New Sol-Gel Routes to Organic-Inorganic Hybrid Materials: Modification of Metal Alkoxide by Phosphonic or Phosphinic Acids

Hybrid materials were synthesized by modification of Ti(O ⁱ Pr)₄ by diphenyl phosphinic (DPPA) or phenyl phosphonic acid (PPA). Different P/Ti and H₂O/Ti ratios have been investigated. The samples were characterized using FTIR and ³¹P MAS NMR spectroscopies, elemental analysis (EDX), and N₂ adsorption-desorption experiments. Both PPA and DPPA act as chemical modifiers. Depending on the H₂O/Ti and P/Ti ratios, and on the nature of the modifier (PPA or DPPA), molecular Ti oxo-alkoxo-phosphonates or phosphinates, stable sols, gels, or precipitates were obtained. In addition, the P/Ti ratio was retained during the hydrolysis whatever the H₂O/Ti ratio.     

New Synthetic Method of Dicarboxyphenylphosphonic Acids

Abstract

Some dicarhoxyphenylphosphonic acids (DCPPA) were prepared by new process. We succeeded in introducing two carhoxyl groups into the phenyl group of phenylphosphonic acid. The dialkyl iso- and tere-phthalate (DACB) were conveniently hrominated with NBS /H₂SO₄ system to provide the corresponding hromidcs (DACBB) in good yields and good selectivities.     

基于哌嗪与二羧酸/羟基羧酸的二元体系的超分子自组装

本文选择哌嗪 (pip) 为研究中心,分别和1,4-环己二甲酸 (H2chda)、间苯二甲酸(H2mpda)、6-羟基-2-萘甲酸 (Hohna)、1-羟基-2-萘甲酸 (Hshna) 进行超分子自组装,得到了四种新的氢键超分子体系：H2pip·chda (1), H2pip·2Hmpda (2), H2pip·ohna·2H2O (3),H2pip·shna (4)。单晶结构分析表明：1-3为三维氢键超分子结构,而 4为一维链状氢键结构。     

Interaction of Tris(3-Hydroxymethyl)Phosphine with Cinnamic Acids

Abstract

Phosphonium zwitterions of the known type R₃P⁺CH(Ar)CH₂CO₂ ^? (II) are obtained as a racemic mixture in moderate yield via a 1:1 reaction of cinnamic acids (Ar = phenyl, or substituted phenyl) with [HO(CH₂)₃]₃P in acetone at room temperature under Ar. The products are characterized by elemental analysis, ³¹P{¹H}-, ¹H-, and ¹³C{¹H}-NMR spectroscopies, and mass spectrometry, although they contain a minor coproduct formed via neutralization of the positive and negative charges of II with the respective acid and phosphine reactants (see Experimental Section). In CD₃OD, the monodeuterated salts R₃P⁺CH(Ar)CH(D)CO₂ ^? are formed as a mixture of diastereomers with d.r. values of ～2 to 8, depending on substituent groups present in the organic acid; in these studies, 2-HO-cinnamic acid is the most reactive, and β-methylcinnamic acid is the least reactive.     

A Mechanistic Study on the Formation of Dronic Acids

Dronic acid derivatives, important drugs against bone diseases, may be synthesized from the corresponding substituted acetic acid either by reaction with phosphorus trichloride in methanesulfonic acid as the solvent or by using also phosphorous acid as the P-reactant if sulfolane is applied as the medium. The energetics of the two protocols were evaluated by high-level quantum chemical calculations on the formation of fenidronic acid and benzidronic acid. The second option, involving (HO)₂P-O-PCl₂ as the nucleophile, was found to be more favorable over the first variation, comprising Cl₂P-O-SO₂Me as the real reagent, especially for the case of benzidronate.     

Pentafluoroethylsilicic Acids

Pure anhydrous hexafluorosilicic acid (H₂[SiF₆]) is a still elusive species, although its existence in aqueous solutions is well documented. Desiccation inevitably leads to decomposition to form tetrafluorosilane and hydrogen fluoride. An oxonium hexafluorosilicate turned out to not be stable at room temperature. Partial substitution of the fluorine atoms with strong electron‐withdrawing perfluoroalkyl groups results in substantial stabilization of the corresponding fluorosilicic acids. Mono‐ and bis(pentafluoroethyl)‐substituted fluorosilicic acids were prepared through conversion of the respective halosilanes (Si(C₂F₅)_nX_4?n, with X=Cl, Br) with aqueous HF, and were obtained as colorless solids. They can be stored at room temperature for several months without decomposition, and thus are the first examples of stable fluorosilicic acids.     

磺酸官能化的磁性核壳结构的纳米材料用于果糖脱水制备5-羟甲基糠醛(英)

通过反相微乳液法制备了以Fe₃O₄为核,磺酸官能化的硅基材料为壳层的磁性酸性催化剂.首先制备纳米Fe₃O₄磁核,然后涂层包覆苯基修饰的纳米级硅层,最后进行苯基磺化修饰,制得固体酸催化剂Fe₃O₄@Si/Ph-SO₃H.在果糖脱水制备5-羟甲基糠醛反应中,该催化剂表现出较好的催化活性,优于传统催化剂A-15,且与均相无机酸催化活性相当.当采用二甲基亚砜作溶剂,在110℃下反应3 h,果糖转化率达到99%,5-羟甲基糠醛收率为82%.另外,该催化剂经磁法回收后可多次重复使用.     

Fluorescent Arylphosphonic Acids: Synergic Interactions between Bone and the Fluorescent Core

Herein, we report the third generation of fluorescent probes (arylphosphonic acids) to target calcifications, particularly hydroxyapatite (HAP). In this study, we use highly conjugated porphyrin-based arylphosphonic acids and their diesters, namely 5,10,15,20-tetrakis[m-(diethoxyphosphoryl)phenyl]porphyrin ( m -H₈TPPA-OEt₈ ) and 5,10,15,20-tetrakis [m-phenylphosphonic acid]porphyrin ( m -H₈TPPA ), in comparison with their positional isomers 5,10,15,20-tetrakis[p-(diisopropoxyphosphoryl)phenyl]porphyrin ( p -H₈TPPA-iPr₈ ) and 5,10,15,20-tetrakis [p-phenylphosphonic acid]porphyrin ( p -H₈TPPA ), which have phosphonic acid units bonded to sp² carbon atoms of the fluorescent core. The conjugation of the fluorescent core is thus extended to the (HAP) through sp²-bonded −PO₃H₂ units, which generates increased fluorescence upon HAP binding. The resulting fluorescent probes are highly sensitive towards the HAP in rat bone sections. The designed probes are readily taken up by cells. Due to the lower reported toxicity of ( p -H₈TPPA ), these probes could find applications in monitoring bone resorption or adsorption, or imaging vascular or soft tissue calcifications for breast cancer diagnosis etc.     

Structural Characterization and Degradability of Poly(L‐lactic acid)s Incorporating Phenyl‐Substituted α‐Hydroxy Acids as Comonomers

Three types of copolymers of poly(L ‐lactic acid) (PLLA) were synthesized by direct polycondensation of L ‐lactic acid and phenyl‐substituted α‐hydroxy acids (L ‐phenyllactic acid and D ‐ and L ‐mandelic acids). It was found that the glass transition temperature of the copolymers comprising L ‐mandelic acid became significantly higher (from 58 to 69 °C) with increasing content of L ‐mandelic acid (from 0 to 50 mol‐%) although the M _w decreased (from 87 000 to 4 000 Da). The cast films of the L ‐mandelic acid containing copolymers showed improved tensile properties compared with those of the PLLA film. This may be due to a pinning effect of the L ‐mandelic acid units on the helix formation of PLLA, although 30% of the units were racemized. The enzymatic degradability of the L ‐mandelic acid containing copolymers was much higher than that of PLLA, as analyzed with Proteinase K® originating from Tritirachium album.

Synthesis of copolymers of L ‐lactic acid and phenyl‐substituted α‐hydroxy acids.     

Transition-Metal-Free Carbon Isotope Exchange of Phenyl Acetic Acids

A transition-metal-free carbon isotope exchange procedure on phenyl acetic acids is described. Utilizing the universal precursor CO₂, this protocol allows the carbon isotope to be inserted into the carboxylic acid position, with no need of precursor synthesis. This procedure enabled the labeling of 15 pharmaceuticals and was compatible with carbon isotopes [¹⁴C] and [¹³C]. A proof of concept with [¹¹C] was also obtained with low molar activity valuable for distribution studies.     

Development of an efficient method for preparation of 1,3,5-trihydroxyisocyanuric acid (THICA) and its use as aerobic oxidation catalyst

1,3,5-Trihydroxyisocyanuric acid (THICA), which serves as an efficient radical-producing catalyst from hydrocarbons, was successfully prepared by two methods. The reaction of O-benzylhydroxyamine with phenyl chloroformate gave formbenzyloxycarbamic acid phenyl ester of which subsequent treatment with dimethylaminopyridine (DMAP) produced 1,3,5-tribenzyloxyisocyanurate leading to THICA by hydrogenation with H₂ on Pd/C. The other method involved the direct synthesis of 1,3,5-tribenzyloxyisocyanurate from O-benzylhydroxyamine and diphenyl carbonate. The aerobic oxidation of p-methylanisole catalyzed using THICA as a key catalyst afforded p-anisic acid in almost quantitative yield (>99%).     

Optimization and Validation of an HPLC-UV Method for Determination of Tranexamic Acid in a Dosage Form and in Human Urine

A simple and reliable high-performance liquid chromatographic method with UV detection at 245 nm has been developed and validated for determination of tranexamic acid (TA) in a dosage form and in human urine. Before injection samples were derivatized with phenyl isothiocyanate (PITC). The reaction temperature, reaction time, and concentration of PITC used for derivatization were optimized. Chromatographic separation was on a C₁₈ column with a 65:35 (v/v) mixture of 10 mM phosphate buffer, pH 3.6, and acetonitrile as mobile phase. Heptaminol hydrochloride was used as internal standard.     

Effect of Acids on Crystallization of Lithium Borate Films

Lithium borate films in amorphous and crystalline (Li₂B₄O₇) states were prepared from alkoxide solutions hydrolyzed in the presence or absence of hydrochloric acid or acetic acid. The acids suppressed crystallization of the amorphous films into Li₂B₄O₇, with acetic acid being the stronger suppressor. In order to determine the suppressing mechanism, we investigated the distribution of boron-containing species in the solutions by¹¹B-NMR. Boron in the non-acidified solution existed as both B(OH) ₄ ⁻ and polyborate species, including B₄O₅(OH) ₄ ²⁻ , which is easily transformed into the crystal nucleous of Li₂B₄O₇. In the solutions containing hydrochloric acid or acetic acid, however, boron was present mainly as B(OH)₃ and the formation of the polyborate species was suppressed, leading in turn to the suppression of crystallization into Li₂B₄O₇. X-ray fluorescence analysis showed that acetic acid produced a larger amount of residual carbon in the films than did hydrochloric acid. We concluded that the residual carbon also inhibited crystallization of the films into Li₂B₄O₇.     

Investigation of the Effect of Four Organic Acids in Radix Isatidis on E. coli Growth by Microcalorimetry

The inhibitory effects of four organic acids (OAs) in Radix Isatidis, a traditional Chinese medicinal herb, on Escherichia coli (E. coli) growth were investigated by microcalorimetry. The power‐time curves of E. coli growth with and without OAs were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k₁, k₂), half inhibitory ratio (IC₅₀), maximum heat output (P_max) and peak time (t_p). The values of k₁ and k₂ of E. coli growth in the presence of the four OAs decreased with the increasing concentrations of OAs. Moreover, P_max was reduced and the value of t_p increased with increasing concentrations of the four drugs. The sequence of anti‐microbial activity of the four OAs was: syringic acid>2‐amino‐benzoic acid>salicylic acid>benzoic acid. IC₅₀ of the four OAs was respectively 56 µg/mL for syringic acid, 75 µg/mL for 2‐amino‐benzoic acid, 86 µg/mL for salicylic acid and 224 µg/mL for benzoic acid. The existence of the functional groups on phenyl ring improves the anti‐microbial activity compared to benzoic acid. The functional groups methoxyl at C(3) and C(5) improve anti‐microbial activity more strongly than the other functional groups, and the functional group amino at C(2) improve anti‐microbial activity more strongly than hydroxyl at C(2) on phenyl ring.     

Evidences for Chelating Complexes of Lithium with Phenylphosphinic and Phenylphosphonic Acids: A Spectroscopic and DFT Study

Abstract

Lithium complexes were prepared with phenylphosphinic and phenylphosphonic acids. The complexes were studied in the solid state using Fourier transform infrared spectroscopy spectroscopy and in solution (methanol) using ¹H, ¹³C, and ³¹P Nuclear magnetic resonance spectroscopy (NMR) spectroscopy; the most preferred structures of the complexes were determined by density functional theory (DFT) computational method. Although methanol has a strong solvation effect on lithium ions and ligands, which causes dissociation of the complexes, significant changes of the NMR spectra of the complexes (relative to those of the free ligands) were observed. The new spectroscopic results indicate the presence of the phenylphosphinic acid tautomer (I: C₆H₅PH(?O)OH) rather than that of phenyl-phosphorous acid (II: C₆H₅P(OH)₂) in deuterated methanol showing PH/PD exchange. On the other hand, tautomer I predominates in the complex with lithium without showing PH/PD exchange. The DFT calculations predict that tautomer I is the preferred structure in the case of free ligand and lithium complex. The absence of a PH/PD exchange in the complex is due to the formation of a chelating complex, rather than of a simple salt between lithium ion and the two oxygen atoms of I, which prevent tautomerization of I into II. DFT calculations support the formation of lithium chelating complexes. The lithium ion was found to affect the spectroscopic properties of phenylphosphinic acid more dramatically than those of phenylphosphonic acid.     

Chemical Condensation of Phosphoramidates with Acids

Abstract

Several phosphoramidates and its phenyl ester were reacted with hydrogen chloride, acetic acid, and oxalic acid at room temperature and/or 60 °C.     

Determination of Glycolate Acid,Mono‐ and Dichloroacetic Acids in Synthetical Betaine by Anion‐exchange Chromatography

An anion‐exchange chromatography method combined solid phase extraction (SPE) was developed for the simultaneous analysis of glycolate acid (GL), monochloroacetic acid (MCA) and dichloroacetic acid (DCA) in synthetical betaine products. The analytes and unknown anionic impurities were well separated on a Metrosep A supp5 anion‐exchange column (150 mm×4 mm) with 2.0 mmol/L Na₂CO₃+2.0 mmol/L NaHCO₃ solution as eluent. Suppressed conductivity detection was used. A strong cation exchange (SCX) solid phase extraction (SPE) cartridge was used to reduce the concentration of matrix betaine and a Cleanert IC‐Ag pretreatment cartridge was used to remove high Cl^? concentration. The detection limits of GL, MCA and DCA were 0.09, 0.017 and 0.05 µg/L, respectively. The relative standard deviations (RSDs) of the retention times and peak areas were less than 0.09% and 0.49%, respectively. The recoveries of the three analytes were between 90.6% and 100.8%. The analytical results showed that GL and DCA were present in high concentration and no MCA was found when the proposed ion chromatography method was applied to three synthetical betaine samples. The proposed method is simple, sensitive and timesaving, and is also suitable for routine analysis in quality control of synthetical betaine products.     

Aqueous Synthesis of N-Phenyl/alkyl-2-quinolinone-3-carboxylic Acids from Coumarin-3-carboxylic Acids

An efficient, ecofriendly aqueous synthesis of aromatic/aliphatic amines with coumarin-3-carboxylic acid in a one pot reaction in a sealed tube or InCl₃/ H₂O in open vessel to afford N-phenyl/alkyl-2-quinolinones is achieved. This method provides high yield of products in shorter time, making it a useful process for the synthesis of structurally diversified 2-quinolinones from corresponding coumarins.     

Two New 3D Lanthanide Coordination Polymers with Benzenesulfonic and Adipic Acids: Synthesis,Structure and Luminescent Properties

Two new lanthanide complexes [Sm₂(ad)_2.5(BSA)(H₂O)₂]_n ( 1 ) and [Nd₂(ad)_2.5(BSA)(H₂O)₂]_n ( 2 ) (H₂ad = adipic acid, HBSA = benzenesulfonic acid) were synthesized hydrothermally from the reaction of the lanthanide ions (Ln³⁺) with flexible aliphatic dicarboxylate and the rigid benzene sulfonic acid and characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. They crystallize monoclinic in space group P2₁/ c. Structural analyses revealed that the two complexes have intricate 3D net structures constructed by the bridging adipic ligand and benzenesulfonic acid. The thermogravimetric analysis of 1 and 2 , as well as photoluminescent properties of 1 are discussed in detail.     

Friedel–Crafts Acylation and Related Reactions Catalyzed by Heteropoly Acids

The Friedel–Crafts acylation of anisole (AN) with acetic anhydride (AA) and the Fries rearrangement of phenyl acetate in the liquid phase catalyzed by bulk and silica-supported heteropoly acids (HPA), mainly H₃PW₁₂O₄₀ (PW), have been studied. In anisole acylation, PW exhibits very high activity, yielding up to 98% para and 2–4% ortho isomer of methoxyacetophenone (MOAP) at 90-110°C and an AN/AA molar ratio of 10–20. The reaction appears to be heterogeneously catalyzed; no contribution of homogeneous catalysis by HPA was observed. PW is almost 100 times more active than the zeolite H-Beta, which is in agreement with the higher acid strength of HPA. The PW catalyst is reusable, although gradual decline of activity was observed due to the coking of the catalyst. The acylation is inhibited by the product because of adsorption of MOAP on the catalyst surface. In contrast to anisole, the acylation of toluene with HPA is far less efficient than that with H-Beta. Evidence is provided that the activity of HPA in toluene acylation is inhibited by preferential adsorption of acetic anhydride on the catalyst. It is demonstrated that PW is a very efficient and reusable catalyst for the Fries rearrangement of phenyl acetate in homogeneous or heterogeneous liquid-phase systems at 100–150°C.