2—（6—硝基—2—苯并噻唑偶氮）—5—二甲氨基苯甲酸与铜显色反应的研…

本研究了２－（６－硝基－２－苯并噻唑偶氮）－５－二甲氨基苯甲酸（６－ＮＯ２－ＢＴＡＭＢ）与铜的显色反应。结果表明，在ｐＨ２．０￣４．５的乙醇水溶液中６－ＮＯ２－ＢＴＡＭＢ与铜形成一种稳定的蓝绿色络合物，其最大吸收波长位于６５０ｎｍ处，表观摩尔吸收系数为７．７５×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，络合物的组成为６－ＮＯ２－ＢＴＡＭＢ∶Ｃｕ＝１∶１，铜浓度在０￣１０μｇ／１０ｍｌ范围内服从比尔定     

1—（5—溴—2—吡啶偶氮）—2—萘酚—6—磺酸与铁（Ⅱ）显色反应的研究及其应用

本研究了１－（５－溴－２－吡啶偶氮）－２－萘酚－６－磺酸（５－Ｂｒ－ＰＡＮ－Ｓ）与铁（Ⅱ）的显色反应，试验表明，在ｐＨ３－１０范围内铁（Ⅱ）与５－Ｂｒ－ＰＡＮ－Ｓ型成稳定的络合物，络合物在５５０ｎｍ和７５０ｎｍ有二个吸收峰，其表现摩尔吸光系数分别为２．３１×１０＾４和１．７７×１０＾４Ｌ．ｍｏｌ＾－＾１．ｃｍ＾－＾１。络合物组成比为铁（Ⅱ）：５－Ｂｒ－ＰＡＮ－Ｓ＝１：２，络合物稳定常数为１．８２     

3,3′,5,5′—四甲基联苯胺吸光光度法测定水中NO2^——N

提出用３,３′,５－５′－四甲基联苯胺（ＴＭＢ）吸光光度法测定水中ＮＯ２＾－－Ｎ。在ＨＯＡｃ－ＮａＯＡｃ缓冲液（ｐＨ３．６）中,ＴＭＢ与ＮＯ２＾－反应生成蓝色的ＴＭＢ－ＴＭＢ亚胺传荷络合物,其最大吸收波长为６５０ｎｍ,表观摩尔吸光系数为２．５９×１０＾４,ＮＯ２＾－－Ｎ与０～０．５μｇ·ｍｌ＾－１范围内服从比耳定律。运用此法测定了环境水样并进行了加标回收试验,结果满意。     

Meso—四—（3,5—二溴—4—羟基苯）卟啉分光光度测定食品中微量铅

研究了溴代卟啉试剂（ＤＢＨＰ）Ｐ分光光度法测定食品中微量铅。在０．０８ｍｏｌ／ＬＮａＯＨ介质中,铅与Ｔ（ＤＢＨＰ）Ｐ反应生成一橙黄色配合物,λｍａｘ＝４７９ｎｍ,ε＝２．２×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１。铅在０－１２μｇ／２５ｍＬ范围内符合比耳定律,用于食品中微量铅的测定,获得满意结果。     

安替比林基重氮基—2,4—二硝基苯及其与镉的显色反应

合成了安替比林基重氮氨基－２，４－二硝基苯（ＡＰＤＮＢＴ）新试剂，并首先研究了它的分析性质及其与镉的显色反应。在ＴｒｉｔｏｎＸ－１００存在下，试剂的两级质子离解常数的ｐＫａ值分别是０．８和１０．８；在ｐＨ＝１０．２～１２．０的Ｂ－Ｒ缓冲溶液中，试剂与镉生成１：２的黄色配合物，呈褪色反应，吸光度差值最大的波长为５４０ｎｍ，其表观摩尔吸光系数为１．５２×１０＾５Ｌ／（ｍｏｌ．ｃｍ），线性范围每２５ｍＬ     

新试剂3,3‘—二甲基联苯重氮氨基—4—苯基—2—噻唑分光光度法测定？…

研究了新试剂３,３’－二甲基联苯重氮氮基－４－苯基－２－噻唑（ＤＭＰＤＰＡＰＴ）在表面活性剂Ｎ－氨代十六烷基吡啶存在下,与汞（Ⅱ）显色反应的适宜条件。在ＰＨ７．２－９．２范围内,汞（Ⅱ）与ＤＭＤＰＤＡＰＴ形成２：２紫红色配合物,其最大吸收波长为５６０ｎｍ,配合物的表观摩尔吸光系数ε＝９．０１＊１０＾４Ｌ．ｍｏｌ＾－１。ｃｍ＾－１。汞（Ⅱ）浓度在０－１２μｇ／２５ｍＬ范围内符合比尔定律。此法已用于水     

大量锆存在下铪镧钼杂多酸—耐尔蓝体系测定给

本文研究了耐尔蓝（ＮＢ）－给镧钼杂多酸（ＨｆＬａＭｏ－聚乙烯醇（ＰＶＡ）体系测定铪的超高灵敏光度法。在ＰＶＡ存在下，铪，镧和钼酸铵形成杂多酸，继而与耐尔蓝形成离子缔合物。其适宜条件为〔ＨＣｌｏ４〕＝１．２ｍｏｌ／Ｌ，〔Ｌａ×３＋〕＝２．９×１０＾－７ｍｏｌ／Ｌ，〔ＭｏＯ４×２－〕＝１．１×１０＾－３ｍｏｌ／Ｌ，〔ＮＢ〕＝２．７×１０＾－６ｍｏｌ／Ｌ，ＰＶＡ０．０８％。离子缔合物的最大吸收波长在５９     

显色剂交换萃取光光度法测定微量铜

用三氯甲烷萃取Ｃｕ－ＤＤＴＣ络合物，然后在ｐＨ＝９．２三羟甲基氨基甲烷（Ｔｒｉｓ）缓冲液中用５－Ｂｒ－ＰＡＤＡＰ交换络合物中ＤＤＴＣ，形成了Ｃｕ－ＰＡＤＡＰ络合物。该络合物最大吸收波长λｍａｘ＝５２０ｎｍ，表观摩尔吸光系数ε５２０＝１．２２×１０＾５，铜量在０．２￣１０．０μｇ／１２ｍｌ范围内服从比耳定律。本法应用于食品、生物材料中微量铜测定，得到较为满意的结果。     

在表面活性剂存在下用5—Br—PADAP吸光光度法测定汞

研究了在阴离子表面活性剂ＳＤＳ存在下,用５－Ｂｒ－ＰＡＤＡＰ测定汞的最佳条件。试验表明,在硼砂－盐酸缓冲介质中,ＰＨ为８．３５￣１０．４０时,络合物的最大吸附波长为λｍａｘ＝５６２ｎｍ,表观摩尔吸光系数为１．１２×１０＾５,络合物的组成为Ｈｇ（Ⅱ）：５－Ｂｒ－ＰＡＤＡＰ＝１：２,线性范围为０￣３５μｇ／２５ｍｌ．方法体系简单,操作方便,是目前光度法测定痕量Ｈｇ（Ⅱ）灵敏度较高的方法之一。     

钍（Ⅳ）与偶氮溴膦—mB和溴化十四烷基吡啶在乙醇—水溶液中的显色反应及其分

在ｐＨ１￣２的酸性介质中,钍（Ⅳ）与偶氮溴膦－ｍＢ（ＢＰＡｍＢ）形成最大吸收波长（λｍａｘ位于６８６ｎｍ的蓝色络合物,摩尔吸光系数（ε）为８．２７×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１。在有少量乙醇存在的０．５￣１．０ｍｏｌ／Ｌ盐酸溶液中,钍（Ⅳ）能与ＢＰＡｍＢ和溴化十四烷基吡啶形成更灵敏的三元络合物,最大吸收位于６９５ｎｍ,具有更大的对比度（Δλ＝１３５ｎｍ）和更高的灵敏度。ε值达１．４１×１０     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.