相转移催化合成对甲氧基肉桂酸-2-乙基己酯的研究

对甲氧基肉桂酸 2 乙基己酯是一种有效的ＵＶＢ防晒剂[1 ,2 ] ,一般采用Ｃｌａｉｓｅｎ Ｓｃｈｍｉｄｔ缩合反应制得[3] ,但由于催化剂ＫＯＨ处于水相 ,对反应物不能充分起到催化作用导致产率较低[4] 。我们利用乙二醇 (ＰＥＧ)为相转移催化剂合成立体专一的反式对甲氧基肉桂酸 2 乙基己酯 ,产率提高到 72 .5 %。合成路线如下 :1　实验部分1 .1　仪器与试剂ＢＩＯ ＲＡＰＦＴ45 0红外光谱仪 ,用液膜法测试 ;Ｂｒｕｒｅｒ ＡＭ 30 0超导核磁共振仪 (溶剂ＤＣ Ｃｌ3) ;ＭＡＴ/44Ｓ ,ＧＣ ＭＳ型色质联用谱仪 ;试剂均为分析纯 ,上海化学试剂…     

单扫示波极谱法测定食品中山梨酸

1　引　　言山梨酸 (ＳＡ)是广泛使用的食品防腐剂。已往测定有ＴＬＣ法、比色法、ＧＣ法及ＨＰＬＣ法等。作者研究发现在 0 .2ｍｏｌ/ＬＮＨ4ＡＣ ＨＡＣ(ｐＨ 5 .7)底液中 ,ＳＡ与联氨反应生成酰肼产物并在电位 (Ｅｐ) - 1.2 6Ｖ(ｖｓ·ＳＣＥ)处产生灵敏的还原波 ,其波高与ＳＡ浓度在一定范围内成正比。据此建立了单扫示波极谱法测定食品中ＳＡ的简便分析方法。2　实验部分2 .1　仪器与试剂　ＭＰ 2型溶出分析仪 (山东电讯七厂 ) ,滴汞电极、甘汞电极和铂电极。ＳＡ标准溶液 (国家标样中心研制ＧＢＷ (Ｅ) 10 0 0 0 7) :1.0 0ｇ/Ｌ ;1.0…     

SAAQ-CTMAB荧光光度法测定微量铝的研究

某些席夫碱具有一定的刚性平面及富电子的共轭体系 ,从而使其显示出良好的荧光特性 ,导致该类试剂在荧光分析中显出越来越重要的作用[1 ] 。虽然荧光法测定铝已有文献[2～4] 报道 ,但本文所提出的ＳＡＡＱ在ＣＴＭＡＢ存在下与铝产生荧光增敏测定微量铝的方法尚未见报道。研究表明在ｐＨ =4.0～ 5.5的乙酸铵缓冲溶液及ＣＴＭＡＢ存在下 ,铝与ＳＡＡＱ形成 1∶2的络合物。该络合物在λｅχ/λｅｍ=378ｎｍ/490ｎｍ处荧光最强 ,线性范围为 0～ 2 0 0 μｇ·ｄｍ- 3,方法用于人发及茶叶中铝含量的测定 ,结果满意。1　试验部分1 .1　仪器与试剂…     

氯化钠-硫氰酸铵-氯化十四烷基吡啶体系浮选分离铜

在水溶液中Ｃｕ(Ⅱ )与硫氰酸铵、氯化十四烷基吡啶形成不溶于水的三元缔合物 ,在少量氯化钠存在下此三元缔合物沉淀浮于水相上层并与水分成界面清晰的两相 ,分相过程中Ｃｕ(Ⅱ )被定量浮选。而Ｆｅ(Ⅲ )、Ｃｏ(Ⅱ )、Ｎｉ(Ⅱ )、Ｍｎ(Ⅱ )、Ｃｄ(Ⅱ )等离子在该体系中不能被浮选 ,借此可实现Ｃｕ(Ⅱ )与这些离子的分离。1　实验部分1 1　仪器与试剂氯化钠 (Ａ .Ｒ .,洛阳市化学试剂厂 ) ;1 .0×1 0 - 2 ｍｏｌ·Ｌ- 1 氯化十四烷基吡啶溶液 (ＴＢＰＣ)(ｐａｃｋｅｄｉｎＳｗｉｔｚｅｒｌａｎｄ) ;0 .2ｍｏｌ·Ｌ- 1 硫氰酸铵标准溶液按文…     

阳极溶出伏安法测定痕量汞的研究

痕量汞的测定方法有很多[1 ] 。原子吸收法虽然具有较高的灵敏性 ,但是仪器设备昂贵 ,分析步骤较繁琐。近年来 ,化学修饰电极阳极溶出伏安法在对汞痕量分析方面的研究报道也不少[2～3] ,测定的检测限一般在 1 0 - 6～ 1 0 - 9ｇ·ｍｌ- 1 ,但它容易产生记忆效应 ,洗脱不良。本文以玻碳电极为工作电极 ,在ＨＣｌ ＮａＣｌ Ｃｄ2 +中 ,示差脉冲阳极溶出伏安法 (ＤＰＳ)测定痕量汞 ,汞的平均回收率达80 %。1　实验部分1 1　主要仪器与试剂ＰＡＲ— 384极谱仪 (美国 ) ;三电极系统 :工作电极为玻碳电极 ,参比电极为Ａｇ/ＡｇＣｌ电极 ,对电极为…     

四元配合物吸光光度法测定铝的研究

提出了在乙酸钠－乙酸介质中,利用Ａｌ－ＥＧＴＡ－ＰＲ－ＣＰＢ四元体系测定铝的新方法。试验表明乙二醇二乙醚二氨基四乙酸（ＥＧＴＡ）,铝,邻苯三酚红（ＰＲ）,溴化十六烷基吡啶（ＣＰＢ）可迅速反应生成四元蓝色配合物Ａｌ·ＥＧＴＡ·ＰＲ３·ＣＰＢ１２,可用于痕量铝的测定,ε＝１．１×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１,ＲＳＤ为５．８％（ｎ＝６）。加标回收率１０１．７％￣１０５．０％,实测水和化学试剂中痕     

示波库仑滴定法测定水中铝

１引言铝在自然界中分布极广，研究表明过量地摄入铝对人体会产生毒性作用。因此，对水中铝含量的监测已成为环境化学中的重要课题。作者采用示波技术与库仑滴定相结合的示波库仑滴定法测定水中Ａｌ３＋含量。方法以过量８－羟基喹啉沉淀Ａｌ３＋，以电生Ｂｒ２反滴定过量的８－羟基喹啉，用两铂电极示波电位法指示终点。水中少量的Ｃａ２＋、Ｍｇ２＋分别以ＣａＣＯ３、Ｍｇ（ＯＨ）２沉淀分离。操作方便、终点指示灵敏、准确。可检测水中含Ａｌ３＋量～１０６ｍｏｌ／Ｌ。２实验部分２．１仪器与试剂ＳＲ－０７ｌＢ型双踪示波器（江苏杨中…     

示波极谱法测定锌锭中的微量锡

微量锡的测定文献 [1～ 5 ]已有报道 ,多采用比色法、ＩＣＰ ＡＥＳ法和ＡＡＳ法 ,有些分析步骤冗长、工作量大 ,有些需要昂贵的仪器设备。本文将样品简单处理后 ,用示波极谱法 ,在氯化钠底液中直接测定锌锭中微量锡。1　试验部分1 1　主要仪器与试剂ＪＰ 2型示波极谱仪 ;饱和甘汞电极 ,铂电极 ,滴汞电极的三电极系统 (成都仪器厂 ) ;锡标准溶液 :1 0ｍｇ·ｍＬ- 1 用光谱纯金属锡按常规法配制而成 ;锡标准工作溶液 :1 0 0 μｇ·ｍＬ- 1 ,使用时用水逐级稀释而成 ;ＮａＣｌ底液 :30 0ｇＮａＣｌ溶于 1 0 0 0ｍＬ水中 ,摇匀 ,备用 ;Ｂａ…     

食品包装材料中双酚A的极谱测定

1　引　　言双酚Ａ(ｂｉｓｐｈｅｎｏｌＡ ,ＢＰＡ)是近几年新发现的一种“破坏内分泌化学物质 (ｅｎｄｏｃｒｉｎｅｄｉｓｒｕｐｔｉｎｇｃｈｅｍｉｃａｌｓ,ＥＤＣ) ,”已引起各国的广泛关注。其测定方法有ＨＰＬＣ法、ＧＣ ＭＳ法、ＬＣ ＭＳ法、荧光光度法及ＥＬＩＳＡ法等 ,而极谱法未见报道。本研究发现在 0 .7ｍｏｌ ＬＮａＮＯ2 介质中 ,ＢＰＡ的亚硝化产物在电位 (Ｅｐ) -0 .4 1Ｖ(ｖｓ.ＳＣＥ)处产生一个十分灵敏的二阶导数还原波。据此建立了用单扫示波极谱法测定ＢＰＡ的简便方法。2　实验部分2 .1　仪器与试剂　ＭＰ 2型溶出分…     

高效毛细管电泳检测克莱保健烟贴中的尼古丁

1　引　　言尼古丁是一种生物碱。尼古丁的检测方法有薄层色谱法、容量法、电导滴定法等。本文研究了用毛细管电泳技术分离测定克莱保健烟贴中的尼古丁 ,获得了比较满意的结果。2　实验部分2 1　仪器与试剂　 12 2 9型高效毛细管电泳仪 (北京新技术应用研究所 ) ,固定波长紫外检测器 ,ＡＣＳ2 0 0 0高压电源 ,ＡＣＳ2 0 0 0色谱工作站 (中国科学院研究生院应用化学研究所 ) ,石英毛细管 5 0 μｍ(ｉｄ)× 6 0ｃｍ ,有效长度约 4 4 5ｃｍ(河北永年光导纤维厂 ) ,ｐＨ ＨＪ90Ｂ型酸度计 (上海雷磁仪器厂 )。尼古丁 (ｎｉｃｏｔｉｎｅ)标样 (…     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.