无溶剂超声辐射下琥珀酸二酰亚胺磺酸铈催化合成5-[(3-吲哚基)-甲基]-2,2-二甲基-1,3-二噁烷-4,6-二酮衍生物

在琥珀酸二酰亚胺磺酸铈催化下,吲哚、醛和2,2-二甲基-1,3-二噁烷-4,6-二酮在无溶剂条件下超声辐射合成了10种5-[(3-吲哚基)-甲基]-2,2-二甲基-1,3-二噁烷-4,6-二酮衍生物.当催化剂的用量为3%(摩尔分数)时,30℃反应30~60 min,收率为68.9%~96.7%.此外,还探讨了琥珀酸二酰亚胺磺酸铈的催化机理.该方法具有条件温和,反应时间短且收率高的优点.催化剂邻琥珀酸二酰亚胺磺酸铈对环境友好且可循环利用.     

脂肪族二酸二烷基双去氢枞基双噁二唑的合成及除草活性

以去氢枞酸为原料,制备去氢枞酸酰氯.以脂肪族二酸为原料,经过脂肪族二酸二乙酯得到脂肪族二酸二酰肼.脂肪族二酸二酰肼与去氧枞酸酰氯在相转移催化下反应得到N,N＇-二去氢枞酰基取代脂肪族二酸二酰肼,再脱水环合,得到5个标题化合物脂肪族二酸二烷基双去氢枞基双噁二唑.通过元素分析,IR,MS,1H NMR和13C NMR对所合成的新化合物进行了结构表征.初步的除草活性测试表明,化合物6b～6e在100 μg/mL浓度下对油菜的胚根生长具有良好的抑制作用,抑制率均超过80％.     

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.     

己二酰肼脂肪族双酰基衍生物的电子轰击电离质谱特征

前文曾报道了己二酰二肼脂肪族双酰基衍生物的金属减活作用 [1] ,在研究中还发现该类化合物在电子轰击电离 (EI)条件下的质谱裂解行为具有特征的规律 .因为 ,在已研制和开发的酰肼类金属减活剂中 ,— NHNH—的封端为芳环者较多 ,为脂肪族碳链者甚少 [2 ,3 ] ;而且该类化合物还是合成具有生物活性及电子传输功能的双 - 1 ,3 ,4-二唑的重要前体 ,正在重新引起重视 [4 ,5] ;再则它们的溶解性普遍很差且使用时浓度较小 ,所以关于该类化合物结构表征的波谱学研究并不多见 .本文报道了己二酰肼脂肪族双酰基衍生物的 EIMS特征 ,对于该类化合…     

金属参与的N-酰基腙的偕二氟烯丙基化反应：高效合成偕二氟高烯丙基胺

金属铟参与醛衍生的N-酰基腙 1a-1q,4a-4g与3-溴-3,3-二氟丙烯 2 的反应,分别高效得到α, α-二氟高烯丙基肼 3a-3q,5a-5g。该反应条件温和,操作简便。硝基,酚羟基,苄氧基,α, β-不饱和醛的碳-碳双键等官能团对该反应具有良好的官能团兼容性。通过用锌粉代替铟粉, 酮衍生的N-酰基腙 6a-6d 也能发生偕二氟烯丙基化反应,以中等产率得到α, α-二氟高烯丙基肼 7a-7d。裂解肼3a的 N-N键顺利得到偕二氟高烯丙基胺 8,化合物 8 经丙烯酰化,随后进行RCM关环反应,可以方便的转化为偕二氟-γ-取代α, β-不饱和内酰胺 11。     

对称双-1,3,4-噁二唑化合物的合成及性质

首先以苯氧乙酰肼和二酰氯为原料反应得到对称双酰肼化合物,再以POCl3合环得到系列对称双-1,3,4-噁二唑化合物。考察了该系列化合物的紫外-可见吸收光谱,其中,间苯双-1,3,4-噁二唑化合物在250nm附近有明显的最大吸收峰,对苯双-1,3,4-噁二唑化合物的最大吸收峰则红移至290nm附近;而脂肪族双-1,3,4-噁二唑化合物没有明显的最大吸收峰,说明没有大的共轭体系,与结构相符合。所有化合物的结构均经元素分析、IR、1H NMR和MS确证。     

N,N′-二芳基己二酰双偶氮化合物的合成及其结构表征

N;N′-二芳基己二酰二肼;N;N′-二芳基己二酰双偶氮化合物;合成     

1,1,1-三氯-2-取代肼基-3-硝基丙烷及其衍生物的合成

叙述了以1,1,1-三氯-2-乙酰氧基-3-硝基丙烷和1,1,1-三氯-2-肼基-3-硝基丙烷为原料,合成脂肪和芳香肼类、酰肼类、偶氮类以及腙类等四十三个新化合物的方法,将N-芳基-N'-[2-(1,1,1-三氯-3-硝基)丙基]肼用N-溴代丁二酰亚胺氧化成1,1-二氯-2-芳偶氮基-3-硝基丙烯后,不经分离直接加入过量的醇和定量的水继续反应,可方便地获得β-硝基丙酮酸酯腙类化合物,收率达60%以上。初步抑菌活性测定结果表明,大多数化合物呈现不同程度的抑菌活性,其中以肼类和偶氮类化合物的活性最高,丙酮酸酯腙类化合物次之。     

1-[6-(3,5-二甲基-1H-吡唑-1-基)-1,2,4,5-四嗪-3-基]酰肼及其衍生物的合成与表征

以水合肼和硝酸胍为原料,经肼化、环化、氧化和肼化四步反应合成了1-[6-(3,5-二甲基-1H吡唑-1-基)-1,2,4,5-四嗪-3-基]酰肼(4);4与酰氯或磺酰氯反应合成了一系列新型的1-[6-(3,5-二甲基-1H-吡唑-1-基)-1,2,4,5-四嗪-3基]酰肼衍生物(6a～6j),其结构经1H NMR,IR...     

己二酰二肼脂肪族双酰基衍生物的金属减活作用

二酰基己二酰二肼;聚丙烯;己二酰二肼脂肪族双酰基衍生物的金属减活作用     

A Rapid HPLC Determination of C2–C7 Aliphatic Diamines by Precolumn Derivatization with Acetylacetone in Methanol-Water

A rapid reversed-phase high performance liquid chromatographic analysis for the determination of seven aliphatic diamines in water is described. Precolumn derivatization with acetylacetone is used for traces of aliphatic diamines in water-methanol (10:1 v/v) medium. The acetylacetone derivatives obtained after 15 min were extracted with an octadecylsilane functionalized silica cartridge, and then injected into the HPLC system. The HPLC system consisted of a reversed-phase column, and a spectrophotometric detector adjusted to 310 nm as elution solvent a methanol-tetrahydrofuran-water (55:3:42 v/v) mixture was used. The acetylacetone derivatives of the C2-C7 diamines were separated with a good resolution in 23 min. The detection limits achieved for each diamine were between 0.18-0.72 ng/ml for a 100 ml water sample. The recovery of diamine derivatives from river and seawater was 88-101%, with relative standard deviations of 2.2-4.0%, and 82-93%, with relative standard deviations of 2.8-4.6%, respectively. Aliphatic diamines are widely used as chemical reagents, occur as metabolic in biomedical studies and are used as chelating agents in analytical chemistry. As they are soluble in water, their use results in their ultimate release to the environment. The need for a sensitive, selective and rapid determination of aliphatic diamines in environmental samples thus has become important. Dobberpuhl et al. [1] have described a highly sensitive pulsed electrochemical detection for aliphatic monoamines and diamines following their chromatographic separation. Although, it is a sensitive method the determination has to be carried out in alkaline conditions. The most common method for the determination of aliphatic amines is high performance liquid chromatography (HPLC), using different derivatives with either fluorescence [2-5] or UV-visible detection [6-11]. The fluorescence detection method most often relies on post-column derivatization, which requires a second pump to deliver the reagent. Acetylacetone is soluble to some degree in water, and has been used as a pre-column derivatization reagent [12]. The reaction only is effective with diamines, and results in UV-active acetylacetone derivatives known as Schiff bases. But acetylacetone requires a long reaction time in water, which makes it rather unsuitable for routine analysis. In this paper an optimized reversed-phase HPLC determination procedure for C2-C7 aliphatic diamines at low ng/ml levels in water is described.     

m-4-m型Gemini表面活性剂对铂电极上亚甲蓝吸附溶出伏安行为的影响

在0.050 mol·L-1磷酸盐缓冲溶液(PBS)中(pH=6.4), 亚甲蓝(MB)在铂电极上于-0.2 V产生一对不明显的伏安峰. 当向溶液中加入阳离子型Gemini表面活性剂Br-C16H33N+(CH3)2-C4H8-N+(CH3)2C16H33Br-, Br-C12H25N+(CH3)2-C4H8-N+(CH3)2C12H25Br-或Br-C8H17N+(CH3)2-C4H8-N+(CH3)2C8H17Br-后, 亚甲蓝的氧化峰显著增高, 还原峰降低, 氧化还原峰峰电位均正移, 这和表面活性剂与MB在电极表面的协同吸附有关. 联接基团相同的Gemini表面活性剂, 其影响程度随烷基链的增长而逐渐增强. 增大表面活性剂的浓度, MB的氧化峰先升高后缓慢降低. 如当Br-C16H33N+(CH3)2-C4H8-N+(CH3)2C16H33Br-的浓度为15 μmol·L-1 时, 5 μmol·L-1 MB的氧化峰峰电流达到最大值. 此外,溶液pH值和富集电位等对MB及表面活性剂的吸附亦有影响.     

超高效液相色谱法测定儿童指画印泥中柚皮苷和苯甲酸地那铵

儿童指画印泥样品用甲醇与0.02mol·L^-1磷酸二氢钾溶液以体积比3∶7组成的混合液超声萃取20min,冷却至室温,于16 000r·min^-1转速下离心15min,取上清液过0.22μm过滤膜过滤,采用超高效液相色谱法测定滤液中柚皮苷和苯甲酸地那铵的含量。以C18色谱柱为分离柱,用乙腈和pH 4.3的0.02mol·L^-1磷酸二氢钾溶液以不同比例混合的溶液为流动相进行梯度洗脱,用二极管阵列检测器测定。柚皮苷和苯甲酸地那铵的质量浓度均在0.1~5.0mg·L^-1内与其对应的峰面积呈线性关系,检出限(3S/N)依次为0.75,1.15mg·kg^-1。以空白样品为基体进行加标回收试验,所得回收率为73.5%~104%,测定值的相对标准偏差(n=6)为4.2%~6.6%。     

草甘膦的邻硝基苯磺酰氯柱前衍生高效液相色谱分析

以邻硝基苯磺酰氯(NBSC)为衍生化试剂,建立了柱前衍生草甘膦的反相高效液相色谱紫外检测法,并对衍生化条件进行了优化.最佳衍生化条件为:衍生温度25℃,反应时间10 min,硼砂缓冲溶液浓度0.25 mol/L(pH 9.0),草甘膦与NBSC的摩尔比为1:5.HPLC分析条件为:采用Lichrospher C18柱,...     

微波灰化-原子荧光光谱法测定卷烟纸中镉

卷烟纸样品于瓷坩埚中,放入微波灰化系统中在450℃灰化20min,残渣加入体积分数为2.5%盐酸溶液溶解转入50mL容量瓶中定容后,供原子荧光光谱仪测定卷烟纸中镉的含量。在优化的仪器条件下,镉的质量浓度在0.2～10μg.L-1范围内与其荧光强度呈线性关系,方法的检出限(3s/k)为0.018μg.L-1。方法用于分析卷烟纸样品,所得回收率在94.4%～98.4%之间。方法的日内和日间相对标准偏差(n=7)分别为2.2%和2.8%。     

无泵负压进样-芯片电泳分离-激光诱导荧光光谱法测定儿茶酚胺类物质

提出了用芯片电泳分离-激光诱导荧光光谱法测定儿茶酚胺类物质的方法。采用自制的无泵负压进样系统,避免了进样歧视效应。在优化的条件下,去甲肾上腺素(NE)、多巴胺(DA)和肾上腺素(E)可在1 min内完全分离。3种儿茶酚胺的平均迁移时间依次为30.59,37.23,46.43 s,其相对标准偏差(n=7)依次为1.10%,1.28%,0.45%。3种物质的线性范围为0.3～5.0 mg.L-1(NE及DA)和0.05～4.0 mg.L-1(E),检出限(3S/N)依次为30,30,10μg.L-1。     

直接衍生离子液体富集高效液相色谱分析水基胶中脂肪族醛酮

建立了以2,4-二硝基苯肼(DNPH)直接衍生,1-丁基-3-甲基咪唑六氟磷酸盐(［BMIM］PF6)萃取富集,高效液相色谱(HPLC)分析水基胶中痕量脂肪族醛酮的方法。分散的水基胶乳液用80 mg/L DNPH衍生化试剂(含0.44 mol/L磷酸)于40 ℃衍生18 min。取离心后的上层衍生液,加入0.5 mL ［BMIM］PF6于30 ℃萃取富集,离子液体相过滤后进行HPLC分析。采用Dionex Acclaim Explosives E2色谱柱(250 mm×4.6 mm, 5 μm),以水-乙腈为流动相在流速1.2 mL/min进行梯度洗脱,色谱柱温度为35 ℃,检测波长为365 nm。结果表明,8种脂肪族醛酮的检出限为0.022～0.221 mg/kg,定量限为0.073～0.738 mg/kg,相对标准偏差为3.5%～7.3%,回收率为84.0%～102.5%。与溶剂萃取法相比,该法具有检出限和定量限低、稳定性高、测定更准确的优势。     

Continuous microwave-assisted extraction coupled on-line with liquid-liquid extraction: determination of aliphatic hydrocarbons in soil and sediments

This paper describes a new extraction method for the determination of aliphatic hydrocarbons (AHs) in soil and sediment samples, using continuous microwave-assisted extraction (MAE) combined with liquid-liquid extraction, for clean-up purposes. Analytical determinations were carried out by gas chromatography coupled with impact ionization mass spectrometry. The influence of the experimental conditions was tested using an agricultural soil spiked with standards (stored at 4 degrees C for 1 month) as reference soil. Maximum extraction efficiencies (80-90%) were achieved using 0.1-1.0g of sample, 60microl of water and 3ml of n-hexane (extractant) and 5min of extraction time; less than 70% of the most volatile hydrocarbons (C(9)-C(12)) were recovered since many evaporated during the drying step of the sample. MAE was compared with a conventional extraction method such as Soxhlet and a good agreement in the results was obtained (average recovery percentage value of 105% by comparing MAE against Soxhlet). Quality parameters such as linear range (0.5-800microg/g), limits of detection (LODs) (0.1-0.2microg/g) and precision (RSD, 4-6%) were determined using spiked soil samples. This method was successfully applied to the analysis of aliphatic hydrocarbons (C(9)-C(27) including pristane and phytane) in contaminated real samples.     

反相高效液相色谱法测定合成反应产物中溴代硝基芴酮

提出了用反相高效液相色谱法测定合成溴代硝基芴酮类化合物的反应产物中2,7-二溴-4-硝基芴酮(DBNFN)的含量。样品用甲醇作溶剂超声溶解,以Elite Hypersil ODS2C18色谱柱及甲醇-水(85+15)混合溶液作流动相进行分离。在所选择的条件下可达到DBNFN与共存物2,7-二溴芴酮(合成所用原料)和芴酮衍生物(副产品)三者之间的完全分离。采用紫外检测(波长254nm)和外标法定量。DBNFN的质量浓度在0.1～2.5g.L-1范围内与其峰面积呈线性关系。方法的检出限(2S/N)为3.8μg.L-1。用标准加入法做回收试验,测得回收率在99.2%～99.8%之间,测定值的相对标准偏差(n=6)在0.35%～0.48%之间。     

Gas chromatographic quantification of aliphatic aldehydes in freshly distilled Calvados and Cognac using 3-methylbenzothiazolin-2-one hydrazone as derivative agent

A new precise and sensitive method was used for the quantification of aliphatic aldehydes from C5 to C11 in highly ethanolic beverages such as freshly distilled spirits. Carbonyl compounds were derivatized using 3-methylbenzothiazolin-2-one hydrazone (MBTH) and then separated and detected by gas chromatography-mass spectrometry (GC-MS). Selective mass spectrometric detection of molecular ions of derivatives was performed to obtain a good sensibility (0.2-1.2 microg l(-1)) and a good selectivity. For a concentration of 20 microg l(-1), relative standard deviations were lower than 10% except for heaviest compounds (decanal and undecanal) where RSD were between 11 and 13%. The concentrations of aliphatic aldehydes were determined in nine samples of freshly distilled Calvados and two samples of freshly distilled Cognac with highest concentrations reported for 3-methylbutanal (from 170 to 1220 microg l(-1) in Calvados and from 1540 to 5500 microg l(-1) in Cognac). 3-Methylbutanal and hexanal, due to their low detection thresholds, could be important olfactive markers of these two products. Less than 1h30 is required to quantify the nine studied aliphatic aldehydes in freshly distilled spirits.