Anion selective polymeric membrane electrodes based on cyclopalladated amine complexes

The potentiometric anion selectivity of two polymer membrane based electrodes (I and II) formulated with two new cyclopalladated amine complexes as the active components are examined. The electrodes exhibit a non-Hofmeister selectivity pattern with a significantly enhanced response towards thiocyanate, iodide and nitrite. The graph potential versus log c is linear over the concentration range 10(-6)-6x10(-2) M thiocyanate with electrode I and 10(-6)-10(-3) M with electrode II; 10(-5)-10(-2) M iodide with electrode I and 10(-3)-6x10(-2) M with electrode II; and 10(-3)-6x10(-2) M nitrite with both electrodes. The influence of the plasticizer and pH are studied. The potentiometric selectivity coefficients for I, II and blank membrane electrodes are reported. The selective interaction between Pd(II) thiocyanate, iodide and nitrite is postulated to be the reason for its higher response.     

从中药繁缕中几个黄酮碳苷成分的分离和分析看LC-MS-MS技术的优势与不足

繁缕[Stellariamedia(L.)Cyr.]为石竹科植物繁缕的茎、叶,具有活血、去瘀、下乳、催生作用,主要含皂苷、黄酮、酚酸、氨基酸等成分。贵州民间作为降血脂药物应用,效果很好。文献调研表明,其活性成分可能为黄酮苷类化合物。我们采用大孔吸附树脂技术,得到了其主要活性部位,并采用液相色谱-质谱技术,初步分析了其中的主要成分。它们主要是黄酮碳苷类化合物,其中3个成分的相对分子质量均为594,分别以不同方式与两个六碳糖相连接;另外3个成分的相对分子质量为564,分别也以不同方式与1个六碳糖和1个五碳糖相连接。本文报道对相对分子质量为594的主要成分的分离和LC-MS-MS分析,结果显示了该技术在中药分离和分析中的巨大优势,同时也显露出它在分析异构体时的局限性。我们采用1D-HOHAHA技术分析出了该成分两个异构体的结构特征。     

Synthesis of 3-substituted-2-benzothiazolinone, 2-benzoxazolinone and benzothiazoline-2-thione

The reaction of 2-benzothiazolinone, 2-benzoxazolinone or benzothiazoline-2-thione under basic conditions with various electrophiles afforded the titled compounds 1-13, 29-31 and 40-48. The 3-(substituted-aminomethyl)-2-benzothiazolinone and related compounds 14-25 were prepared by the reaction of 3-(hydroxymethyl)-2-benzothiazolinone or the appropriate 2-benzothiazolinone and formaldehyde with the appropriate amine or substituted aniline. The reaction of 9, 13 or 25 with methyl iodide afforded the quaternary ammonium iodides 26-28. The reaction of the appropriate potassium salts of various phenol with 3-(chloromethyl)-2-benzothiazolinone afforded the 3-(substituted-phenoxymethyl)-2-benzothiazolinone and related compounds 32-39. The ethyl or isopropylxanthates 49-54 were synthesized by the reaction of 3-(chloromethyl)-2-benzo-thiazolinone and appropriate compounds with potassium ethyl or isopropyl xanthate. The reaction of 3-(chloromethyl)-2-benzothiazolinone with sodium sulfide afforded the sulfide 55.     

Lithiation and reactions of stilbene oxides: synthetic utility

The lithiation of trans- and cis-stilbene oxides (+/-)-1 and 8 has been investigated. While with 8, lithiation occurred exclusively at the benzylic position, with the trans isomer (+/-)-1, ortho-lithiation competed with alpha-lithiation depending upon the experimental conditions. The configurational stability of the alpha-lithiated cis- and trans-stilbene oxides (+/-)-2 and (+/-)-9, respectively, was proved as well as that of scalemic stilbene oxide (R,R)-2.     

无外加催化剂条件下邻取代芳香醛与5,5-二甲基-1,3-环己二酮的反应研究

在DMF溶剂中,不外加催化剂使邻取代芳香醛(1)与5,5-二甲基-1,3-环己三酮(2)发生缩合和加成反应生成3,3,6,6-四甲基-4a-羟基-9-芳基-1,8二氧化-2,3,4,4a,5,6,7,8,9a-十氢化-1H氧杂蒽(3a～3d)。在同样条件下,邻羟基芳香醛与5,5-二甲基-1,3-环己三酮则发生缩合,加成和脱水反应生成3,3-二甲基-9-(5,5-二甲基-3-羟基-2-环己烯-1-酮-2-基)-1-氧代-2,3,4,9-四氢化-1 氧杂蒽(4a～4b)。用单晶X-射线分析法确定了产物3a和4a的晶体结构。     

[Z]-1-[2-(三芳基锡基)乙烯基]环辛醇的合成和性质

本文用三苯基氢化锡、三对甲苯基氢化锡作为锡氢化试剂与1-乙炔基环辛醇进行反应, 合成了两个有机锡化合物: [Z]-1-[2-(三苯基锡基)乙烯基]环辛醇(1)和[Z]-1-[2-(三对甲苯基锡基)乙烯基]环辛醇(2), 并测定了1的晶体结构。1和2分别与ICl, Br2, I~2反应, 得到六个有机锡一卤化物和三个有机锡二卤化物(3-11)。有机锡二卤化物6和一卤化物5与KOH乙醇溶液反应, 分别得到相应的锡氧化物和锡氢氧化物(12, 13)。有机锡二卤化物8分别与含氮双齿配体[2,2'-联吡啶(Bipy),5-硝基-1,10-邻菲罗啉(Nphen),8-羟基喹啉(Oxin)]反应, 得到三个相应的配合物(14-16)。十六个新化合物通过元素分析、锡含量测定、IR、^1H NMR测定对其结构进行了表征, 同时提出了1和2的生成反应历程。     

无外加催化剂条件下芳香醛与活性亚甲基化合物的缩合反应和迈克尔加成反应

在DMF溶剂中,不外加催化剂使芳香醛(1)与2,2-二甲基-1,3-二氧六环-4,6-二酮(2)发生缩合反应生成2,2-二甲基-5-芳亚甲基-1,3-二氧六环-4,6-二酮(3a～f)。在同样条件下,芳香醛与5,5-二甲基-1,3-环己二酮(4)则发生缩合和迈克尔加成反应生成2,2’-芳亚甲基双(3-羟基-5,5-二甲基-2-环己烯-1-酮)(5a～h)。用单晶X-射线分析法确定了产物5b的晶体结构。     

Syntheses of (-)-funebrine and (-)-funebral, using sequential transesterification and intramolecular cycloaddition of a chiral nitrone

The first syntheses of (-)-funebrine [(-)-1] and (-)-funebral [(-)-2] are described. The syntheses feature sequential formation of nitrone VI from methyl glyoxylate (5) with oxime 6, transesterification of nitrone VI with (E)-crotyl alcohol (4), and intramolecular cycloaddition of the resulting nitrone VII bearing crotyl ester to afford cycloadduct 7 as a major product. The adduct 7 was readily elaborated to amino lactone (-)-3, the key synthetic intermediate of (-)-1 and (-)-2.     

Synthesis of Optically Active Vasicinone Based on Intramolecular Aza-Wittig Reaction and Asymmetric Oxidation(1)

Both optical isomers of a quinazoline alkaloid, vasicinone, were synthesized by two different methods. The first method used (3S)-3-hydroxy-gamma-lactam as a chiral synthon, which was, after O-TBDMS protection, o-azidobenzoylated followed by treatment with tri-n-butylphosphine to afford (S)-(-)-vasicinone via the tandem Staudinger/intramolecualr aza-Wittig reaction. The second method utilized asymmetric oxygenation of deoxyvasicinone with (1S)-(+)- or (1R)-(-)-(10-camphorsulfonyl)oxaziridine (the Davis reagent), respectively. The aza-enolate anion of deoxyvasicinone was treated with (S)-(+)-reagent to afford (R)-(+)-vasicinone in 71% ee, while the reaction with (R)-(-)-reagent gave (S)-(-)-vasicinone in 62% ee. The optical purity was analyzed by HPLC on specially modified cellulose as a stationary phase. These results provided a facile method to prepare both optical isomers of vasicinone and confirmed the recently reversed stereochemistry of natural (-)-vasicinone.     

Reactions of dimethyl acetylenedicarboxylate—X: Reaction with salicylaldehyde,ortho hydroxyacetophenone, 2-hydroxychalcones and 2,2′-dihydroxychalcones

Salicylaldehyde reacts with dimethyl acetylenedicarboxylate in benzene solution to give a mixture of dimethyl o-formylphenoxymaleate, dimethyl o-formylphenoxyfumarate, 2,3-dicarbomethoxychrom - 2 - en - 4 - ol, 2,3 - dicarbomethoxychrom - 3 - en - 2 - ol, dimethyl (2,3 - dicarbomethoxychrom - 2 - en - 4 - yl) - oxalacetate and dimethyl fumarate. 2,3 - Dicarbomethoxychrom - 3 - en - 2 - ol in this reaction is formed from 2,3 - dicarbomethoxychrom - 2 - en - 4 - ol through a benzopyrylium intermediate. The reaction of salicylaldehyde with excess of dimethyl acetylenedicarboxylate, however, gives a mixture of 2,3 - dicarbomethoxychrom - 3 - en - 2 - ol and dimethyl (2,3 - dicarbomethoxychrom - 3 - en) - 2 - oxyfumarate. 2,3 - Dicarbomethoxychrom - 3 - en - 2 - ol itself reacts further with dimethyl acetylenedicarboxylate to give 2,3,12 - tricarbomethoxychrom - 3,4 - eno[2,3 - b] pyrone. Similarly, the reaction of o-hydroxyacetophenone with dimethyl acetylendicarboxylate gives a mixture of dimethyl o-acetylphenoxymaleate, dimethyl o-acetylphenoxyfumarate, 2,3 - dicarbomethoxy - 4 - methylchrom - 2 - en - 4 - ol and 2,3 - dicarbomethoxy - 4 - methylchrom - 3 - en - 2 - ol. Both 2-hydroxychalcone and 2 - hydroxy - 4′ - methoxychalcone give mixtures of chalcone - 2 - oxymaleate and chalcone - 2 - oxyfumarate. The reaction of 2,2t?-dihydroxychalcone, however, gives 2′-hydroxyflavone, in addition to the expected maleate and fumarate. Similar reactions of 5 - chloro - 2,2′ - dihydroxychalcone and of 3,5 - dibromo - 2,2′ - dihydroxychalcone, on the other hand, give 2,3 - dicarbomethoxy - 4 - (o - hydroxyphenacyl) - 6 - chlorochrom - 2 - ene and 2,3 - dicarbomethoxy - 4 - (o - hydroxyphenacyl) 6,8 - dibromochrom - 2 - ene, respectively, together with the corresponding maleates and fumarates.     

(E)-1-alkyl-4-

(E)-1-Alkyl-4-[2-(alkylsulfonyl)-1-ethenyl]pyridinium salts were synthesized in two steps. These sulfones were stable at pH 7.3 and underwent a nucleophilic vinylic substitution (S(N)V) with mercaptans, including thiouracile, to give the corresponding 4-(thiovinyl)-pyridinium salts. The X-ray diffraction structure of (E)-1-methyl-4-[2-(ethylsulfanyl)-1-ethenyl]pyridinium iodide indicated conjugation of the sulfur with the pyridinium ring. (Z)-1-Methyl-4-[2-(methylsulfanyl)-1-ethenyl]pyridinium iodide, prepared from the corresponding thioether by reaction with methyl iodide in diethyl ether, underwent isomerization to the E isomer in a first-order reaction in deuterated [D6]DMSO with an activation energy of 14 kcalmol(-1). At pH 7, the (E)-1-methyl-4-[2-(methylsulfonyl)-1-ethenyl]pyridinium iodide (19) reacted specifically with thiols. The reaction of this sulfone with glutathione in a TES buffer at pH 7 was a second-order reaction (k = 4,100 M(-1)s(-1) at 30 degrees C) and gave the corresponding substitution product with an intense long wavelength absorption band (lambdamax=360 nm, epsilon = 27,500 M(-1)cm(-1)). The modification of different enzymes of known structure with 19 showed the high selectivity of this reagent towards thiol groups and its usefulness in the quantitative determination of free thiol groups in proteins.     

Characterization of a 10.3-microm pulsed DFB quantum cascade laser

We have measured the output parameters of a 10.3-microm pulsed distributed-feedback (DFB) quantum cascade (QC) laser manufactured by Alpes Lasers and intended for high-sensitivity detection of ammonia and ethylene. The laser beam was collimated with an AR-coated aspheric ZnSe lens with focal length of 11.6mm and clear aperture of 16.5mm. Near- and far-field distributions of the laser emission were recorded with an infrared imaging camera. The fast-and slow-axis laser beam divergences were measured to be 1.2 and 1.4 mrad (FWHM), respectively. The divergence was found to be increasing with injection current. An air-spaced Fabry-Perot interferometer with free spectral range of 0.05 cm(-1) was used to measure the frequency tuning rates of the laser. The laser was tuned by either heat sink temperature, injection current or pulse repetition rate with rates of approximately -8 x 10(-2)cm(-1)K(-1), -7 x 10(-2)cm(-1)A(-1) and -9 x 10(-4)cm(-1)kHz(-1), respectively. The laser frequency decreased linearly with a rate of 10(-2)cm(-1)ns(-1) ( approximately 300 MHzns(-1)) for laser pulses varied from 10 to 50 ns, and the frequency chirp rate was found to decrease for longer laser pulses.     

Ph~2C(OH)CH=CHSnAr~3的卤化物的合成、表征和性质

首次以非碳环醇(Z)-3-三芳基锡基-1,1-二苯基-2-丙烯基-1-醇[Ph~2C(OH)CH=CHSnAr~3]和卤素或拟卤素发生取代反应得到卤化物,并以此合成了氢氧化物、氧化物和配合物。通过元素分析、IR和^1HNMR等对上述17种新化合物的结构进行了表征,并提出了卤化物的性质。     

光学活性N-N-二烷基-β-氨基醇硼烷配合物对酮肟醚的不对称还原反应(Ⅱ)

光学活性(S)-(-)-2-(1-吡咯烷基)-1,1-二苯基-丙醇-1(1a)和(S)-(-)-2(1-吡咯烷基)-1,1,3-三苯基-丙醇-1(1b), 分别与过量的硼烷反应, 生成相应的硼烷-手性翁唑硼烷配合物, 可用于脂肪酮肟醚和芳香酮肟醚的碳-氮双键的不对称还原反应, 得到光学活性伯胺, 化学收率则为52~76%, 光学收率为6~99%, 讨论了不同还原底物的结构对立体选择性的影响作用。     

Atmospheric chemistry of 3-pentanol: kinetics, mechanisms, and products of Cl atom and OH radical initiated oxidation in the presence and absence of NOX

Smog chamber/FTIR techniques were used to study the atmospheric chemistry of 3-pentanol and determine rate constants of k(Cl+3-pentanol) = (2.03 +/- 0.23) x 10 (-10) and k(OH+3-pentanol) = (1.32 +/- 0.15) x 10 (-11) cm (3) molecule (-1) s (-1) in 700 Torr of N 2/O 2 diluent at 296 +/- 2 K. The primary products of the Cl atom initiated oxidation of 3-pentanol in the absence of NO were (with molar yields) 3-pentanone (26 +/- 2%), propionaldehyde (12 +/- 2%), acetaldehyde (13 +/- 2%) and formaldehyde (2 +/- 1%). The primary products of the Cl atom initiated oxidation of 3-pentanol in the presence of NO were (with molar yields) 3-pentanone (51 +/- 4%), propionaldehyde (39 +/- 2%), acetaldehyde (44 +/- 4%) and formaldehyde (4 +/- 1%). The primary products of the OH radical initiated oxidation of 3-pentanol in the presence of NO were (with molar yields) 3-pentanone (58 +/- 3%), propionaldehyde (28 +/- 2%), and acetaldehyde (37 +/- 2%). In all cases the product yields were independent of oxygen concentration over the partial pressure range 10-700 Torr. The reactions of Cl atoms and OH radicals with 3-pentanol proceed 26 +/- 2 and 58 +/- 3%, respectively, via attack on the 3-position to give an alpha-hydroxyalkyl radical, which reacts with O 2 to give 3-pentanone. The results are discussed with respect to the literature data and atmospheric chemistry of 3-pentanol.     

Syntheses of 4-(2-hydroperoxy-2,2-diarylethyl)-3,5-dimethylpyrazoles, 4-(2-hydroxy-2,2-diarylethyl)-3,5-dimethylpyrazoles and the related compounds

The reactions of 1,1-disubstituted ethenes with 2,4-pentanedione in the presence of manganese(III) acetate and atmospheric oxygen yielded 4-acetyl-6,6-diaryl-3-methyl-1,2-dioxan-3-ols. The latter gave 4-(2-hydroperoxy-2,2-diarylemyl)-3,5-dimethylpyrazoles by the reaction with hydrazines in methanol-acetic acid (1:1 v/v) at 50° in 15-77% yields, or 4-(2-hydroxy-2,2-diarylethyl)-3,5-dimethylpyrazoles by the reaction with hydrazines in methanol in 2-78% yields. The acid-catalyzed reaction of 4-(2-hydroperoxy-2,2-diarylethyl)-3,5-dimethylpyrazoles yielded 4-(aroylmethyl)-3,5-dimethylpyrazoles (15-55%) and 4-(2,2-diarylethenyl)-3,5-dimethylpyrazoles (9-29%).     

苯并氮杂冠醚的反式结构及性能的理论研究

用分子动力学模拟退火找出苯并氮杂冠醚(C~1~8H~2~3O~7N)的最低能量构型后,用半经验量子化学方法AM1分别优化出了该苯并氮杂冠醚的顺、反式构型,对反式进行了前沿轨道、电荷密度计算,并作了振动分析。优化计算苯并氮杂冠醚反式构型的化合物结构数据与X射线晶体测定结果一致。对其振动分析,指认了化合物不同种类键的振动红外特征吸收峰。结构分析表明这种苯并氮杂冠醚的反式结构呈马蹄铁型,分子内有较大空腔,能够嵌入稀土金属阳离子,有较好的配位性。     

Acid-promoted rearrangement of drimane type epoxy compounds and their application in natural product synthesis

The reactions of (±)-α-epoxy drimenol (4) and (±)-α-epoxy drimenyl cyanide (6) with acids (proton acid or Lewis acid) selectively gave the rearranged aldehyde (±)-13 and (±)-15 having the hydroindane skeleton, respectively, while the reactions of (±)-4 and (±)-6 with Dibal-H selectively afforded the allyl alcohol (±)-14 and (±)-16, respectively. The reactions of (8aR)-6 and (8aS)-6 with Dibal-H were applied for the determination of the absolute structure of natural 7β-acetoxy-ent-labda-8(17),13(14)E-dien-15-ol (18). The reaction of (±)-α-epoxy bicyclofarnesol (5) and (8aS)-5 with proton acid selectively provided the rearranged ketol (±)- and (8aS)-31 having the hydroindane skeleton, respectively. The optically active (8aS)-31 was converted to the natural (9S)-austrodoric acid (33).     

Selective reduction of tertiary alkyl,benzyl, and allyl halides to hydrocarbons using lithium 9,9-di-n-butyl-9-borabicyclo[3.3.1]nonanate

The title 9-borabicyclo[3.3.1]nonane(9-BBN) ate complex (1) brings about selective removal of tertiary alkyl, benzyl and allyl halides to give the corresponding hydrocarbons in excellent yields without concomitant attack on secondary, primary and aryl derivatives. The reduction of cis- and trans - 4 - t - butyl - 1 - methylcyclohexyl chlorides (2) with 1 gives 4 - t - butyl - 1 - methylcyclohexanes (3) with partial inversion of configuration in cyclohexane, while that in benzene gives thermodynamically stable trans-3 predominantly. The reactions of 1,1 - dimethyl - 5 - hexenyl chloride (4) and 1,7,7 - trimethylbicyclo[2.2.1]hept - 2 - yl chloride (8) with 1 proceed with the rearrangements characteristic to a carbonium ion intermediate. The reduction of 1 - ethyl - 1 - methylpentyl chloride with 1 follows a second-order rate equation.     

Synthesis and reactions of 4-(arylhydrazino)coumarins

The interaction of 4-hydroxycoumarin with phenyl-, 2-chlorophenyl- and 4-bromophenyhydrazine hydrochlorides in the presence of triethylamine led in all cases to the corresponding 4-(arylhydrazino)-coumarins and 1-aryl-3-(2-hydroxyphenyl)-2H-pyrazolin-5-ones. 4-(Arylhydrazino)coumarins reacted with 4-chlorobenzaldehyde in the presence of piperidine acetate to give the corresponding 2-aryl-3-(4-chlorophenyl)[1]benzopyrano[4,3-b]pyrazol-4-ones. The reaction of 4-(4-bromophenylhydrazino)-coumarin with 4-chlorobenzaldehyde in the presence of piperidine acetate and an excess of piperidine gave 2-(4-bromophenyl)-5-(4-chlorophenyl)-3-(2-hydroxyphenyl)-4-(piperidinocarbonyl)pyrazole, but the reaction of phenyl- and 4-(2-chlorophenylhydrazino)coumarins with 4-chlorobenzaldehyde gave 1-aryl-5-(4-chlorophenyl)-3-(2-hydroxyphenyl)-4-(1-piperidino)carbonyl-4,5-dihydropyrazoles.