5-(2-羟基苯基)-1,3,4-噻二唑-2-硫基乙酰腙化合物的合成及抑菌活性

以2-巯基-5-(2-羟基苯基)-1,3,4-噻二唑为原料,经硫醚化、肼解、腙化反应合成了9个5-(2-羟基苯基)-1,3,4-噻二唑-2-硫基乙酰腙化合物,其结构由1H NMR,13C NMR,IR,MS表征和元素分析,并初步研究了目标化合物的抑菌活性.结果表明它们大多数具有优良的抑菌活性,芳香醛-5-(2-羟基苯基)-1,3,4-噻二唑-2-硫基乙酰腙(4a～4h)比2-丁烯醛-5-(2-羟基苯基)-1,3,4-噻二唑-2-硫基乙酰腙(4i)有更好的抑菌活性.     

2-氨基-5-取代-1,3,4-噻二唑与2-氯代-1-(2,4-二氯苯基)乙酮的反应研究

2-氨基-5-烷基/芳基1,3,4-噻二唑与2-氯代-1-(2′,4′-二氯苯基)乙酮在热乙醇中反应生成一系列2-烷基/芳基-6-(4,4-二氯)苯基咪唑并[2-1-b]-1,3,4-噻二唑.产物通过元素分析, IR, 1H NMR, 13C NMR及MS分析,化合物5g的X衍射晶体结构分析表明,产物的芳基是在咪唑并[2-2-b]-1,3,4-噻二唑的6-位而不在5-位.     

2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑的合成

通过对称双酰肼与P_2S_5的缩合反应合成2,5-二-羟苯基-1,3,4-噻二唑,并由此制备了2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑及其相关化合物,同时测定了它们的生物活性。     

2-氨基-5-烷基-1,3,4-噻二唑修饰环糊精的制备与表征

在N2气保护下, 用单-(6-对甲苯磺酰基)-CD(β-CD-6-OTs)和过量的2-氨基-5-烷基-1,3,4-噻二唑在80 ℃反应2 d, 合成了5种新的2-氨基-5-烷基-1,3,4-噻二唑修饰β-环糊精. 化合物的结构用IR, 1H NMR, 13C NMR, UV, MS和元素分析等方法进行了表征. 由于环糊精的屏蔽效应, 在2-氨基-1,3,4-噻二唑修饰β-环糊精的 1H NMR中, 修饰产物中的噻二唑质子发生了高场位移. 其它的谱图数据同理论值相吻合, 这证明合成与分离方法是可行的. 研究了产物的生物活性, 结果显示部分化合物(2d, 2e)的抗菌活性明显增强.     

[5-(芳氧乙酰氨基)-1,3,4-噻二唑-2-基]硫乙酸乙酯的合成及生物活性研究

以2-氨基-5-巯基-1,3,4-噻二唑和氯乙酸乙酯为原料,水相快速合成中间体(5-氨基-1,3,4-噻二唑-2-基)硫乙酸乙酯,该中间体再与芳氧乙酰氯反应,高产率得到6种目标化合物[5-(芳氧乙酰氨基)-1,3,4-噻二唑-2-基]硫乙酸乙酯(5a-5f)。所有这些化合物都经过了红外、元素分析以及核磁共振氢谱的表征。采用离体平皿法对目标化合物进行了除草活性试验,部分化合物显示出良好的除草活性,而小麦对其耐受。     

硒催化羰基化合成1,3,4-噻二唑-2-氨基甲酸酯

以非金属硒作为催化剂,以CO替代剧毒光气作为羰基化试剂,以O₂作为氧化剂,通过2-氨基-1,3,4-噻二唑与醇以"一锅法"方式发生硒催化氧化羰基化反应,提出了一种成本低、原子经济性高、合成路线简短及环境相对友好的合成1,3,4-噻二唑-2-氨基甲酸酯类化合物的新方法.研究了反应温度、醇的用量、压力及碱的种类等对合成1,3,4-噻二唑-2-氨基甲酸酯的影响,在优化反应条件下,2-氨基-1,3,4-噻二唑可与一系列醇顺利发生羰基化反应,以45%~90%的收率得到1,3,4-噻二唑-2-氨基甲酸酯类化合物.     

3,6-二取代苯基-二-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑衍生物的合成

以2,5-二巯基-1,3,4-噻二唑为原料, 与水合肼缩合, 生成2,5-二肼基-1,3,4-噻二唑. 2,5-二肼基-1,3,4-噻二唑与苯甲酰氯反应生成2,5-二酰肼基-1,3,4-噻二唑, 以POCl₃为环合剂环合酰肼基-1,3,4-噻二唑, 合成3,6-二取代苯基- 二-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑衍生物, 合成的新化合物的结构通过元素分析、红外光谱、核磁共振氢谱和质谱予以证实, 并提出了环化反应机理.     

2,5-二芳基-噻二唑的合成及其缓蚀性能研究

合成了四种噻二唑衍生物:2,5-二苯基-1,3,4-噻二唑(DPTD),2,5-二(2-羟基苯)-1,3,4-噻二唑(2-DHPTD),2,5-二(3-羟基苯)-1,3,4-噻二唑(3-DHPTD)和2,5-二(4-羟基苯)-1,3,4-噻二唑(4-DHPTD)。采用Tafel极化测试、电化学阻抗谱(EIS)和扫描电子显微镜(SEM)研究了噻二唑衍生物在50 mg·L-1硫-乙醇体系中对银的缓蚀作用。实验结果表明:添加缓蚀剂后,银片腐蚀得到抑制,且缓蚀效率大小顺序为:[DPDT][2-DHPDT][3-DHPDT][4-DHPDT]。通过量子化学计算和分子动力学模拟进一步研究了四种噻二唑衍生物的缓蚀机理,理论计算结果与实验结果一致。     

1,3,4-噁二唑和1,3,4-噻二唑衍生物的设计、合成和生物活性研究

为了寻求新型抗肿瘤药物,设计并合成了一系列新型1,3,4-噁二唑和1,3,4-噻二唑衍生物,对这些化合物在人类四种癌细胞:B-16(皮肤黑色素瘤细胞)、PC-3(人前列腺癌细胞)、U87(人原发性胶质母细胞瘤细胞)和A549(人非小细胞肺癌细胞)进行抗肿瘤活性评价.结果显示部分化合物具有较好的抗肿瘤活性,尤其是5-{6-[4-(2-羟基乙基)哌嗪-1-基]-2-甲基嘧啶-4-基氨基}-[1,3,4-噻二唑-2-羧酸(2-甲氧基苯基)酰胺(8b)]和5-{6-[4-(2-羟基乙基)哌嗪-1-基]-2-甲基嘧啶-4-基氨基}-[1,3,4-噻二唑-2-羧酸(4-甲氧基苯基)酰胺(8c)],对四种癌细胞都显示出较高的抗肿瘤活性,其抑制活性均优于阳性对照达沙替尼,随后对这类化合物抑制肿瘤的可能靶点开展了进一步研究.     

新型4-(5-N-取代-1,3,4-噻二唑-2-巯基)-苯并[4,5]呋喃[3,2-d]嘧啶类衍生物的合成及其抗癌活性

将5-取代胺基-2-巯基-1,3,4-噻二唑引入苯并[4,5]呋喃[3,2-d]嘧啶中,设计并合成了10个新型的4-(5-N-取代-1,3,4-噻二唑-2-巯基)-苯并[4,5]呋喃[3,2-d]嘧啶类衍生物(3a～3j),其结构经1H NMR,13C NMR,IR和MS确认。用MTT法测定了3a～3j对人胃腺癌细胞体(MGC)的体外增殖活性。结果表明,3a～3j均具有不同程度的抑制MGC的活性,其中4-(5-N-2’-甲氧基苯基-1,3,4-噻二唑-2-巯基)-苯并[4,5]呋喃[3,2-d]嘧啶(3j)在10μmol·L-1的浓度下对MGC的抑制率为86.4%。     

Determination of estrogens and progestogens by mass spectrometric techniques (GC/MS, LC/MS and LC/MS/MS)

Steroid sex hormones and related synthetic compounds have been shown to provoke alarming estrogenic effects in aquatic organisms, such as feminization, at very low concentrations (ng/L or pg/L). In this work, different chromatographic techniques, namely, gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS), are discussed for the analysis of estrogens, both free and conjugated, and progestogens, and the sensitivities achieved with the various techniques are inter-compared. GC/MS analyses are usually carried out after derivatization of the analytes with bis(trimethylsilyl)trifluoroacetamide (BSTFA). For LC/MS and LC/MS/MS analyses, different instruments, ionization techniques (electrospray (ESI) and atmospheric pressure chemical ionization (APCI)), ionization modes (negative ion (NI) and positive ion (PI)) and monitoring modes (selected ion monitoring (SIM) and selected reaction monitoring (SRM)) are generally employed. Based on sensitivity and selectivity, LC/ESI-MS/MS is generally the method of choice for determination of estrogens in the NI mode and of progestogens in the PI mode (instrumental detection limits (IDLs) 0.1-10 ng/mL). IDLs achieved by LC/ESI-MS in the SIM mode and by LC/ESI-MS/MS in the SRM mode were, in general, comparable, although the selectivity of the latter is significantly higher and essential to avoid false positive determinations in the analysis of real samples. Conclusions and future perspectives are outlined.     

Mass spectrometry of rhenium complexes: a comparative study by using LDI‐MS,MALDI‐MS,PESI‐MS and ESI‐MS

A group of rhenium (I) complexes including in their structure ligands such as CF₃SO₃‐, CH₃CO₂‐, CO, 2,2′‐bipyridine, dipyridil[3,2‐a:2′3′‐c]phenazine, naphthalene‐2‐carboxylate, anthracene‐9‐carboxylate, pyrene‐1‐carboxylate and 1,10‐phenanthroline have been studied for the first time by mass spectrometry. The probe electrospray ionization (PESI) is a technique based on electrospray ionization (ESI) that generates electrospray from the tip of a solid metal needle. In this work, mass spectra for organometallic complexes obtained by PESI were compared with those obtained by classical ESI and high flow rate electrospray ionization assisted by corona discharge (HF‐ESI‐CD), an ideal method to avoid decomposition of the complexes and to induce their oxidation to yield intact molecular cation radicals in gas state [M]^+. and to produce their reduction yielding the gas species [M]^–.. It was found that both techniques showed in general the intact molecular ions of the organometallics studied and provided additional structure characteristic diagnostic fragments. As the rhenium complexes studied in the present work showed strong absorption in the UV–visible region, particularly at 355 nm, laser desorption ionization (LDI) mass spectrometry experiments could be conducted. Although intact molecular ions could be detected in a few cases, LDI mass spectra showed diagnostic fragments for characterization of the complexes structure. Furthermore, matrix‐assisted laser desorption ionization (MALDI) mass spectra were obtained. Nor‐harmane, a compound with basic character, was used as matrix, and the intact molecular ions were detected in two examples, in negative ion mode as the [M]^–. species. Results obtained with 2‐[(2E)‐3‐(4‐tert‐buthylphenyl)‐2‐methylprop‐2‐enylidene] malononitrile (DCTB) as matrix are also described. LDI experiments provided more information about the rhenium complex structures than did the MALDI ones. Copyright © 2012 John Wiley & Sons, Ltd.     

Organotin speciation in aquatic matrices by CGC/FPD, ECD and MS, and LC/MS

Summary The sensitivity and reproducibility of CGC coupled to selective detectors for the determination of alkyl and aryltin compounds (R_xSnY_z, where R=C₄H₉ or C₆H₅, and Y=CH₃ or Cl) (x+z=4) have been evaluated. In this regard, single or dual flame FPD configurations, with or without interference filter (600 nm) have been compared. The electron impact (EI) selected ion monitoring detection (SIM) CGC-MS was also considered for confirmation of the FPD assignments as well as for quantitative purposes. Alternatively, the accuracy and sensitivity of the direct analysis of organotin chlorides (Y=Cl) by cold on-column injection CGC-ECD or by thermospray LC-MS were determined. According to this, an analytical protocol based on acid digestion, extraction with organic solvents modified with tropolone, derivatization with CH₃MgCl, cleanup with alumina and CGC-FPD analysis has been successfully applied to the characterization of organotin compounds in seawater, sediments and biota. The relative detection limits of the whole procedure were dependent of the tin species and the environmental compartment considered, ranging from 0.5 to 6.5 ng l^–1 for seawater, in the filterless operation mode, and 0.1–2 ng g^–1 and 0.7–8 ng g^–1 for sediments and biota, respectively, using a 600 nm interference filter. Reproducibility was in the range of 15% RSD. Aryl and hydroxyalkyltin were identified for the first time in the aquatic compartments.     

Archaeological wood characterisation by PY/GC/MS, GC/MS, NMR and GPC techniques

The chemical characterisation of waterlogged archaeological wood is of paramount importance in terms of understanding not only the degradation processes of wood in artistic and archaeological objects but also the development of consolidation and conservation procedures. The two different types of archaeological waterlogged wood were characterized using several analytical techniques. The analytical protocol consists in using PY/GC/MS with in situ derivatisation with hexamethyldisilazane, GC/MS of the extractives, ¹H, ¹³C and ³¹P NMR analysis, and GPC. The main results showed that one of the ancient samples was a gymnosperm wood from the Pinaceae family, whereas the other type of wood was an angiosperm. Lignin from the angiosperm was oxidised in a benzylic position of β-O-4 to give oxo functional groups, in primary alcohol moiety to give carboxylic groups. In addition, the formation of a new intermonomeric bond 5-O-4 was observed.     

UHPLC‐MS/MS quantification of buprenorphine,norbuprenorphine, methadone,and glucuronide conjugates in umbilical cord plasma

Opioid use during pregnancy can result in the newborn being physically dependent on the substance, thus experiencing drug withdrawal, termed neonatal abstinence syndrome (NAS). Buprenorphine and methadone are two drugs used to treat opioid withdrawal and are approved for use in pregnancy. Quantification of these compounds in umbilical cord plasma would help assess in utero exposure of neonates in cases of buprenorphine or methadone use during pregnancy. An LC‐MS/MS method using solid‐phase extraction sample preparation was developed and validated for the simultaneous quantification of methadone, buprenorphine, norbuprenorphine, and glucuronide metabolites in umbilical cord plasma. The average accuracy (percentage error) and precision (relative standard deviation) were <15% for each validated concentration. Our data establishes a 2 week maximum freezer storage window in order to achieve the most accurate cord plasma concentrations of these analytes. Additionally, we found that the umbilical cord tissue analysis was less sensitive compared with analysis with umbilical cord blood plasma, indicating that this may be a more appropriate matrix for determination of buprenorphine and metabolite concentrations. This method was successfully applied to the analysis of cord blood from women with known buprenorphine or methadone use during pregnancy. Copyright © 2015 John Wiley & Sons, Ltd.     

Metabolic profile and pharmacokinetics of polyphyllin I,an anticancer candidate,in rats by UPLC‐QTOF‐MS/MS and LC‐TQ‐MS/MS

Polyphyllin I (PPI), a natural steroidal saponin originating from rihzome of Paris polyphylla , is a potential anticancer candidate. Previous pharmacokinetics study showed that the oral bioavailability of PPI was very low, which suggested that certain amount of PPI might be metabolized in vivo . However, to date, information regarding the final metabolic fates of PPI is very limited. In this study, metabolites of PPI and their pharmacokinetics in rats were investigated using UPLC‐QTOF‐MS/MS and LC‐TQ‐MS/MS. A total of seven putative metabolites, including six phase I and one phase II metabolites, were detected and identified with three exact structures by comparison with authentic standards for the first time. Oxidation, deglycosylation and glucuronidation were found to be the major metabolic processes of the compound in rats. The pharmacokinetics of prosapogenin A, trillin and diosgenin, three deglycosylation metabolites of PPI with definite anticancer effects, were further studied, which suggested that the metabolites underwent a prolonged absorption and slower elimination after intragastric administration of PPI at the dose of 500 mg/kg. This study provides valuable and new information on the metabolic fate of PPI, which will be helpful in further understanding its mechanism of action.     

Comprehensive analysis of proteins of pH fractionated samples using monolithic LC/MS/MS, intact MW measurement and MALDI-QIT-TOF MS

A comprehensive platform that integrates information from the protein and peptide levels by combining various MS techniques has been employed for the analysis of proteins in fully malignant human breast cancer cells. The cell lysates were subjected to chromatofocusing fractionation, followed by tryptic digestion of pH fractions for on-line monolithic RP-HPLC interfaced with linear ion trap MS analysis for rapid protein identification. This unique approach of direct analysis of pH fractions resulted in the identification of large numbers of proteins from several selected pH fractions, in which approximately 1.5 microg of each of the pH fraction digests was consumed for an analysis time of ca 50 min. In order to combine valuable information retained at the protein level with the protein identifications obtained from the peptide level information, the same pH fraction was analyzed using nonporous (NPS)-RP-HPLC/ESI-TOF MS to obtain intact protein MW measurements. In order to further validate the protein identification procedures from the fraction digest analysis, NPS-RP-HPLC separation was performed for off-line protein collection to closely examine each protein using MALDI-TOF MS and MALDI-quadrupole ion trap (QIT)-TOF MS, and excellent agreement of protein identifications was consistently observed. It was also observed that the comparison to intact MW and other MS information was particularly useful for analyzing proteins whose identifications were suggested by one sequenced peptide from fraction digest analysis.     

HPLC,MS and LC/MS Studies of the Interaction of Gossypol with Alcohols

Abstract

Gossypol reacts with alcohol solvents to form a complex series of hemiketal and ketal derivatives of its various tautomeric forms, which revert to gossypol or to the readily hydratable anhydrogossypol on attempted isolation and during mass spectrometry.