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911.
The use of open-access mass spectrometry to monitor synthetic chemistry reactions, and also the integrity and purity of new chemical entities, has been a part of the medicinal chemist's tool-box for more than 5 years. Originally in our group at Wyeth Research there were two open-access methods available to the chemists, flow injection analysis (FIA) and liquid chromatography/mass spectrometry (LC/MS). The FIA method was approximately 3 min long, while the LC/MS method was approximately 20 min long (including an 8 min gradient). Within the first 2 years, the total number of open-access analyses increased by approximately 125%. It is interesting, however, that the number of LC/MS analyses increased by more than 285%. This is attributed to the fact that the chemists began using the LC/MS data to monitor reactions and also to check final product integrity and purity. In addition, the number of chemists performing parallel synthesis reactions has increased; thus, individual chemists can produce sample sets of up to 100 vials. This paper describes the implementation of new methodology, which accommodates the need for much faster run times and also the ability to acquire alternating positive and negative ion spectra within the same run. In addition, the instrument has been configured to e-mail the resulting processed data report to the submitting chemist. Several methods have been developed, including structure elucidation using in-source collision-induced dissociation (CID) and night-time analysis. The LC/MS methods for this system are described herein and are applicable to both industrial and academic synthetic chemistry optimization efforts.  相似文献   
912.
IntroductionCatal}ticrcactionsaffcctcdb}'diffosionaIlimitationincatal}'stporcshavcbccnextensive1}dcaltx`ithinlit.rat.rcll~5I.Scvcraltcchniqucsonthcspccialcase0fFischcr-Tropschs}'nthcsis(FTS)t\crcapplicdtocxplorcthebchaviorofthiscatal}ticrcactionundercxpcrimcntalandopcrationaIconditionsI3~5l.It`"ouldbeofvaluctoindicatchcrcthatthcseinvcstigationsx"ercmainl}'bascdonthesimplcstkineticsofthcfirstordcrinH2proposedbyAndersonl6]attheearIystages.However-thesetboents,striCtlyspeaking,areinvalidfor…  相似文献   
913.
The doubly deprotonated form of calix[6]arene, with two protonated triethylamines as counter-ions, crystallizes in the monoclinic system: space groupP21/n,a=8.465(4),b=17.822(8),c=15.182(6) Å,=90.18(4)°,V=2291(2) Å3,Z=2. Refinement led to a final conventionalR value of 0.063 for 1046 reflections. The macrocycle conformation is not apinched cone, usual for freeR-calix[6]arene, but a distorted 1,2,3-alternate cone, since the molecule lies on a symmetry center. Furthermore, one of the torsion angles defined by the methylene bridges is near to zero, which is unusual in calixarene structures. Supplementary Data relating to this article (atomic coordinates for hydrogen atoms, anisotropic displacement parameters for oxygen and nitrogen atoms, and observed and calculated structure factors) are deposited with the British Library as Supplementary Publication No. SUP 82182 (7 pages).  相似文献   
914.
以二氨基磺酸盐配合物合成了一系列主链上合金属元素(Ca,Ni,Co,Cu)的聚脲聚合物。用IR和1HNMR对其结构进行了表征,以TG-DTA研究了其热性能,并讨论了金属元素种类及其含量对聚脲聚合物溶液粘度的影响。  相似文献   
915.
合成了两个酰腙类荧光探针1和2,在DMSO-H_2O(7∶3,体积比)体系中,两者分别在478 nm和460 nm处对Al~(3+)具有较好的荧光选择识别作用。Job's法、核磁滴定、质谱分析表明,探针1和2与Al~(3+)的配位比均为1∶2,且对Al~(3+)的检出限分别为9.58×10~(-8) mol/L和6.52×10~(-8) mol/L。同时提出了探针1和2对Al~(3+)的荧光传感机理。实际应用研究表明,探针1和2可用于河水和自来水中一定浓度范围内Al~(3+)的检测。  相似文献   
916.
以Al2O3为基质,添加ZrO2和La2O3,制成La2O3-ZrO2-Al2O3复合载体,然后采用SO42-进行改性,再负载上Cu2+,制备了铜基SO42-改性的复合载体催化剂(Cu/SO42-/La2O3-ZrO2-Al2O3)。考察了它在富氧条件下对丙烯选择还原NO的催化性能,并借助XRD、SEM、TG、Py-IR、NH3-TPD、FTIR和TPR等方法研究了Cu/SO42-/La2O3-ZrO2-Al2O3的结构和性能的关系。结果表明,ZrO2的加入主要有利于提高催化剂的低温活性;La2O3的加入则主要有利于提高催化剂的热稳定性和还原性能;SO42-能够与Zr形成螯合双配位结构,大幅度促使催化剂表面酸量增加并且酸性增强;因此,有效地提高了Cu/SO42-/La2O3-ZrO2-Al2O3在富氧条件下对丙烯选择还原NO的催化活性和水热稳定性。在无水条件下,Cu/SO42-/La2O3-ZrO2-Al2O3能使NO的最大转化率高达84.3%,即使在275 ℃ 10%水蒸气存在的情况下,仍能使NO的转化率高达81.2%。  相似文献   
917.
水热条件下,合成了三个新的配合物[Ni(en)3] (ndt) ·H2O 1, [Co(en)3] (ndt) ·H2O 2 和[Mn(en)3] (ndt) ·H2O 3。晶体结构通过X-射线单晶衍射进行了表征。三个配合物均属于单斜晶系,Cc空间群。[M(en)3]2+阳离子、ndt阴离子和结晶水分子通过氢键自组装出相同结构的三维网。通过紫外-可见-近红外漫反射光谱对这三个配合物的光吸收性能和能带进行了测定。  相似文献   
918.
Binary zirconium orthophosphates R1/3Zr2(PO4)3 and M1/4Zr2(PO4)3, where R = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu; M = Th, U, have been synthesized and studied by IR spectroscopy [structural family of NaZr2(PO4)3 (NZP)]. Vibrational analysis for the PO4 tetrahedron and investigation of symmetry relations among trigonal NZP phases showed that ordering of lanthanide atoms in structures of NaZr2(PO4)3 type with space group R c leads to symmetry reduced to P c. The lanthanide atoms occupy the 2b sites. The phosphorus atoms occupy two independent sites: 6f with C 2 symmetry and 12g with C 1 symmetry. Factor group analysis admits that the IR spectrum can contain eight v3 bands and two v1 bands of the stretching vibrations of the PO4 ions. The M atoms of actinides occupy statistical positions in the structure, and space group R c is retained.Original Russian Text Copyright © 2004 by V. S. Kurazhkovskaya, D. M. Bykov, and A. I. Orlova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1013–1019, November–December, 2004.  相似文献   
919.
《Tetrahedron letters》2003,44(46):8445-8448
Fused β-carboline systems, as indolo[2,3-a]indolizidinones, indolo[2,3-a]quinolizidinones, their 2-oxa analogues, and benzo[a]indolo[2,3-a]indolizidinones are prepared efficiently via an RLi addition-N-acyliminium ion cyclisation sequence on readily available imides. In an enantioselective variant of these α-amidoalkylation reactions, the addition of MeLi to a chiral non-racemic imide derived from tryptophan yielded an oxo amide, which was cyclised diastereoselectively upon treatment with BF3·OEt2, to afford 5,11b-trans-indoloindolizidinone in moderate yield and high ee (99%).  相似文献   
920.
A new layered aluminophosphate, denoted AlPO-CJ12, has been synthesized in the system Al(OPri)3-H3PO4-tetramethylethylenediamine-triethyleneglycol and its structure solved by single-crystal X-ray diffraction analysis. It is further characterized by X-ray powder diffraction, ICP, TG, DTA, and elemental analyses. The compound has an empirical formula of [Al3P4O16][(CH3)2NHCH2CH2NH(CH3)2][H3O], and crystallizes in the triclinic space group P-1 (No. 2) with a=8.9907(6) Å b=9.8359(6) Å, c=14.5566(8) Å, α=75.872(3)°, β=88.616(3)°, γ=63.404(3)°, Z=2, R1=0.0451, and wR2=0.1094. The alternation of tetrahedral AlO4 and PO3 (=O) units forms a sheet structure with a 4×6×8 network. The inorganic layers stacked in an AAAA sequence are held together by the protonated organic amine and water molecules. The co-templating role of the water molecules is studied by the calculation of the nonbonding host-guest interaction energies through a computational simulation.  相似文献   
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