A Rapid Isolation of Human Chorionic Gonadotropin and Its Subunits by Reversed-Phase High Performance Liquid Chromatography

Abstract

A rapid isolation of human chorionic gonadotropin and its subunits from a commercially available concentrate of human urine has been achieved using reversed-phase high performance liquid chromatography. With μBondapak C₁₈ columns and a gradient employing aqueous trifluoroacetic acid as one solvent and dilute trifluoroacetic acid in acetonitrile as the other, complete separation can be accomplished in one day whereas standard column chromatographic procedures take about two weeks. Specific radioimmunoassays, polyacrylamide gel electrophoresis, and amino acid analyses were used to identify and characterize chromatographic peaks.     

Synthesis of hydroxyl‐bearing polyurethanes from naturally occurring myo‐inositol

A route from naturally occurring myo‐inositol to hydroxyl‐bearing polyurethanes has been developed. The diol prepared from the bis‐acetalization of myo‐inositol with 1,1‐dimethoxycyclohexane was reacted with a rigid diisocyanate, 1,3‐bis(isocyanatomethyl)cyclohexane to afford the corresponding polyurethane, of which glass transition temperature (T_g) was quite high as 192 °C. The polyurethane contains side chains inherited from the acetal moieties of the diol monomer and was treated with trifluoroacetic acid to hydrolyze the acetal moieties and afford the target polyurethane functionalized with hydroxyl groups. The presence of many hydroxyl groups in the side chains, which can form hydrogen bonds with each other, resulted in a high T_g, 186 °C. In addition, the hydroxyl groups were reacted with isocyanates to achieve further side‐chain modifications. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1358–1364     

A NEW EFFICIENT SYNTHESIS OF TRIFLUOROACETYL HALIDES AND MIXED ANHYDRIDES OF PHOSPHORUS AND TRIFLUOROACETIC ACIDS

Abstract

Reaction of trifluoroacetic anhydride with chloroanhydrides of phosphorus acids R₂P(O)CI results in formation of mixed anhydrides R₂P(O) OCOCF₃ and trifluoroacetic acid halides CF₃COX (X=Cl, Br, I) in quantitative yield.     

N-donor co-ligand-driven zinc coordination polymers based upon a bithiophene dicarboxylate: syntheses,structures, and luminescent properties

Three zinc compounds assembled from a bithiophene dicarboxylic acid (H₂DMTDC) and different N-donor co-ligands, [Zn(DMTDC)(bpt)(H₂O)]_n (1), {[Zn(DMTDC)(5,5-dmbpy)]·0.5DMF·1.5H₂O}_n (2), and {[Zn(DMTDC)(1,3-bimb)]·2DMF·H₂O}_n (3) (H₂DMTDC?=?3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid, bpt?=?4-amino-3,5-bis(4-pyridyl)1,2,4-triazole, 5,5′-dmbpy?=?5,5′-dimethyl-2,2′-bipyridyl, 1,3-bimb?=?1,3-bis(imidazol-1ylmethyl)benzene), were solvothermally synthesized and characterized. Compounds 1 and 2 are 1-D linear and zigzag chains with different supramolecular structures. In 1, adjacent chains form zipper-like structures through N–H?N interactions. In 2, however, chains in adjacent layers are stacked in an unusual unparallel level through C–H?O interactions. Compound 3 features a highly corrugated 2-D (4,4) layer and the layers are penetrated by each other to give 3-D polycatenations. Right- and left-handed helical Zn-bimb chains are arranged alternately within and between the layers, leading to mesomeric property of the whole network. Thermal stability and the decomposed products of all compounds were investigated. Luminescent properties of the ligands and compounds in the solid state at room temperature have also been explored. Moreover, the luminescence intensities of the compounds in different solvents are largely dependent on the solvent.     

Reversed Phase Thin Layer Chromatography of Amino Acids

Abstract

The use of reversed phase layers for the thin layer chromatography of amino acids is described. Only when a modifier was added to the mobile phase was clear separation of the amino acids achieved. Ion paring with trifluoroacetic acid overcame problems with streaking and poor separation on C₂ or C₁₈ reversed phase layers. All amino acids could not be separated with a single mobile phase. Thus, three different combination of acetonitrile-0.4% trifluoroacetic acid were used to separate eighteen amino acids with derivatization. No derivative was required.     

Synthesis,characterization and crystal structure of a chiral polymeric Cu(II) complex bridged by tartrate

A chiral metal-organic coordination polymer, [Cu(Tar)(2,2′-bipy) · 5H₂O] (1) (Tar = L-tartrate dianion, 2,2′-bipy = 2,2′-bipyridine), has been synthesized by hydrothermal reaction of Cu(OAc)₂, Na₂T (H₂T = 2,3-O-isopropylidene-L-tartaric acid) and 2,2′-bipyridine, and characterized by IR, UV–vis spectra, elemental analyses, TG-DTA, and single crystal X-ray diffraction. In the hydrothermal reaction, the protection group isopropylidene for tartaric acid was hydrolyzed. The crystal structure of the coordination polymer 1 shows that each tartrate chelates two Cu(II) ions at opposite ends using one carboxylate oxygen and one hydroxyl oxygen and each Cu(II) ion is chelated by two halves of tartrate dianions, forming coordination polymer chains. Distorted octahedral geometry around copper is completed by a chelating 2,2′-bipyridine molecule. The 2,2′-bipyridine groups in two of parallel 1-D chains are interwoven, constituting ladder-shaped double chains. Strong offset π–π stacking interactions with a face-to-face distance of 3.33 Å for pyridine rings are observed. All the lattice water molecules hydrogen-bond to each other or to the carbonyl oxygen of tartrate, forming a 3-D supramolecular structure.     

Homoleptic dirhodium tetraoctanoate and its pyridine adduct: synthesis and crystal structures

Dirhodium tetraoctanoate (1), without any exogenous axial ligands, has been obtained in crystalline form by slow evaporation from ethanol. The molecules are linked by axially ligating each other to form infinite chains, which is similar to the only other two structurally characterized rhodium(II) carboxylates, Rh₂(O₂CCF₃)₄ and Rh₂(O₂CC₃H₇)₄, which also lack exogenous axial ligands. The infinite chains of 1 are cleaved by strong donor solvents such as pyridine to produce the corresponding pyridine adduct (2). Both the complexes were characterized by elemental analysis, MS, IR and NMR spectra.     

The hydroxylation of alkanes and alkyl chains

A solution of 30% aqueous H₂O₂ in trifluoroacetic acid converts linear alkanes and cycloalkanes to an equilibrium mixture of secondary alcohols and their trifluoroacetates. There is no trace of further oxidation to ketones. Yields and conversions can be 70–90%, but are limited by elimination and epoxidation to form vicinal glycols. Linear alkyl chains are also hydroxylated in good yields with selectivity for introducing the alcohol group remote from electronegative substituents. The active reagent is trifluoroperoxyacetic acid, and it is effective in the presence of 4–10% water. When tertiary hydrogens are present, the oxidations are more complex.     

Hydrophobic Interaction Chromatography in the Detection of Hemoglobinopathies

Abstract

We describe a rapid method of high-performance liquid chromatography that utilizes the principle of hydrophobic interaction to separate the mutant globin ß chains found in certain hemoglobinopathies. We used this method to analyse blood globin chains in patients with all the known diagnostized hemoglobinopathies found in Finland, that is Hb_Helsinki' Hb_Linköping' Hb_Vaasa' Hb_Hiiiyama and Hb_Syracuse. As reference we also analyzed normal adult and fetal blood hemoglobins. Our method allowed good separation of the mutant ß globin chains from intact chains in the heterozygous patients as well as from α globin chain and fetal γ globin chains. We used two different systems of liquid chromatographic columns for the analyses, each column giving a slightly different elution selectivity and complementing the other. The analyses we describe are rapid and automated and allow hemoglobinopathies to be diagnosed precisely and, owing to the different principles of separation, complement other methods in common use.     

Synthesis,spectroscopic, and structural characterization of two malate zinc coordination polymers with imidazole or 2,2′-bipyridine

Zinc(II) coordination polymers, [Zn(Hmal)(im)(H₂O)] _n · 2nH₂O (1) and [Zn(Hmal)(bpy)] _n · 3nH₂O (2) (H₃mal = malic acid, im = imidazole, bpy = 2,2′-bipyridine), were synthesized from aqueous solution and characterized by elemental analyses, infrared and fluorescence spectra, thermogravimetric analyses, and single-crystal X-ray structural analyses. In 1, zinc is coordinated by imidazole, water, and tridentate malate in octahedral geometry. The β-carboxy group of malate further bridges with the other zinc forming 1-D polymeric chains. A pair of 1-D chains self-assemble to generate a double chain by strong hydrogen bonds between imidazole and malate. Furthermore, neighboring pairs of double chains are extended to form the final 3-D framework through intermolecular hydrogen bonds. In 2, the malates link Zn in a bidentate–monodentate fashion to form spiral-shaped chains that extend into a 3-D supramolecular structure by π–π stacking interactions and intermolecular hydrogen bonds. Complex 1 exhibits strong fluorescence at room temperature.     

含苯并咪唑基配体Zn(Ⅱ)、Cd(Ⅱ)配位聚合物的合成、结构以及荧光性质研究(英文)

以3,5-二(苯并咪唑基)吡啶(L)、间苯二甲酸(m-H2BDC)、4-羧基肉桂酸(H2CCA)、ZnSO4·7H2O和Cd(NO3)2·4H2O为原料,使用溶剂热方法合成了两个配位聚合物[Zn(L)(m-BDC)](1)和[Cd(L)(CCA)]·2H2O(2),利用红外、元素分析、热重分析和X-射线粉末衍射对其进行了表征,利用X-射线单晶衍射对结构进行了测定,并研究了配合物的荧光性质。在配合物1中,L与金属离子连接形成了一维(1D)链结构,而间苯二甲酸根离子与金属离子构成了一个M2(m-BDC)2(M=金属离子)的单元。一维链之间通过M2(m-BDC)2单元连接形成二维网状(2D)结构。在配合物2中,和配合物1类似,L与金属离子连接形成一维链,但与1不同的是羧酸配体与金属离子配位也构成了一维链结构,两种一维链通过配位作用连接构成二维结构。     

含苯并咪唑基配体Zn(Ⅱ)、Cd(Ⅱ)配位聚合物的合成、结构以及荧光性质研究

以3,5-二(苯并咪唑基)吡啶(L)、间苯二甲酸(m-H₂BDC)、4-羧基肉桂酸(H₂CCA)、ZnSO₄·7H₂O和Cd(NO₃)₂·4H₂O为原料,使用溶剂热方法合成了两个配位聚合物[Zn(L)(m-BDC)] (1)和[Cd(L)(CCA)]·2H₂O (2),利用红外、元素分析、热重分析和X-射线粉末衍射对其进行了表征,利用X-射线单晶衍射对结构进行了测定,并研究了配合物的荧光性质。在配合物1中,L与金属离子连接形成了一维(1D)链结构,而间苯二甲根离子与金属离子构成了一个M₂(m-BDC)₂(M=金属离子)的单元。一维链之间通过M₂(m-BDC)₂单元连接形成二维网状(2D)结构。在配合物2中,和配合物1类似,L与金属离子连接形成一维链,但与1不同的是羧酸配体与金属离子配位也构成了一维链结构,两种一维链通过配位作用连接构成二维结构。     

Hydrothermal synthesis and crystal structure of a layered coordination polymer: [Zn2(C2O4)2(C3N2H4)2] n

A new metal-organic coordination polymer [Zn₂(C₂O₄)₂(C₃N₂H₄)₂] _n (1) has been hydrothermally synthesized with ZnCl₂·2H₂O, oxalic acid and imidazole. The compound has a 2D network, consisting of infinite zinc(II) oxalate chains connected to each other by three-coordinate oxygen atoms. Within the chains, the zinc atoms are each octahedrally coordinated by one nitrogen atom from imidazole and five oxygen atoms from oxalate groups. Furthermore, there are two coordination modes of oxalate to zinc ions: chelate bis-bidentate and chelate/bridging bis-bidentate in compound 1, and the latter is rare among related compounds. Crystal data: monoclinic, P2(1)/c, a?=?8.4310(17), b?=?9.4060(19), c?=?8.2790(17)?Å, β?=?93.15(3)°, V?=?655.5(2)?ų, Z?=?2, R ₁?=?0.0322, wR ₂?=?0.0850.     

Alkylation of nitrogen heterocycles with 1,3-bis(hydroxymethyl)ferrocene. Generation of the ferrocene dicarbocation [{1,3-(CH2)2C5H3}Fe(C5H5)]2+

The alkylation of imidazole and 5-benzyloxycarbonyl-3,4-diethylpyrrole with 1,3-bis-(hydroxymethyl)ferrocene (1) afforded bis-imidazole (4) and bis-pyrrole (7) derivatives of ferrocene, respectively. The reaction of diol 1 with trifluoroacetic acid gave the dicarbocationic complex [{1,3-(CH₂)₂C₅H₃}Fe(C₅H₅)]²⁺ (2) characterized by ¹H NMR spectroscopy.     

The Influence of Reversed-Phase n-Alkyl Chain Length on Protein Retention,Resolution and Recovery: Implications for Preparative HPLC

Abstract

High-performance liquid chromatography (HPLC) of proteins on reversed-phase columns of varying n-alkyl chain length (C₂ to C₂₂ was studied using a trifluoroacetic acid/2-propanol mobile phase system. Protein resolution was influenced by chain length but retention times for proteins, unlike those of small molecules, were relatively constant, independent of chain length or carbon loading. Loading capacities were found to be affected by chain length, and aspects of protein interaction with stationary phase are discussed.     

Identification and isolation of human insulin A and B chains by high-performance liquid chromatography

A method for the isolation, identification and quantification of human insulin A and B chains by high-performance liquid chromatography (HPLC) is described. These chains were isolated from a peptide mixture produced by E. coli with modified genes obtained by genetic engineering. The method is based on the use of hydrophilic reagents, forming ion pairs in a reversed-phase column. Because some undesirable effects resulting from the use of phosphoric acid were observed, especially with the B chain, a new HPLC method was developed for each of the two human insulin chains. The use of trifluoroacetic acid as a counter ion for the A chain and of formic acid for the B chain led to the rapid isolation and purification of each chain by HPLC. The advantage of this method is that it provides a highly pure product, which was identified by polyacrylamide gel electrophoresis and amino acid analysis.     

Semi‐maleate salts of L‐ and DL‐serinium: the first example of chiral and racemic serinium salts with the same composition and stoichiometry

L‐Serinium semi‐maleate, (I), and DL‐serinium semi‐maleate, (II), both C₃H₈NO₃⁺·C₄H₃O₄⁻, provide the first example of chiral and racemic anhydrous serine salts with the same organic anion. A comparison of their crystal structures with each other, with the structures of the pure components (L‐serine polymorphs, DL‐serine and maleic acid) and with other amino acid maleates is important for understanding the formation of the crystal structures, their response to variations in temperature and pressure, and structure–property relationships. As in other known crystal structures of amino acid maleates, there are no direct links between the semi‐maleate anions in the two new structures. The serinium cations have different conformations in (I) and (II). In (I), they are linked into infinite chains via hydrogen bonds between carboxylic acid and hydroxy groups. In (II), there are no such chains formed by the serinium cations. In both (I) and (II), there are C₂²(12) chains consisting of alternating semi‐maleate anions and serinium cations. Two types of such chains are present in (I) and (II), termed C₂²(12) and C₂²(12)′. In (I), these chains, lying in the same plane, are further linked to each other via hydrogen bonds, whereas in (II) they are not.     

1-D wave-like chain,twofold 2-D layer,and chiral 3-D open framework based on multidentate ligand: structural diversities,thermal properties,and photoluminescence

From 1-D to 3-D zinc coordination polymers based on multifunctional flexible 4-(1,2,4-triazole-methylene)-benzonitrile (tzbt), {[Zn(tzbt)₂(bdc)]·2H₂O}_n (1), [Zn(tzbc)₂]_n (2), and [Zn(bpdc)(H₂O)]_n (3) (bdc = 1,4-benzenedicarboxylic acid, tzbc = 4-(1,2,4-triazole-methylene)-benzoic acid, bpdc = 4,4′-biphenyldicarboxylic acid), were synthesized under hydrothermal conditions. The tzbt was synthesized by N-alkylation and hydrolyzed in situ to produce tzbc (in 2). Single-crystal X-ray diffraction analysis reveals that 1 displays 1-D wave-like chains based on [Zn(bdc)]_n. 2 is a chiral twofold interpenetrating 2-D architecture constructed with “V”-shaped tzbc. 3 is a 3-D chiral compound constructed from achiral H₂bpdc with right-handed helical chains. 1–3 display stable blue-emitting luminescence with emission maxima ranging from 383 to 410 nm, depending on ligand-centered π*→π transitions. The effects of different polarity solvents and temperature on luminescence are discussed. TGA and VT-XPRD reveal that 2 has thermal stability to 360 °C.     

Glycinium semi‐malonate and a glutaric acid–glycine cocrystal: new structures with short O—H...O hydrogen bonds

Glycinium semi‐malonate, C₂H₆NO₂⁺·C₃H₃O₄⁻, (I), and glutaric acid–glycine (1/1), C₂H₅NO₂·C₅H₈O₄, (II), are new examples of two‐component crystal structures containing glycine and carboxylic acids. (II) is the first example of a glycine cocrystal which cannot be classified as a salt, as glutaric acid remains completely protonated. In the structure of (I), there are chains formed exclusively by glycinium cations, or exclusively by malonate anions, and these chains are linked with each other. Two types of very short O—H...O hydrogen bonds are present in the structure of (I), one linking glycinium cations with malonate anions, and the other linking malonate anions with each other. In contrast to (I), no direct linkages between molecules of the same type can be found in (II); all the hydrogen‐bonded chains are heteromolecular, with molecules of neutral glutaric acid alternating with glycine zwitterions, linked by two types of short O—H...O hydrogen bonds.     

基于2-丙基-4,5-咪唑二甲酸的锰(Ⅱ)和铜(Ⅰ)配合物的合成、晶体结构及性质研究(英文)

采用水热法合成了2个化合物{[Cu2(Hpimdc)(4,4′-bpy)]·H2O}n(1)和[Mn3(pimdc)2·6H2O]n(2)(H3pimdc=2-丙基-4,5-咪唑二甲酸,4,4′-bpy=4,4′-联吡啶),并对2个化合物进行了红外、元素分析、晶体结构和热稳定性分析。晶体结构分析发现化合物1之中的H3pimdc和4,4′-bpy交替与铜(Ⅰ)配位形成一维链线性铜(Ⅰ)配合物。沿a轴和(100)面去观察,2个一维链分子通过游离水连接而形成1个"U"型拓扑结构。而化合物2通过2-丙基-4,5-咪唑二甲酸链与锰(Ⅱ)连接为三维的网状结构。沿b轴方向,三维结构中存在交替的左/右手螺旋状二维结构。