Synthesis and structures of azine-based crown-containing hetarylphenylethenes

Condensation of methyl-substituted six-membered heteroaromatics containing one or two nitrogen atoms with aldehyde derived from benzo-15-crown-5 ether in DMF in the presence of Bu^tOK afforded 15-crown-5-containing hetarylphenylethenes. According to the results of NMR spectroscopy, these compounds exist as mixtures of syn and anti conformers in solution (MeCN-d₃). The structures of two compounds were established by X-ray diffraction analysis. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1650–1659, July, 2005.     

Complexes of Manganese Hematoporphyrin IX With Picoline and other Nitrogenous Bases

Abstract

The results of polarography and cyclic voltammetry studies of hematoporphyrin IX with eight different added ligands (other than H₂O and OH^?) in aqueous solvent are reported. Two nitrogenous ligand molecules were found to coordinate with both manganese (III) and manganese(II) hematoporphyrin IX. Oxygenated ligands such as acetate and pyrophosphate showed no tendency to coordinate with either manganese (III) or manganese (II) porphyrin. Porphyrin adsorption on the mercury electrode is quite evident. The adsorption mechanism appears to be complicated.     

Comprehensive stability‐indicating high‐performance liquid chromatography coupled with diode array detection method for simultaneous determination of amprolium hydrochloride and ethopabate in powder dosage form for veterinary use

This research deals with the development of a stability‐indicating high‐performance liquid chromatography method for simultaneous determination of amprolium hydrochloride and ethopabate. To the best of our knowledge, no comprehensive stability‐indicating method has been reported for analysis of this mixture. Separation was achieved using Kromasil cyano column with gradient elution of the mobile phase composed of sodium hexane sulfonate solution and methanol. Quantification was based on measuring peak areas at 266 nm. Amprolium and ethopabate peaks eluted at retention times 10.42 and 18.53 min, respectively. The proposed procedure was validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Linearity ranges for amprolium and ethopabate were 1.5–240 and 1–160 μg/mL, respectively. Analytes were subjected to stress conditions of hydrolysis, oxidation and thermal degradation. The proposed method enabled resolution of drugs from their forced‐degradation products and amprolium related substance (2‐picoline). Moreover, specificity was verified by resolution of the analytes from about 22 drugs used in antimicrobial veterinary products. The validated method was successfully applied to assay of the combined veterinary powder dosage form, additionally it was implemented in the accelerated stability study of the dosage form when stored for six months at 40°C and 75% relative humidity.     

稀土(Ⅲ)-三氟乙酰丙酮-4-皮考林-N-氧化物混配配合物的合成与表征

首次合成了稀土（Ⅲ）- 三氟乙酰丙酮（TFA）－4－皮考林－N－氧化物（4－picNO)混配配合物,通过元素分析确定其组成为Ln(TFA)2(3-picNO)(Ln=La,Nd,Eu,Tb),通过电导率,紫外光谱,IR和荧光光谱的测试,讨论了它们的性质。     

New Preparation Methodology of Functionalized Picolines

Under the organomagnesium complex n‐Bu₂CH₃MgLi conditions, picoline compounds provide a new entry to a broad range of polyfunctional picoline derivatives, after reaction with various electrophiles.     

La和KF改性Y型分子筛催化丙烯醛二乙缩醛/氨合成吡啶和3-甲基吡啶

在连续流动固定床反应中,以丙烯醛二乙缩醛、水和氨为原料,合成了吡啶和3-甲基吡啶。 比较了La-和KF-改性Y型分子筛的活性大小,考察了La负载量和改性方式、KF负载量及KF/Y的焙烧温度的影响。 研究结果表明,与纯Y型分子筛相比,La和KF改性Y型分子筛均能增强催化活性。 采用浸渍法和La负载量为1%(质量分数)时,吡啶和3-甲基吡啶总收率达到最高值;与浸渍法相比,采用离子交换法制备La-Y的活性更好。 采用浸渍法、KF负载量为1%(质量分数)和KF/Y的焙烧温度为700 ℃时,吡啶和3-甲基吡啶总收率达到最大值。     

Synthesis,crystal structure,spectroscopy, thermal properties and carbonic anhydrase activities of new metal(II) complexes with mefenamic acid and picoline derivatives

The mononuclear six metal(II) complexes ([Co(mef)₂(3-pic)₂(CH₃OH)₂] (1), [Ni(mef)₂(3-pic)₂(CH₃OH)₂] (2), [Cu(mef)₂(3-pic)₂] (3), [Co(mef)₂(4-pic)₂] (4), [Ni(mef)₂(4-pic)₂] (5), and [Cu(mef)₂(4-pic)₂] (6) with mefenamic acid and picoline ligands were synthesized, characterized, and their carbonic anhydrase inhibitory activities were evaluated. The six complexes were characterized by elemental analysis, FT-IR spectroscopy, and thermal analyses. The crystal structures of 1, 3, and 6 were determined by X-ray crystallography. The complexes have octahedral geometry. In 1, the mefenamato ligand behaved as monodentate whereas in 3 and 6, the mefenamato ligand acted as a bidentate ligand. Complexes 3 and 6 consist of the mefenamate and 4-picoline ligands. In 1, unlike the other complexes, methanol acted as a ligand and was involved in the coordination. Carbonic anhydrase I and II isoenzymes were purified from human erythrocytes. The in vitro effects of mefenamic acid, 3-picoline, 4-picoline, and the six metal(II) complexes on these isoenzymes were evaluated.     

簇合物〔WOS_3Cu_3(V-pic)_6〕Br 的合成和晶体结构

簇合物〔ＷＯＳ３Ｃｕ３（γ－ｐｉｃ）６〕Ｂｒ（Ｃ３６Ｈ４２ＢｒＯＮ６Ｓ３Ｃｕ３Ｗ, Ｍｒ＝ １１２５．３４） 属于三方晶系,空间群为Ｐ３,晶胞参数为：ａ＝ １２．２６４（５）, ｃ＝ １５．９０５（８） , γ＝ １２０．００°, Ｖ＝２０７１（２）３, μ（ＭｏＫα）＝ ５．４９０ｍ ｍ － １, Ｚ＝ ２, Ｄｃ＝ １．８０４ｇ／ｃｍ ３, Ｆ（０００）＝ １１０４ , Ｒ＝ ０．０５２ , ｗ Ｒ＝ ０．０５３． 可观察衍射点１９０１ （Ｉ≥２σ（Ｉ））。该簇合物的分子由游离的阴离子Ｂｒ－ 和簇阳离子〔ＷＯＳ３Ｃｕ３（γ－ｐｉｃ）６〕＋ 构成。阳离子中的Ｗ 原子、Ｓ原子和Ｃｕ原子构成１ 个巢状骨架结构,且该结构中存在一个通过Ｗ 和Ｏ原子的Ｃ３ 轴。     

More crystal field theory in action: the metal–4‐picoline (pic)–sulfate [M(pic)x]SO4 complexes (M = Fe,Co, Ni,Cu, Zn,and Cd)

Seven crystal structures of five first‐row (Fe, Co, Ni, Cu, and Zn) and one second‐row (Cd) transition metal–4‐picoline (pic)–sulfate complexes of the form [M(pic)_x]SO₄ are reported. These complexes are catena‐poly[[tetrakis(4‐methylpyridine‐κN)metal(II)]‐μ‐sulfato‐κ²O:O′], [M(SO₄)(C₆H₇N)₄]_n, where the metal/M is iron, cobalt, nickel, and cadmium, di‐μ‐sulfato‐κ⁴O:O‐bis[tris(4‐methylpyridine‐κN)copper(II)], [Cu₂(SO₄)₂(C₆H₇N)₆], catena‐poly[[bis(4‐methylpyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′], [Zn(SO₄)(C₆H₇N)₂]_n, and catena‐poly[[tris(4‐methylpyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′], [Zn(SO₄)(C₆H₇N)₃]_n. The Fe, Co, Ni, and Cd compounds are isomorphous, displaying polymeric crystal structures with infinite chains of M^II ions adopting an octahedral N₄O₂ coordination environment that involves four picoline ligands and two bridging sulfate anions. The Cu compound features a dimeric crystal structure, with the Cu^II ions possessing square‐pyramidal N₃O₂ coordination environments that contain three picoline ligands and two bridging sulfate anions. Zinc crystallizes in two forms, one exhibiting a polymeric crystal structure with infinite chains of Zn^II ions adopting a tetrahedral N₂O₂ coordination containing two picoline ligands and two bridging sulfate anions, and the other exhibiting a polymeric crystal structure with infinite chains of Zn^II ions adopting a trigonal bipyramidal N₃O₂ coordination containing three picoline ligands and two bridging sulfate anions. The structures are compared with the analogous pyridine complexes, and the observed coordination environments are examined in relation to crystal field theory.     

Thermochemistry of amineborane adduct formation of pyridine and picoline isomers

The enthalpy of reaction of pyridine, 2-, 3-, and 4-picoline with BH₃·THF and the enthalpy of solution of the same amines in THF were determined by reaction-solution calorimetry. From these data, the enthalpies of formation of the corresponding amineborane adducts in solution of THF were also determined. The results can be explained by considering the steric and inductive effects of the methyl group on the pyridine ring and the basicity of amines. The enthalpy of formation of the adducts in solution of THF correlates well with the available literature values of pK _a of amines also determined in THF, and the influence of the solvent on the basicity features of studied amines is verified.