Name: solid-phase synthesis of [4.4] spirocyclic oximes
Uploaded: 2019-02-06T13:00:00
Description: Watch this Scientific Journal Video about Solid-phase Synthesis of [4.4] Spirocyclic Oximes at JoVE.com

这项工作的资金来自教师研究委员会向黄克萨 (美国阿祖萨太平洋大学) 提供的赠款。c. r. 德里斯科是约翰·施陶弗奖学金和根卡雷拉本科生研究补助金的获得者。格里芬获得了生物和化学系的 s2s 本科生研究奖学金。
<img alt="Image 1" src="/files/ftp_upload/58508/58508img1.jpg">
作者 (从左到右) 科迪·德里斯科、凯文·黄博士和西拉斯·格里芬进行了实验并准备了手稿。科迪·德里斯科是约翰·斯陶弗研究员, 也是根卡雷拉研究资助金的获得者。塞拉斯是 azusa 太平洋大学的 s2s 研究员。黄博士提供研究指导, 是阿祖萨太平洋大学教师研究委员会资助的获得者。

注意: 使用前请查阅所有相关材料安全数据表 (msds)。这些合成中使用的几种化学物质具有剧毒性和致癌性。在进行以下反应时, 请使用所有适当的安全惯例, 包括使用工程控制 (通风罩、红外和 nmr 光谱仪) 和个人防护设备 (安全护目镜、手套、实验室外套、全长裤子和闭脚鞋)。
1. 在快速眼动器中添加呋喃胺
注: 此步骤的持续时间为设置的25分钟和24小时的反?...

在典型的 rem linker 固相合成策略中, 在固体支撑释放胺之前, 形成季铵盐至关重要, 如协议39第4节所述。由于三环系统和笨重的 r2基团 (苯基和辛卤化物) 的位阻, 在这一反应中只能使用小的烷基化试剂 (甲基和烯丙基卤化物)。通过简单的改性, 允许添加和使用较大的甾体试剂, 通过打开前32的异烷基化步骤, 降低了三环结构的刚性。...

尽管最近发现在许多生物系统1中使用高度功能化的螺旋体杂环, 但一个方便的途径仍然是易于制造所必需的。这些杂环的系统和用途包括: mdm2 抑制和其他抗癌活性2,3,4,5, 酶抑制6,7,8, 抗生素活性9,10, 荧光标记10,11, 12, 对映体选择性结合的 dna 探针13,14, 15和 rna 针对16, 以及许多潜在的应用于治疗 17,18,19。随着对这些杂环的需求不断增加, 目前的文献对于哪种合成途径是最好的仍存在分歧。现代合成方法的这个问题使用异锡和异锡衍生物作为起始材料为各种杂环20,21, 复杂分子内重组22,23 ,24,25, lewis 酸1,26,27或过渡金属催化 17,28,29, 30, 或不对称进程31。虽然这些程序成功地生产了功能有限的特定螺旋体血氧基, 但研究了一种合成策略, 以产生具有高环氧选择性的分子库, 相对较少32。
这里介绍的技术表明, 这些感兴趣的分子可以使用一些很好理解的合成技术同时生成。从使用快速眼动链接器和分子内西丽基硝酸-烯烃环加 (isoc) 在固体载体上合成分子开始, 提出的路径展开了一条非线性路径, 其特征是在三环系统中切断了键, 从而留下高度功能化的杂环。快速眼动链接器以其便利性和可回收性而闻名, 它利用坚实的支撑来合成三胺33。由于通过简单过滤可轻松地将其认证为 rem 链接器, 这种固相合成技术为科学家提供了一种可回收且无示的链接器, 并已在此处使用。反应完成后, rem 链接器将被重新生成, 并可多次重复使用。rem 链接器也是无痕量的, 因为与许多固相链接器不同, 产品与聚合物之间的连接点无法区分 34,35。此外, 对 isoc 反应也有很好的研究和了解, 该反应在合成吡咯烷酮类氧基 36,37中非常有用。这些反应也许被更好地称为 1, 3-偶极极环加成, 形成了许多具有高副选择性的杂环 38,39, 40,41, 42,43,44,45. 利用改进的 rem-耦合-isoc 技术合成螺旋体循环分子, 产生了一种高度不相关的选择性产物。在此, 我们报告了螺旋体血氧的有效生产使用一种新的合成方法, 结合了两种众所周知的途径和现成的起始材料。

<table>
	<tbody>
		<tr>
			<td>Chemicals</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>REM Resin</td>
			<td>Nova Biochem</td>
			<td>8551010005</td>
			<td>Solid Polymer Support; 1.1 mmol/g loading</td>
		</tr>
		<tr>
			<td>Furfurylamine</td>
			<td>Acros Organics</td>
			<td>119800050</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Dimethylformamide (DMF)</td>
			<td>Sigma-Aldrich</td>
			<td>227056</td>
			<td>Solvent</td>
		</tr>
		<tr>
			<td>Dichloromethane (DCM)</td>
			<td>Sigma-Aldrich</td>
			<td>270997</td>
			<td>Solvent</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma-Aldrich</td>
			<td>34860</td>
			<td>Solvent</td>
		</tr>
		<tr>
			<td>trans-4-bromo-&#946;-nitrostyrene</td>
			<td>Sigma-Aldrich</td>
			<td>400017</td>
			<td>Nitro-olefin solid</td>
		</tr>
		<tr>
			<td>trans-3,4-dimethoxy-&#946;-nitrostyrene</td>
			<td>Sigma-Aldrich</td>
			<td>S752215</td>
			<td>Nitro-olefin solid</td>
		</tr>
		<tr>
			<td>trans-2,4-dichloro-&#946;-nitrostyrene</td>
			<td>Sigma-Aldrich</td>
			<td>642169</td>
			<td>Nitro-olefin solid</td>
		</tr>
		<tr>
			<td>trans-&#946;-nitrostyrene</td>
			<td>Sigma-Aldrich</td>
			<td>N26806</td>
			<td>Nitro-olefin solid</td>
		</tr>
		<tr>
			<td>Triethylamine (TEA)</td>
			<td>Sigma-Aldrich</td>
			<td>T0886</td>
			<td>Solvent</td>
		</tr>
		<tr>
			<td>Trimethylsilyl chloride (TMSCl)</td>
			<td>Sigma-Aldrich</td>
			<td>386529</td>
			<td>Reagent; CAUTION - highly volatile; creates HCl gas</td>
		</tr>
		<tr>
			<td>Tetra-n-butylammonium fluoride (TBAF) in Tetrahydrofuran (THF)</td>
			<td>Sigma-Aldrich</td>
			<td>216143</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Tetrahydrofuran (THF)</td>
			<td>Sigma-Aldrich</td>
			<td>401757</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>1-Bromooctane</td>
			<td>Sigma-Aldrich</td>
			<td>152951</td>
			<td>Alkyl-halide</td>
		</tr>
		<tr>
			<td>Iodomethane</td>
			<td>Sigma-Aldrich</td>
			<td>289566</td>
			<td>Alkyl-halide</td>
		</tr>
		<tr>
			<td>Allylbromide</td>
			<td>Sigma-Aldrich</td>
			<td>337528</td>
			<td>Alkyl-halide</td>
		</tr>
		<tr>
			<td>Benzylbromide</td>
			<td>Sigma-Aldrich</td>
			<td>B17905</td>
			<td>Alkyl-halide</td>
		</tr>
		<tr>
			<td>Glassware/Instrumentation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>25 mL solid-phase reaction vessel</td>
			<td>Chemglass</td>
			<td>CG-1861-02</td>
			<td>Glassware with filter</td>
		</tr>
		<tr>
			<td>Thermo Scientific Nicole iS5</td>
			<td>Thermo Scientific</td>
			<td>IQLAADGAAGFAHDMAZA</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>AVANCE III NMR Spectrometer</td>
			<td>Bruker</td>
			<td>N/A</td>
			<td>Instrument; 300 MHz; Solvents: CDCl3 and CD3OH</td>
		</tr>
		<tr>
			<td>Wrist-Action Shaker Model 75</td>
			<td>Burrell Scientific</td>
			<td>757950819</td>
			<td>Instrument</td>
		</tr>
	</tbody>
</table>

solid-phase synthesis of [4.4] spirocyclic oximes

由于螺旋体杂环在生物系统中的潜在应用, 一种方便的杂环合成路线备受追捧。通过固相合成、再生 michael (rem) 链接器策略和 1, 3-偶极环加法, 可以构建一个结构相似的杂环库, 无论是否有螺旋体中心。固支撑合成的主要优点如下: 第一, 每个反应步骤都可以使用大量过量的试剂驱动完成, 从而产生较高的产量;其次, 利用市售的原料和试剂, 将成本保持在较低水平;最后,反应步骤易于通过简单的过滤进行净化。快速眼动链接器策略具有吸引力, 因为它具有可回收性和无迹性。反应方案完成后, 链接器可以重复使用多次。在典型的固相合成中, 产品包含部分或整个链接器, 这可能被证明是不可取的。rem 链接器是 "无痕" 的, 产品与聚合物之间的连接点是无法区分的。分子内1、3-偶极环加成的高亚光选择性是有据可查的。受固体支撑的不溶解性的限制, 反应进展只能通过红外 (ir) 光谱学对官能团 (如果有的话) 的变化进行监测。因此, 中间体的结构识别不能用常规核磁共振 (nmr) 光谱来表征。这种方法的其他局限性来自于聚合物链剂与所需化学反应方案的兼容性。在此, 我们报告了一个协议, 允许方便生产螺旋体杂环, 只需简单的修改, 就可以通过高通量技术实现自动化。

如上述过程所述, 螺旋体血氧的合成路线 (见图 1) 始于迈克尔在化合物1(rem 链接器) 中添加呋喃胺, 以承受2。随后的迈克尔加法和 1, 3-偶极环加成的支持2使用各种β-硝基苯衍生物产生三环化合物3, n-水杨质异恶唑嗪具有四个独特的立体原代中心。3与 tbaf 的脱硅产生螺旋体氧基 4, 仍...

Watch this Scientific Journal Video about Solid-phase Synthesis of [4.4] Spirocyclic Oximes at JoVE.com

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

在这里, 我们提出了一个协议, 以证明一种有效的方法, 合成螺旋体杂环。五步过程采用固相合成和再生迈克尔链接器策略。通常很难合成, 我们提出了一个可定制的方法, 合成螺旋体环分子, 否则无法进入其他现代方法。

[4.4] 刺环氧基的固相合成

A convenient synthetic route for spirocyclic heterocycles is well sought after due to the molecule&#39;s potential use in biological systems. By means of ...

这种固相有机合成技术可以在组合库的构建中找到应用，同时合成螺旋环杂环，利用生物测定测试抗癌活性。虽然这种方法可用于合成螺旋体化合物，但也可以应用于其他小分子，如异黄酮和异氧酮。开始合成，加入25毫升固体相反应容器1克 REM 树脂，20 毫莱特二甲酰酰胺，和 2.4 毫升的富利明。盖住容器，并在室温下在摇床上搅拌 24 小时，用富利明将树脂装载。然后排干毛皮丙胺轴承树脂，用五毫升的 DMF 搅拌约三分钟，清洗它。之后，清洗树脂四次，在五毫升二氯甲烷之间交替膨胀树脂，并在五毫升甲醇之间交替收缩树脂。然后用压缩空气彻底干燥树脂，通常需要大约30分钟。接下来，在通风良好的烟气罩中，在干燥的喃自一胺轴承树脂中加入1.48毫升三乙胺、10毫升无水甲苯和637克β硝基苯乙烯。在反应混合物中加入一毫升三甲基硅氯。使容器保持打开状态，直到混合物释放完盐酸气。然后盖上容器，在室温下搅拌混合物48小时，形成二氧化氮中间体。之后，加入五毫升甲醇来抑制反应。摇动混合物三分钟，然后浸泡两分钟。然后排干树脂并洗涤四次，在五毫升 DCM 和五毫升甲醇之间交替。用压缩空气彻底干燥洗净的树脂。接下来，在干树脂中加入一毫升无水四氢黄醇。然后在THF中加入1.24毫升的一摩尔溶液中的四-n-丁醇酰胺，并在室温下搅拌混合物12小时，以打开伊索沙酮环。之后，对树脂进行应变，用5毫升的THF清洗，然后四次洗涤在5毫升DCM和5毫升甲醇之间交替。用压缩空气彻底干燥树脂。接下来，在树脂中加入五毫升 DMF，然后加入一毫升的溴化烷。在室温下搅拌混合物24小时，形成四元胺。然后排干树脂，用五毫升的 DMF 清洗。在 DCM 和甲醇之间交替，用压缩空气干燥，然后清洗树脂四次。接下来，在干树脂中加入三毫升DCM，然后加入1.5毫升 TEA。搅拌混合物24小时，从聚合物支持中切出螺旋环氧化。然后，将粗制产品收集在小瓶或烧瓶中。在 DCM 和甲醇之间交替清洗树脂四次，并收集产品小瓶中的洗涤液。在旋转蒸发器上去除产品混合物中的挥发性。然后，用5毫升沸腾的甲醇对粗产品进行三化，并小心地取出液体。用五毫升的 DCM 部分清洗树脂两次，用压缩空气干燥，以便在随后的实验中重复使用。具有各种替代剂的螺旋旋风氧化合成具有出色的立体选择性。总体产量表示每个合成步骤的平均产量为 80 至 88%。通过伊索萨佐尔环开口的反应进展可以通过红外光谱进行监测。一般来说，对这种方法的新鲜人很难选择合适的聚合物支持链接器。在合成过程中，链接器必须坚固地满足所有反应条件。尝试此过程时，请记住在下一个反应步骤之前清洗和干燥树脂。上一步的剩余试剂将使整体合成复杂化，并影响螺旋体产品的产量和纯度。

solid-phase-synthesis-of-44-spirocyclic-oximes

Research

JoVE Journal

Chemistry

Synthesis of Immunotargeted Magneto-plasmonic Nanoclusters

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications including contrast enhancement in novel magnetomotive imaging modalities, simultaneous capture&#160;and detection of circulating tumor cells (CTCs),&#160;and multimodal molecular imaging combined with photothermal therapy of cancer cells. These applications have stimulated significant interest in development of protocols for synthesis of magneto-plasmonic nanoparticles with optical absorbance in the near-infrared (NIR) region and a strong magnetic moment. Here, we present a novel protocol for synthesis of such hybrid nanoparticles that is based on an oil-in-water microemulsion method. The unique feature of the protocol described herein is synthesis of magneto-plasmonic nanoparticles of various sizes from primary blocks which also have magneto-plasmonic characteristics. This approach yields nanoparticles with a high density of magnetic and plasmonic functionalities which are uniformly distributed throughout the nanoparticle volume. The hybrid nanoparticles can be easily functionalized by attaching antibodies through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting.

Here, we describe a protocol for synthesis of magneto-plasmonic nanoparticles with a strong magnetic moment and a strong near-infrared (NIR) absorbance. The protocol also includes antibody conjugation to the nanoparticles through the Fc moiety for various biomedical applications which require molecular specific targeting.

Immunotargeted的合成磁等离子团簇

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications ...

科研

化学

Synthetic Methodology for Asymmetric Ferrocene Derived Bio-conjugate Systems via Solid Phase Resin-based Methodology

Early detection is a key to successful treatment of most diseases, and is particularly imperative for the diagnosis and treatment of many types of cancer. The most common techniques utilized are imaging modalities such as Magnetic Resonance Imaging (MRI), Positron Emission Topography (PET), and Computed Topography (CT) and are optimal for understanding the physical structure of the disease but can only be performed once every four to six weeks due to the use of imaging agents and overall cost. With this in mind, the development of &#8220;point of care&#8221; techniques, such as biosensors, which evaluate the stage of disease and/or efficacy of treatment in the clinician&#8217;s office and do so in a timely manner, would revolutionize treatment protocols.1 As a means to exploring ferrocene based biosensors for the detection of biologically relevant molecules2, methods were developed to produce ferrocene-biotin bio-conjugates described herein. This report will focus on a biotin-ferrocene-cysteine system that can be immobilized on a gold surface.

The synthesis of asymmetric species of ferrocene is challenging using solution techniques. This report focuses on the methods carried out to produce a ferrocene-biotin bioconjugate using facile and clean reactions accomplished via solid-phase synthesis. Incorporation of a thiolate moiety is shown to impart the ability for immobilization on gold surfaces.

合成方法通过固相树脂为基础的方法不对称二茂铁产生的生物共轭系统

Early detection is a key to successful treatment of most diseases, and is particularly imperative for the diagnosis and treatment of many types of cancer. ...

Synthesis of Indoxyl-glycosides for Detection of Glycosidase Activities

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are rapidly oxidized, for example by atmospheric oxygen, to indigo type dyes. This reaction enables fast and easy screening in vivo without isolation or purification of enzymes, as well as rapid tests on agar plates or in solution (e.g., blue-white screening, micro-wells) and is used in biochemistry, histochemistry, bacteriology and molecular biology. Unfortunately the synthesis of such substrates proved to be difficult, due to various side reactions and the low reactivity of the indoxyl hydroxyl function. Especially for glucose type structures low yields were observed. Our novel approach employs indoxylic acid ester as key intermediates. Indoxylic acid esters with varied substitution patterns were prepared on scalable pathways. Phase transfer glycosylations with those acceptors and peracetylated glycosyl halides can be performed under common conditions in high yields. Ester cleavage and subsequent mild silver mediated glycosylation yields the peracetylated indoxyl glycosides in high yields. Finally deprotection is performed according to Zempl&#233;n.

Indoxyl glycosides are well-established and widely used tools for enzyme screening and enzyme activity monitoring. Especially for glucose type structures previous syntheses proved to be challenging and low yielding. Our novel approach employs indoxylic acid esters as precious intermediates to yield a considerable number of indoxyl glycosides in good yields.

的吲哚酚苷的检测糖苷酶活动的合成

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are ...

Hydroquinone Based Synthesis of Gold Nanorods

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag+) present in the "growth solution". By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM.

This paper describes a protocol for the synthesis of gold nanorods, based on the use of hydroquinone as reducing agent, plus the different mechanisms for controlling their size and aspect ratio.

金纳米棒基于对苯二酚合成

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the ...

Synthesis of Hierarchical ZnO/CdSSe Heterostructure Nanotrees

A two-step chemical vapor deposition procedure is here employed to prepare tree-like hierarchical ZnO/CdSSe hetero-nanostructures. The structures are composed of CdSSe branches grown on ZnO nanowires that are vertically aligned on a transparent sapphire substrate. The morphology was measured via scanning electron microscopy. The crystal structure was determined by X-ray powder diffraction analysis. Both the ZnO stem and CdSSe branches have a predominantly wurtzite crystal structure. The mole ratio of S and Se in the CdSSe branches was measured by energy dispersive X-ray spectroscopy. The CdSSe branches result in strong visible light absorption. Photoluminescence (PL) spectroscopy showed that the stem and branches form a type-II heterojunction. PL lifetime measurements showed a decrease in the lifetime of emission from the trees when compared to emission from individual ZnO stems or CdSSe branches and indicate fast charge transfer between CdSSe and ZnO. The vertically aligned ZnO stems provide a direct electron transport pathway to the substrate and allow for efficient charge separation after photoexcitation by visible light. The combination of the abovementioned properties makes ZnO/CdSSe nanotrees promising candidates for applications in solar cells, photocatalysis, and opto-electronic devices.

Here, we prepare and characterize novel tree-like hierarchical ZnO/CdSSe nanostructures, where CdSSe branches are grown on vertically aligned ZnO nanowires. The resulting nanotrees are a potential material for solar energy conversion and other opto-electronic devices.

分层的ZnO / CdSSe异质Nanotrees的合成

A two-step chemical vapor deposition procedure is here employed to prepare tree-like hierarchical ZnO/CdSSe hetero-nanostructures. The structures are ...

Integration of Miniaturized Solid Phase Extraction and LC-MS/MS Detection of 3-Nitrotyrosine in Human Urine for Clinical Applications

Free 3-nitrotyrosine (3-NT) has been extensively used as a possible biomarker for oxidative stress. Increased levels of 3-NT have been reported in a wide variety of pathological conditions. However, existing methods lack the sufficient sensitivity and/or specificity necessary to measure the low endogenous level of 3-NT reliably and are too cumbersome for clinical applications. Hence, analytical improvement is urgently needed to accurately quantify the levels of 3-NT and verify the role of 3-NT in pathological conditions. This protocol presents the development of a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) detection combined with a miniaturized solid phase extraction (SPE) for the rapid and accurate measurement of 3-NT in human urine as a non-invasive biomarker for oxidative stress. SPE using a 96-well plate markedly simplified the process by combining sample cleanup and analyte enrichment without tedious derivatization and evaporation steps, reducing solvent consumption, waste disposal, risk of contamination and overall processing time. The employment of 25 mM ammonium acetate (NH4OAc) at pH 9 as the SPE elution solution substantially enhanced the selectivity. Mass spectrometry signal response was improved through adjustment of the multiple reaction monitoring (MRM) transitions. Use of 0.01% HCOOH as additive on a pentafluorophenyl (PFP) column (150 mm x 2.1 mm, 3 &#181;m) improved signal response another 2.5-fold and shortened the overall run time to 7 min. A lower limit of quantitation (LLOQ) of 10 pg/mL (0.044 nM) was achieved, representing a significant sensitivity improvement over the reported assays. This simplified, rapid, selective and sensitive method allows two plates of urine samples (n = 192) to be processed in a 24 h time-period. Considering the markedly improved analytical performance, and non-invasive and inexpensive urine sampling, the proposed assay is beneficial for pre-clinical and clinical studies.

A selective and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method coupled with an efficient solid phase extraction on a mixed-mode cation-exchange (MCX) 96-well microplate was developed for the measurement of free 3-nitrotyrosine (3-NT) in human urine with high throughput, which is suitable for clinical applications.

微型固相萃取和LC-MS / MS检测人尿中3-硝基酪氨酸的临床应用

Free 3-nitrotyrosine (3-NT) has been extensively used as a possible biomarker for oxidative stress. Increased levels of 3-NT have been reported in a wide ...

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 of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

通过活性表面生长机制合成基片束缚金纳米线

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a non-radioactive precursor in solution. This approach necessitates purification of the tracer by high performance liquid chromatography (HPLC) followed by reformulation in a biocompatible solvent for human administration. We recently developed a novel 11C-methylation approach for the highly efficient synthesis of carbon-11 labeled PET radiopharmaceuticals, taking advantage of solid phase cartridges as disposable &#34;3-in-1&#34; units for the synthesis, purification and reformulation of the tracers. This approach obviates the use of preparative HPLC and reduces the losses of the tracer in transfer lines and due to radioactive decay. Furthermore, the cartridge-based technique improves synthesis reliability, simplifies the automation process and facilitates compliance with the Good Manufacturing Practice (GMP) requirements. Here, we demonstrate this technique on the example of production of a PET tracer Pittsburgh compound B ([11C]PiB), a gold standard in vivo imaging agent for amyloid plaques in the human brains.

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

We report an efficient carbon-11 radiolabeling technique to produce clinically relevant tracers for Positron Emission Tomography (PET) using solid phase extraction cartridges. 11C-methylating agent is passed through a cartridge preloaded with precursor and successive elution with aqueous ethanol provides chemically and radiochemically pure PET tracers in high radiochemical yields.

用于生产PET示踪剂的固体阶段11C甲基化、纯化和配方

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a ...

Gas Chromatography-Mass Spectrometry Paired with Total Vaporization Solid-Phase Microextraction as a Forensic Tool

Gas Chromatography &#8211; Mass Spectrometry (GC-MS) is a frequently used technique for the analysis of numerous analytes of forensic interest, including controlled substances, ignitable liquids, and explosives. GC-MS can be coupled with Solid-Phase Microextraction (SPME), in which a fiber with a sorptive coating is placed into the headspace above a sample or immersed in a liquid sample. Analytes are sorbed onto the fiber which is then placed inside the heated GC inlet for desorption. Total Vaporization Solid-Phase Microextraction (TV-SPME) utilizes the same technique as immersion SPME but immerses the fiber into a completely vaporized sample extract. This complete vaporization results in a partition between only the vapor phase and the SPME fiber without interference from a liquid phase or any insoluble materials. Depending upon the boiling point of the solvent used, TV-SPME allows for large sample volumes (e.g., up to hundreds of microliters). On-fiber derivatization may also be performed using TV-SPME. TV-SPME has been used to analyze drugs and their metabolites in hair, urine, and saliva. This simple technique has also been applied to street drugs, lipids, fuel samples, post-blast explosive residues, and pollutants in water. This paper highlights the use of TV-SPME to identify illegal adulterants in very small samples (microliter quantities) of alcoholic beverages. Both gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) were identified at levels that would be found in spiked drinks. Derivatization by a trimethylsilyl agent allowed for conversion of the aqueous matrix and GHB into their TMS derivatives. Overall, TV-SPME is quick, easy, and requires no sample preparation aside from placing the sample into a headspace vial.

Total Vaporization Solid Phase Microextraction (TV-SPME) completely vaporizes a liquid sample whilst analytes are sorbed onto a SPME fiber. This allows for partitioning of the analyte between only the solvent vapor and the SPME fiber coating.

气相色谱-质量光谱学与总蒸发固体相微切成一对，作为取证工具

Gas Chromatography &#8211; Mass Spectrometry (GC-MS) is a frequently used technique for the analysis of numerous analytes of forensic interest, including ...