphorylpyrazoles: Primarily formed 3H-pyrazoles 9 undergo spontaneous sigmatropic shift of the anionic PO-group to yield 10. α-Diazophosph
- Regitz, Manfred,Martin, Roland
-
p. 1641 - 1652
(2007/10/02)
-
- Phosphonosulfates. Metal Ion Catalysis in the Hydrolysis of 2-Pyridyl- and 2-Pyridylmethylphosphonosulfate
-
The hydrolysis rates of phosphonosulfates, having a neighboring 2-pyridyl group, 2-pyridyl- (1) and 2-pyridylmethylphosphonosulfate (2), have been compared with those of the corresponding phenyl- (3) and benzylphosphonosulfate (4) in a pH range of 1-9.All
- Eiki, Toshio,Horiguchi, Tetsuo,Ono, Michimasa,Kawada, Shuji,Tagaki, Waichiro
-
p. 1986 - 1991
(2007/10/02)
-