- Tetraalkyl hydroxymethylene-bisphosphonate and dialkyl 1-diphenylphosphinoyl-1-hydroxy-ethylphosphonate derivatives by the pudovik reaction and their rearranged products
-
The reaction of diethyl α-oxoethylphosphonate and diethyl oxobenzylphosphonate with diethyl phosphite, dimethyl phosphite, and diphenylphosphine oxide affords, depending on the substrates and conditions (nature and quantity of the amine catalyst, temperat
- Keglevich, Gy?rgy,Szalai, Zsuzsanna
-
-
- Enantioselective vinylogous aldol reaction of acylphosphonates with 3-alkylidene oxindoles
-
A simple strategy for yielding chiral tertiary α-hydroxy phosphonates that integrates two highly biologically relevant scaffolds namely 3-alkylidene-2-oxindoles and phosphonates has been described. The hydrogen bonding ability of the bifunctional thiourea catalyst allows simultaneous dual activation of a vinylogous oxindole nucleophile and an acylphosphonate electrophile, affording hydroxyphosphonato-3-alkylidene-2-oxindoles as aldol adducts in high yields (up to 92%) with excellent stereocontrol (up to 99% ee).
- Jaiswal, Manish K.,Singh, Ravi P.,Singh, Sanjay
-
supporting information
p. 7861 - 7866
(2021/09/28)
-
- Controllable phosphorylation of thioesters: Selective synthesis of aryl and benzyl phosphoryl compounds
-
The controllable phosphorylations of thioesters were developed. When the reaction was catalyzed by a palladium catalyst, aryl or alkenyl phosphoryl compounds were generated through decarbonylative coupling, while the benzyl phosphoryl compounds were produced through deoxygenative coupling when the reaction was carried out in the presence of only a base.
- Xu, Kaiqiang,Liu, Long,Li, Zhaohui,Huang, Tianzeng,Xiang, Kang,Chen, Tieqiao
-
p. 14653 - 14663
(2020/12/29)
-
- Visible photocatalysis of novel oxime phosphonates: Synthesis of β-aminophosphonates
-
A novel type of oxime phosphonate was synthesized and used in the intermolecular cascade radical addition reaction of alkenes to access β-aminophosphonates via visible-light-driven N-centered iminyl radical-mediated and redox-neutral selective C-P single-bond cleavage in an active phosphorus radical route. The procedure is characterized by its ability to achieve the construction of Csp3-P and Csp3-N bonds without the requirement for oxidants and bases.
- Li, Yong-Hong,Wang, Chun-Hai,Gao, Su-Qian,Qi, Feng-Ming,Yang, Shang-Dong
-
supporting information
p. 11888 - 11891
(2019/10/11)
-
- Visible-Light-Catalyzed Phosphonation-Annulation: an Efficient Strategy to Synthesize β-Phosphonopyrrolidines and β-Phosphonolactones
-
A new type of phosphine radical precursor for C—P bond formation has been developed and successfully used in visible-light-catalyzed phosphonation-annulation of unsaturated sulfonamides and carboxylic acids. The catalytic process is simple and green acces
- Li, Chong,Qi, Zhi-Chao,Yang, Qiang,Qiang, Xiao-Yue,Yang, Shang-Dong
-
supporting information
p. 1052 - 1058
(2018/09/25)
-
- Carbene-catalyzed enal γ-carbon addition to α-ketophosphonates for enantioselective access to bioactive 2-pyranylphosphonates
-
A carbene-catalyzed enantioselective [4+2] cycloaddition reaction between α,β-unsaturated aldehydes and α-ketophosphonates is developed. The reaction affords chiral 2-pyranylphosphonates with excellent enantioselectivities. The optically enriched phosphonate products bear multiple functional groups, including unsaturated lactone and phosphonate moieties that often lead to unique bio-activities. Preliminary studies show that the products from our reactions exhibit anti-bacterial (X. oryzae pv. oryzae) and anti-viral (Tobacco Mosaic Virus) activities for potential use in plant protection.
- Sun, Jun,He, Fangcheng,Wang, Zhongyao,Pan, Dingwu,Zheng, Pengcheng,Mou, Chengli,Jin, Zhichao,Chi, Yonggui Robin
-
supporting information
p. 6040 - 6043
(2018/06/18)
-
- Catalytic Aldol-Cyclization Cascade of 3-Isothiocyanato Oxindoles with α-Ketophosphonates for the Enantioselective Synthesis of β-Amino-α-hydroxyphosphonates
-
A cascade aldol-cyclization reaction between 3-isothiocyanato oxindoles and α-ketophosphonates has been developed for the synthesis of β-amino-α-hydroxyphosphonate derivatives. Catalyzed by a quinine-based tertiary amino-thiourea derivative, this reaction
- Kayal, Satavisha,Mukherjee, Santanu
-
supporting information
p. 5508 - 5511
(2015/11/18)
-
- Pd-catalyzed carbonylative access to aroyl phosphonates from (hetero)aryl bromides
-
The first transition-metal catalysed carbonylation with a phosphorus nucleophile is presented. This transformation provides efficient and mild access to aroylphosphonates under mild conditions, thus ensuring a broad substrate scope. The utility of aroylph
- Lian, Zhong,Yin, Hongfei,Friis, Stig D.,Skrydstrup, Troels
-
supporting information
p. 7831 - 7834
(2015/05/13)
-
- Synthesis of acylphosphonates by a palladium-catalyzed phosphonocarbonylation reaction of aryl iodides with phosphites
-
Acylphosphonates are conveniently synthesized from aryl iodides by a palladium-catalyzed reaction with dialkyl phosphites under an atmospheric pressure of carbon monoxide. The reaction demonstrates the first example of the use of phosphorus nucleophiles in related metal-catalyzed carbonylation reactions.
- Masuda, Yusuke,Ishida, Naoki,Murakami, Masahiro
-
supporting information
p. 321 - 324
(2015/02/05)
-
- Asymmetric homoenolate additions to acyl phosphonates through rational design of a tailored N-heterocyclic carbene catalyst
-
A highly selective NHC-catalyzed synthesis of γ-butyrolactones from the fusion of enals and α-ketophosphonates has been developed. Computational modeling of competing transition states guided a rational design strategy to achieve enhanced levels of enanti
- Jang, Ki Po,Hutson, Gerri E.,Johnston, Ryne C.,McCusker, Elizabeth O.,Cheong, Paul H.-Y.,Scheidt, Karl A.
-
supporting information
p. 76 - 79
(2014/01/23)
-
- Palladium-catalyzed asymmetric hydrogenation of N-hydroxya-imino phosphonates using bronsted acid as activator: The first catalytic enantioselective approach to chiral N-hydroxy-aamino phosphonates
-
The enantioselective synthesis of ring-substituted [N-(hydroxy)amino] ACHTUNGTRENUNG(phenyl)methylphos- ACHTUNGTRENUNGphonic esters via asymmetric hydrogenation of the corresponding N-hydroxy-a-imino phosphonates with up to 90% ee was developed using cata
- Goulioukina, Nataliya S.,Shergold, Ilya A.,Bondarenko, Grigorii N.,Ilyin, Mikhail M.,Davankov, Vadim A.,Beletskaya, Irina P.
-
supporting information
p. 2727 - 2733
(2013/01/15)
-
- Nicotinium dichromate (= 3-carboxypyridinium dichromate; NDC) as an efficient reagent for the oxidative deamination of amines and aminophosphonates
-
A new method for the efficient synthesis of aldehydes, ketones, and oxophosphonates from various types of amines (primary and secondary) and aminophosphonates via oxidative deamination by nicotinium dichromate (= 3-carboxypyridinium dichromate; NDC) is described.
- Sobhani, Sara,Aryanejad, Sima,Maleki, Mahdi Faal
-
experimental part
p. 613 - 617
(2012/05/20)
-
- Preparation of α-ketophosphonate derivatives and their application in the synthesis of 1-(N-alkylcarbamoyl)-1-(diethoxyphosphoryl)alkyl benzoates via Passerini reaction
-
Chemical Equation Presented The Passerini reaction of α- ketophosphonates, isocyanides, and benzoic acid derivatives leads to 1-(N-alkylcarbamoyl)-1-(diethoxyphosphoryl)alkyl benzoates in one step at room temperature. The structures of products were assig
- Azizian, Javad,Ramazani, Ali,Haji, Mohammad
-
experimental part
p. 326 - 333
(2011/04/22)
-
- Room-temperature alternative to the arbuzov reaction: The reductive deoxygenation of Acyl phosphonates
-
The reductive deoxygenation of acyl phosphonates using a Wolff-Kishner-like sequence is described. This transformation allows direct access to alkyl phosphonates from acyl phosphonates at room temperature. The method can be combined with acyl phosphonate synthesis into a one pot, four-step procedure for the conversion of carboxylic acids into alkyl phosphonates. The methodology works well for a variety of aliphatic acids and shows a functional group tolerance similar to that of other hydrazone-forming reactions.
- Kedrowski, Sean M. A.,Dougherty, Dennis A.
-
supporting information; experimental part
p. 3990 - 3993
(2010/11/02)
-
- Oxidative deamination of α-aminophosphonates and amines by zinc dichromate trihydrate (ZnCr2O73H2O) under solvent-free conditions at room temperature
-
A novel method for the rapid and efficient conversion of a variety of -aminophosphonates to α-ketophosphonates using ZnCr2O 73H2O via oxidative deamination under solvent-free conditions at room temperature is described. This method is also applicable to the rapid and highly selective oxidation of various types of ordinary amines (primary and secondary) to aldehydes and ketones in good to high yields. Georg Thieme Verlag Stuttgart New York.
- Sobhani, Sara,Maleki, Mahdi Faal
-
experimental part
p. 383 - 386
(2010/04/05)
-
- Asymmetrie hydrogenation of α,ss-unsaturated esterphosphonates
-
The rhodium-catalyzed asymmetric hydrogenation of readily available α,ss-unsaturated esterphosphonates affords the corresponding α-chiral phosphonates in excellent yield and ee. The resulting products are useful multifunctional building blocks applied in
- Huang, Yange,Berthiol, Florian,Stegink, Bart,Pollard, Michael M.,Minnaard, Adriaan J.
-
experimental part
p. 1423 - 1430
(2009/12/24)
-
- Asymmetric hydrogenation of α-keto phosphonates with chiral palladium catalysts
-
Under atmospheric hydrogen pressure, a catalytic amount of palladium(II) trifluoroacetate and (R)-MeO-BIPHEP in 2,2,2-trifluoroethanol promoted the asymmetric hydrogenation of diisopropyl α-keto phosphonates 1 to afford the corresponding α-hydroxy phospho
- Goulioukina, Nataliya S.,Bondarenko, Grigorii N.,Bogdanov, Alexei V.,Gavrilov, Konstantin N.,Beletskaya, Irina P.
-
experimental part
p. 510 - 515
(2009/07/19)
-
- Catalytic hydrogenation of α-iminophosphonates as a method for the synthesis of racemic and optically active α-aminophosphonates
-
It was shown that the catalytic hydrogenation of α-iminophosphonates by molecular hydrogen can serve as a convenient method for the synthesis of racemic and optically active α-aminophosphonates. Up to 94% ee was achieved in the rhodium-catalyzed enantiose
- Goulioukina, Nataliya S.,Bondarenko, Grigorii N.,Lyubimov, Sergey E.,Davankov, Vadim A.,Gavrilov, Konstantin N.,Beletskaya, Irina P.
-
supporting information; experimental part
p. 482 - 492
(2009/04/10)
-
- Efficient method for the asymmetric reduction of α- and β-ketophosphonates
-
An efficient and versatile method for the asymmetric reduction of α- and β-ketophosphonates using chiral reactant derived from sodium borohydride and l-(+)- or d-(-)-tartaric acid is developed. The methodology was used for the preparation of a number of biologically interesting enantiomerically pure products: including 2,3-epoxypropylphosphonate 11, 2-hydroxy-3-aminopropylphosphonic acid 14 (phospho-GABOB), phospho-carnitine 19, and others in multigram scale.
- Nesterov,Kolodiazhnyi
-
p. 6720 - 6731
(2008/02/07)
-
- PRODRUGS OF DRUG-PHOSPHATE CONJUGATES AND ANALOGS THEREOF
-
Phosphate-substituted therapeutic compounds and analogs thereof that may serve as prodrugs are described. The prodrugs may include phosphorus-containing compounds, drug-phosphate conjugates, and analogs of drug-phosphate conjugates. Also described are ana
- -
-
Page/Page column 26
(2010/10/20)
-
- Enantioselective reduction of ketophosphonates using chiral acid adducts with sodium borohydride
-
A method for asymmetric reduction of α-and β-ketophosphonates using a chiral complex prepared from sodium borohydride and D-or L-tartaric acid is developed. Reduction of α-or β-ketophosphonates by these reagents led to formation of corresponding (S)-or (R
- Nesterov,Kolodyazhnyi
-
p. 1022 - 1030
(2008/02/05)
-
- N-sulfonyl-and N-phosphorylbenzimidoylphosphonates
-
A procedure for preparing N-sulfonyl-and N- phosphorylbenzimidoylphosphonates by oxidation of the corresponding α-(sulfonylamino)-and α-(phosphorylamino)benzylphosphonates was developed. The σ constants of imidoylphosphonate groups were evaluated by 19F NMR spectroscopy, and specific features of their electronic effects were considered. The reactions of the imidoylphosphonates obtained with O-, S-, P-, and N-nucleophiles were studied. The phosphonate-phosphoramidate rearrangement of α-aminobenzylidene-bisphosphonates was found. Nauka/Interperiodica 2006.
- Kolotilo,Sinitsa,Rassukanaya,Onys'ko
-
p. 1210 - 1218
(2008/02/03)
-
- Highly enantioselective aerobic oxidation of α-hydroxyphosphonates catalyzed by chiral vanadyl(V) methoxides bearing N-salicylidene-α- aminocarboxylates
-
An unprecedented vanadyl(V) methoxide complex 4 derived from 3,5-dibromo-N-salicylidene-l-tert-leucinate enables highly enantioselective aerobic oxidations of α-hydroxyphosphonates at ambient temperature with selectivity factors ranging from 3 to >99. Cop
- Pawar, Vijay D.,Bettigeri, Sampada,Weng, Shiue-Shien,Kao, Jun-Qi,Chen, Chien-Tien
-
p. 6308 - 6309
(2007/10/03)
-
- Preparation of α-ketophosphonates by oxidation of α-hydroxyphosphonates with chromium-based oxidants
-
Various types of diethyl α-hydroxyphosphonates were efficiently converted to diethyl α-ketophosphonates by nicotinium dichromate (NDC), nicotinium chlorochromate (NCC), and isonicotinium dichromate (INDC) in high yields.
- Firouzabadi, Habib,Iranpoor, Nasser,Sobhani, Sara
-
p. 1463 - 1471
(2007/10/03)
-
- Preparation of α-ketophosphonates by oxidation of α-hydroxyphosphonates with Pyridinium Chlorochromate (PCC)
-
Various types of diethyl α-hydroxyphosphonates were converted efficiently to their corresponding diethyl α-ketophosphonates by pyridiinum chlorochromate (PCC) without cleavage of C(O) - P bond in the absence of solvent or in solution in high yields.
- Firouzabadi, Habib,Iranpoor, Nasser,Sobhani, Sara
-
p. 1483 - 1491
(2007/10/03)
-
- Preparation of α-ketophosphonates by oxidation of α-hydroxyphosphonates with neutral alumina supported potassium permanganate (NASPP) under solvent-free conditions and potassium permanganate in dry benzene
-
Various types of α-hydroxyphosphonates were converted to α-ketophosphonates in high yields by potassium permanganate in dry benzene or by neutral alumina supported potassium permanganate (NASPP) under solvent-free conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Sobhani, Sara
-
p. 477 - 480
(2007/10/03)
-
- High yield preparation of α-ketophosphonates by oxidation of α-hydroxyphosphonates with zinc dichromate trihydrate (ZnCr2O7·3H2O) under solvent-free conditions
-
Various types of α-hydroxyphosphonates were converted to α-ketophosphonates by zinc dichromate trihydrate in high yields and rates under solvent-free conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Sobhani, Sara,Sardarian, Ali-Reza
-
p. 4369 - 4371
(2007/10/03)
-
- A convenient and mild procedure for the preparation of α-keto phosphonates of 1-hydroxyphosphonates under solvent-free conditions using microwave
-
The Reactions of 1-hydroxyphosphonates on the alumina-supported CrO3 are accelerated by microwave irradiation under solvent-free conditions to afford a high yielding synthesis of α-keto phosphonates.
- Kaboudin,Nazari
-
p. 2245 - 2250
(2007/10/03)
-
- Surface-mediated solid-phase reactions: The preparation of acyl phosphonates by oxidation of 1-hydroxyphosphonates on the solid surface
-
Alumina-supported CrO3, under solvent-free conditions, was found to be an efficient oxidizing reagent for the preparation of acyl phosphonates from 1-hydroxyphosphonates. This method is an easy, rapid, and high-yielding reaction for the prepara
- Kaboudin, Babak
-
p. 3169 - 3171
(2007/10/03)
-
- Reactions of acyl tributylphosphonium chlorides and dialkyl acylphosphonates with Grignard and organolithium reagents
-
Ketones and esters (4) were effectively prepared by reaction of Grignard reagents with acyl tributylphosphonium chlorides (2), diethyl acylphosphonates (5), or diisopropyl acylphosphonate (6) derived from acid chlorides and chloroformates (1). Although by the method with 2, 4 is prepared in one-pot operation from 1 and generally in a higher yield, the method with 5 or 6 proved to compensate for the synthesis of 4 with 2 in some respects. The reactivities of 2, 5, and 6 as electrophiles were also evaluated by comparing their reduction potential with those of acid chlorides.
- Maeda, Hatsuo,Takahashi, Kenji,Ohmori, Hidenobu
-
p. 12233 - 12242
(2007/10/03)
-
- A simple synthesis of 1-aminophosphonic acids from 1-hydroxyiminophosphonates with NaBH4 in the presence of transition metal compounds
-
A new procedure has been developed for the synthesis of 1-aminophosphonic acids. Diethyl phosphonates are converted to hydroxyiminophosphonates when treated with hydroxylamine hydrochloride. Reduction of hydroiminophosphonates with NaBH4 in MeOH in the presence of MoO3 or NiCl2 and hydrolysis of 1-aminophosphonates gave 1-aminophosphonic acids in good yields.
- Demir, Ayhan S.,Tanyeli, Cihangir,Sesenoglu, Oezge,Demic, Serafettin,Evin, Oezden Oezel
-
p. 407 - 410
(2007/10/02)
-
- Asymmetric Synthesis of Chiral, Nonracemic Dialkyl α-Hydroxyarylmethyl- and α-, β- and γ-Hydroxyalkylphosphonates from Keto Phosphonates
-
The enantioselective synthesis of α-hydroxyarylmethylphosphonates 2a-p by the oxazaborolidine-catalyzed reduction of α-keto phosphonates 1a-p using different boranes 4a-c was studied in detail.Moderate to good enantioselectivities are found (up to 80perce
- Meier, Chris,Laux, Wolfgang H. G.,Bats, Jan W.
-
p. 1963 - 1980
(2007/10/03)
-
- The Schmidt reaction of dialkyl acylphosphonates
-
The scope of the Schmidt rearrangement of ketones has been extended to dialkyl acylphosphonates (11a-11l). Surprisingly, it was found that 11a-11d and 11g, in which the acyl moiety was benzoyl alone or benzoyl bearing an electron-attracting or mildly electron-releasing substituent, yielded an overwhelming portion of products resulting from C-to-N migration of the aryl group (N-arylcarbamoylphosphonates, 12, and N-arylformamides, 15). Contrariwise, the arenecarbonylphosphonates, which carry a powerful electron-releasing p-alkoxy group, yielded products resulting from phosphonate group migration from C to N or elimination (dialkyl N-arenecarbonylphosphoramidates, 13, and arenecarbonitriles, 17, respectively). These counterintuitive results are rationalized by application of the concept of "degree of electron demand" to this area of intramolecular rearrangements. The possible existence of an additional pathway for the Schmidt rearrangement, involving protonation of the iminodiazonium ion, is proposed.
- Sprecher, Milon,Kost, Daniel
-
p. 1016 - 1026
(2007/10/02)
-
- REACTIONS OF 2-SUBSTITUTED 1,3,2-OXATHIAPHOSPHOLENES WITH ACYL HALIDES
-
2-Substituted 1,3,2-oxathiaphospholenes react with acyl halides with opening of the endocyclic P-S bond and formation of vinyl phosphites, subsequent transformations of which yield 2-halo-1,3,2-oxathiaphospholenes, vinyl ketophosphonates, and diethyl benz
- Burilov, A. R.,Nikolaeva, I. L.,Pudovik, M. A.
-
p. 688 - 690
(2007/10/02)
-
- SYNTHESIS AND PROPERTIES OF β-FUNCTIONALIZED VINYL PHOSPHITES
-
By phosphorylating (acylthio)acetones with dialkyl phosphorochloridites, the corresponding vinyl phosphites were synthesized and some their properties, e.g., sulfonation and reactions with chloral and acyl halides, were studied. (Acylthio)acetones react w
- Burilov, A. R.,Nikolaeva, I. L.,Pudovik, M. A.
-
p. 542 - 545
(2007/10/02)
-
- Studies on organophosphorus compounds; LXXV: A facile synthesis of 1-(hydroxyamino)alkyl(or aryl)phosphonic acids
-
Reduction of dialkyl 1-(hydroxyimino)alkyl(aryl)phosphonate 1 with borane-pyridine complex proceeds smoothly to give dialkyl 1-(hydroxyamino)alkyl(or aryl)phosphonate 2 which is then easily converted into the corresponding hydroxyaminophosphonic acid 3 by
- Yuan,Chen,Zhou,Maier
-
p. 955 - 957
(2007/10/02)
-
- 31P Hyperfine Interaction in a New Type of Phosphorus-Containing Iminoxy Free Radicals. An ESR Study
-
Iminoxy radicals of a new type, having the general formula RC(=NO.)P(O)(OEt)2, were synthesized and characterized by means of ESR spectroscopy.The presence of two isomers due to the different position of the C=NO. fragment with respe
- Siatecki, Zdzislaw,Chmielewski, Piotr J.,Jezierski, Adam
-
p. 163 - 168
(2007/10/02)
-
- Sulphonic Acid-induced Fragmentation of Dialkyl Acylphosphonates, Formation of Alkyl Carboxylates and Alkyl Sulphonates
-
Heating of dialkyl acylphosphonates with sulphonic acids under anhydrous conditions leads to the formation of alkyl sulphonates and alkyl carboxylates. 31P N.m.r. spectroscopy revealed that the reaction of equimolar amounts of dimethyl benzoylphosphonate (1) and toluene-p-sulphonic acid at room temperature gives dimethyl phosphonate (6) in 50percent yield.It is proposed that the by-product of this reaction, benzoic toluene-p-sulphonic anhydride (8), reacts with the excess of toluene-p-sulphonic acid, to yield toluene-p-sulphonic anhydride (9) and benzoic acid.Heating of these two compounds with dimethyl phosphonate was shown to yield methyl toluene-p-sulphonate and methyl benzoate, respectively.A postulated by-product of these reactions is phosphenous acid (HPO2).Quantum mechanical calculations by the MNDO/H method carried out on dimethyl benzoylphosphonate and its protonation products show that the preferred site of protonation of dimethyl benzoylphosphonate is the P=O oxygen, and that protonation at this site is followed by C-P bond breaking, with zero energy of activation, leading to dimethyl phosphite and benzoylium cation.
- Breuer, Eli,Karaman, Rafik,Goldblum, Amiram,Leader, Haim
-
p. 2029 - 2034
(2007/10/02)
-
- α-OXYIMINOPHOSPHONATES: CHEMICAL AND PHYSICAL PROPERTIES. REACTIONS, THEORETICAL CALCULATIONS, AND X-RAY CRYSTAL STRUCTURES OF (E) AND (Z)-DIMETHYL α-HYDROXYIMINOBENZYLPHOSPHONATES
-
Dialkyl α-oxyiminoalkylphosphonates, obtained by treatment of dialkyl acylphosphonates with hydroxylamine or methoxylamine, are mostly mixtures of E and Z isomers.Structural assignments of the oximes were based on X-ray crystallographic analysis of representative compounds: (E)- and (Z)-dimethyl α-hydroxyiminobenzylphosphonates .The (31)P n.m.r. chemical shifts of the E isomers always appear at lower field than those of the corresponding Z isomers.Thermal fragmentation of (1a) affords benzonitrile and dimethyl hydrogen phosphate, with (Z)-(1a) reacting faster than the E isomer. α-Oxyiminophosphonates undergo EZ isomerisation catalysed either by acid or by base under certain conditions, the E isomer being the thermodinamically more stable one.An E + Z mixture of dialkyl α-oxyiminophosphonates can be mono-de-alkylated by non-basic nucleophiles (e.g.NaI) to afford monoalkyl oxyiminophosphonates of unchanged isomeric composition.The geometrical isomers of α-hydroxyiminophosphonates differ in their behaviour under basic conditions.While treatment of (E)-(1a) with NaOH in boiling methanol leads, by mono-de-alkylation, to sodium methyl α-hydroxyiminobenzylphosphonate , under the same conditions (Z)-(1a) undergoes fragmentation, by C-P bond cleavage, to benzonitrile and dimethyl hydrogen phosphate.Control experiments established that the fragmentation of (Z)-α-hydroxyiminophosphonates involves an intramolecular attack on the phosphorous atom by the ionized Z oriented oxime oxygen.Similar differences in behaviour are noted between the isomers of the monoanions of α-hydroxyiminophosphonates.MNDO/H Calculations demonstrate the feasibility of forming internal hydrogen bonds in Z isomers, and their possible contribution to conformational preferences.Single-crystal X-ray diffraction studies of (E)- and (Z)-(1a), and (E)-(2b), clearly identified the geometric isomers and correlated them with (1H) and (31)P n.m.r. resonances.
- Breuer,Eli,Karaman, Rafik,Goldblum, Amiram,Gibson, Dan,Leader, Haim,et. al.
-
p. 3047 - 3058
(2007/10/02)
-
- Chelation
-
Hydroxymethane diphosphonic acid and alkali metal or ammonium salt of such acid are prepared. They are useful in detergent compositions and in sequestering and chelating polyvalent metals.
- -
-
-
- EXPERIMENTAL TESTS OF THE STEREOELECTRONIC EFFECT AT PHOSPHORUS: MICHAELIS-ARBUSOV REACTIVITY OF PHOSPHITE ESTERS.
-
Whereas triethyl phosphite readily reacts with benzoyl chloride to yield the Michaelis-Arbusov product, diethyl benzoyl phosphonate, 1-methyl-4-phospha-3,5,8-trioxabicyclooctane, 1, is essentially unreactive, even at a higher temperature.The bicyclic phosphite 1 also reacts slower than the triethyl phosphite 2 in an oxidation with t-butyl hydroperoxide.These results are interpreted in terms of the stereoelectronic effect.
- Taira, Kazunari,Gorenstein, David G.
-
p. 3215 - 3222
(2007/10/02)
-
- Acylphosphonates: P-C Bond Cleavage of Dialkyl Acylphosphonates by Means of Amines. Substituent and Solvent Effects for Acylation of Amines
-
Studies on the benzoylation of amines of dialkyl benzoylphosphonates (1A-F) were described in detail. Stoichiometric reactions of diethyl benzoylphosphonate (1B) with a variety of amines (2a-i) gave amides as the main products along with diethyl phosphonate (4B) and α-(phosphoryloxy)benzyl phosphonate (5B). The yields of amides increased with the ratio of 1B/2a-i. The use of hindered dialkyl benzoylphosphonates resulted in high yields of amides while the reaction rates decreased markedly. The benzoylations of n-propylamine (2d) with 1B in various solvents having dielectric constants of 1.9-36.7 were conducted. The yields of N-n-propylbenzamide (3d) and 5B were surprisingly almost constant. However, the reaction rates varied as follows. In nonpolar solvents such as n-hexane and cyclohexane benzoylation was remarkably rapid while the benzoylation in methylene chloride was much slower than that in other solvents used. Compound 1B underwent smooth reaction with aliphatic amines but did not react with aromatic amines under the same conditions. Selective N-benzoylation of the bifunctional amine, ethanolamine, was achieved by means of diisopropyl benzoylphosphonate (1C) in tetrahydrofuran. The use of the hindered dialkyl benzoylphosphonate 1C resulted in poorer yields of amides in the case of the reaction with a hindered amine such as diethylamine, but higher yields of amides in the case of primary amines. Addition of triethylamine and 4-(dimethylamino)pyridine (DMAP) slightly accelerated the benzoylation, but yields of amides were similar to those in the absence of the catalysts. Optimum conditions for high yields of amides were proposed for the practical use of dialkyl benzoylphosphonates as the acylating agents in the present reaction.
- Sekine, Mitsuo,Satoh, Masaki,Yamagata, Hikaru,Hata, Tsujiaki
-
p. 4162 - 4167
(2007/10/02)
-