Investigation of Reaction Mechanism of Amino Acids and Phosphorus Trichloride by 31P NMR and ESI‐MS/MS

The reaction of amino acids and phosphorus trichloride in THF was studied by ³¹P NMR tracing and ESI‐MS/MS. A series of hydridophoranes and cyclic dipeptides were obtained. The reaction presented interesting diversity and the reaction mechanism was proposed. The mechanism suggests that phosphorus plays an important role in the synthesis of amino acid hydridophorane and cyclic dipeptides. The results also show that ³¹P NMR and ESI‐MS/MS are useful tools for the investigation of reaction mechanism.     

Organophosphorus Synthesis Without Phosphorus Trichloride: The Case for the Hypophosphorous Pathway

Abstract

The vast majority of organophosphorus compounds is currently synthesized from phosphorus trichloride (PCl₃), even though the final consumer products do not contain reactive phosphorus–chlorine bonds. In order to bypass phosphorus trichloride, significant interest has been devoted to functionalizing elemental phosphorus (P₄, the precursor to PCl₃), red phosphorus (P_red), or phosphine (PH₃). Yet, other industrial-scale precursors are hypophosphorous derivatives (H₃PO₂ and its alkali salts), but their use as phosphorus trichloride replacements has been completely overlooked. Here, the case is made for an alternative approach to the industrial synthesis of organophosphorus compounds based on hypophosphites.     

Reactions of Ammonium Alkylene Dithiophosphates with Phosphorus Trichloride and Thiophosphoryl Chloride *

Phosphorus trichloride and thiophosphoryl chloride derivatives of alkylene dithiophosphates of the type PCl_{3 ? n} () _n and P(S)Cl_{3? n} () _n (where G = -CH₂CH₂CHMe-, -CMe₂CMe₂-, -CH₂CH₂CH₂CH₂- and -CMe₂CH₂ CHMe-, n = 1, 2, 3] have been synthesized for the first time by reacting the ammonium salt of alkylene dithiophosphoric acid with phosphorus trichloride and thiophosphoryl chloride in different stoichiometric ratios under anhydrous reaction conditions. The newly synthesized derivatives are either colorless liquids or viscous semisolids, hygroscopic in nature and are soluble in common organic solvents. These are characterized by elemental analysis, molecular weight determinations and physicochemical studies IR, NMR (¹H and ³¹P). On the basis of above studies the formation of P-S-P and S = P–S–P(S) chemical linkages have been established. ²³¹P NMR studies provide convincing evidence regarding the chemical bonding mode in these derivatives.     

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.     

三氯化钛水溶液与氨基酮在碱性介质中的反应

氨基醇具有一定的镇静生理活性,通常由氨基酮还原制得。β-或α-氨基酮经Al-Hg齐和电化学还原可得到相应的二氨基听呐醇,然而,此法操作不便,产率很低,又具有毒性。我们以甲醇为溶剂,用9种氨基酮盐酸盐1与15％的三氯化钛水溶液在碱性条件和Ar气保护下反应,得到相应的双分子还原产物——二氨基(口片)呐醇,并分离出dl-和meso-异构体。     

基于Willgerodt-Kindler反应的两种二茂铁羧酸的合成及机理研究

以Na2S•9H2O为催化剂, 通过Willgerodt-Kindler反应分别合成了二茂铁乙酸和1,1’-二茂铁二乙酸, 用IR, 1H NMR, MS和元素分析对产物分别进行了结构表征, 并利用GC-MS研究了该反应机理, 推测反应是由多硫阴离子进攻羰基α碳所引发, 同时讨论了影响反应的各种因素.     

Synthesis and Characterization of Novel Cycloalkanespiro-5-Hydantoin Phosphonic Acids

A series of new cycloalkanespiro-5-hydantoin phosphonic acids have been synthesized and characterized. The mixture of [(2,4-dioxo-1,3-diazaspiro-alkane-3-yl)-methyl]phosphonic acids and [(2,4-dioxo-1,3-diazaspiro-alkane-1,3-diyl)dimethyl]diphospho-nic acids was obtained from cycloalkanespiro-5-hydantoins, formaldehyde, and phosphorus trichloride in a molar ratio of 1:2:2, by a procedure modified by us. Their structures were proved by means of IR, ¹H, ¹³C{¹H} and ³¹P NMR spectroscopy.     

CO32-对羟基乙叉二膦酸体系铜电结晶的影响

采用循环伏安和计时安培法研究了羟基乙叉二膦酸(HEDPA)镀铜液中铜在玻碳电极上电结晶的初期行为。结果表明：羟基乙叉二膦酸(HEDPA)镀铜体系中,铜的电沉积过程经历了晶核形成过程;当溶液中不含CO32-时,其电结晶按连续三维成核方式进行,而CO32-的加入,使得铜电结晶按瞬时三维成核方式进行;成核数密度都随着电位的提高而增加。这可能是CO32- -以第二配体形式进入HEDPA和Cu2+构成的络合结构,从而形成更稳定的络合物吸附在电极表面所致。     

Dual Functionalization of α‐Monoboryl Carbanions through Deoxygenative Enolization with Carboxylic Acids

A dual functionalization of 1,1‐diborylalkanes through deoxygenative enolization with carboxylic acids was developed. 1,1‐Diborylalkanes were activated by MeLi to generate α‐monoboryl carbanions. In situ IR spectroscopy indicated an interaction between carboxylic acid and 1,1‐diborylalkane before addition of the activation reagent. Release of the active α‐monoboryl carbanion from the masked form was necessary for its reaction with carboxylate to afford enolate species. Electrophilic trapping of enolate species with various electrophiles achieved dual functionalization of 1,1‐diborylalkanes to afford a variety of α‐mono, di‐, and tri‐substituted ketones.     

The Photokinetics of Electron Transfer Reaction of Methylene Blue with Titanium Trichloride in Aqueous–Alcoholic Solvents

The kinetics of photoinduced electron transfer reaction of methylene blue (MB) and titanium trichloride was investigated in water and different aqueous–alcoholic solvents. The reaction is pseudo‐first order, dependent only on the concentration of titanium trichloride at a fixed concentration of MB. The effect of water and aqueous–alcoholic solvents was studied in the acidic pH range (4–7). It was observed that the quantum yield (ϕ ) of the reaction increased with increase in polarity of the reaction medium. The quantum yield was high under acidic conditions and decreased with further increase in acidity. The addition of ions and increase in temperature increased the rate and quantum yield of the reaction. The absence of any reaction intermediate was confirmed by spectroscopic investigations. A mechanism for the reaction has been proposed in accordance with the kinetics of the reaction. The activation energy (E _a) was calculated by the Arrhenius relation. Thermodynamic parameters such as E _a, enthalpy change (ΔH ), free energy change (ΔG ), and entropy change (ΔS ) were also evaluated.     

CO2-3对羟基乙叉二膦酸镀铜液的影响

研究羟基乙叉二膦酸(HEDPA)镀铜液中CO2-3含量对电沉积时阴、阳极过程及镀层的择优取向的影响. 通过分析阴、阳极的动电位极化曲线, 发现镀液中逐渐加入的CO2-3提高了阴极的极化, 使电结晶晶粒细化, 直至达到稳定; 同时促进了铜阳极的溶解. 而X射线衍射(XRD)结果表明, 铜镀层的晶面择优取向从(222)逐渐向(111)转变. 通过镀液中固体络合物的红外光谱分析表明, CO2-3的加入以第二配体的方式进入该镀液的放电络合离子结构中, 参与Cu2+的络合, 形成更稳定的络合物, 从而导致铜沉积电位负移, 镀层(111)晶面取向增强.     

反相高效液相色谱分离果酸的研究

水果和蔬菜中含有的有机酸,称谓果酸,果酸的定量方法很多,气相色谱法需要将果酸衍生后才能分析。本文阐述用反相高效液相色谱及紫外与示差折光检测器,流动相为0.01M(NH_4)_2HPO_4,用H_3PO_4调节pH值为2.5,使果酸得到分离。用保留时间定性,用标准酸样的直线方程进行定量。并对橙子中的柠檬酸、健力宝饮料中的酒石酸作了定量测定。回收率达90%以上。此法快速,分离效果较好,是食品生产与分析发展的趋势。     

Synthesis of Aryl Ketones by Cross-Coupling Reaction of Arylboronic Acids with Carboxylic Anhydrides in Aqueous Phase

A highly efficient aqueous system of PdCl₂-catalyzed cross-coupling reaction of arylboronic acid with carboxylic anhydride (Suzuki-type reaction) without the use of phosphine ligands was developed. The reactions went smoothly in acetone/H₂O phase to give good yields of aryl ketones in short reaction times (1–3 h) at room temperature in air and were unaffected by the presence of electron-releasing and electron-withdrawing substituents in both the arylboronic acids and carboxylic anhydrides.     

Modification of Amorphous Mesoporous Zirconia Nanoparticles with Bisphosphonic Acids: A Straightforward Approach for Tailoring the Surface Properties of the Nanoparticles

The use of readily prepared bisphosphonic acids obtained in few steps through a thio-Michael addition of commercially available thiols on tetraethyl vinylidenebisphosphonate enables the straightforward surface modification of amorphous mesoporous zirconia nanoparticles. Simple stirring of the zirconia nanoparticles in a buffered aqueous solution of the proper bisphosphonic acid leads to the surface functionalization of the nanoparticles with different kinds of functional groups, charge and hydrophobic properties. Formation of both chemisorbed and physisorbed layers of the bisphosphonic acid take place, observing after extensive washing a grafting density of 1.1 molecules/nm² with negligible release in neutral or acidic pH conditions, demonstrating stronger loading compared to monophosphonate derivatives. The modified nanoparticles were characterized by IR, XPS, ζ-potential analysis to investigate the loading of the bisphosphonic acid, FE-SEM to investigate the size and morphologies of the nanoparticles and ³¹P and ¹H MAS NMR to investigate the coordination motif of the phosphonate units on the surface. All these analytical techniques demonstrated the strong affinity of the bisphosphonic moiety for the Zr(IV) metal centers. The functionalization with bisphosphonic acids represents a straightforward covalent approach for tailoring the superficial properties of zirconia nanoparticles, much straightforward compared the classic use of trisalkoxysilane or trichlorosilane reagents typically employed for the functionalization of silica and metal oxide nanoparticles. Extension of the use of bisphosphonates to other metal oxide nanoparticles is advisable.     

碱性树脂吸附有机羧酸的溶胀现象

选用强碱性树脂（201×4）,弱碱性树脂（D301G）为吸附剂,以乳酸和乙酸稀溶液为吸附分离对象,实验测定了碱性树脂对有机酸和水的组分吸附量,讨论了树脂的溶胀现象．结果表明,随吸附温度的上升,碱性树脂的溶胀程度增大;随着树脂上酸的吸附量的增大,水的组分吸附量也增大．通过对水的组分吸附量的分析,提出溶胀中存在吸水量和表面增益量两个方面的影响．以水的表面增益量为基础,讨论了强碱性树脂201×4和弱碱性树脂D301G对酸－水体系的选择分离性能．     

噻吩基1,2-迁移制备2-噻吩基酸类的研究

以α-卤代烷基噻吩基酮为原料,制得2-(2-噻吩基)丙酸、2-(5-溴-2-噻吩基)丙酸和2-(5-乙基-2-噻吩基)丙酸,研完了α-卤代烷基噻吩基酮的迁移基团、烷基、离去基、催化剂、温度和溶剂等对重排的影响,以及光学活性的2-(5-乙基-2-噻吩基)丙酸的制备,证明噻吩基1,2-迁移属邻基参与的S_N2缺电子重排。     

新型固体酸催化酯化反应研究

硫酸钛经高温焙烧制得一类新型固体酸，吸附吡啶的红外光谱表明，该类催化剂的表面存在明显的Bronsted酸性位，400-450℃焙烧得到的固体酸在己二酸二丁酯的合成中具有较好的起始活性，在下列条件下己二酸的转化率达到99％：0．1mol己二酸，0．35mol丁醇，T—450催化剂0．5g，油浴温度150℃，100min.该类催化剂对其它脂肪酸丁酯和异戊酯的合成具有极好的催化活性，60-120min时间内，转化率可达96％以上，催化剂回收容易，可重复使用多次。