作者感谢德意志研究联合会，德国拜耳制药公司，科聚亚公司有机金属有限公司在Bergkamen，拜耳服务公司，巴斯夫公司和沙索GmbH的财政支持。

1。钛（IV）的叔 -butoxide/Triethylchlorosilane溶液的制备<ol><li>钛（IV）， 叔丁醇钾（1毫摩尔）在10毫升无水二氯甲烷中溶解400毫克（400微升）。添加150毫克（170微升）三乙基氯硅烷（1毫摩尔）至该溶液在RT。 1ml该二氯甲烷溶液中含有0.1毫摩尔钛（IV），叔丁醇钾和0.1毫摩尔三乙基氯硅烷。 </li></ol> 2。四苯基-1,2 - 乙二醇的硼酸频哪醇 - 反应（1）与2 - 乙基丁醛<ol><li>解决366毫克四苯基-1,2 -乙二醇（1，1毫摩尔）和新蒸馏的2 -乙基丁醛（3毫摩尔）在3毫升无水二氯甲烷中的300毫克（370微升）中。 </li><li>加入0.5毫升分别制备的钛（IV）的叔 -butoxide/triethylchlorosilane溶液（0.05毫摩尔）。 </li><li>搅拌在室温下在密封的反应管中，所得混合物。 </li><li>置信硅胶TLC板（60F 254） - （9/1己烷/丙酮洗脱）Rm中的反应通过薄层色谱法完成。就达到了在当四苯基-1,2 -乙二醇1不能再被检测到（〜12小时）的时间反应结束。产物的Rf值是0.3 14。 </li><li>用50毫升二氯甲烷稀释得到的反应混合物。 </li><li>通过20ml饱和氯化铵水溶液和碳酸氢钠溶液在分液漏斗依次洗涤稀释的反应混合物中。 </li><li>通过分液漏斗分离出有机层。 </li><li>通过边搅拌边干燥硫酸镁干燥有机层。 </li><li>由波纹纸过滤器滤除悬浮并收集滤液。 </li><li>从在真空下将滤液在40℃下用旋转蒸发器（10-30毫米汞柱）除去二氯甲烷。蒸发溶剂将需要20分钟。 </li><li>纯化剩余的残余物通过硅胶柱（0.035-0.070毫米，ACROS），用己烷/丙酮梯度洗脱（从19点01开始并延续到16时04分），以获得280毫克的1,2 -二醇2F闪式柱色谱（0.99毫摩尔）。 </li><li>通过1 H核磁共振光谱（NMR）的使用为CDCl 3溶剂中确认的1,2 -二醇2f的身份。对于300MHz的NMR光谱仪，二醇的1 H-NMR谱如下所示：δ= 0.78（吨，3H，J = 7.4赫兹），0.87（吨，3H，J = 7.3赫兹）,1.18-1 .40（米，4H）,1.75-1 .81（M，1H），1.91（S，1H，OH），3.12（S，1H，OH），4.68（D，1H，J = 1.2赫兹）,7.19-7 .37（M，6H ）,7.44-7 .46（M，2H）,7.61-7 .63（M，2H）。 </li></ol> 3。四苯基-1,2 - 乙二醇的硼酸频哪醇 - 反应（1）和二乙基甲酮<ol><li>解决366毫克四苯基-1,2 -乙二醇（1，1毫摩尔）和345毫克（423微升）二乙基甲酮（4毫摩尔）在3的毫升无水二氯甲烷。 </li><li>加入1 ml的单独制备的钛（Ⅳ） 叔 -butoxide/triethylchloro-silane溶液（0.1毫摩尔）。 </li><li>搅拌在室温下在密封的反应管中，所得混合物。 </li><li>确认反应完成后，用薄层色谱：硅胶TLC板（60F 254）（洗脱剂：己烷/丙酮，9:1）。在达到反应结束的时候，当四苯基-1,2 -乙二醇1不能被检测到（〜12小时）。产物的Rf为0.3 14。 </li><li>用50毫升二氯甲烷稀释得到的反应混合物。 </li><li>通过20ml饱和氯化铵水溶液和碳酸钠溶液在分液漏斗依次洗涤稀释的反应混合物中。 </li><li>通过分液漏斗分离出有机层。 </li><li>通过边搅拌边干燥硫酸镁干燥有机层。 </li><li>由波纹纸过滤滤液中的悬浮之三，收集滤液。 </li><li>使用旋转蒸发器（10-30毫米汞柱）于40℃ 在真空下除去二氯甲烷。挥发性成分蒸发需要30分钟。 </li><li>通过硅胶柱（0.035-0.070毫米，ACROS），用己烷/丙酮梯度洗脱（从19点01开始并延续到16时04分）纯化通过快速柱色谱剩余的残余物以获得250毫克1， 2 -二醇4023（0.93毫摩尔）。 </li><li>通过1 H核磁共振光谱（NMR）的使用为CDCl 3溶剂确认商品的标识。对于300MHz的NMR光谱仪，二醇4023的1 H-NMR谱如下所示：δ= 0.92（T，6H，J = 7.6赫兹），1.78（M，4H），2.03（S，1H，OH）， 2.83（S，1H，OH）,7.26-7 .35（M，6H）,7.69-7 .71（M，4H）。 </li></ol>

<ol>
	<li>Hirao, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catalytic+reductive+coupling+of+carbonyl+compounds+-+The+pinacol+coupling+reaction+and.">Catalytic reductive coupling of carbonyl compounds - The pinacol coupling reaction and.</a> 279, 53-75 (2007).</li><li>Chatterjee, A., Joshi, N. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+the+stereoselective+pinacol+coupling+reaction.">Evolution of the stereoselective pinacol coupling reaction.</a> Tetrahedron. 62, 12137-12158 (2006).</li><li>Ladipo, F. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-valent+titanium-mediated+reductive+coupling+of+carbonyl+compounds.">Low-valent titanium-mediated reductive coupling of carbonyl compounds.</a> Curr. Org. Chem. 10, 965-980 (2006).</li><li>Gans&#228;uer, A., Bluhm, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reagent-controlled+transition-metal-catalyzed+radical+reactions.">Reagent-controlled transition-metal-catalyzed radical reactions.</a> Chem. Rev. 100, 2771-2788 (2000).</li><li>Duan, X. -. F., Feng, J. X., Zi, G. -. F., Zhang, Z. -. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Convenient+synthesis+of+unsymmetrical+pinacols+by+coupling+of+structurally+similar+aromatic+aldehydes+mediated+by+low-valent+titanium.">A Convenient synthesis of unsymmetrical pinacols by coupling of structurally similar aromatic aldehydes mediated by low-valent titanium.</a> Synthesis. , 277-282 (2009).</li><li>Paquette, L. A., Lai, K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pinacol+macrocyclization-based+route+to+the+polyfused+medium-sized+CDE+ring+system+of+lancifodilactone.">Pinacol macrocyclization-based route to the polyfused medium-sized CDE ring system of lancifodilactone.</a> G. Org. Lett. 10, 3781-3784 (2008).</li><li>Maekawa, H., Yamamoto, Y., Shimada, H., Yonemura, K., Nishiguchi, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mg-+promoted+mixed+pinacol+coupling.">Mg- promoted mixed pinacol coupling.</a> Tetrahedron Lett. 45, 3869-3872 (2004).</li><li>Kang, M., Park, J., Pedersen, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pinacol+cross+coupling+reactions+of+ethyl+2-alkyl-2-formylpropionates.+stereoselective+synthesis+of+2,2,4-+trialkyl-3-hydroxy-&#947;-butyrolactones.">Pinacol cross coupling reactions of ethyl 2-alkyl-2-formylpropionates. stereoselective synthesis of 2,2,4- trialkyl-3-hydroxy-&#947;-butyrolactones.</a> Syn. Lett. , 41-43 (1997).</li><li>Askham, F. R., Carroll, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anionic+zirconaoxiranes+as+nucleophilic+aldehyde+equivalents.+application+to+intermolecular+pinacol+cross+coupling.">Anionic zirconaoxiranes as nucleophilic aldehyde equivalents. application to intermolecular pinacol cross coupling.</a> J. Org. Chem. 58, 7328-7329 (1993).</li><li>Hou, Z., Takamine, K., Aoki, O., Shiraishi, H., Fujiwara, Y., Taniguchi, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nucleophilic+Addition+of+lanthanoid+metal+umpoled+diaryl+ketones+to+electrophiles.">Nucleophilic Addition of lanthanoid metal umpoled diaryl ketones to electrophiles.</a> J. Org. Chem. 53, 6077-6084 (1988).</li><li>Groth, U., Jung, M., Vogel, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intramolecular+chromium(II)-catalyzed+pinacol+cross+coupling+of+2-Mmethylene-&#945;,&#969;-dicarbonyls.">Intramolecular chromium(II)-catalyzed pinacol cross coupling of 2-Mmethylene-&#945;,&#969;-dicarbonyls.</a> Syn. Lett. , 1054-1058 (2004).</li><li>Appendino, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+Modified+Ingenol+Esters.">Synthesis of Modified Ingenol Esters.</a> Eur. J. Org. Chem. , 3413-3420 (1999).</li><li>Spaccini, R., Pastori, N., Clerici, A., Punta, C., Porta, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Key+role+of+Ti(IV)+in+the+selective+radical-radical+cross-coupling+mediated+by+the+Ingold-Fischer+effect.">Key role of Ti(IV) in the selective radical-radical cross-coupling mediated by the Ingold-Fischer effect.</a> J. Am. Chem. Soc. 130, 18018-18024 (2008).</li><li>Leonard, J., Lyfo, B., Procter, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Advanced Practical Organic Chemistry. , (2013).</li><li>Scheffler, U., Stoesser, R., Mahrwald, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retropinacol+/+cross-pinacol+coupling+reactions+-+a+catalytic+access+to+1,2-unsymmetrical+diols.">Retropinacol / cross-pinacol coupling reactions - a catalytic access to 1,2-unsymmetrical diols.</a> Adv. Synth. Cat. 354, 2648-2652 (2012).</li></ol>

作者宣称没有竞争的财务权益。

在反应时间和较高的产量总体下降是由部署的富电子的羰基化合物（17， 表1或表项19与13， 表2比较条目3）观察到。另外，在酮与大体积取代基的反应中收率的降低相当条件下观察到的（使用11， 表2比较条目12）。 尽管广泛的羰基化合物可以在本新方法被应用，不同的起始偕二醇要求的反应条件的优化。...

频哪醇偶联反应是用于对称地连二醇（1,2 - 二醇，片呐醇）制备的一般和常用的方法。综合评价在这一领域见参考文献1平尾，查特吉和Joshi 2，Ladipo 3，和Gansäuer和BLUHM 4。在对比的是，只有少数报道发表指一种高效实现跨频哪醇偶联反应，得到相应的非对称1,2 -二醇（钛（Ⅳ）氯化物/锰5，钐（Ⅱ），碘化6，镁/三甲基氯硅烷7，钒（II）8，锆/锡9，镱10）。因此，分子间的交频哪醇偶联反应，仍然是一个巨大的挑战在有机化学，这种转化，特别是催化的执行。 交叉偶联产物的形成是不受欢迎的动力学下一个经典频哪醇偶联的条件。为了获得足够数量的非对称产品的延迟增加一个羰基化合物是可能的。存在哪些正在开发这种概念的几个例子，但是它们是基于几个具体的实验操作，因此不能一概而论。另外，在这些变换1的羰基化合物的加入所需的过量导致了复杂的产物混合物11的费力的分离。就此而言，另一种是由一种反应物呈现所需的额外试剂等摩尔量的precomplexation表示。 可逆频哪醇反应的各种实例已描述12。这些导致了这样的条件可能是最好的起点的交叉偶联产物的选择性合成的代价。因为低价金属以及反应性自由基物质在原位同时形成，非对称的二元醇可在适宜的羰基反应物的存在下完全形成。给我们所知这样的方法还没有被前（Porta 等。由其他部署的AIBN的化学计量的量（2,2&#39; -偶氮二异丁腈）中所述的类似的频哪醇裂解和随后的偶联，生成报告所需基团）13。 在此协议是可视化提供了一个快速，操作上简单地访问不对称1,2 - 二醇。非对称频那醇产品大多在访问优秀的产率（&gt; 95％）。不需要的对称频那醇产品没有观察到。这个新的跨频哪醇的方法是基于一个retropinacol /跨频哪醇偶联序列。它将由benzopinacole的（1,1,2,2 -四苯基-1,2 -乙二醇，1）与2 -乙基丁醛（在醛系列）和w代表反应被证明在以下第i二乙酮（在酮系列）。

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">1.2-Dichloromethane</td>
			<td style="width:179px;">Sigma-Aldrich</td>
			<td style="width:137px;">319929</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Titanium(IV)tert-butoxide</td>
			<td>VWR International</td>
			<td>200014-852</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2-Ethylbutyraldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>110094</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Benzopinacol</td>
			<td>Aldrich</td>
			<td>B9807</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Triethylchlorosilane</td>
			<td>Aldrich</td>
			<td>&#160;235067</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">hexane, certified ACS</td>
			<td>Fisher scientific</td>
			<td>H29220</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">acetone, certified ACS</td>
			<td>ACROS</td>
			<td>42324</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ammonium chloride</td>
			<td>ACROS</td>
			<td>19997</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium hydrogen carbonate</td>
			<td>ACROS</td>
			<td>12336</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Magnesium sulphate</td>
			<td>ACROS</td>
			<td>41348</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">silica gel 60 F254 TLC plates</td>
			<td>VWR International</td>
			<td>1,057,140,001</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;silica gel, 0.035-0.070 for flash-chromatography</td>
			<td>ACROS</td>
			<td>240360300</td>
			<td style="width:79px;"></td>
		</tr>
	</tbody>
</table>

retropinacol/cross-pinacol coupling reactions - a catalytic access to 1,2-unsymmetrical diols

非对称的1,2 - 二醇是通过还原频哪耦合过程难以进入。成功执行这种转变势必清楚地认识和严格区分的两个类似的羰基化合物（醛→二次1,2 - 二醇或酮→三级1,2 - 二醇）。这种微调仍是一个有机的化学家一个挑战，也是一个没有解决的问题。存在着对成功执行这种转型的一些报告，但他们也不能一概而论。在这里，我们描述一个催化直接频哪耦合过程通过 retropinacol /跨频哪醇偶联序列进行。因此，不对称取代的1,2 - 二醇可以几乎定量的产率通过非常温和的条件下运作简单的性能的手段访问。人工技术，诸如注射器泵技术或反应物的延迟加法是没有必要的。我们描述的程序提供了一个非常快速的访问交频哪醇产物（1,2 - 二醇，连二醇）。进一步扩展这一新的进程， 例如，一个对映选择性的性能可为不对称的手性1,2 -二醇合成一个非常有用的工具。

在四苯基-1,2 -乙二醇和1丙酮中，有催化量的钛（Ⅳ）的醇盐，我们观察到的1,1 -二苯基-1的形成-1,2 -二醇4a和在同一时间形成的存在下反应二苯甲酮3（方案1）。没有检测到由丙酮中具有竞争力的频哪醇偶联形成相应的对称的1,2 - 二醇。然而，需要获得定量的转换非常长的和不可接受的反应时间在这些条件下。在反应发生率显着上升，观察通过添加trialkylchloros...

Watch this Scientific Journal Video about Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols at JoVE.com

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

一种新型账户的基础上retropinacol /跨频哪醇偶联机制不对称的1,2 - 二醇的合成描述。由于催化执行该反应的相当大的改进的相对于传统的交频哪醇偶合的实现。

Retropinacol /跨频哪醇偶联反应 - 催化访问1,2  - 非对称二醇

Unsymmetrical 1,2-diols are hardly accessible by reductive pinacol coupling processes. A successful execution of such a transformation is bound to a clear ...

retropinacolcross-pinacol-coupling-reactions-catalytic-access-to-12

Research

Education

JoVE Journal

JoVE Core

Organic Chemistry

Chemistry

Unit 1

Alcohols and Phenols

SCIENTISTS IN ACTION

12.9K 次观看.  Humboldt University of Berlin. 一种新型账户的基础上retropinacol /跨频哪醇偶联机制不对称的1,2 - 二醇的合成描述。由于催化执行该反应的相当大的改进的相对于传统的交频哪醇偶合的实现。 

视频: Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family of easy accessible, very cheap, and air stable, but highly active and universally applicable C-C cross-coupling catalysts with an excellent functional group tolerance. Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1), the least stable complex within this series towards protons; e.g. in the form of water, allows an eased nanoparticle formation and hence, proved to be the most active Heck catalyst within this series at 100 &#176;C and is a very rare example of an effective and versatile catalyst system that efficiently operates under mild reaction conditions. Rapid and complete catalyst degradation under work-up conditions into phosphonates, piperidinium salts and other, palladium-containing decomposition products assure an easy separation of the coupling products from catalyst and ligands. The facile, cheap, and rapid synthesis of 1,1',1"-(phosphinetriyl)tripiperidine and 1 respectively, the simple and convenient use as well as its excellent catalytic performance in the Heck reaction at 100 &#176;C make 1 to one of the most attractive and greenest Heck catalysts available.
We provide here the visualized protocols for the ligand and catalyst syntheses as well as the reaction protocol for Heck reactions performed at 10 mmol scale at 100 &#176;C and show that this catalyst is suitable for its use in organic syntheses.

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1&#039;,1&#039;&#039;-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1) is an easy accessible, cheap, and air stable, but highly active Heck catalyst with an excellent functional group tolerance that efficiently operates under mild reaction conditions to give the coupling products in very high yields.

Mizoroki-哎呀交叉偶联反应由二氯{双[1,1&#39;，1&#39;&#39;  - （phosphinetriyl）tripiperidine]}钯催化在温和的反应条件

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family ...

科研

化学

Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions

Isothermal titration calorimetry (ITC) is a well-described technique that measures the heat released or absorbed during a chemical reaction, using it as an intrinsic probe to characterize virtually every chemical process. Nowadays, this technique is extensively applied to determine thermodynamic parameters of biomolecular binding equilibria. In addition, ITC has been demonstrated to be able of directly measuring kinetics and thermodynamic parameters (kcat, KM, &#916;H) of enzymatic reactions, even though this application is still underexploited. As heat changes spontaneously occur during enzymatic catalysis, ITC does not require any modification or labeling of the system under analysis and can be performed in solution. Moreover, the method needs little amount of material. These properties make ITC an invaluable, powerful and unique tool to study enzyme kinetics in several applications, such as, for example, drug discovery.
In this work an experimental ITC-based method to quantify kinetics and thermodynamics of enzymatic reactions is thoroughly described. This method is applied to determine kcat and KM of the enzymatic hydrolysis of urea by Canavalia ensiformis (jack bean) urease. Calculation of intrinsic molar enthalpy (&#916;Hint) of the reaction is performed. The values thus obtained are consistent with previous data reported in literature, demonstrating the reliability of the methodology.

Isothermal titration calorimetry measures heat flow released or absorbed in chemical reactions. This method can be used to quantify enzyme-catalysis. In this paper, the protocol for instrumental setup, experiment running, and data analysis is generally described, and applied to the characterization of enzymatic urea hydrolysis by jack bean urease.

热生物催化：等温滴定量热法表征酶促反应

Isothermal titration calorimetry (ITC) is a well-described technique that measures the heat released or absorbed during a chemical reaction, using it as ...

Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. Isonicotinic acid, or its derivatives, are coupled to variable length diaminoalkane chains under an inert atmosphere in anhydrous DMF or DMSO with the use of a weak base, triethylamine, and a coupling agent, 1-propylphosphonic anhydride. The products precipitate from solution upon formation or can be precipitated by the addition of water. If desired, the ligands can be further purified by recrystallization from hot water. Dinuclear platinum complex synthesis using the bispyridine ligands is done in hot water using transplatin. The most informative of the chemical characterization techniques to determine the structure and gross purity of both the bispyridine ligands and the final platinum complexes is 1H NMR with particular analysis of the aromatic region of the spectra (7-9 ppm). The platinum complexes have potential application as anticancer agents and the synthesis method can be modified to produce trinuclear and other multinuclear complexes with different hydrogen bonding functionality in the bridging ligand.

This protocol describes the use of amide coupling reactions of isonicotinic acid and diaminoalkanes to form bridging ligands suitable for use in the synthesis of multinuclear platinum complexes, which combine aspects of the anticancer drugs BBR3464 and picoplatin.

酰胺偶联反应为双吡啶基配体及其络合合成，以白金为双核抗癌药物

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. ...

Real-time Monitoring of Reactions Performed Using Continuous-flow Processing: The Preparation of 3-Acetylcoumarin as an Example

By using inline monitoring, it is possible to optimize reactions performed using continuous-flow processing in a simple and rapid way. It is also possible to ensure consistent product quality over time using this technique. We here show how to interface a commercially available flow unit with a Raman spectrometer. The Raman flow cell is placed after the back-pressure regulator, meaning that it can be operated at atmospheric pressure. In addition, the fact that the product stream passes through a length of tubing before entering the flow cell means that the material is at RT. It is important that the spectra are acquired under isothermal conditions since Raman signal intensity is temperature dependent. Having assembled the apparatus, we then show how to monitor a chemical reaction, the piperidine-catalyzed synthesis of 3-acetylcoumarin from salicylaldehyde and ethyl acetoacetate being used as an example. The reaction can be performed over a range of flow rates and temperatures, the in-situ monitoring tool being used to optimize conditions simply and easily.

Real-time monitoring allows for fast optimization of reactions performed using continuous-flow processing. Here the preparation of 3-acetylcoumarin is used as an example. The apparatus for performing in-situ Raman monitoring is described, as are the steps required to optimize the reaction.

反应执行使用连续流处理的实时监控：3  - 乙酰基香豆素的制备为例

By using inline monitoring, it is possible to optimize reactions performed using continuous-flow processing in a simple and rapid way. It is also possible ...

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form catalytically active N-Heterocyclic Carbenes (NHCs). Here we have used ILs as precatalysts in the addition of &#945;,&#946;-unsaturated aldehydes to chalcones to form 1,6-ketoesters, incorporating an anti-diphenyl moiety in a highly stereoselective fashion. The reaction has a broad substrate scope and several functional groups and heteroaromatics can be integrated into the ketoester backbone in generally good yields with maintained stereoselectivity. The reaction protocol is robust and scalable. The starting materials are inexpensive and the products can be obtained after simple filtration, avoiding solvent-demanding chromatography. Furthermore, the IL can be recycled up to 5 times without any loss of reactivity. Moreover, the 1,6-ketoester end product is a potent gelator in several hydrocarbon based solvents. The method enables rapid access to and evaluation of a new class of low molecular weight gelators (LMWGs) from recyclable and inexpensive starting materials.

Ionic liquids (ILs) mediate fast, simple and cheap access to 1,6-ketoesters in high diastereoselectivities and good yields. The reaction protocol is robust and the 1,6-ketoesters can be obtained in gram scale after a simple filtration protocol. Moreover, the 1,6-ketoesters are potent gelators in hydrocarbon solvents.

1,6-酮酯高立体选择性合成离子液体介导：三组分反应启用快速进入低分子量胶凝剂的新型类

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form ...

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) hydrogen fuel cells. Researchers seeking to develop such systems require a method of measuring the generated hydrogen. Herein, we describe a simple, low-cost, and robust method to measure the hydrogen generated from the reaction of solids with aqueous solutions. The reactions are conducted in a conventional one-necked round-bottomed flask placed in a temperature controlled water bath. The hydrogen generated from the reaction in the flask is channeled through tubing into a water-filled inverted measuring cylinder. The water displaced from the measuring cylinder by the incoming gas is diverted into a beaker on a balance. The balance is connected to a computer, and the change in the mass reading of the balance over time is recorded using data collection and spreadsheet software programs. The data can then be approximately corrected for water vapor using the method described herein, and parameters such as the total hydrogen yield, the hydrogen generation rate, and the induction period can also be deduced. The size of the measuring cylinder and the resolution of the balance can be changed to adapt the setup to different hydrogen volumes and flow rates.

The study of methods to generate on-demand hydrogen for fuel cells continues to grow in importance. However, systems to measure hydrogen evolution from the reaction of chemicals with water can be complicated and expensive. This article details a simple, low-cost, and robust method to measure the evolution of hydrogen gas.

一种简单，低成本和强大的系统来测量氢气与水溶液化学反应放出的音量

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) ...

Laboratory Production of Biofuels and Biochemicals from a Rapeseed Oil through Catalytic Cracking Conversion

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil (HGO) for production of transportation fuels through a fluid catalytic cracking (FCC) route. Cracking experiments are performed with a fully automated reaction unit at a fixed weight hourly space velocity (WHSV) of 8 hr-1, 490-530 &#176;C, and catalyst/oil ratios of 4-12 g/g. When a feed is in contact with catalyst in the fluid-bed reactor, cracking takes place generating gaseous, liquid, and solid products. The vapor produced is condensed and collected in a liquid receiver at -15 &#176;C. The non-condensable effluent is first directed to a vessel and is sent, after homogenization, to an on-line gas chromatograph (GC) for refinery gas analysis. The coke deposited on the catalyst is determined in situ by burning the spent catalyst in air at high temperatures. Levels of CO2 are measured quantitatively via an infrared (IR) cell, and are converted to coke yield. Liquid samples in the receivers are analyzed by GC for simulated distillation to determine the amounts in different boiling ranges, i.e., IBP-221 &#176;C (gasoline), 221-343 &#176;C (light cycle oil), and 343 &#176;C+ (heavy cycle oil). Cracking of a feed containing canola oil generates water, which appears at the bottom of a liquid receiver and on its inner wall. Recovery of water on the wall is achieved through washing with methanol followed by Karl Fischer titration for water content. Basic results reported include conversion (the portion of the feed converted to gas and liquid product with a boiling point below 221 &#176;C, coke, and water, if present) and yields of dry gas (H2-C2's, CO, and CO2), liquefied petroleum gas (C3-C4), gasoline, light cycle oil, heavy cycle oil, coke, and water, if present.

This paper presents an experimental method to produce biofuels and biochemicals from canola oil mixed with a fossil-based feed in the presence of a catalyst at mild temperatures. Gaseous, liquid, and solid products from a reaction unit are quantified and characterized. Conversion and individual product yields are calculated and reported.

通过催化裂化转换从菜籽油生物燃料和生物化学实验室生产

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil ...

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic nature of the monomer is conserved. The resulting polymer, polynorbornene, has a very high glass transition temperature, Tg, and interesting optical and electrical properties. However, the polymerization of functional norbornenes by this mechanism is complicated by the fact that the endo substituted norbornene monomer has, in general, a very low reactivity. Furthermore, the separation of the endo substituted monomer from the exo monomer is a tedious task. Here, we present a simple protocol for the polymerization of substituted norbornenes (endo:exo ca. 80:20) bearing either a carboxylic acid or a pendant double bond. The process does not require that both isomers be separated, and proceeds with low catalyst loadings (0.01 to 0.02 mol%). The polymer bearing pendant double bonds can be further transformed in high yield, to afford a polymer bearing pendant epoxy groups. These simple procedures can be applied to prepare polynorbornenes with a variety of functional groups, such as esters, alcohols, imides, double bonds, carboxylic acids, bromo-alkyls, aldehydes and anhydrides.

We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature.

功能性降冰片烯的催化聚合插入一种简单高效的协议

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic ...

A Protocol for Safe Lithiation Reactions Using Organolithium Reagents

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents warrants proper technique, thorough training, and proper personal protective equipment. To aid in the training of researchers using organolithium reagents, a thorough, step-by-step protocol for the safe and effective use of tert-butyllithium on an inert gas line or within a glovebox is described. As a model reaction, preparation of lithium tert-butyl amide by the reaction of tert-butyl amine with one equivalent of tert-butyl lithium is presented.

The safe and proper use of organolithium reagents is described.

使用有机锂试剂的一个协议安全的锂化反应

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents ...

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. Detailed and generalized protocols are also presented for testing the catalytic activity of such complexes in arylation and Suzuki-Miyaura cross-coupling reactions. Representative results are shown for the catalytic activity of the four complexes in arylation and Suzuki-Miyaura type reactions. For each of the reactions investigated, at least one of the four complexes successfully catalyzed the reaction, qualifying them as promising candidates for catalysis of many carbon-carbon bond-forming reactions. The protocols presented are general enough to be adapted for the synthesis, purification and catalytic activity testing of new palladium N-heterocyclic carbene complexes.

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. The complexes were tested for catalytic activity in arylation and Suzuki-Miyaura reactions. For each reaction investigated, at least one of the four complexes successfully catalyzed the reaction.

钯<em&gt;ñ</em&gt; - 杂环碳烯配合物：苯并咪唑盐的合成和碳 - 碳键合反应中的催化活性

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...