(R)-N-酰基四氢噻唑-2-硫酮-4-羧酸在DCC存在下与胺的反应

由Ｎ－乙酰四氢噻唑－２－硫酮－４－羧酸（［α］２０Ｄ－１０９．８３°），及Ｎ－苯甲酰四氢噻唑－２－硫酮－４－羧酸（［α］２０Ｄ－１１２．２２°），在Ｎ，Ｎ′－二环己基二亚胺（ＤＣＣ）存在下分别与环己胺、苯胺反应得到光学活性产物（Ｒ）－Ｎ－乙酰四氢噻唑－２－硫酮－４－甲酰环己胺（［α］１７Ｄ－７４．５°），及（Ｒ）－Ｎ－苯甲酰四氢噻唑－２－硫酮－４－甲酰苯胺（［α］１９Ｄ－７．０４°）。用量子化学ＰＭ３方法研究了反应物和产物的电子结构。     

（R）—N—乙酰四氢噻唑—2—硫酮—4—羧酸与醇的反应

（Ｒ）－Ｎ－乙酰四氢噻唑－２－硫酮－４－羧酸与醇反应，在ＳＯＣｌ２存在下得到乙酸酯及四氢噻唑－２－硫酮－４－羧酸酯；在碳酸钾存在下得到乙酸酯及四氢噻唑－２－硫酮－４－羧酸；在二环己基碳二亚胺（ＤＣＣ）存在下得到缩水产物Ｎ－乙酰四氢噻唑－２－硫酮－４－羧酸酯。     

α-溴代丙酰氯与四氢噻唑-2-硫酮衍生物的反应及量子化学研究

α－溴代丙酰氯分别同四氢噻唑－２－硫酮及（Ｒ）－四氢噻唑－２－硫酮－４－羧酸乙酯反应得到四氢噻唑－２－α－溴代丙酰硫酯２ａ及光学活性４－乙氧羰基四氢噻唑－２－α－溴代丙酰硫酯２ｂ．用半经验的量子化学ＰＭ３方法研究了反应物和产物的电子结构和反应的焓变，得到反应物１ａ异构化的过渡态．     

（R）－N－（γ－烃基－δ－酮己酰基）四氢噻唑－2－硫酮－4－羧酸乙酯的合成及其同（R，S）－α－苯乙胺的反应

γ－甲基－δ－酮己酸，γ－异丙基－δ－酮己酸在碘化Ｎ－甲基－２－氯吡啶盐存在下分别同（Ｒ）－四氢噻唑－２－硫酮－４－羧酸乙酯反应，得到光学活性的（Ｒ）－Ｎ－（γ－甲基－δ－酮己酰基）四氢噻唑－２－硫酮－４－羧酸乙酯（１ａ）及光学活性的（Ｒ）－Ｎ－（γ－异丙基－δ－酮己酰基）四氢噻唑－２－硫酮－４－羧酸乙酯（１ｂ）。１ａ，１ｂ分别同（Ｒ，Ｓ）－α－苯乙胺反应得到光学活性的酰胺２ａ，２ｂ，同时使（Ｒ，Ｓ）－α－苯乙胺拆分，得到光学活性的α－苯乙胺。     

α-溴代丙酰氯空间效应的量子化学研究

丙酰氯同四氢噻唑２硫酮及（Ｒ）四氢噻唑２硫酮４羧酸乙酯反应生成Ｎ酰基四氢噻唑２硫酮２ａ及光学活性Ｎ酰基（Ｒ）四氢噻唑２硫酮４羧酸乙酯２ｂ，而α溴代丙酰氯分别同四氢噻唑２硫酮及（Ｒ）四氢噻唑２硫酮４羧酸乙酯反应得到四氢噻唑２α溴代丙酰硫酯３ａ及光学活性４乙氧羰基四氢噻唑２α溴代丙酰硫酯３ｂ．用半经验的量子化学ＰＭ３方法研究了反应物和产物的电子结构和反应的焓变，得到了反应物１ａ异构化的过渡态．     

(R)-2-硫代四氢噻唑-4-羧酸及其酯的合成

L-半胱氨酸盐酸盐与二硫化碳, 氢氧化钠在硝酸铅存在下进行成环反应得到(R)-四氢噻唑-2-硫酮-4-羧酸产率76% , 后者与 醇在硫酸铁水合物催化下反应得到(R)-四氢噻唑-2-硫酮-4-羧酸酯, 产率40～82% .     

（R）—N—（γ—烃基—δ—酮己酰基）四氢噻唑—2—硫酮—4—羧酸乙酯的合成及…

γ－甲基－δ酮己酸，γ－异丙基－δ－酮己酸在碘化Ｎ－甲基－２－氯吡啶盐存在下分别用（Ｒ）－四氢噻唑－２－硫酮－４－羧酸乙酯反应，得到光学活性的（Ｒ）－Ｎ－（γ－甲基－δ－酮己酰基）四氢噻唑－２硫酮－４羧酸乙酯（ｌａ）及光学活性的（Ｒ）－Ｎ－（γ－异丙基－δ－酮己酰基）四氢噻唑－２－硫酮－４－羧酸乙酯（１ｂ），ｌａ，ｌｂ分别同（Ｒ，Ｓ）－α－苯乙胺反应得到光学活性的酰胺２ａ，２ｂ，同时使（Ｒ，Ｓ）＝     

新拆分试剂R(-)四氢噻唑-2-硫酮-4-羧酸对R,S-α-苯乙胺拆分的研究

Ｒ（－）四氢噻唑－２－硫酮－４－羧酸［简称Ｒ（－）ＴＴＣＡ］可作为检查尿样中ＣＳ２含量的标准试剂，我们对其结构［１］及性质进行了研究，发现它有很好的手性识别功能，可作为新的拆分试剂对Ｒ，Ｓ－α－苯乙胺进行拆分．光学活性的α－苯乙胺已被广泛地用来代替光...     

R-四氢噻唑-2-硫酮-4-羧酸二聚反应的量子化学研究

R-四氢噻唑-2-硫酮-4-羧酸反应得到有光学活性的二聚体酰胺双四氢噻唑-2-硫酮并二氧代氢化吡嗪,用半经验量子化学PM3方法研究了反应物、中间产物和二聚体的电子结构.     

R－四氢噻唑－2－硫酮－4－羧酸酯的合成

R-四氢噻唑-2-硫酮-4-羧酸甲酯可作为不对称合成试剂[1],它是由L-半胱氨酸甲醋盐酸盐与二硫化碳反应成环得到的.我们曾由R-四氢唾哇-2-硫酮-4-羧酸(TTCA)与乙醇反应在硫酸铁水合物催化下得到R-四氢噻唑-2-硫酮-4-羧酸乙酯,产率为68%.     

Esterification and Chemoselective Synthesis of R-Tetrahydrothiazo-2- thione-4-carboxylic Esters Catalyzed by TiCl4

A series of esters of R-tetrahydrothiazo-2-thione-4-carboxylic acid[R-TTCA] was synthesized by direct esterification of R-TTCA with alcohols(CH3OH,C2H5OH,n-C3H7OH,i-C3H7OH,n-C4H9OH,sec-C4H9OH)in the presence of TiCl4 as the catalyst at room temperature without using any other solvent or dehydrant in high yields,91.6%-99.1% for primary alcohols and 55%- 80% for secondary alcohols.The catalyst has a strong chemoselective activity for the esterification of primary alcohols with R-TTCA in the presence of secondary alcohols.Owing to high yield,high chemoselectivity,and mild conditions used,this is an efficient method for the esterification of primary alcohols with R-TTCA.     

（R）—四氢噻唑—2—硫酮—4—羧酸的合成及其晶体结构

由Ｌ－半胱氨酸盐酸盐与二硫化碳在ＮａＯＨ及ＣｕＳＯ４．Ｈ２Ｏ存在下反应得到（Ｒ）－四氢噻唑－２－硫酮－４－羧酸，「α」＾２０Ｄ－８７．５°，产率６６％。用Ｘ射线衍射法测得其晶体结构，属正交晶系，Ｐｚ１ｚ１ｚ１空间群，晶体学参数：α＝０．５０２９（２）ｎｍ，ｂ＝０．７７４９９（５）ｎｍ，ｃ＝１．６３００（５）ｎｍ，Ｖ＝０．６３５０（５）ｎｍ＾３，Ｚ＝４。用分子轨道方法研究了该化合物的电子结构，得到其     

Photooxidation of Transition Metal Complexes of 1,3-Dithiole-2-thione-4,5-dithiolate (dmit) and 1,2-Dithiole-3-thione-4,5-dithiolate (dmt)

Metall(II) bis-chelates of 1,3-dithiole-2-thione-4,5-dithiolate (dmit) and 1,2-dithiole-3-thione-4,5-dithiolate (dmt) undergo in CHCl₃/CH₃CN (ratio 1:24) photooxidation to the metal(III) bis-chelates when irradiated at 313 nm. No side reactions were observed. There is no correlation between the quantum yields of photooxidation and the electrochemical halve-wave potentials. This holds also in comparison to maleonitriledithiolato chelates.     

Synthesis and Quantum Chemistry Studies of (R)-N-(Propionylthiazolidine-2-thione-4-methoxycarbonyl)germanium Sesquioxide

ＳｙｎｔｈｅｓｉｓａｎｄＱｕａｎｔｕｍＣｈｅｍｉｓｔｒｙＳｔｕｄｉｅｓｏｆ（Ｒ）┐Ｎ┐（Ｐｒｏｐｉｏｎｙｌｔｈｉａｚｏｌｉｄｉｎｅ┐２┐ｔｈｉｏｎｅ┐４┐ｍｅｔｈｏｘｙｃａｒｂｏｎｙｌ）ｇｅｒｍａｎｉｕｍＳｅｓｑｕｉｏｘｉｄｅ＊ＬＩＹｅ－ｚｈｉ＊＊,...     

1,3-二硫杂环戊烯-2-硫酮-4,5-二巯基的不对称二硫纶金属(Cd,Zn)配合物的热行为和热分解反应动力学

用TG-DTG-DTA联用技术研究了两种1,3-二硫杂环戊烯-2-硫酮-4,5-二巯基的不对称二硫纶金属(Cd,Zn)配合物在动态氮气气氛中的热行为,通过应用EDS技术和元素分析方法对热分解过程中各步反应中间体的组成进行了探索,并结合其物质结构进行了讨论。协同使用四种热分析动力学方法获得了各步反应的热分解动力学参数,并推断了它们的最可能分解反应机理。     

THE 31P NMR SPECTRA OF ISOMERIC DIAMINOHEXA-CHLOROCYCLOTETRAPHOSPHAZATETRAENES; EXAMPLES OF A2B2 AND AA'BB' SPIN SYSTEMS

Abstract

The ³¹P nmr spectra of 2,4- and 2,6-diamino-derivatives of octachlorocyclotetraphosphazatetraene, N₄P₄Cl₆(NR¹R²)₂ (R¹ = H, R² = Bu^t; R¹ = H, R² = CH₂Ph; R¹ = Me, R² = Ph), have been measured. The 2,4- and 2,6-isomers were analysed as AA'BB' and A₂B₂ spin systems respectively. In the 2,4-isomers the spin-spin couplings ²J(PNP) and ⁴J(PNPNP) were of opposite sign.     

Two spin systems based on [Ni(dmit)2]− building blocks exhibiting 1-D chain and 2-D sheet structures: crystal structures and magnetic properties

The crystal structures and magnetic properties for two ion-pair complexes, [MG][Ni(dmit)₂] (1) and [RhB][Ni(dmit)₂] (2) (MG⁺ = N-(4-((4-(dimethylamino)phenyl)(phenyl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium, RhB⁺ = 9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthylium; dmit^2? = 1,3-dithiole-2-thione-4,5-dithiolate), have been investigated. Complex 1 crystallizes in the monoclinic space group P2₁/c, the stacking interactions between the GM⁺ and [Ni(dmit)₂]^? lead to the anion exhibiting a banana-shaped molecular geometry; the neighboring anions form a 1-D alternating chain along the crystallographic [1 1 0] direction via intermolecular lateral-to-lateral and head-to-head S ··· S contacts. The temperature dependence of magnetic susceptibility from 2–350 K does not display the magnetic character of a 1-D chain; the magnetic susceptibility data were fit to the Curie–Weiss equation to give C = 0.351(15) emu K mol^?1, θ = ?3.51(28) K, and χ ₀ = 8.00(3) × 10^?5 emu mol^?1. Complex 2 belongs to the triclinic space group P-1 with two crystallographic inequivalent [Ni(dmit)₂]^? anions, which exhibit perfect planar geometry. Two ethyl groups of RhB⁺ are disordered over two positions at 296 K, and one becomes ordered at 150 K. The [Ni(dmit)₂]^? anions form a 2-D molecular layer via intermolecular lateral-to-lateral and head-to-lateral S ··· S interactions with the anionic layer parallel to the crystallographic (0 1 ?1) plane. The temperature variation of magnetic susceptibility from 2 to 350 K shows that antiferromagnetic coupling dominates in the anionic layer, and the disorder–order changes of cationic structure are not coupled to magnetic property.     

Synthesis and characterization of Boc-protected 4-amino- and 5-amino-pyrrole-2-carboxylic acid methyl esters

Syntheses of Boc-protected 4-amino- and 5-amino-pyrrole-2-carboxylic acid methyl esters have been achieved and the structures of these compounds have been fully characterized by detailed NMR studies.     

EFFECT OF VARIOUS IMPURITIES ON ELECTROPHOTOGRAPHIC PROPERTIES OF Se AND Se-Te ALLOYS

Abstract

Effect of various impurities and additives on electrophotographic properties of Se and Se-Te alloys has been systematically investigated by the xerographic measurement technique. It was found that oxygen has a profound effect on the residual potential of pure Se. In order to find Se-Te alloys with the residual potential as low as possible, various quarternary alloys with V group elements (Bi, Sb) and halogens have been prepared and evaluated. Se-Te-Sb-Cl alloy showed the best electrophotographic properties with the lowest residual potential and dark decay. The experimental results are explained by modifying the structural defect model developed by Kastner et al.