Financial support from the DFG (Heisenberg scholarship to M.K., KL 2221/4-1; KL 2221/3-1) and the Max-Planck-Institut fuer Kohlenforschung is gratefully acknowledged.

テトラヒドロカルバゾールヒドロペルオキシドの1の合成<ol><li>テトラヒドロカルバゾールが非常に着色されている場合は、ヒドロペルオキシドの形成が遅くなる。この場合、無色の出発物質を得るために、トルエン/ペンタンを用いて再結晶により、またはカラムクロマトグラフィーによりそれを精製する。カラムクロマトグラフィーによる精製は、シリカゲル及びアルミナの上部層の下層でカラムを詰める。カラムの上部にテトラヒドロカルバゾールを入れて、トルエンで溶出する。すべての不要な黄色と黒色の副生成物は、カラムに吸着され、無色のテトラヒドロカルバゾールを溶出している。すぐに溶媒を蒸発し、暗所でアルゴン雰囲気下で精製された白色の生成物を保管してください。 </li><li> 250mlフラスコ中に、（1、報告された方法16に従って合成）のテトラヒドロカルバゾール又は置換されたテトラヒドロカルバゾール1gを秤量。このフラスコに100mLのトルエンを追加します。 </li><li> 2（ローズベンガルを量るmg）及び上記反応混合物に追加します。 </li><li>攪拌棒を加え、セプタムでフラスコをカバーしています。 </li><li>隔壁を通して酸素バルーンを追加します。これは、反応に酸素雰囲気の正圧を保持します。 </li><li> 23ワットランプで反応混合物を照射する。 </li><li> （70:30の比率でヘキサン/酢酸エチルの混合物を使用して、TLC、本明細書に記載のヒドロペルオキシドのR f値は、0.2と0.3の間である）薄層クロマトグラフィーにより反応の進行状況を確認から、または1 H NMRによってサンプル撮影（ロータリーエバポレーターで溶剤を蒸発させ、DMSO-d6中の残留物を溶解させる）。反応時間は1.1部で述べたように、光源と、出発物質の純度に依存して変化し得る。一般的には、テトラヒドロカルバゾール1の完全な変換は、3時間かかります。 </li><li>出発物質の完全な変換後に析出した固体を濾過する。固体の洗浄のほとんどを除去するためにペンタンを用いて行うことができるトルエンが、精製のために必要ではない。 </li><li>減圧下で単離した固体を乾燥させます。 </li></ol>注意：私たち一緒に働くのか、この作品に記載されている化合物の処理にも問題を経験したことはありませんが、過酸化物を処理する場合、予防措置を講じなければならない。特に、加熱するか、金属または金属塩とそれらを混合するためにニート過酸化物を露出させるために、可能な限り避けるべきである。ブラストシールドの背後にあるこのような反応を行うことは推奨されます。 図2カップリング反応 - メタノール中の10モル％トリフルオロ酢酸を用いた方法A <ol><li> （ステップ1から。0.49ミリモル、1.0当量）のヒドロペルオキシドを計量し、所望のアニリンの求核（0.49ミリモル、1.0当量）を12ミリリットルバイアルまたは適切な丸底フラスコに。 </li><li>トリフルオロ酢酸10ミリリットルのメタノールを追加し、その後に3.74μL（TFAを、0.049ミリモル、0.1当量）をバイアルまたは丸底フラスコに。 </li><li>キャップ付きの容器を閉め、4時間室温で反応混合物を撹拌する。 （反応の過程で沈殿する製品のための） 後処理変種A1： </li><li>所望の生成物を得るために、沈殿した固形物をろ過する。メタノール（3×0.5ml）で生成物を洗浄。 </li><li>製品の第二画分を得るために、ろ液からメタノールを蒸発させる。室温に冷却し、次いで、40℃で酢酸エチル5mlの粗生成物を溶解し、純粋な生成物が沈殿する3〜5mlのペンタンを加える。 </li><li>製品の異なる画分を組み合わせて、高真空下に乾燥させます。 （沈殿しない製品のための） 後処理変種A2： </li><li>直接ロータリーエバポレーターを用いて反応後、溶媒を蒸発させて、所望の生成物を得た（シリカゲル、ヘキサン/酢酸エチル/トリエチルアミン）で指定されたカラムクロマトグラフィーにより残渣を精製する。 </li></ol> 3カップリング反応 - 。方法B酢酸を用いて<ol><li> （ステップ1から。0.49ミリモル、1.0当量）のヒドロペルオキシドを計量し、所望のアニリンの求核（0.49ミリモル、1.0当量）を12ミリリットルバイアルまたは適切な丸底フラスコに。 </li><li>バイアルまたは丸底フラスコにに10ミリリットルの酢酸（AcOH中）を追加します。 </li><li>キャップ付きの容器を閉め、4時間室温で反応混合物を攪拌する。 （反応の過程で沈殿する製品のための） 後処理変種B1： </li><li>所望の生成物を得るために、沈殿した固形物をろ過する。のAcOH（3×0.5ml）で生成物を洗浄。 </li><li>製品の第二画分を得るために、ろ液から酢酸を蒸発させる。室温に冷却し、次いで、40℃で酢酸エチル5mlの粗生成物を溶解し、純粋な生成物が沈殿する3〜5mlのペンタンを加える。 </li><li>製品の異なる画分を組み合わせて、高真空下に乾燥させます。 後処理変種B2 </strオング&gt;（沈殿しない製品の場合）： </li><li>直接ロータリーエバポレーターを用いて反応後、溶媒を蒸発させて、所望の生成物を得た（シリカゲル、ヘキサン/酢酸エチル/トリエチルアミン）で指定されたカラムクロマトグラフィーにより残渣を精製する。 </li></ol>

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著者らは、開示することは何もありません。

要約すると、我々は、テトラヒドロカルバゾールにおけるCH結合は都合の二段階の方法でCN-カップリング生成物を生成するために官能化され得ることを実証できた。 最初のステップは、ヒドロペルオキシド2を与え、テトラヒドロカルバゾール（1）又は酸素元素17,19とその誘導体の周知の光触媒酸化である。トルエン中で実行した場合、?...

C-H結合の直接官能化は、有機化学1で重要と長年の目標である。このような変換は、グループの活性化や演出の導入および除去を必要とする従来の方法に比べて、ステップ、時間と材料を保存することで、合成を合理化するために、非常に強力なことができます。そのため、C-H結合の官能もグリーンケミストリー2のための魅力的である。酸化条件下で、2個のCH結合または1つのヘテロ原子及びCH-H結合は、それぞれ、（ 図1）3-9 CCに変換され、C-ヘテロ原子結合することができる。多くの場合、これらの酸化的カップリング反応は、合成酸化剤、高価な触媒や高温度を必要とする。したがって、多くの試みが端末酸化剤10として安価な触媒は、良性状態及び酸素又は空気を使用する方法を開発するために行われる。 <img alt="図1" fo:content-wIDTH = &quot;5インチ&quot; SRC = &quot;/ files/ftp_upload/51504/51504fig1highres.jpg&quot;幅= &quot;500&quot; /&gt; 図1。酸化的カップリング反応。 <a href="https://www.jove.com/files/ftp_upload/51504/51504fig1highres.jpg" target="_blank">この図の拡大版を表示するには、こちらをクリックしてください。</a> 多くの有機化合物はヒドロペルオキシド部分11,12を形成し 、効果的にO 2を挿入することにより、C-H結合を官能することができます自動酸化反応で空気中の酸素とゆっくり反応する。自動酸化プロセスは、炭化水素原料から生成された含酸素化合物を工業的規模で使用されるが、それは、貴重な化合物または材料の分解をもたらす場合には自動酸化はまた、望ましくないプロセスであるている。いくつかの場合において、例えばジエチルエーテル、大気中で形成されたヒドロペルオキシドも爆発することができる。最近では、酸化還元活性触媒13,14を必要とせずにC-H結合から新しいC-C結合を形成するための自動酸化を利用して反応を発見</SUP&gt;。単に、酸触媒の存在下で、酸素の下で基板を撹拌し、新製品の形成につながる。反応の鍵は、酸触媒15によって、第2の基板で置換されている中間ヒドロペルオキシド、の容易な形成である。この反応は、しかしながら、キサンテンに制限し、容易に酸素と生成物の雰囲気下で酸化されているいくつかの関連化合物は、これまでに見つかっていないアプリケーションを有している。それにもかかわらず、この発見に触発され、私たちは、薬学的に活性なインドール誘導体16を合成するための中間過酸化物（チップ）を経由して、CH官能の原理を利用し、関連する酸化カップリング法を開発した。 インドール類、特に1テトラヒドロカルバゾール、容易に可視光増感剤20を用いて生成することができる一重項酸素17-19の存在下で2クメンに酸化することができる。 hydroperoxide部分は、脱離基として、原則として同法に酸触媒により活性化されている場合と求核21,22の導入を可能にすることができる。またクメンヒドロペルオキシド、ホック法23からのフェノールの工業的合成に利用される酸は転位触媒反応を受けることが知られている。慎重な最適化研究によって、我々は再配列16による不要な分解経路上のアニリン3様N-求核試薬で所望の置換反応を支持するための条件を見つけることができる。ここでは、可視光のみ、増感剤、酸素および酸を用いて、詳細には、この二段階のCHIPSの手順が記載されている。選択された商品の中でも、高い抗ウイルス活性を示すまたは腫瘍治療のための重要な24〜26であることができる血管内皮増殖因子（VGF）を阻害するインドール誘導体4である。

<table border="0" cellpadding="0" cellspacing="0" width="797">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1,2,3,4-Tetrahydrocarbazole</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td style="width:151px;">T12408</td>
			<td style="width:291px;">If coloured, purification may be necessary. See Protocol 1.1</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Methanol</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td>322415</td>
			<td>99.8% purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-Nitroaniline</td>
			<td style="width:139px;">Acros Organics</td>
			<td>128371000</td>
			<td>99% purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Trifluoroacetic acid</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td>T6508</td>
			<td>99% purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Acetic acid</td>
			<td style="width:139px;">J. T. Baker</td>
			<td style="width:151px;">JTB RS 426960101</td>
			<td>99-100% purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Aniline</td>
			<td style="width:139px;">Merck</td>
			<td>8222560100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">4-Aminobenzonitrile</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td>147753</td>
			<td>98% purity</td>
		</tr>
	</tbody>
</table>

synthesis of antiviral tetrahydrocarbazole derivatives by photochemical and acid-catalyzed c-h functionalization via intermediate peroxides (chips)

The direct functionalization of C-H bonds is an important and long standing goal in organic chemistry. Such transformations can be very powerful in order to streamline synthesis by saving steps, time and material compared to conventional methods that require the introduction and removal of activating or directing groups. Therefore, the functionalization of C-H bonds is also attractive for green chemistry. Under oxidative conditions, two C-H bonds or one C-H and one heteroatom-H bond can be transformed to C-C and C-heteroatom bonds, respectively. Often these oxidative coupling reactions require synthetic oxidants, expensive catalysts or high temperatures. Here, we describe a two-step procedure to functionalize indole derivatives, more specifically tetrahydrocarbazoles, by C-H amination using only elemental oxygen as oxidant. The reaction uses the principle of C-H functionalization via Intermediate PeroxideS (CHIPS). In the first step, a hydroperoxide is generated oxidatively using visible light, a photosensitizer and elemental oxygen. In the second step, the N-nucleophile, an aniline, is introduced by Br&#248;nsted-acid catalyzed activation of the hydroperoxide leaving group. The products of the first and second step often precipitate and can be conveniently filtered off. The synthesis of a biologically active compound is shown.

1 - （5 -ニトロインドリン-1 -イル）-2,3,4,9 -テトラヒドロ-1H-カルバゾール（図4a）。 方法A は、R f = 0.63（ヘキサン/酢酸エチル70:30）に従って合成。 精製 ：方法A、精密検査変種A1（2.4、2.5、2.6ステップ）を使用して生成物を精製する。オレンジ色の固体、収率：95％。 1</sup...

Watch this Scientific Journal Video about Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS at JoVE.com

Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS

A two-step procedure for the synthesis of pharmaceutically active indole-derivatives by C-H functionalization with anilines is described, using photo- and Br&#248;nsted acid catalysis.

中間過酸化物を介した光化学および酸触媒CH機能化による抗ウイルステトラヒドロカルバゾール誘導体の合成（チップ）

The direct functionalization of C-H bonds is an important and long standing goal in organic chemistry. Such transformations can be very powerful in order ...

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Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides (CHIPS)

Unit 1

Acids and Bases

SCIENTISTS IN ACTION

13.7K ビュー.  Max-Planck-Institut fuer Kohlenforschung. A two-step procedure for the synthesis of pharmaceutically active indole-derivatives by C-H functionalization with anilines is described, using photo- and Brønsted acid catalysis.

ビデオ: Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS

Anticancer Metal Complexes: Synthesis and Cytotoxicity Evaluation by the MTT Assay

Titanium (IV) and vanadium (V) complexes are highly potent anticancer agents. A challenge in their synthesis refers to their hydrolytic instability; therefore their preparation should be conducted under an inert atmosphere. Evaluation of the anticancer activity of these complexes can be achieved by the MTT assay.
The MTT assay is a colorimetric viability assay based on enzymatic reduction of the MTT molecule to formazan when it is exposed to viable cells. The outcome of the reduction is a color change of the MTT molecule. Absorbance measurements relative to a control determine the percentage of remaining viable cancer cells following their treatment with varying concentrations of a tested compound, which is translated to the compound anticancer activity and its IC50 values. The MTT assay is widely common in cytotoxicity studies due to its accuracy, rapidity, and relative simplicity.
Herein we present a detailed protocol for the synthesis of air sensitive metal based drugs and cell viability measurements, including preparation of the cell plates, incubation of the compounds with the cells, viability measurements using the MTT assay, and determination of IC50 values.

A method for synthesis of air-sensitive titanium and vanadium anticancer agents is described, along with the evaluation of their cytotoxic activity towards human cancer cell line by the MTT Assay.

MTTアッセイにより合成と細胞毒性の評価：抗がん金属錯体

Titanium (IV) and vanadium (V) complexes are highly potent anticancer agents. A challenge in their synthesis refers to their hydrolytic instability; ...

化学

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

合成、キャラクタリゼーション、およびハイブリッドのAu / CdSのとAu / ZnSのコア/シェルナノ粒子の機能化

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

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.

の合成のためのプロトコル<em&gt;オルソ</em&gt; -trifluoromethoxylatedアニリン誘導体

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

Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous solution. In a carbon nanotube/PEO105-PPO70-PEO105 (poloxamer 407) aqueous solution, the amphiphilic poloxamer 407 adsorbs onto the carbon nanotube surfaces and self-assembles into continuous layers, driven by intermolecular interactions between constituent molecules. The addition of 5-methylsalicylic acid changes the self-assembled structure from spherical-micellar to a cylindrical morphology. The fabricated poloxamer 407/carbon nanotube hybrid particles exhibit thermo-responsive structural features so that the density and thickness of poloxamer 407 layers are also reversibly controllable by varying temperature. The detailed structural properties of the poloxamer 407/carbon nanotube particles in suspension can be characterized by small-angle neutron scattering experiments and model fit analyses. The distinct curve shapes of the scattering intensities depending on temperature control or addition of aromatic additives are well described by a modified core-shell cylinder model consisting of a carbon nanotube core cylinder, a hydrophobic shell, and a hydrated polymer layer. This method can provide a simple but efficient way for the fabrication and in-situ characterization of carbon nanotube-based nano particles with a structure-tunable encapsulation.

A method for the functionalization of carbon nanotubes with structure-tunable polymeric encapsulation layers and structural characterization using small-angle neutron scattering is presented.

小角中性子散乱による熱可逆性ブロック共重合体と特性を持つ単層カーボンナノチューブの機能化

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous ...

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.

タンパク質のバイオコンジュゲートの合成<em&gt;経由で</em&gt;システイン - マレイミドケミストリー

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

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.

アクティブな表面の成長メカニズムを介して基質結合 Au ナノワイヤの作製

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

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Disaccharide nucleosides, which consist of disaccharide and nucleobase moieties, have been known as a valuable group of natural products having multifarious bioactivities. Although chemical O-glycosylation is a commonly beneficial strategy to synthesize disaccharide nucleosides, the preparation of substrates such as glycosyl donors and acceptors requires&#160;tedious protecting&#160;group manipulations and a purification at each synthetic step. Meanwhile, several research groups have reported that boronic and borinic esters serve as a protecting or activating group of carbohydrate derivatives to achieve the regio- and/or stereoselective acylation, alkylation, silylation, and glycosylation. In this article, we demonstrate the procedure for the regioselective O-glycosylation of unprotected ribonucleosides utilizing boronic acid. The esterification of 2&#39;,3&#39;-diol of ribonucleosides with boronic acid makes the temporary protection of diol, and, following O-glycosylation with a glycosyl donor in the presence of p-toluenesulfenyl chloride and silver triflate, permits the regioselective reaction of the 5&#39;-hydroxyl group to afford the disaccharide nucleosides. This method could be applied to various nucleosides, such as guanosine, adenosine, cytidine, uridine, 5-metyluridine, and 5-fluorouridine. This article and the accompanying video represent&#160;useful (visual) information for the O-glycosylation of unprotected nucleosides and their analogs for the synthesis of not only disaccharide nucleosides, but also a variety of biologically relevant derivatives.

Regioselective O-Glycosylation of Nucleosides via the Temporary 2&#039;,3&#039;-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Here, we present protocols for the synthesis of disaccharide nucleosides by the regioselective O-glycosylation of ribonucleosides via a temporary protection of their 2&#39;,3&#39;-diol moieties utilizing a cyclic boronic ester. This method applies to several unprotected nucleosides such as adenosine, guanosine, cytidine, uridine, 5-methyluridine, and 5-fluorouridine to give corresponding disaccharide nucleosides.

ヌクレオシドを介して一時 2'、3'-ジオール保護ホウ酸エステル糖ヌクレオシドの合成のためのOの位置選択的グリコシル化反応

Disaccharide nucleosides, which consist of disaccharide and nucleobase moieties, have been known as a valuable group of natural products having ...

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

&#945;-Functionalization of ketones via umpolung of enolates by hypervalent iodine reagents is an important concept in synthetic organic chemistry. Recently, we have developed a two-step strategy for ketone enolate umpolung that has enabled the development of methods for chlorination, azidation, and amination using azoles. In addition, we have developed C-C bond&#8211;forming arylation and allylation reactions. At the heart of these methods is the preparation of the intermediate and highly reactive enolonium species prior to addition of a reactive nucleophile. This strategy is thus reminiscent of the preparation and use of metal enolates in classical synthetic chemistry. This strategy allows the use of nucleophiles that would otherwise be incompatible with the strongly oxidizing hypervalent iodine reagents. In this paper we present a detailed protocol for chlorination, azidation, N-heteroarylation, arylation, and allylation. The products include motifs prevalent in medicinally active products. This article will greatly assist others in using these methods.

A two step one-pot protocol for the umpolung of ketone enolates to enolonium species and addition of a nucleophile to the &#945;-position is described. Nucleophiles include chloride, azide, azoles, allyl-silanes, and aromatic compounds.

Enolonium 種によるケトン類の極性転換を高機能化 2 段階のプロトコル

&#945;-Functionalization of ketones via umpolung of enolates by hypervalent iodine reagents is an important concept in synthetic organic chemistry. ...

Surface Functionalization of Metal-Organic Frameworks for Improved Moisture Resistance

Metal-organic frameworks (MOFs) are a class of porous inorganic materials with promising properties in gas storage and separation, catalysis and sensing. However, the main issue limiting their applicability is their poor stability in humid conditions. The common methods to overcome this problem involve the formation of strong metal-linker bonds by using highly charged metals, which is limited to a number of structures, the introduction of alkylic groups to the framework by post-synthetic modification (PSM) or chemical vapour deposition (CVD) to enhance overall hydrophobicity of the framework. These last two usually provoke a drastic reduction of the porosity of the material. These strategies do not permit to exploit the properties of the MOF already available and it is imperative to find new methods to enhance the stability of MOFs in water while keeping their properties intact. Herein, we report a novel method to enhance the water stability of MOF crystals featuring Cu2(O2C)4&#160;paddle-wheel units, such as HKUST (where HKUST stands for Hong Kong University of Science &#38; Technology), with the catechols functionalized with alkyl and fluoro-alkyl chains. By taking advantage of the unsaturated metal sites and the catalytic catecholase-like activity of CuII ions, we are able to create robust hydrophobic coatings through the oxidation and subsequent polymerization of the catechol units on the surface of the crystals under anaerobic and water-free conditions without disrupting the underlying structure of the framework. This approach not only affords the material with improved water stability but also provides control over the function of the protective coating, which enables the development of functional coatings for the adsorption and separations of volatile organic compounds. We are confident that this approach could also be extended to other unstable MOFs featuring open metal sites.

Robust functional catechol coatings were produced in one step by direct reaction of the material known as HKUST with synthetic catechols under anaerobic conditions. The formation of homogeneous coatings surrounding the entire crystal is ascribed to the biomimetic catalytic activity of Cu(II) dimers on the external surface of the crystals.

金属有機性フレームワークの耐湿性を向上のための表面機能化

Metal-organic frameworks (MOFs) are a class of porous inorganic materials with promising properties in gas storage and separation, catalysis and sensing. ...

Synthesis of Esters Via a Greener Steglich Esterification in Acetonitrile

The Steglich esterification is a widely-used reaction for the synthesis of esters from carboxylic acids and alcohols. While efficient and mild, the reaction is commonly performed using chlorinated or amide solvent systems, which are hazardous to human health and the environment. Our methodology utilizes acetonitrile as a greener and less hazardous solvent system. This protocol exhibits rates and yields that are comparable to traditional solvent systems and employs an extraction and wash sequence that eliminates the need for the purification of the ester product via column chromatography. This general method can be used to couple a variety of carboxylic acids with 1&#176; and 2&#176; aliphatic alcohols, benzylic and allylic alcohols, and phenols to obtain pure esters in high yields. The goal of the protocol detailed here is to provide a greener alternative to a common esterification reaction, which could serve useful for ester synthesis in both academic and industrial applications.

A modified Steglich esterification reaction was used to synthesize a small library of ester derivatives with primary and secondary alcohols. The methodology uses a non-halogenated and greener solvent, acetonitrile, and enables product isolation in high yields without the need for chromatographic purification.

アセトニ トリル中で環境に優しい転移エステルを介してエステルの合成

The Steglich esterification is a widely-used reaction for the synthesis of esters from carboxylic acids and alcohols. While efficient and mild, the ...