- 2D Ultrafast HMBC 1H,31P: Obtaining mechanistic details on the Michaelis-Arbuzov reaction
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Ultrafast NMR spectroscopy (UF-NMR) can be used to monitor chemical reactions in real time and to provide insights into their mechanisms and the nature of the intermediates formed. Here, we have developed a 2D 1H,31P UF-HMBC method and the corresponding NMR experimental setup to enable the study of a Michaelis-Arbuzov reaction at two different temperatures, 25 and 70 °C. The specific reaction studied was between triethyl phosphite and benzyl bromide to produce diethylbenzyl phosphonate. Our results show that at 70 °C the reaction takes place directly, without the detection of an intermediate by 1H,31P UF-HMBC. In contrast, at 25 °C, using zinc bromide as a catalyst, our results show the formation of benzyltriethoxy phosphonium bromide as an intermediate. The experiments again show the power of UF-NMR in mechanistic studies of reactions involving various phosphorus chemical species.
- Fernández-Valle, María Encarnación,Martínez-álvarez, Roberto,Molero-Vílchez, Dolores,Pardo, Zulay D.,Sáez-Barajas, Elena,Herrera, Antonio
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- Pseudodimeric Complexes of an (18-Crown-6)stilbene with Styryl Dyes Containing an Ammonioalkyl Group: Synthesis, Structure, and Stereospecific [2 + 2] Cross-Photocycloaddition
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A new efficient method was proposed for the synthesis of (18-crown-6)stilbene; the structure of the product was confirmed by X-ray diffraction analysis. In MeCN, this compound forms pseudodimeric complexes with N-(2-ammonioethyl)-4-styrylpyridinium and N-(3-ammoniopropyl)-4-styrylpyridinium diperchlorates via hydrogen bonding between the ammonium group and the crown ether oxygen atoms. The ammonioethyl derivative was synthesized for the first time. The stability constants and spectral characteristics of the complexes were measured by spectrophotometric and fluorescence titration. Photoirradiation of the pseudodimeric complex of (18-crown-6)stilbene with the ammoniopropyl dye resulted in the stereospecific [2 + 2] cross-photocycloaddition reaction. The replacement of the stilbene moiety in the crown compound by a styrylpyridine moiety led to a 5-fold increase in the quantum yield of the photoprocess. The most probable cause for this effect is the presence of photoinduced electron transfer in (18-crown-6)stilbene complexes. This assumption is confirmed by fluorescence lifetime spectroscopy and density functional theory calculations.
- Martyanov, Timofey P.,Ushakov, Evgeny N.,Nuriev, Vyacheslav N.,Aleksandrova, Nadezhda A.,Sazonov, Sergey K.,Vedernikov, Artem I.,Kuz'mina, Lyudmila G.,Klimenko, Lubov S.,Martyanova, Elena G.,Gromov, Sergey P.
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- Lanthanoid-metal-mediated reaction of acylphosphonates: evidence for the formation of an acyllanthanoid complex
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The reactions of diethyl acylphosphonates (1a-e) with Yb and Sm were examined.Reactivities of Yb to 1a-e are different from those of Li and Na.Typically, ethyl benzoylphosphonate (1a) reacts with Yb metal in tetrahydrofuran-hexamethylphosphoramide to afford diethyl 1,2-diphenyl-2-oxoethyl phosphate (2a) and diethyl 1-(diethyl-phosphoryloxy)-1-phenylmethylphosphonate (3a) The formations of 2a and 3a were explained best by the formation of acylytterbium complexes.Keywords: Ytterbium; Samarium; Acylphosphonate; Phosphorus
- Taniguchi, Yuki,Fujii, Nobuto,Takaki, Ken,Fujiwara, Yuzo
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- Crystal structures of the apo form and a complex of human LMW-PTP with a phosphonic acid provide new evidence of a secondary site potentially related to the anchorage of natural substrates
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Low molecular weight protein tyrosine phosphatases (LMW-PTP, EC 3.1.3.48) are a family of single-domain enzymes with molecular weight up to 18 kDa, expressed in different tissues and considered attractive pharmacological targets for cancer chemotherapy. Despite this, few LMW-PTP inhibitors have been described to date, and the structural information on LMW-PTP druggable binding sites is scarce. In this study, a small series of phosphonic acids were designed based on a new crystallographic structure of LMW-PTP complexed with benzylsulfonic acid, determined at 2.1 ?. In silico docking was used as a tool to interpret the structural and enzyme kinetics data, as well as to design new analogs. From the synthesized series, two compounds were found to act as competitive inhibitors, with inhibition constants of 0.124 and 0.047 mM. We also report the 2.4 ? structure of another complex in which LMW-PTP is bound to benzylphosphonic acid, and a structure of apo LMW-PTP determined at 2.3 ? resolution. Although no appreciable conformation changes were observed, in the latter structures, amino acid residues from an expression tag were found bound to a hydrophobic region at the protein surface. This regions is neighbored by positively charged residues, adjacent to the active site pocket, suggesting that this region might be not a mere artefact of crystal contacts but an indication of a possible anchoring region for the natural substrate - which is a phosphorylated protein.
- Fonseca, Emanuella M.B.,Trivella, Daniela B.B.,Scorsato, Valéria,Dias, Mariana P.,Bazzo, Natália L.,Mandapati, Kishore R.,De Oliveira, Fábio L.,Ferreira-Halder, Carmen V.,Pilli, Ronaldo A.,Miranda, Paulo C.M.L.,Aparicio, Ricardo
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- Rapid and efficient Arbuzov reaction under microwave irradiation
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Diethyl alkylphosphonates are efficiently and rapidly prepared in good yields (75-99%) from trialkylphosphates and alkyl halides under short microwaves irradiations.
- Villemin, Didier,Simeon, Fabrice,Decreus, Hugues,Jaffres, Paul-Alain
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- SIMPLE CONVERSION OF ARYL BROMIDES TO ARYLMETHYLPHOSPHONATES
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Aryl bromides in tetrahydrofuran when combined with t-butyllithium and then with cuprous iodide and diethyl chloromethylphosphonate give diethyl arylmethylphosphonates.
- Poindexter, Michael K.,Katz, Thomas J.
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- The photoisomerization of: Cis, trans -1,2-dideuterio-1,4-diphenyl-1,3-butadiene in solution. No bicycle-pedal
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cis,trans-1,2-Dideuterio-1,4-diphenyl-1,3-butadiene (ct-DPBd2) was synthesized and its cis-trans photoisomerization in cyclohexane-d12 (C6D12) at room temperature was monitored by 1H NMR spectroscopy. The results reveal formation of only trans,trans-1,2-dideuterio-1,4-diphenyl-1,3-butadiene (tt-DPBd2). The failure to detect formation of trans,cis-1,2-dideuterio-1,4-diphenyl-1,3-butadiene (tc-DPBd2) eliminates the possibility that an identity bicycle pedal process contributes to inefficiency in the cis-trans photoisomerization of cis,trans-1,4-diphenyl-1,3-butadiene (ct-DPB).
- Saltiel, Jack,Redwood, Christopher E.,Ratheesh Kumar
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- Palladium-catalyzed cross-coupling reactions of organocopper derivatives of methylphosphonic esters and amides with aryl and hetaryl iodides
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Copper derivatives of methylphosphonic amides are sufficiently stable thermally and can be used in palladium-catalyzed arylation reactions resulting in synthesis of previously unknown aryl- and hetaryl-methylphosphonic tetramethyldiamides in high yields.
- Lukashev,Tarasenko,Beletskaya
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- Synthesis, UV/vis spectra and electrochemical characterisation of arylthio and styryl substituted ferrocenes
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Two series of substituted ferrocenes were synthesised using either the Horner-Wadswor th-Emmons reaction or monolithiation of ferrocene. The series consist of arylthio- and styryl-ferrocenes with different substituents in the para position of the aryl rings of the systems. The electronic communication was investigated by comparing the substituent effects in absorption spectroscopy and in cyclic voltammetry. A small substituent effect was found in the electronic transitions of the styryl substituted ferrocenes. The oxidation of the ferrocene derivatives showed clear substituent effects as illustrated by the linear Hammett plots. The effect was shown to be an order of magnitude larger in the arylthio-systems than in the styryl systems. It is suggested that the reason behind the large effect is a direct sulfur-iron orbital overlap. Versita Sp. z o.o.
- Sorensen, Thomas J.,Nielsen, Merete F.
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- Acetic acid mediated synthesis of phosphonate-substituted titanium oxo clusters
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New phosphonate/acetate-substituted titanium oxo/alkoxo clusters were prepared from Ti(OiPr)4 and bis(trimethylsilyl) phosphonates in the presence of acetic acid, which served to generate water in situ through ester formation. The process led to clusters with a higher degree of condensation than in previously known phosphonate-substituted titanium oxo clusters. The clusters [Ti6O4(OiPr)10(OAc)2(O 3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions. This cluster type, which is also retained in solution, therefore appears to be very robust. Two other clusters, [Ti5O(OiPr)11(OAc)(O 3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O 3P-xylyl)2], were only isolated in special cases. Several acetate/phosphonate-substituted titanium cage compounds were obtained from the reaction of titanium isopropoxide with bis(trimethylsilyl) phosphonates in the presence of acetic acid as water generator.
- Czakler, Matthias,Artner, Christine,Schubert, Ulrich
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- White light emission in water through admixtures of donor-π-acceptor siblings: Experiment and simulation
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Donor-acceptor π-conjugated molecules with triphenylamine donor and different acceptor (H, cyano, and pyridinium) units with a double bond spacer were synthesized. These compounds exhibit bathochromic shifts in absorption and emission with an increase in the acceptor strength. Solvatochromic measurements in water reveal emitting states characterized by a polar nature with three distinct emission spectral regions from blue to red. Interestingly, binary mixtures of the stilbenes in acetonitrile and water gave white light emission. MD simulations of the admixtures reveal that the emission data directly correlate to the structural arrangements of the molecules driven by intermolecular and solvent interactions with micelle-like structural arrangements for one set and uniform homogenous mixing for the other two sets. Such a tunable emission strategy using simple structural siblings could offer great potential towards designing novel emitting systems.
- Kumari, Beena,Singh, Amit,Jana, Palash,Radhakrishna, Mithun,Kanvah, Sriram
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- Surface-mediated solid phase reactions: Microwave assisted Arbuzov rearrangement on the solid surface
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Microwave assisted Arbuzov rearrangement under solvent-free condition was found to be an efficient method for the preparation of dialkyl alkylphosphonates of alkyl halides. This method is an easy, rapid, and high-yielding reaction for the Arbuzov rearrangement.
- Kaboudin,Balakrishna
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- Copper-catalyzed synthesis of alkylphosphonates from H-phosphonates and N-tosylhydrazones
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A new catalytic system for the alkylation of H-phosphonates and diphenylphosphine oxide with N-tosylhydrazones has been developed. In the presence of copper(I) iodide and base, H-phosphonates react with N-tosylhydrazones to afford the corresponding coupled alkylphosphonates in good to excellent yields without any ligands. Alkylphosphonates can also be prepared in a one-pot process directly from carbonyl compounds without the isolation of tosylhydrazone intermediates.
- Miao, Wenjun,Gao, Yuzhen,Li, Xueqin,Gao, Yuxing,Tang, Guo,Zhao, Yufen
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- Photophysical studies of substituted 1,2-diarylethenes: Twisted intramolecular charge transfer fluorescence in dimethoxycyano-substituted 1,2-diarylethene
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1,2-Diarylethenes, namely (E)-1-(4-cyanophenyl)-2-phenylethene (1), (E)-1-(4-methoxyphenyl)-2-phenylethene (2), (E)-1-(3,4-dimethoxyphenyl)-2-phenylethene (3), (E)-1-(4-cyanophenyl)-2-(4-methoxyphenyl)ethene (4) and (E)-1-(4-cyanophenyl)-2-(3,4-dimethoxyphenyl)ethene (5), have been synthesized and their absorption and fluorescence properties at room temperature in different organic solvents and also in 1,4-dioxane-water binary mixtures have been investigated. Additionally, the fluorescence of these compounds has been examined at 77 K in an ethanol-methanol (1:1 v/v) matrix. Photophysical parameters like absorption, excitation and fluorescence spectra, fluorescence quantum yields, excited state dipole moment changes, and correlation of solvatochromic fluorescence with solvent parameters like ET(30)-values and the π*-scale have been made. Compound 5, with one cyano and two methoxy substituents, has been found to exhibit solvent polarity-dependent dual fluorescence. The shorter wavelength fluorescence is attributed to an initially excited delocalized planar state, while the longer wavelength t fluorescence is attributed to a non-planar twisted intramolecular charge transfer excited state.
- Singh, Anil K.,Kanvah, Sriram
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- Two trans-1-(9-anthryl)-2-phenylethene derivatives as blue-green emitting materials for highly bright organic light-emitting diodes application
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1-(9-Anthryl)-2-phenylethene (t-APE) is a blue-green material with high fluorescence quantum yield (Фf 0.44). However, it is easily crystallized. Herein, Two asymmetric blue-green emitting materials based on t-APE, (E)-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-1-yl)anthracene (6) and (E)-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-2-yl)anthracene (7) were firstly designed and synthesized. The two compounds possess high thermal stability, morphological durability, and bipolar characteristics. The non-doped blue-green organic light-emitting diodes (OLEDs) using 6 and 7 as emitting layers showed emission at 495 nm, full width at half maximum of 80 nm, maximum brightness of 13,814, 10,579 cd m?2, maximum current efficiency of 3.62, 7.16 cd A?1, and Commission Internationale de L'Eclairage (CIE) coordinate of (0.20, 0.43), respectively. Furthermore, when employing 6 and 7 as blue-green emitting layers and rubrene doped in tris-(8-hydroxyquinolinato)aluminum (Alq3) as the orange emitting layers to fabricate white OLEDs (WOLEDs), the WOLEDs exhibit a maximum brightness of 10,984, 14,652 cd m?2, maximum current efficiency of 2.04, 2.70 cd A?1, and CIE coordinate of (0.30, 0.40), (0.37, 0.47), Color Rendering Index (CRI) of 65, 60, stable EL spectra, respectively. This study demonstrates that the t-APE-type derivatives have the excellent properties for the emitting materials of OLEDs.
- Zhou, Nonglin,Shao, Xiaona,Wang, Shirong,Xiao, Yin,Li, Xianggao
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- Photochemical Radical C–H Halogenation of Benzyl N-Methyliminodiacetyl (MIDA) Boronates: Synthesis of α-Functionalized Alkyl Boronates
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α-Haloboronates are useful organic synthons that can be converted to a diverse array of α-substituted alkyl borons. Methods to α-haloboronates are limiting and often suffer from harsh reaction conditions. Reported herein is a photochemical radical C-H halogenation of benzyl N-methyliminodiacetyl (MIDA) boronates. Fluorination, chlorination, and bromination reactions were effective by using this protocol. Upon reaction with different nucleophiles, the C?Br bond in the brominated product could be readily transformed to a series of C?C, C?O, C?N, C?S, C?P, and C?I bonds, some of which are difficult to forge with α-halo sp2-B boronate esters. An activation effect of B(MIDA) moiety was found.
- Yang, Ling,Tan, Dong-Hang,Fan, Wen-Xin,Liu, Xu-Ge,Wu, Jia-Qiang,Huang, Zhi-Shu,Li, Qingjiang,Wang, Honggen
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- Lewis acid catalyzed room-temperature Michaelis-Arbuzov rearrangement
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The taming of the shrew! For the first time, a broadly applicable efficient room-temperature Arbuzov rearrangement is described. This reaction is accomplished through an atom-economical Lewis acid catalyzed process (see scheme, TMSOTf=trimethylsilyl trifluoromethane-sulfonate). The method has been generalized to primary and activated secondary phosphites, phosphinites, and phosphonites.
- Renard, Pierre-Yves,Vayron, Philippe,Leclerc, Eric,Valleix, Alain,Mioskowski, Charles
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- Microwave irradiation in organophosphorus chemistry. III. Moderate scale synthesis of reagents for olefin formation
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Representative phosphonates and phosphonium salts have been prepared on a moderate scale (25-50 g) using a domestic microwave oven. The reactions, conducted in sealed hydrogenation vessels, showed remarkable rate acceleration and excellent yields (>95%) employing this methodology.
- Kiddle
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- Advantages of organophosphorus synthesis in ionic liquids: "Green" approaches to useful phosphorus-substituted building blocks
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Novel examples concerning the application of ionic liquids as a promoting reaction media in organophosphorus chemistry are discussed. Imidazolium ionic liquids were found to accelerate the Michaelis-Arbuzov reaction allowing to perform it under very mild conditions. Both phosphonium and imidazolium ILs give the possibility to perform easily direct amidation of phosphoryl acetic acids by various amines. Nucleophilic displacement reactionin a series of bromoalkylphosphonates was carried out in quantitative yield to afford azidoalkylphosphonates using the [bmim][PF6]/H2O system. Copyright Taylor & Francis Group, LLC.
- Odinets,Matveeva,Sharova,Artyushin,Kozlov,Vorob'eva,Osipov,Roeschenthaler
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- Palladium-catalyzed copper(I) salt-mediated arylation of a bis(dimethylamino)phosphonyl-stabilized carbanion
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The synthesis of new arylmethylphosphonic acid tetramethyl diamides by a palladium-catalyzed cross-coupling reaction of a bis(dimethylamino)phosphonylmethylcopper(I) reagent with aryl iodides is described. (C) 2000 Elsevier Science Ltd.
- Tarasenko, Elena A.,Lukashev, Nikolai V.,Beletskaya, Irina P.
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- Color tuning of doped PLEDs by energy transfer from PVK to dopant constituted with biphenyl and butadienyl unit
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A dopant, 4,4'-bis(dimethyl[4-(2-phenyl-buta-1,3-dienyl)phenyl]amine) biphenyl (BPAB), was synthesized, and single layered polymer light emitting diode (PLED)s, ITO/Host:Dopant/Al, were fabricated with blends of poly(vinyl carbazole) (PVK) as host and BPAB as dopant. The electroluminescence (EL) was observed in doped PLEDs. From the EL and photoluminescence (PL) spectra, the existence of energy transfer from host to dopant was verified. With increasing content of dopant (BPAB), blue emission originated from PVK reduced, but didn't completely disappear, suggesting inefficient energy transfer from PVK to BPAB. When the content of BPAB was 15 wt%, yellow green emission from PLED was observed due to partial energy transfer from PVK to BPAB.
- Han, Yoon Soo,Kim, Hoyoung,Choi, Byeong Dae,Kwon, Younghwan,Hur, Youngjune,Kwak, Giseop,Kim, Soon Hak,Park, Lee Soon,Choi, Byeong-Dae
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- Ionic-liquid-promoted Michaelis-Arbuzov rearrangement
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Room-temperature imidazolium ionic liquids, [Rmim][X], proved to be environmentally benign recyclable solvents promoting the Michaelis-Arbuzov rearrangement, which can be performed even at room temperature in a short period of time. The best ionic liquid of choice depended on the starting phosphorus(III) ester, namely, for triethyl phosphite [bmim][NTf2] demonstrated better results while for ethyl diphenylphosphinite it was [hmim][Br].
- Matveeva,Odinets,Kozlov,Shaplov,Mastryukova
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- Identification of novel non-nucleoside vinyl-stilbene analogs as potent norovirus replication inhibitors with a potential host-targeting mechanism
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Norovirus (NV), is the most common cause of acute gastroenteritis worldwide. To date, there is no specific anti-NV drug or vaccine to treat NV infections. In this study, we evaluated the inhibitory effect of different stilbene-based analogs on RNA genome replication of human NV (HNV) using a virus replicon-bearing cell line (HG23). Initial screening of our in-house chemical library against NV led to the identification of a hit containing stilbene scaffold 5 which on initial optimization gave us a vinyl stilbene compound 16c (EC50 = 4.4 μM). Herein we report our structure-activity relationship study of the novel series of vinyl stilbene analogs that inhibits viral RNA genome replication in a human NV-specific manner. Among these newly synthesized compounds, several amide derivatives of vinyl stilbenes exhibited potent anti-NV activity with EC50 values ranging from 1 to 2 μM. A trans-vinyl stilbenoid with an appended substituted piperazine amide (18k), exhibited potent anti-NV activity and also displayed favorable metabolic stability. Compound 18k demonstrated an excellent safety profile, the highest suppressive effect, and was selective for HNV replication via a viral RNA polymerase-independent manner. Its potential host-targeting antiviral mechanism was further supported by specific activation of heat shock factor 1-dependent stress-inducible pathway by 18k. These results suggest that 18k might be a promising lead compound for developing novel NV inhibitors with the novel antiviral mechanism.
- Harmalkar, Dipesh S.,Lee, Sung-Jin,Lu, Qili,Kim, Mi Il,Park, Jaehyung,Lee, Hwayoung,Park, Minkyung,Lee, Ahrim,Lee, Choongho,Lee, Kyeong
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- Determination and application of the excited-state substituent constants of pyridyl and substituted phenyl groups
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Thirty six 1-pyridyl-2-arylethenes XCH=CHArY (abbreviated XAEY) were synthesized, in which, X is 2-pyridyl, 3-pyridyl and 4-pyridyl and Y is OMe, Me, H, Br, Cl, F, CF3, and CN. Their ultraviolet absorption spectra were measured in anhydrous ethanol, and their wavelengths of absorption maximum λmax were recorded. Also, the 234 λmax values of 1-substituted phenyl-2-arylethylene compounds (XAEY, where X is substituted phenyl) were collected. The excited-state substituent constants (Formula presented.) of three pyridyl groups and 23 substituted phenyl groups (total of 26) were obtained by means of curve-fitting method. Taking the λmax values of 358 samples of bi-arylethene derivatives as a data set and 126 samples of bi-aryl Schiff bases (including nine compounds synthesized by this work) as another data set, quantitative correlation analyses were performed by employing the obtained (Formula presented.) as a parameter, and good results were obtained for the two data sets. The reliability of the obtained (Formula presented.) values was verified. The results of this paper can provide excited-state substituent constants for the study and application of optical properties of conjugated organic compounds containing aryl groups.
- Cao, Chao-Tun,Yan, Lu,Cao, Chenzhong
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- Vinyl-Stilbene Compounds and Uses Thereof
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The present invention relates to a biphenyl - stilbene (Vinyl-stilbene) - based compound and a pharmaceutical composition for preventing or treating norovirus infection comprising the same as an active ingredient. The present invention can be usefully used as a pharmaceutical composition for treating norovirus infection by showing superior norovirus inhibitory activity and lower cell toxicity as compared to previously known compounds.
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Paragraph 0255-0262
(2021/06/22)
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- Selective esterification of phosphonic acids
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Here, we report straightforward and selective synthetic procedures for mono-and diesteri-fication of phosphonic acids. A series of alkoxy group donors were studied and triethyl orthoacetate was found to be the best reagent as well as a solvent for the performed transformations. An important temperature effect on the reaction course was discovered. Depending on the reaction temperature, mono-or diethyl esters of phosphonic acid were obtained exclusively with decent yields. The sub-strate scope of the proposed methodology was verified on aromatic as well as aliphatic phosphonic acids. The designed method can be successfully applied for small-and large-scale experiments without significant loss of selectivity or reaction yield. Several devoted experiments were performed to give insight into the reaction mechanism. At 30?C, monoesters are formed via an intermediate (1,1-diethoxyethyl ester of phosphonic acid). At higher temperatures, similar intermediate forms give diesters or stable and detectable pyrophosphonates which were also consumed to give diesters.31P NMR spectroscopy was used to assign the structure of pyrophosphonate as well as to monitor the reaction course. No need for additional reagents and good accessibility and straightforward purification are the important aspects of the developed protocols.
- Brodzka, Anna,Koszelewski, Dominik,Ostaszewski, Ryszard,Trzepizur, Damian
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supporting information
(2021/09/27)
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- Visible-light-mediated phosphonylation reaction: formation of phosphonates from alkyl/arylhydrazines and trialkylphosphites using zinc phthalocyanine
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In this work, we developed a ligand- and base-free visible-light-mediated protocol for the photoredox syntheses of arylphosphonates and, for the first time, alkyl phosphonates. Zinc phthalocyanine-photocatalyzed Csp2-P and Csp3-P bond formations were efficiently achieved by reacting aryl/alkylhydrazines with trialkylphosphites in the presence of air serving as an abundant oxidant. The reaction conditions tolerated a wide variety of functional groups.
- Hosseini-Sarvari, Mona,Koohgard, Mehdi
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p. 5905 - 5911
(2021/07/12)
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- Selective hydrolysis of phosphorus(v) compounds to form organophosphorus monoacids
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An azide and transition metal-free method for the synthesis of elusive phosphonic, phosphinic, and phosphoric monoacids has been developed. Inert pentavalent P(v)-compounds (phosphonate, phosphinate, and phosphate) are activated by triflate anhydride (Tf2O)/pyridine system to form a highly reactive phosphoryl pyridinium intermediate that undergoes nucleophilic substitution with H2O to selectively deprotect one alkoxy group and form organophosphorus monoacids.
- Ash, Jeffrey,Cordero, Paula,Huang, Hai,Kang, Jun Yong
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p. 6007 - 6014
(2021/07/21)
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- Palladium-catalyzed phosphorylation of benzyl ammonium triflates with P(O)H compounds
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A palladium-catalyzed phosphorylation of benzyl ammonium triflates with P(O)H compounds has been developed. Various benzylphosphorus compounds were produced in good to excellent yields with high functional group tolerance. All the three kinds of hydrogen phosphoryl compounds, i.e. H-phosphonates, H-phosphinates and secondary phosphine oxides, were applicable to this reaction. The successful scale-up experiment and one-pot synthetic operation also well demonstrated its practicality.
- Chen, Tieqiao,Huang, Tianzeng,Liu, Long,Wang, Wenqi,Wang, Yuan,Xu, Hanshuang,Xu, Kaiqiang
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- Developing glutathione-activated catechol-type diphenylpolyenes as small molecule-based and mitochondria-targeted prooxidative anticancer theranostic prodrugs
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Developing concise theranostic prodrugs is highly desirable for personalized and precision cancer therapy. Herein we used the glutathione (GSH)-mediated conversion of 2,4-dinitrobenzenesulfonates to phenols to protect a catechol moiety and developed stable pro-catechol-type diphenylpolyenes as small molecule-based prooxidative anticancer theranostic prodrugs. These molecules were synthesized via a modular route allowing creation of various pro-catechol-type diphenylpolyenes. As a typical representative, PDHH demonstrated three unique advantages: (1) capable of exploiting increased levels of GSH in cancer cells to in situ release a catechol moiety followed by its in situ oxidation to o-quinone, leading to preferential redox imbalance (including generation of H2O2 and depletion of GSH) and final selective killing of cancer cells over normal cells, and is also superior to 5-fluorouracil and doxorubicin, the widely used chemotherapy drugs, in terms of its ability to kill preferentially human colon cancer SW620 cells (IC50 = 4.3 μM) over human normal liver L02 cells (IC50 = 42.3 μM) with a favourable in vitro selectivity index of 9.8; (2) permitting a turn-on fluorescent monitoring for its release, targeting mitochondria and therapeutic efficacy without the need of introducing additional fluorophores after its activation by GSH in cancer cells; (3) efficiently targeting mitochondria without the need of introducing additional mitochondria-directed groups.
- Bao, Xia-Zhen,Dai, Fang,Wang, Qi,Jin, Xiao-Ling,Zhou, Bo
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p. 406 - 418
(2019/02/06)
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- Preparation method of aryl methyl phosphine acylate
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The invention discloses a preparation method of aryl methyl phosphine acylate. The method uses (hetero) aryl acetic acid as the starting material, and the raw materials are easily available and have agreat variety. The product obtained by the method provided by the invention has various types and wide uses. The aryl methyl phosphine acylate can be easily converted into a bis (hetero)arylethene derivative, and the compound can be used for preparation of dyes, fluorescent agents, whiteners, light-emitting diodes and other devices. In addition, the method disclosed by the invention has the advantages of easily available, stable and low toxicity raw materials, mild reaction conditions, high yield of target product, low pollution, simple reaction operation and post-treatment process, and is suitable for industrial production.
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Paragraph 0037
(2019/10/01)
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- Transition metal-free access to 3,4-dihydro-1,2-oxaphosphinine-2-oxides from phosphonochloridates and chalcones through tandem Michael addition and nucleophilic substitution
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A novel and transition metal-free synthesis of 3,4-dihydro-1,2-oxaphosphinine 2-oxides was developed. LiHMDS-mediated tandem Michael addition and nucleophilic substitution of readily available phosphonochloridates and chalcones afforded a variety of valuable 3,4-dihydro-1,2-oxaphosphinine 2-oxides bearing diverse functionalities in excellent yields and satisfactory to good diastereoselectivity (up to 99% yield and up to 99?:?1 dr).
- Fu, Zhicheng,Sun, Simin,Yang, Anjian,Sun, Fang,Xu, Jiaxi
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supporting information
p. 13124 - 13127
(2019/11/11)
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- A chiral phosphorus alkene ligand, synthetic method and the application of the asymmetric reaction in (by machine translation)
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The invention relates to a chiral phosphorus alkene ligand, a synthesis method and application thereof in asymmetric reaction. Specifically, the invention discloses a chiral phosphorus alkene compound, which has a structural formula shown as formula I or formula II in the specification, wherein R, R, R, R, R, R, R, R and R are defined in the specification. The chiral phosphorus alkene compound can be prepared from chiral 2, 2'-binaphthol or its derivative as the starting material through two to four steps of reaction by means of four methods. The chiral phosphorus alkene compound can be used as a chiral ligand in asymmetric addition reaction of rhodium catalyzed boric acid and prochiral C=X (X=C, O, N) double bond, and can achieve good yield and enantioselectivity.
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Paragraph 0153-0155
(2018/05/24)
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- Direct Aryloxylation/Alkyloxylation of Dialkyl Phosphonates for the Synthesis of Mixed Phosphonates
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A strategy for the direct functionalization strategy of inertial dialkyl phosphonates with hydroxy compounds to afford diverse mixed phosphonates with good yields and functional-group tolerance has been developed. Mechanistic investigations involving both NMR studies and DFT studies suggest that an unprecedented highly reactive PV species (phosphoryl pyridin-1-ium salt), a key intermediate for this new synthetic transformation, is generated in situ from dialkyl phosphonate in the presence of Tf2O/pyridine.
- Huang, Hai,Denne, Johanna,Yang, Chou-Hsun,Wang, Haobin,Kang, Jun Yong
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supporting information
p. 6624 - 6628
(2018/05/14)
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- Alcohol-based Michaelis-Arbuzov reaction: An efficient and environmentally-benign method for C-P(O) bond formation
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The famous Michaelis-Arbuzov reaction is extensively used both in the laboratory and industry to manufacture tons of widely-used organophosphoryl compounds every year. However, this method and the modified Michaelis-Arbuzov reactions developed recently still have some limitations. We now report a new alcohol-version of the Michaelis-Arbuzov reaction that can provide an efficient and environmentally-benign method to address the problems of the known Michaelis-Arbuzov reactions. That is, a wide range of alcohols can readily react with phosphites, phosphonites, and phosphinites to give all the three kinds of phosphoryl compounds (phosphonates, phosphinates, and phosphine oxides) using an n-Bu4NI-catalyzed efficient C-P(O) bond formation reaction. This general method can also be easily scaled up and used for further synthetic transformations in one pot.
- Ma, Xiantao,Xu, Qing,Li, Huan,Su, Chenliang,Yu, Lei,Zhang, Xu,Cao, Hongen,Han, Li-Biao
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supporting information
p. 3408 - 3413
(2018/08/06)
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- Benzyl Mono-P-Fluorophosphonate and Benzyl Penta-P-Fluorophosphate Anions Are Physiologically Stable Phosphotyrosine Mimetics and Inhibitors of Protein Tyrosine Phosphatases
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α,α-Difluoro-benzyl phosphonates are currently the most popular class of phosphotyrosine mimetics. Structurally derived from the natural substrate phosphotyrosine, they constitute classical bioisosteres and have enabled the development of potent inhibitors of protein tyrosine phosphatases (PTP) and phosphotyrosine recognition sites such as SH2 domains. Being dianions bearing two negative charges, phosphonates, however, do not permeate membranes and thus are often inactive in cells and have not been a successful starting point toward therapeutics, yet. In this work, benzyl phosphonates were modified by replacing phosphorus-bound oxygen atoms with phosphorus-bound fluorine atoms. Surprisingly, mono-P-fluorophosphonates were fully stable under physiological conditions, thus enabling the investigation of their mode of action toward PTP. Three alternative scenarios were tested and mono-P-fluorophosphonates were identified as stable reversible PTP1B inhibitors, despite of the loss of one negative charge and the replacement of one oxygen atom as an H-bond donor by fluorine. In extending this replacement strategy, α,α-difluorobenzyl penta-P-fluorophosphates were synthesized and found to be novel phosphotyrosine mimetics with improved affinity to the phosphotyrosine binding site of PTP1B.
- Wagner, Stefan,Accorsi, Matteo,Rademann, J?rg
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supporting information
p. 15387 - 15395
(2017/11/09)
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- Palladium-catalyzed benzylic substitution of benzyl carbonates with phosphorus nucleophiles
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A wide range of benzyl carbonates reacted with dimethyl phosphonate or diphenylphosphine oxide in the presence of the palladium catalyst, [Pd(η3-allyl)Cl]2DPEphos, to give dimethyl benzylphosphonates and benzyldiphenylphosphine oxides in high yields. The catalytic phosphonylation was applied to the one-pot synthesis of alkenes from the benzyl esters.
- Makida, Yusuke,Usui, Kazumi,Ueno, Satoshi,Kuwano, Ryoichi
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p. 1814 - 1817
(2017/11/23)
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- Activation of anti-oxidant Nrf2 signaling by substituted trans stilbenes
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Nrf2, which is a member of the cap'n’ collar family of transcription factors, is a major regulator of phase II detoxification and anti-oxidant genes as well as anti-inflammatory and neuroprotective genes. The importance of inflammation and oxidative stress in many chronic diseases supports the concept that activation of anti-oxidant Nrf2 signaling may have therapeutic potential. A number of Nrf2 activators have entered into clinical trials. Nrf2 exists in the cytosol in complex with its binding partner Keap1, which is a thiol-rich redox-sensing protein. In response to oxidative and electrophilic stress, select cysteine residues of Keap1 are modified, which locks Keap1 in the Nrf2-Keap1 complex and allows newly synthesized Nrf2 to enter the nucleus. Numerous Nrf2-activating chemicals, including a number of natural products, are electrophiles that modify Keap1, often by Michael addition, leading to activation of Nrf2. One concern with the design of Nrf2 activators that are electrophilic covalent modifiers of Keap1 is the issue of selectivity. In the present study, substituted trans stilbenes were identified as activators of Nrf2. These activators of Nrf2 are not highly electrophilic and therefore are unlikely to activate Nrf2 through covalent modification of Keap1. Dose-response studies demonstrated that a range of substituents on either ring of the trans stilbenes, especially fluorine and methoxy substituents, influenced not only the sensitivity to activation, reflected in EC50values, but also the extent of activation, which suggests that multiple mechanisms are involved in the activation of Nrf2. The stilbene backbone appears to be a privileged scaffold for development of a new class of Nrf2 activators.
- Deck, Lorraine M.,Whalen, Lisa J.,Hunsaker, Lucy A.,Royer, Robert E.,Vander Jagt, David L.
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p. 1423 - 1430
(2017/02/18)
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- Synthetic method for alkyl group phosphorous acid diester compounds or alkyl group phosphinic acid ester compounds
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The invention discloses a synthetic method for alkyl group phosphorous acid diester compounds or alkyl group phosphinic acid ester compounds. According to the synthetic method, alcohols which are cheap, easy to get, wide in source, stable and low in toxicity serve as alkylating reagents, iodine salt which is cheap and easy to get serves as catalysts, no solvent is needed, and the alkyl group phosphorous acid diester compounds can be selectively directly obtained after a reaction. The reaction method is simple, the condition is mild, no organic solvent is needed and operation is simple. According to the method, the requirements for reaction conditions are low, various types of alcohols such as a benzyl group type, an allyl type and a fat type can be utilized as the alkylate reagents to implement the synthesis of different types of substituted alkyl group phosphorous acid diester, and the method can be further expanded to the synthesis of the alkyl group phosphinic acid ester compounds through the reaction between the substituted phosphonous acid diester and the alcohols.
- -
-
Paragraph 0022; 0023; 0024; 0025
(2017/04/26)
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- Investigation of reactive intermediates and reaction pathways in the coupling agent mediated phosphonamidation reaction
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The preparation of carboxamides through the coupling agent mediated reaction of carboxylic acids and amines is one of the most frequently employed reaction types of modern organic synthesis and has largely replaced older methods of amide formation based on reactive acyl chloride intermediates. However, the preparations of analogous phosphonamidates still rely on the use of phosphonochloridate intermediates - a method that is incompatible with sensitive functional groups. Herein, we present a comprehensive study in which different coupling agents are tested in the phosphonamidation reaction. The procedures, parallel to those typically applied to the preparation of carboxamides, were generally unsuccessful with regard to the coupling reactions of monoesters of phosphonic acids and amines, with the exception of those mediated by (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBOP). The implementation of a preactivation period in the absence of the amine coupling partner allowed for efficient phosphonamidate formation with coupling agents such as (1-cyano-2-ethyoxy-2-oxoethylideneaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU), [ethyl cyano(hydroxyimino)acetato-O2]tri-1-pyrrolidinylphosphonium hexafluorophosphate (PyOxim), dicyclohexyl carbodiimide (DCC), N,N′-diisopropylcarbodiimide (DIC), and N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uronium hexafluorophosphate (HBTU). The reactive intermediates observed by 31P NMR analysis were individually synthesized and examined to understand their influence on the reaction. A phosphonamidation reaction that uses (1-cyano-2-ethyoxy-2-oxoethylideneaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU) to mediate the coupling of monoalkyl esters of phosphonic acids and amines was developed. A preactivation period without the amine was needed to obtain the product. Using this step allowed for other coupling agents to be successfully used in the reaction.
- Fredriksen, Kim Alex,Amedjkouh, Mohamed
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supporting information
p. 474 - 482
(2016/02/18)
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- Tetrahydropyrrolization of Resveratrol and Other Stilbenes Improves Inhibitory Effects on DNA Oxidation
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The inhibitory effect of resveratrol on DNA oxidation caused by 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH) was found to be enhanced if the C=C bond in resveratrol was converted into tetrahydropyrrole by reaction with azomethine ylide (CH2=N+(CH3)CH2?). This encouraged us to explore whether the inhibitory activities of other stilbenes could also be increased by the same method. We found that the inhibitory effects of the tetrahydropyrrole derivatives on AAPH-induced oxidation of DNA were higher than those of the corresponding stilbenes, because the tetrahydropyrrole motif can provide hydrogen atoms to be abstracted by radicals. Therefore, the tetrahydropyrrolization offered an advantage for enhancing the antioxidant effects of stilbenes. Notably, (CH3)3SiCH2N(CH3)CH2OCH3(in the presence of CF3COOH) and (CH3)3NO (in the presence of LiN(iPr)2) can be used to generate azomethine ylide for the tetrahydropyrrolization of stilbenes containing electron-withdrawing and -donating groups, respectively.
- Bao, Liang-Liang,Liu, Zai-Qun
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p. 1617 - 1625
(2016/08/28)
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- TRIARYLAMINE DERIVATIVE AND ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MEMBER
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A triarylamine derivative is represented by general formula (1) shown below. In general formula (1), R1, R2, and R3 each represent, independently of one another, a halogen atom, an optionally substituted alkyl group having a carbon number of at least 1 and no greater than 6, an optionally substituted alkoxy group having a carbon number of at least 1 and no greater than 6, or an optionally substituted aryl group having a carbon number of at least 6 and no greater than 12. In general formula (1), o, p, and q each represent, independently of one another, an integer of at least 0 and no greater than 4, and m and n each represent, independently of one another, an integer of at least 1 and no greater than 2.
- -
-
Paragraph 0091; 0092; 0093
(2016/06/28)
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- Palladium-catalyzed allylation/benzylation of H-phosphinate esters with alcohols
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The Pd-catalyzed direct alkylation of H-phosphinic acids and hypophosphorous acid with allylic/benzylic alcohols has been described previously. Here, the extension of this methodology to H-phosphinate esters is presented. The new reaction appears general,
- Fers-Lidou, Anthony,Berger, Olivier,Montchamp, Jean-Luc
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- Naturally occurring Batatasins and their derivatives as α-glucosidase inhibitors
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Batatasins are endogenous plant hormones found in yams and other related plant species. These plants are widely consumed as botanical dietary supplements in many parts of the world. This study investigated the inhibitory effects and mechanisms of Batatasin I, III, IV, V against α-glucosidase regarding their antidiabetic activities. The results revealed that Batatasin I, III, IV inhibited α-glucosidase in a reversible and noncompetitive manner, with IC50 values of 2.55, 1.89 and 2.52 mM respectively, while Batatasin V completely abolished its inhibitory activity even at the highest concentrations tested. Furthermore, a class of Batatasin-derived compounds with different substitution patterns was synthesized and subjected to the assay to clarify the structure-activity relationships, which suggested that the hydroxyl at the C-2′ position may play a significant role in improving the inhibitory activities. Their probable binding modes and the specificity of the binding sites were studied using molecule docking simulation. It was concluded that Batatasins, especially Batatasin III and IV, are promising α-glucosidase inhibitors, which therefore could be used as functional food to alleviate postprandial hyperglycemia and as potential candidates for the development of antidiabetic agents.
- Hu, Wei-Ping,Cao, Guo-Dong,Zhu, Jin-Hua,Li, Jia-Zhong,Liu, Xiu-Hua
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p. 82153 - 82158
(2015/10/12)
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- Synthetic Strategy and Performances of a UV-Curable Poly Acryloyl Phosphinate Flame Retardant by Carbene Polymerization
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A route to synthesize poly ethyl (4-acrylamidebenzyl) phosphinate (PPAC) was discussed and the optimal route was determined. Diethyl benzylphosphonate was synthesized by Arbuzov reaction, then, a nitryl was introduced onto the aromatic ring by the nitration reaction of ethyl benzylphosphonate. Subsequently the carbene polymerization of the product was carried out. Finally, the nitryls were reduced and amidated to introduce the acryloyl group into the prepolymer to obtain the target product (PPAC). PPAC can rapidly photopolymerize under UV light irradiation. The addition of PPAC decreased the smoke production rate (SPR), CO2 production (CO2P), and CO production (COP) of the UV-cured resin.
- Yu, Jia,Li, Minglei,Yu, Yong,Gao, Yanjing,Liu, Jiancheng,Sun, Fang
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p. 1958 - 1970
(2015/12/12)
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- Selective photoisomerization of methyl substituted nitro diphenylbutadienes
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A series of p-nitro substituted trans-diphenylbutadienes is synthesized and their photophysical and photochemical properties are investigated. All the dienes have a very low quantum yield of fluorescence but exhibit remarkable solvatochromic emission shifts attributed to twisted intramolecular charge transfer. Photochemical irradiation of simple p-nitro substituted diphenylbutadienes reveals inefficient or no detectable photoisomerization. However, substituting a methyl group on the butadiene chain of p-nitro substituted diphenylbutadiene or replacing the nitro group with cyano group yields the corresponding trans-cis isomers. In the case of simple nitrodienes, strong intramolecular charge transfer character in the excited state aids dissipation of absorbed energy through non-photochemical and non-radiative channels. The steric effect caused by the presence of methyl group lowers the isomerization barrier in methyl substituted dienes leading to a regioselective isomerization.
- Agnihotri, Harsha,Palakollu, Veerabhadra,Kanvah, Sriram
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- Acetic acid mediated synthesis of phosphonate-substituted titanium oxo clusters
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New phosphonate/acetate-substituted titanium oxo/alkoxo clusters were prepared from Ti(OiPr)4 and bis(trimethylsilyl) phosphonates in the presence of acetic acid, which served to generate water in situ through ester formation. The process led to clusters with a higher degree of condensation than in previously known phosphonate-substituted titanium oxo clusters. The clusters [Ti6O4(OiPr)10(OAc)2(O3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions. This cluster type, which is also retained in solution, therefore appears to be very robust. Two other clusters, [Ti5O(OiPr)11(OAc)(O3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O3P-xylyl)2], were only isolated in special cases. Several acetate/phosphonate-substituted titanium cage compounds were obtained from the reaction of titanium isopropoxide with bis(trimethylsilyl) phosphonates in the presence of acetic acid as water generator.
- Czakler, Matthias,Artner, Christine,Schubert, Ulrich
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p. 2038 - 2045
(2015/04/27)
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- Discovery of inhibitors of the mitotic kinase TTK based on N-(3-(3-sulfamoylphenyl)-1H-indazol-5-yl)-acetamides and carboxamides
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TTK kinase was identified by in-house siRNA screen and pursued as a tractable, novel target for cancer treatment. A screening campaign and systematic optimization, supported by computer modeling led to an indazole core with key sulfamoylphenyl and acetamido moieties at positions 3 and 5, respectively, establishing a novel chemical class culminating in identification of 72 (CFI-400936). This potent inhibitor of TTK (IC50 = 3.6 nM) demonstrated good activity in cell based assay and selectivity against a panel of human kinases. A co-complex TTK X-ray crystal structure and results of a xenograft study with TTK inhibitors from this class are described.
- Laufer, Radoslaw,Ng, Grace,Liu, Yong,Patel, Narendra Kumar B.,Edwards, Louise G.,Lang, Yunhui,Li, Sze-Wan,Feher, Miklos,Awrey, Don E.,Leung, Genie,Beletskaya, Irina,Plotnikova, Olga,Mason, Jacqueline M.,Hodgson, Richard,Wei, Xin,Mao, Guodong,Luo, Xunyi,Huang, Ping,Green, Erin,Kiarash, Reza,Lin, Dan Chi-Chia,Harris-Brandts, Marees,Ban, Fuqiang,Nadeem, Vincent,Mak, Tak W.,Pan, Guohua J.,Qiu, Wei,Chirgadze, Nickolay Y.,Pauls, Henry W.
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p. 4968 - 4997
(2014/10/16)
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- Antimalarial and structural studies of pyridine-containing inhibitors of 1-deoxyxylulose-5-phosphate reductoisomerase
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1-Deoxy-d-xylulose-5-phosphate reductoisomerase (DXR) in the nonmevalonate isoprene biosynthesis pathway is a target for developing antimalarial drugs. Fosmidomycin, a potent DXR inhibitor, showed safety as well as efficacy against Plasmodium falciparum malaria in clinical trials. On the basis of our previous quantitative structure-activity relationship (QSAR) and crystallographic studies, several novel pyridine-containing fosmidomycin derivatives were designed, synthesized, and found to be highly potent inhibitors of P. falciparum DXR (PfDXR) having Ki values of 1.9-13 nM, with the best one being ～11× more active than fosmidomycin. These compounds also potently block the proliferation of multidrug resistant P. falciparum with EC 50 values as low as 170 nM. A 2.3 A? crystal structure of PfDXR in complex with one of the inhibitors is reported, showing that the flexible loop of the protein undergoes conformational changes upon ligand binding and a hydrogen bond and favorable hydrophobic interactions between the pyridine group and the PfDXR account for the enhanced activity.
- Xue, Jian,Diao, Jiasheng,Cai, Guobin,Deng, Lisheng,Zheng, Baisong,Yao, Yuan,Song, Yongcheng
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supporting information
p. 278 - 282
(2013/03/29)
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- Reductive coupling reactions: A new strategy for C(sp3)-P bond formation
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The C(sp3)-P bond forming reaction utilizing N-tosylhydrazones as readily available alkylating reagents was developed, which provides a new opportunity for preparing phosphine oxide derivatives with moderate to good yields. This reductive coupling reaction is proposed to proceed through an insertion of copper carbene into P-H bond of H-phosphorus oxides. The salient features of the reaction are operational simplicity and functional-group tolerance.
- Chen, Zi-Sheng,Zhou, Zhao-Zhao,Hua, Hui-Liang,Duan, Xin-Hua,Luo, Jian-Yi,Wang, Jia,Zhou, Ping-Xin,Liang, Yong-Min
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p. 1065 - 1068
(2013/02/25)
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- Synthesis of 3,5-diaryl substituted indole derivatives and its selective iodide ion chemosensing
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In this contribution, we have synthesized series of 1-ethyl-3,5-bis[2- (aryl)ethenyl]-1H-indole based derivatives with different functional groups using Wadsworth-Emmons coupling. The sensing ability of the receptors has been studied for halides like tetrabutylammonium fluoride, chloride, bromide, iodide and bisulphate by UV-vis spectroscopy methods. In THF solution, compound A-E exhibits excellent selectivity with iodide ions over the other ions like tetrabutylammonium bromide (TBABr), tetrabutylammonium chloride (TBACl), tetrabutylammonium fluoride (TBAF) and tetrabutylammonium bisulphate (TBAHSO4). The indole cores were observed effectively and selectively recognized biologically important iodide was reported. Significant absorption change was observed only for tetrabutylammonium iodide and no change with other anions. The absorption spectra indicated the formation of complex between host and guest is in 1:1 stoichiometric ratio. The association constants of A-E for iodide ions were found to be 3.2 × 104 M-1, 3.9 × 104 M-1, 4.2 × 103 M -1, 2.9 × 103 M-1 and 2.14 × 103 M-1, respectively.
- Rathikrishnan, Krishnaswamy R.,Indirapriyadharshini, Vellore K.,Ramakrishna, Seeram,Murugan, Rajendiran
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scheme or table
p. 640 - 644
(2012/02/05)
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- PH-switched HRP-catalyzed dimerization of resveratrol: A selective biomimetic synthesis
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A selective, concise and green biomimetic synthesis strategy of seven resveratrol dimers from natural resveratrol monomer as starting material is described. By succinct adjustment of environmental pH, the enzyme used, horseradish peroxidase (HRP), can perform in three distinctly different patterns and five dimers form with considerable selectivity. Two other derivative dimers are subsequently synthesized.
- Li, Chang,Lu, Jing,Xu, Xiaofei,Hu, Ruilin,Pan, Yuanjiang
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supporting information
p. 3281 - 3284
(2013/01/16)
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- Oxidative functionalization of benzylic C-H bonds by DDQ
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C-H activation of the methyl group of toluene and related ArCH3 derivatives by 2,3-dichloro-4,5-dicyano-1,4-benzoquinone (DDQ) gives insertion products, ArCH2O[C6Cl2(CN)2]OH via a rate-determining hydride abstraction by DDQ. The resulting benzylic ether can undergo reactions with phosphines to give benzylic phosphonium salts (Wittig reagents) and with phosphites to give phosphonate esters (Horner-Wadsworth- Emmons reagents). The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.
- Batista, Victor S.,Crabtree, Robert H.,Konezny, Steven J.,Luca, Oana R.,Praetorius, Jeremy M.
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p. 1141 - 1144
(2012/07/02)
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- Synthesis of dialkyl and diaryl benzylphosphonates through a ZnI 2-mediated reaction
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Several trialkyl and two triaryl phosphites have been tested for their reactivity in the zinc iodide mediated conversion of benzyl alcohol to the corresponding phosphonates. Most react smoothly to afford the desired phosphonate diesters, including hindered and nonracemic phosphites. The implications of this reactivity on the reactions involved in the transformation are discussed.
- Richardson, Rebekah M.,Barney, Rocky J.,Wiemer, David F.
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supporting information
p. 6682 - 6684
(2013/01/15)
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- A comprehensive investigation on the cooperative branch effect on the optical properties of novel conjugated compounds
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This paper presents a variety of conjugated derivatives with different number of arms (4-styryltriphenylamine: C1, 4, 4'-di-styryltriphenylamine: C2, 4, 4', 4.-tri-styryltriphenylamine: C3). The linear absorption and fluorescence maxima and the molar extinction coefficients are in the order of C1C2C3 in various solvents. Two-photon absorption (TPA) up-converted emission of the derivatives were determined with Ti: sapphire femtosecond laser. The maximal TPA emission wavelength and the two-photon absorption cross section of the derivatives are also in the order of C1C2C3 in various solvents. The dipole moment changes of the derivatives between the excited state and the ground state were estimated from experiment, and they are in the order of C1C2C3, which is confirmed further by the molecular geometry optimization of the derivatives. The electron density distribution and the energy levels of the frontier orbital of the derivatives were analyzed. The cyclic voltammograms of the derivatives were performed and discussed.
- Yang, Long,Gao, Fang,Liu, Jian,Zhong, Xiaolin,Li, Hongru,Zhang, Shengtao
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scheme or table
p. 545 - 554
(2012/05/05)
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- The synthesis and photophysical properties of novel poly(diarylamino) styrenes
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A series of novel diamines linked by varying conjugated bridges were characterized using FTIR, NMR and UV-visible spectroscopy, mass spectrometry and elemental analysis. The photoluminescence and thermal properties of the compounds were related to structure and quantum chemical calculations were employed to study the optimized ground state geometry of the compounds. The diarylamines exhibited blue to green fluorescence emission and displayed high thermal stability and high glass transition temperature. As such, the compounds might be very useful as hole-transporting materials in organic light-emitting diodes.
- Wang, Hai-Ying,Chen, Gang,Xu, Xiao-Ping,Chen, Hua,Ji, Shun-Jun
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experimental part
p. 358 - 365
(2011/06/11)
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- Inhibition of 1-deoxy-d-xylulose-5-phosphate reductoisomerase by lipophilic phosphonates: SAR, QSAR, and crystallographic studies
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1-Deoxy-d-xylulose-5-phosphate reductoisomerase (DXR) is a novel target for developing new antibacterial (including antituberculosis) and antimalaria drugs. Forty-one lipophilic phosphonates, representing a new class of DXR inhibitors, were synthesized, among which 5-phenylpyridin-2-ylmethylphosphonic acid possesses the most activity against E. coli DXR (EcDXR) with a K i of 420 nM. Structure-activity relationships (SAR) are discussed, which can be rationalized using our EcDXR:inhibitor structures, and a predictive quantitative SAR (QSAR) model is also developed. Since inhibition studies of DXR from Mycobacterium tuberculosis (MtDXR) have not been performed well, 48 EcDXR inhibitors with a broad chemical diversity were found, however, to generally exhibit considerably reduced activity against MtDXR. The crystal structure of a MtDXR:inhibitor complex reveals the flexible loop containing the residues 198-208 has no strong interactions with the 3,4-dichlorophenyl group of the inhibitor, representing a structural basis for the reduced activity. Overall, these results provide implications in the future design and development of potent DXR inhibitors.
- Deng, Lisheng,Diao, Jiasheng,Chen, Pinhong,Pujari, Venugopal,Yao, Yuan,Cheng, Gang,Crick, Dean C.,Prasad, B. V. Venkataram,Song, Yongcheng
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experimental part
p. 4721 - 4734
(2011/09/19)
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- Synthesis of α-arylphosphonates using copper-catalyzed α-arylation and deacylative α-arylation of β-ketophosphonates
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Efficient methods for the direct arylation and deacylative arylation of β-ketophosphonates with iodoarenes in presence of a copper(I) or a copper(II) salt as the catalysts have been developed. The corresponding α-arylphosphonates were obtained in high yields. A tentative mechanism for the deacylative arylation reaction was proposed on the basis of the experimental data. Copyright
- Rout, Laxmidhar,Regati, Sridhar,Zhao, Cong-Gui
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scheme or table
p. 3340 - 3346
(2012/01/17)
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- Direct conversion of benzylic and allylic alcohols to phosphonates
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Benzyl phosphonate esters often serve as reagents in Horner-Wadsworth- Emmons reactions. In most cases, they can be prepared from benzylic alcohols via formation of the corresponding halide followed by an Arbuzov reaction. To identify a more direct synthesis of phosphonate esters, we have developed a one-flask procedure for conversion of benzylic and allylic alcohols to the corresponding phosphonates through treatment with triethyl phosphite and ZnI2.
- Barney, Rocky J.,Richardson, Rebekah M.,Wiemer, David F.
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supporting information; experimental part
p. 2875 - 2879
(2011/05/19)
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- Preparation of benzylphosphonates via a palladium(0)-catalyzed cross-coupling of H-phosphonate diesters with benzyl halides. Synthetic and mechanistic studies
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We have developed a new, efficient method for the synthesis of benzylphosphonate and benzylphosphonothioate diesters via a palladium(0)- catalyzed cross-coupling reaction between benzyl halides and H-phosphonate or H-phosphonothioate diesters, using Pd2(dba)3(CHCl 3) as a palladium source and Xantphos as a supporting ligand. Some mechanistic aspects of these reactions were investigated using 31P NMR spectroscopy.
- Laven, Gaston,Kalek, Marcin,Jezowska, Martina,Stawinski, Jacek
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experimental part
p. 967 - 975
(2010/08/04)
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- Pure branch effect on the optical properties of novel conjugated derivatives
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Pure cooperative branch effects on one- and two-photon optical properties of conjugated derivatives are presented. AMI calculations demonstrate that the electron density distribution of the frontier orbital and the dipole moment changes of the derivatives are related to the number of branches. The theoretical results show that not only the energy level of the frontier orbital could be mediated by the number of branches, but the HOMOLUMO gap could be regulated.
- Yang, Long,Gao, Fang,Liu, Jian,Zhong, Xiaolin,Li, Hongru,Zhang, Shengtao
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experimental part
p. 582 - 583
(2010/10/02)
-
