对于财政的支持，我们非常感谢EPSRC（职业加速奖学金到申诉; EP/J001538/1），拉姆齐纪念信托（研究奖学金2009-2011 JAB），和伦敦帝国学院。谢谢教授艾伦·阿姆斯特朗的慷慨支持和建议。

Iodoaziridines 1。准备与Diiodomethyllithium <ol><li>火焰干燥含有搅拌棒并配备有隔膜，在氩气气流下在100毫升圆底烧瓶中，然后允许在氩气氛下冷却至室温。注：玻璃在烘箱中干燥过夜（125℃），并冷却至室温以类似的方式也是合适的。 </li><li>到烧瓶中， 通过微量添加5.7毫升无水THF和2.7毫升无水Et 2 O等，通过注射器，和新蒸馏的六甲基二硅烷（1.50毫摩尔，315微升）。 </li><li>搅拌所得的溶液并冷却至-78℃，在一个大小合适的杜瓦瓶用干冰/丙酮浴中，使烧瓶中得到很好的淹没。用铝箔覆盖的杜瓦瓶，以减少反应器中的暴露于光。 </li><li> 通过注射器在2-3分钟向此溶液， 加正丁基锂（1.50毫摩尔，0.60毫升，2.5M的己烷）滴加于-78℃。允许该混合物搅拌，在-78℃进行另外30分钟，以形成将LiHMDS的0.17摩尔溶液。注意：无BuLi溶液是易燃，对皮肤有腐蚀性和自燃。在注射器中过量的试剂应相应地淬灭。 </li><li> 30分钟后， 通过微型注射器加入1 ml无水THF中，通过注射器经火焰干燥10毫升圆底烧瓶中，接着二碘甲烷（1.70毫摩尔，135微升），并确保它们充分混合。 </li><li>添加二碘甲烷溶液滴加2分钟到锂六甲基二硅的溶液在-78℃下离开此溶液20分钟，于-78℃。 </li><li>在此期间，称重从 N - [（E）-4 - methylphenylmethylidene] -4 -甲基苯磺酰胺（137毫克，0.50毫摩尔）到另一个火焰干燥的10毫升圆底烧瓶中，溶解于2.0毫升的无水THF中。 </li><li>后20分钟的去质子化的时候，该亚胺溶液逐滴加到在5分钟的diiodomethyllithium溶液在-78＆＃176; C。 </li><li>紧接在后滴加完成后，解除该反应容器出来的干冰浴中，并转移至冰/水浴中于0℃下重新盖上铝箔，并在0℃下离开15分钟注：该解决方案应该是橙色。 </li><li> 15分钟后，在0℃，淬火通过加入30毫升饱和碳酸氢钠水溶液中进行反应。将混合物转移到分液漏斗中，加入30毫升二氯甲烷2 Cl 2中。摇动该混合物，并除去下部的CH 2 Cl 2层。重复这一提取过程2进一步倍，并结合的CH 2 Cl 2层。 </li><li>添加硫酸钠对有机层以除去任何存在于溶液中的水，然后滤出硫酸钠，并在250毫升圆底烧瓶中收集滤液。 </li><li>下在旋转蒸发器减压，得到期望的iodoaziridine产物的不纯的样品除去溶剂。 </li></ol>产品稳定性2。评估，以固定相的色谱<ol><li>溶解在CH 2 Cl 2（16毫升）中的粗丙啶样品和添加1,3,5 -三甲氧基苯（28.0毫克，0.167毫摩尔）作为内部标准，以确保此完全溶解。采取等分试样（2ml）中从该混合物中除去溶剂，减压和通过1 H NMR光谱法分析该样品。 </li><li>打开使用标准NMR处理软件所记录的1 H NMR谱。在Mestrenova，右键单击该频谱，并选择“一体化”，然后选择“手动”，以提供集成工具。单击并拖动以弥补峰的宽度在6.08 ppm或4.87 ppm的内标和氮丙啶CHI信号的信号分别进行整合。就在6.08 ppm的积分为峰值单击鼠标右键，选择“编辑组成”和“规范化”值更改为3.0。 NOTE：类似的步骤可以与其它软件包可以应用。 </li><li>使用积分更新后的值的氮丙啶CHI信号（4.87 ppm的），以确定iodoaziridine的产量，这里使用（100/3）×（该CHI信号的积分），这使59％计算收率。注意：给定的内标物（0.167毫摩尔），和对应于1个质子的产物峰的已知量，iodoaziridine的收率计算由下面的公式：100×（积分产物峰的质量）×（内部标准摩尔）/摩尔起始原料。 </li><li>准备以下的固定相（25克）的浆料：二氧化硅，二氧化硅+1％纯3（三乙胺），中性氧化铝，碱性氧化铝（活性Ⅰ），碱性氧化铝（活性IV）和硅酸镁，各在5％乙酸乙酯/己烷（50毫升）中，在含有搅拌器棒六个独立250毫升锥形瓶中。在另一个锥形瓶中制备5％EtOAc /己烷溶液（50毫升）中，被用作对照实验。注意：硅酸采用凝胶，氧化铝和其他固定相是如果吸入，因此应始终在一个有效的通风橱处理的危险。 </li><li>加入2毫升分装在iodoaziridine /内标溶液各锥形瓶在室温的。搅拌30分钟浆料混合物。注意：这表示持续时间的正常快速柱色谱过程中的化合物可暴露于固定相。 </li><li>过滤用多孔漏斗将浆液混合物，并在250毫升圆底烧瓶中收集滤液。用CH 2 Cl 2（2×30毫升）在烧结漏斗洗涤残余物。对剩余的浆液重复这个滤波处理。注：这是适当的相互抵消固定相的开始，以便有时间过滤等保持相同的时间为每个固定相材料。 </li><li>在减压下从得到的样品，除去溶剂，并通过1 H-NMR分光分析SCOPY计算iodoaziridine回收在每种情况下，如在第2.2节中描述的量。 </li><li>比较iodoaziridine从与第2.1节中得到的测试每个固定相获得的收益率。注：样品给产量最高，理想的情况是一样的2.1，表明最佳的固定相色谱法。在这个例子中，碱性氧化铝（活性Ⅳ）被视为最佳的固定相进行纯化。 </li></ol>该Iodoaziridine的碱性氧化铝和纯化3。停用<ol><li>重复第1节，以产生粗iodoaziridine混合物。 </li><li>以产生碱性氧化铝（活性IV）中，加入100 g碱性氧化铝（活性Ⅰ）到500ml圆底烧瓶中，然后加入10毫升的水到烧瓶中，并适合用玻璃塞。 </li><li>摇动烧瓶大力至无结块是可见的，这说明即使蔓延的水整个氧化铝。使氧化铝冷却至室温。注意：在吸附水化是放热反应，所以在烧瓶可能会变热，并可能导致压力的积聚。释放任何压力积聚频繁。 </li><li>使用碱性氧化铝（活性Ⅳ）作为固定相，用己烷洗脱，分级，以5％乙酸乙酯/己烷通过柱色谱法纯化粗iodoaziridine。注意：高浓度的EtOAc不应与碱性氧化铝使用。在这些情况下，可以使用二乙醚代替。 </li><li>合并含有产物的级分并减压浓缩，得到纯iodoaziridine除去溶剂。 </li></ol>

<ol>
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The authors declare that they have no competing financial interests.

一个程序的顺式非对映选择性制备- N-TS-iodoaziridines进行了说明，连同稳定性研究协议来定量表示通过快速柱色谱法的最佳固定相的潜在不稳定的化合物的纯化。可以设想，通过这种方法获得iodoaziridines将使方法来访问了广泛的氮丙啶被开发，通过完整环的衍生化。 适当修改的程序亚胺与α-质子，是用亚胺 - 甲苯亚磺酸的加合物作为原料代替亚胺的材料由于改进的...

该方法的目的是制备iodoaziridines，提供潜力进一步官能化，以氮丙啶衍生物。该方法包含一个协议，用于定量选择最佳固定相的色谱。 氮丙啶，为三元环，posses固有的环张力，使有机化学其中1重要组成部分。他们的反应显示了浩大常累及氮丙啶开环2,3，特别是在官能胺4,5的合成中间体，或其他含氮杂环化合物6,7的形成。一系列由包含一个完整的氮丙啶环的前体官能氮丙啶衍生物的合成已成为一个可行的策略8。官能团 - 金属交换，以产生一个氮丙啶基的阴离子，并与亲电子反应已经被证明是有效<su对&gt; 9,10,11，和最近区域选择性和立体选择性的N-保护的氮丙啶的去质子化方面也取得了12-15。最近，钯催化的交叉偶联方法，形成由官能氮丙啶的前体芳基氮丙啶已开发Vedejs 16,17，和自己18。 的杂原子取代的吖丙啶化学开辟了反应性和稳定性19的有趣的问题。我们一直关心iodoaziridines的编制作为提供可能提供的前体范围广衍生物具有互补的反应，以现有的氮丙啶官能化反应的一种新的官能团。在2012年我们报道的芳基的N-Boc-iodoaziridines 20的第一个准备，最近报道的芳基和烷基取代的N-TS-iodoaziridines 21的准备。 该方法对ACCESS iodoaziridines使用diiodomethyllithium，最近也被用在diiodoalkanes 22,23的制备试剂，diiodomethylsilanes 22,24和乙烯基碘化物25-27。该试剂的卡宾样性质要 ​​求编制和使用在低温下22,28。在iodoaziridines编制用于diiodomethyllithium的产生的技术和条件说明如下。 而二氧化硅已成为首选色谱29的材料，它被证明是不适宜的N-TS-iodoaziridines的纯化。硅胶通常是在有机化学快速色谱由于可用性和有效的分离采用的第一个也是唯一的固相物质。然而，硅胶的酸性性质可以在纯化过程中会引起敏感的底物的分解，防止了所需材料的隔离。而其他STationary阶段或改性硅胶可用于色谱30，没有办法来评估这些不同材料的靶标分子的相容性。由于iodoaziridines的敏感性质，我们建立了一个协议，以评估化合物的稳定性固定相21，这是这里展示的数组。这具有在很宽范围内具有灵敏的官能团的化合物的合成中的应用潜力。下面的协议提供了有效的访问的N-TS iodoaziridines，允许两个烷基和芳顺 iodoaziridines高产率的非对映选择性合成。

<table border="0" cellpadding="0" cellspacing="0" width="871">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:209px;">Hexamethyldisilazane</td>
			<td style="width:273px;">999-97-3</td>
			<td style="width:197px;">Alfa Aesar</td>
			<td style="width:192px;">Distill from KOH under argon prior to use.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:209px;">n-Butyllithium</td>
			<td style="width:273px;">109-72-8</td>
			<td style="width:197px;">Sigma Aldrich</td>
			<td style="width:192px;">2.5 M in hexanes, titrate prior to use.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:209px;">Diiodomethane</td>
			<td style="width:273px;">75-11-6</td>
			<td style="width:197px;">Alfa Aesar</td>
			<td style="width:192px;">Contains copper as a stabilizer.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:209px;">1,3,5-Trimethoxybenzene</td>
			<td style="width:273px;">621-23-8</td>
			<td style="width:197px;">Sigma Aldrich</td>
			<td style="width:192px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:209px;">Silica</td>
			<td style="width:273px;">112945-52-5</td>
			<td style="width:197px;">Merck</td>
			<td style="width:192px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:209px;">Basic alumina</td>
			<td style="width:273px;">1344-28-1</td>
			<td style="width:197px;">Sigma Aldrich</td>
			<td style="width:192px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:209px;">Neutral alumina</td>
			<td style="width:273px;">1344-28-1</td>
			<td style="width:197px;">Merck</td>
			<td style="width:192px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:209px;">Florisil</td>
			<td style="width:273px;">1343-88-0</td>
			<td style="width:197px;">Sigma Aldrich</td>
			<td style="width:192px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:23px;width:209px;">THF</td>
			<td colspan="3" rowspan="3" style="width:663px;">All anhydrous solvents were dried through activated alumina purification columns.&#160;</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:209px;">Et2O</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:209px;">CH2Cl2</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NMR spectrometer</td>
			<td>Bruker AV 400&#160;</td>
			<td>n/a</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:209px;">NMR processing software</td>
			<td>MestReNova&#160;</td>
			<td>7.0.2-8636</td>
			<td></td>
		</tr>
	</tbody>
</table>

synthesis and purification of iodoaziridines involving quantitative selection of the optimal stationary phase for chromatography

高非对映选择性制备顺式 -通过diiodomethyllithium与N-TS醛亚胺反应的N-TS-iodoaziridines描述。 Diiodomethyllithium通过二碘甲烷与将LiHMDS的去质子化制得，于THF /乙醚混合物中，在-78℃下 在黑暗中。这些条件是所产生的荔枝2试剂的稳定至关重要。随后滴加N-TS醛亚胺对预制diiodomethyllithium溶液，得到一种氨基-二碘化中间体，这是不隔离。将反应混合物至0℃的迅速升温促进环化反应，得到iodoaziridines用专用的顺式非对映选择性。该反应的加成和环化阶段被小心控制温度介导在一个反应​​烧瓶中。 由于iodoaziridines来净化，PU合适的方法评估的敏感性rification是必需的。一个协议，以评估敏感的化合物的稳定性，为柱层析固定相进行描述。这种方法适合于应用到新iodoaziridines，或其他潜在的敏感的新化合物。因此该方法可以应用于合成的项目范围。该过程涉及首先反应产率，在纯化前，通过1 H NMR谱与对比内部标准进行评估。不纯的产物混合物的部分则暴露于适合各种色谱固定相的淤浆，在适合于作为在闪式色谱洗脱剂的溶剂体系。搅拌30分钟，以模仿色谱法，随后进行过滤后，将样品的1 H核磁共振光谱仪进行分析。对于每个固定的相位计算出的产量进行比较，以从粗反应混合物最初获得的。所得结果可为T的定量评估该化合物的不同固定相的他的稳定性;因此，最佳的可选择。碱性氧化铝的选择，修改为活动四，作为一个合适的固定相已经允许某些iodoaziridines隔离的优良率和纯度。

该过程描述能提供顺式 - （±）-2 -碘-3 - （4 -甲苯基）-1 - （4 -甲苯磺酰基）氮丙啶作为单一对映异构体和具有优异的纯度（ 图1）。在纯化前，对iodoaziridine产品的59％的产率进行了计算，用1 H NMR谱。然而，这iodoaziridine是特别具有挑战性的净化和经历显著分解的二氧化硅。如通过固定相来确定屏幕上的纯化碱性氧化铝（活性Ⅳ）所允许的产品来进行分离产率为48...

Watch this Scientific Journal Video about Synthesis and Purification of Iodoaziridines Involving Quantitative Selection of the Optimal Stationary Phase for Chromatography at JoVE.com

Synthesis and Purification of Iodoaziridines Involving Quantitative Selection of the Optimal Stationary Phase for Chromatography

一个协议的非对映选择性一锅准备顺 - N-TS-iodoaziridines描述。的diiodomethyllithium，除了N-TS醛亚胺和氨基宝石 -二碘化中间体iodoaziridines被证实环化生成。还包括的是一种协议通过色谱法快速和定量评估的最合适的固定相进行纯化。

合成和Iodoaziridines纯化涉及定量选择最优固定相的色谱

The highly diastereoselective preparation of cis-N-Ts-iodoaziridines through reaction of diiodomethyllithium with N-Ts aldimines is described. ...

synthesis-purification-iodoaziridines-involving-quantitative

Research

JoVE Journal

Chemistry

12.4K 次观看.  Imperial College London. 一个协议的非对映选择性一锅准备顺 - N-TS-iodoaziridines描述。的diiodomethyllithium，除了N-TS醛亚胺和氨基宝石 -二碘化中间体iodoaziridines被证实环化生成。还包括的是一种协议通过色谱法快速和定量评估的最合适的固定相进行纯化。 

视频: Synthesis and Purification of Iodoaziridines Involving Quantitative Selection of the Optimal Stationary Phase for Chromatography

Determination of the Gas-phase Acidities of Oligopeptides

Amino acid residues located at different positions in folded proteins often exhibit different degrees of acidities. For example, a cysteine residue located at or near the N-terminus of a helix is often more acidic than that at or near the C-terminus 1-6. Although extensive experimental studies on the acid-base properties of peptides have been carried out in the condensed phase, in particular in aqueous solutions 6-8, the results are often complicated by solvent effects 7. In fact, most of the active sites in proteins are located near the interior region where solvent effects have been minimized 9,10. In order to understand intrinsic acid-base properties of peptides and proteins, it is important to perform the studies in a solvent-free environment.
We present a method to measure the acidities of oligopeptides in the gas-phase. We use a cysteine-containing oligopeptide, Ala3CysNH2 (A3CH), as the model compound. The measurements are based on the well-established extended Cooks kinetic method (Figure 1) 11-16. The experiments are carried out using a triple-quadrupole mass spectrometer interfaced with an electrospray ionization (ESI) ion source (Figure 2). For each peptide sample, several reference acids are selected. The reference acids are structurally similar organic compounds with known gas-phase acidities. A solution of the mixture of the peptide and a reference acid is introduced into the mass spectrometer, and a gas-phase proton-bound anionic cluster of peptide-reference acid is formed. The proton-bound cluster is mass isolated and subsequently fragmented via collision-induced dissociation (CID) experiments. The resulting fragment ion abundances are analyzed using a relationship between the acidities and the cluster ion dissociation kinetics. The gas-phase acidity of the peptide is then obtained by linear regression of the thermo-kinetic plots 17,18.
The method can be applied to a variety of molecular systems, including organic compounds, amino acids and their derivatives, oligonucleotides, and oligopeptides. By comparing the gas-phase acidities measured experimentally with those values calculated for different conformers, conformational effects on the acidities can be evaluated.

The determination of the gas-phase acidities of cysteine-containing oligopeptides is described. The experiments are performed using a triple quadrupole mass spectrometer. The relative acidities of the peptides are measured using collision-induced dissociation experiments, and the quantitative acidities are determined using the extended Cooks kinetic method.

寡肽测定气相酸性

Amino acid residues located at different positions in folded proteins often exhibit different degrees of acidities. For example, a cysteine residue ...

科研

化学

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid phase by using combinatorial chemistry. One of the most well studied classes of peptidomimetics is peptoids. Peptoids are easy to synthesize and have been shown to be proteolysis-resistant and cell-permeable. Over the past decade, many useful protein ligands have been identified through screening of peptoid libraries. However, most of the ligands identified from peptoid libraries do not display high affinity, with rare exceptions. This may be due, in part, to the lack of chiral centers and conformational constraints in peptoid molecules. Recently, we described a new synthetic route to access peptide tertiary amides (PTAs). PTAs are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. With side chains on both &#945;-carbon and main chain nitrogen atoms, the conformation of these molecules are greatly constrained by sterical hindrance and allylic 1,3 strain. (Figure 1) Our study suggests that these PTA molecules are highly structured in solution and can be used to identify protein ligands. We believe that these molecules can be a future source of high-affinity protein ligands. Here we describe the synthetic method combining the power of both split-and-pool and sub-monomer strategies to synthesize a sample one-bead one-compound (OBOC) library of PTAs.

Peptide tertiary amides (PTAs) are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. Here we describe a synthetic method which combines&#160;both split-and-pool and sub-monomer strategies to synthesize a one-bead one-compound library of PTAs.

分裂和池合成及肽叔酰胺图书馆表征

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

Quantitative Detection of Trace Explosive Vapors by Programmed Temperature Desorption Gas Chromatography-Electron Capture Detector

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive vapor samples. The direct liquid deposition method yields a higher fidelity between the analysis of vapor samples and the analysis of solution standards than using separate injection methods for vapors and solutions, i.e., samples collected on vapor collection tubes and standards prepared in solution vials. Additionally, the method can account for instrumentation losses, which makes it ideal for minimizing variability and quantitative trace chemical detection. Gas chromatography with an electron capture detector is an instrumentation configuration sensitive to nitro-energetics, such as TNT and RDX, due to their relatively high electron affinity. However, vapor quantitation of these compounds is difficult without viable vapor standards. Thus, we eliminate the requirement for vapor standards by combining the sensitivity of the instrumentation with a direct liquid deposition protocol to analyze trace explosive vapor samples.

Trace explosive vapors of TNT and RDX collected on sorbent-filled thermal desorption tubes were analyzed using a programmed temperature desorption system coupled to GC with an electron capture detector. The instrumental analysis is combined with direct liquid deposition method to reduce sample variability and account for instrumentation drift and losses.

定量检测痕量爆炸物蒸气通过程序升温脱附 - 气相色谱 - 电子捕获检测器

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive ...

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 &#197;. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride.

Nitrogen is an effective supercritical fluid for extraction or drying processes due to its small molecular size, high density in the near-liquid supercritical regime, and chemical inertness. We present a supercritical nitrogen drying protocol for the purification treatment of reactive, porous materials.

超临界氮处理的活性多孔材料的净化

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. ...

A Quantitative Glycomics and Proteomics Combined Purification Strategy

There is a growing desire in the biological and clinical sciences to integrate and correlate multiple classes of biomolecules to unravel biology, define pathways, improve treatment, understand disease, and aid biomarker discovery. N-linked glycosylation is one of the most important and robust post-translational modifications on proteins and regulates critical cell functions such as signaling, adhesion, and enzymatic function. Analytical techniques to purify and analyze N-glycans have remained relatively static over the last decade. While accurate and effective, they commonly require significant expertise and resources. Though some high-throughput purification schemes have been developed, they have yet to find widespread adoption and often rely on the enrichment of glycopeptides. One promising method, developed by Thomas-Oates et al., filter aided N-glycan separation (FANGS), was qualitatively demonstrated on tissues. Herein, we adapted FANGS to plasma and coupled it to the individuality normalization when labeling with glycan hydrazide tags strategy in order to achieve accurate relative quantification by liquid chromatography mass spectrometry and enhanced electrospray ionization. Furthermore, we designed new functionality to the protocol by achieving tandem, shotgun proteomics and glycosylation site analysis on hen plasma. We showed that N-glycans purified on filter and derivatized by hydrophobic hydrazide tags were comparable in terms of abundance and class to those by solid phase extraction (SPE); the latter is considered a gold standard in the field. Importantly, the variability in the two protocols was not statistically different. Proteomic data that was collected in-line with glycomic data had the same depth compared to a standard trypsin digest. Peptide deamidation is minimized in the protocol, limiting non-specific deamidation detected at glycosylation motifs. This allowed for direct glycosylation site analysis, though the protocol can accommodate 18O site labeling as well. Overall, we demonstrated a new in-line high-throughput, unbiased, filter based protocol for quantitative glycomics and proteomics analysis.

A high-throughput protocol was developed for combined proteomics and glycomics purification and LC-MS/MS quantification in plasma. Deamidation analysis of N-linked glycosylation motifs was specific to deglycosylated sites. Accurate quantitation of N-glycans was achieved by coupling filter aided N-glycan separation to the individuality normalization when labeling with glycan hydrazide tags strategy.

定量糖组学和蛋白质组学组合式净化策略

There is a growing desire in the biological and clinical sciences to integrate and correlate multiple classes of biomolecules to unravel biology, define ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

协议的合成<em&gt;邻</em&gt; -trifluoromethoxylated苯胺类化合物

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

蛋白质生物缀合物的合成<em&gt;通过</em&gt;半胱氨酸马来酰亚胺化学

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

使用Photoredox催化剂蠕虫状胶束的简便合成可见光介导的分散聚合

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-O-thiophenylmethyl Modification and Characterization via Circular Dichroism

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular methodology for applications in various fields and for different research purposes. The procedure described herein focuses on the synthesis, purification, and characterization of dodecamers of RNA 5&#39;-[CUA CGG AAU CAU]-3&#39; containing zero, one, or two modifications located at the C2&#39;-O-position. The probes are based on 2-thiophenylmethyl groups, incorporated into RNA nucleotides via standard organic synthesis and introduced into the corresponding oligonucleotides via their respective phosphoramidites. This report makes use of phosphoramidite chemistry via the four canonical nucleobases (Uridine (U), Cytosine (C), Guanosine (G), Adenosine (A)), as well as 2-thiophenylmethyl functionalized nucleotides modified at the 2&#39;-O-position; however, the methodology is amenable for a large variety of modifications that have been developed over the years. The oligonucleotides were synthesized on a controlled-pore glass (CPG) support followed by cleavage from the resin and deprotection under standard conditions, i.e., a mixture of ammonia and methylamine (AMA) followed by hydrogen fluoride/triethylamine/N-methylpyrrolidinone. The corresponding oligonucleotides were purified via polyacrylamide electrophoresis (20% denaturing) followed by elution, desalting, and isolation via reversed-phase chromatography (Sep-pak, C18-column). Quantification and structural parameters were assessed via ultraviolet-visible (UV-vis) and circular dichroism (CD) photometric analysis, respectively. This report aims to serve as a resource and guide for beginner and expert researchers interested in embarking in this field. It is expected to serve as a work-in-progress as new technologies and methodologies are developed. The description of the methodologies and techniques within this document correspond to a DNA/RNA synthesizer (refurbished and purchased in 2013) that uses phosphoramidite chemistry.

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2&#039;-O-thiophenylmethyl Modification and Characterization via Circular Dichroism

This article provides a detailed procedure on the solid-phase synthesis, purification, and characterization of dodecamers of RNA modified at the C2&#39;-O-position. UV-vis and circular dichroism photometric analyses are used to quantify and characterize structural aspects, i.e., single-strands or double-strands.

用于固相合成含有2&#39;-<em&gt; 0</em通过圆二色性修饰和表征

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular ...

Synthesis and Mass Spectrometry Analysis of Oligo-peptoids

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have been thought of as a type of molecular information storage. Mass spectrometry analysis has been considered the method of choice for sequencing peptoids. Peptoids can be synthesized via solid phase chemistry using a repeating two-step reaction cycle. Here we present a method to manually synthesize oligo-peptoids and to analyze the sequence of the peptoids using tandem mass spectrometry (MS/MS) techniques. The sample peptoid is a nonamer consisting of alternating N-(2-methyloxyethyl)glycine (Nme) and N-(2-phenylethyl)glycine (Npe), as well as an N-(2-aminoethyl)glycine (Nae) at the N-terminus. The sequence formula of the peptoid is Ac-Nae-(Npe-Nme)4-NH2, where Ac is the acetyl group. The synthesis takes place in a commercially available solid-phase reaction vessel. The rink amide resin is used as the solid support to yield the peptoid with an amide group at the C-terminus. The resulting peptoid product is subjected to sequence analysis using a triple-quadrupole mass spectrometer coupled to an electrospray ionization source. The MS/MS measurement produces a spectrum of fragment ions resulting from the dissociation of charged peptoid. The fragment ions are sorted out based on the values of their mass-to-charge ratio (m/z). The m/z values of the fragment ions are compared against the nominal masses of theoretically predicted fragment ions, according to the scheme of peptoid fragmentation. The analysis generates a fragmentation pattern of the charged peptoid. The fragmentation pattern is correlated to the monomer sequence of the neutral peptoid. In this regard, MS analysis reads out the sequence information of the peptoids.

A protocol is described for the manual synthesis of oligo-peptoids followed by sequence analysis by mass spectrometry.

寡 peptoids 的合成及质谱分析

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have ...