、ラムゼイ記念·トラスト（JABに研究員2009-2011）、インペリアル·カレッジ·ロンドン、財政支援のために我々は感謝EPSRC（EP/J001538/1 JABへのキャリア加速フェローシップを）認めます。寛大なサポートやアドバイスを教授アラン·アームストロングに感謝します。

DiiodomethyllithiumとIodoaziridinesの1。準備<ol><li>火炎を、アルゴン雰囲気下で室温まで冷却させる次いで、アルゴン気流下、攪拌棒及びセプタムを取り付けを含有する100mlの丸底フラスコを乾燥させる。 NOTE：ガラス器具はオーブンで一晩（125℃）中で乾燥させ、類似の方法で、室温まで冷却もまた適切である。 </li><li>フラスコに、マイクロシリンジ 5.7ミリリットルの無水THFを追加し、2.7ミリリットルの無水Et 2 Oを、シリンジを介して、新たに蒸留したヘキサメチルジシラザン（1.50ミリモル、315μL）。 </li><li>フラスコは充分に浸漬されるように適切な大きさのデュワーでドライアイス/アセトン浴中で-78℃に得られた溶液を撹拌し、涼しい。光に反応容器の曝露を最小限にするために、アルミホイルでデュワーを覆う。 </li><li> -78℃の溶液に2〜3分かけて、シリンジを介して滴下するNブチルリチウム（1.50モル、0.60ミリリットル、ヘキサン中2.5M）混合物は0.17 MのLiHMDSの溶液を形成するためにさらに30分間-78℃で撹拌する。注意：N BuLi溶液は、可燃性の皮膚に対して腐食性および自然発火性である。注射器内の過剰な試薬は、それに応じて停止させなければならない。 </li><li> 30分後、 マイクロシリンジジヨードメタン（1.70ミリモル、135μL）に続いて、注射器を経由して 、火炎乾燥した丸10ミリリットル底フラスコに1ミリリットルの無水THFを追加して、よく混合していることを確認してください。 </li><li> -78℃でリチウムヘキサメチルジシラザンの溶液に2分間かけてジヨードメタン液滴下する-78℃で20分間この溶液を残す</li><li>別の火炎乾燥10mLの丸底フラスコに[（E）-4 - methylphenylmethylidene] -4 -メチルベンゼンスルホンアミド（137ミリグラム、0.50 mmol）および2.0ミリリットルで無水THFに溶解させる-この時間の間に、Nを量る。 </li><li> 20分間の脱プロトン化時間の後、-78＆＃で5分間かけdiiodomethyllithium溶液にイミン溶液を滴下して加える176; C. </li><li>滴下が完了した直後に、ドライアイス浴から反応容器を持ち上げて、0℃の氷/水浴に移し再カバーアルミホイルで、0℃で15分間のままに注：解決策は色でオレンジ色にする必要があります。 </li><li> 0℃で15分後、30mlの飽和重炭酸ナトリウム水溶液の添加により反応をクエンチした。分液ロートに混合を移し、30ミリリットルのCH 2 Cl 2を追加します。混合物を振ると下位の CH 2 Cl 2層を除去する。この抽出手順を2回繰り返し、さらに、そしてCH 2 Cl 2層を兼ね備えています。 </li><li>硫酸ナトリウムを濾別し、次いで、溶液中に存在する水を除去し、丸底フラスコに250mlの濾液を収集するために、有機層に硫酸ナトリウムを加える。 </li><li>希望iodoaziridine製品の不純なサンプルを得たロータリーエバポレーターで減圧下、溶媒を除去。 </li></ol>クロマトグラフィーの固定相への製品の安定性の2。評価<ol><li> の CH 2 Cl 2（16ミリリットル）中の粗アジリジンサンプルを溶解し、内部標準として1,3,5 -トリメトキシベンゼン（28.0ミリグラム、0.167ミリモル）を追加し、これが完全に溶解して確保すること。この混合物からのアリコート（2ml）に取り、減圧下で溶媒を除去し、1 H NMR分光法によってこのサンプルを分析する。 </li><li>標準的なNMR処理ソフトウェアを使用して記録1 H NMRスペクトルを開く。 Mestrenovaでは、右の統合ツールを提供するために、それから「手動」スペクトルをクリックして、「統合」を選択しました。それぞれ内部標準およびアジリジンCHI信号のシグナルを統合する6.08 ppmにし、4.87 ppmのピークの幅をカバーするためにクリックしてドラッグ。 6.08 ppmのピークの積分を右クリックし、「一体編集」を選択し、3.0に「正規化」の値を変更します。 NOTE：類似の手順は、他のソフトウェアパッケージに適用することができる。 </li><li> 59パーセントの計算された収量が得られる（100/3）×（CHI信号の積分）を使用して、ここで、iodoaziridineの収量を決定するために、アジリジンCHI信号（4.87 ppm）の積分の更新された値を使用してください。 NOTE：内部標準（0.167ミリモル）、および1プロトンに対応する生成物ピークの既知量を考えると、iodoaziridineの収率は次式で計算される：100×（生成物ピークの積分値）×（内部標準のモル数）/出発材料モルである。 </li><li>次の固定相（25グラム）のスラリーを準備します。シリカ、+1％のNEt 3（トリエチルアミン）、中性アルミナ、塩基性アルミナ（活動I）、塩基性アルミナ（活動IV）およびフロリジル、それぞれ5％酢酸エチル/ヘキサンスターラーバーを含む6つの別個の250mlの三角フラスコ（50ml）中、。別の三角フラスコに対照実験として使用されるように、5％のEtOAc /ヘキサン溶液（50ml）に調製。注意：ケイ吸入するとゲル、アルミナおよび使用される他の固定相は危険ですので、常に効果的なドラフト内で処理する必要があります。 </li><li> RTで三角フラスコのそれぞれにiodoaziridine /内部標準溶液2ミリリットルずつを追加します。 30分間のスラリー混合物をかき混ぜる。注：この化合物は、通常のフラッシュカラムクロマトグラフィー手順中の固定相に露出してもよい期間を表す。 </li><li>焼結漏斗を用いてスラリー混合物をフィルタリングし、250ミリリットルの丸底フラスコ中にろ液を集める。 の CH 2 Cl 2（2×30ml）で焼結漏斗上で残留物を洗う。残りのスラリーは、このフィルタリング処理を繰り返します。 NOTE：これは、濾過のための時間を可能にし、従って、固定相材料の各々について同じ時間を維持するために、各固定相の開始をオフセットすることが適切である。 </li><li> 1 H NMR分光によって、減圧下得られた試料から溶媒を除去し、分析するセクション2.2で説明したようにiodoaziridineは、それぞれの場合に回収量を算出するSCOPY。 </li><li> 2.1節で得られたものと、試験した各固定相から得iodoaziridineの収量を比較してください。注：最高収率、2.1のように、理想的には同じを与えるサンプルは、クロマトグラフィーのための最適な固定相を示している。この例では、塩基性アルミナ（活性IV）を精製するための最良の固定相とみなされた。 </li></ol> Iodoaziridineの塩基性アルミナおよび精製の3。無効化<ol><li>原油iodoaziridine混合物を生成するために、第1を繰り返します。 </li><li> 、塩基性アルミナ（活動IV）を生成し500ミリリットルの丸底フラスコに塩基性アルミナ（活動I）の100グラムを追加してから、フラスコに水10mlを加え、ガラス栓に合うように。 </li><li>塊があっても、アルミナを通して水の広がりを示す、表示されなくなるまで、フラスコを激しく振る。アルミナは、室温まで冷却させる。注意：adsorp水のTiONは発熱反応であるため、フラスコを熱くなることがあり、圧力の蓄積の原因となります。任意の圧力頻繁にビルドをリリースする。 </li><li> 5％のEtOAc /ヘキサングレーディング、ヘキサンで溶出し、固定相として塩基性アルミナ（活性IV）を用いるカラムクロマトグラフィーによって粗iodoaziridineを精製する。注：酢酸エチル高濃度の塩基性アルミナと一緒に使用してはならない。これらの場合には、ジエチルエーテルを代わりに使用することができる。 </li><li>画分を含む製品を組み合わせて、純粋なiodoaziridineを減圧下に溶媒を除去する。 </li></ol>

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C., Kahn, M., Mitra, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+chromatographic+technique+for+preparative+separations+with+moderate+resolution.">Rapid chromatographic technique for preparative separations with moderate resolution.</a> J. Org. Chem. 43 (14), 2923-2925 (1978).</li><li>Armarego, W. L. F., Chai, L. L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Purification of laboratory chemicals. , (2003).</li></ol>

The authors declare that they have no competing financial interests.

シスジアステレオ選択的調製のための手順- N-Tsは-iodoaziridinesを定量フラッシュカラムクロマトグラフィーにより潜在的に不安定な化合物の精製の ​​ための最良の固定相を示すために、安定性試験プロトコールに沿って、説明する。それは、このアプローチを通じてiodoaziridinesへのアクセスはそのままリングの誘導体化によって、開発されるアジリジンの広い範囲にアクセスす...

この方法の目的は、アジリジン誘導体へのさらなる機能化のための可能性を提供iodoaziridinesを準備することです。この方法は、クロマトグラフィーのための最適な固定相を定量的に選択するためのプロトコルが組み込まれています。 アジリジン、有機化学1にそれらの重要なビルディングブロックを作る三員環、武装隊固有の環の歪みである。彼らは、特に官能化されたアミン4,5の合成における中間体として、多くの場合、アジリジン開環2,3が関与する反応性の広大な配列、または他の窒素含有ヘテロ環6,7の形成が表示されます。無傷のアジリジン環を含有する前駆体の官能化によるアジリジン誘導体の範囲の合成が実行可能な戦略8として浮上している。アジリジニルアニオンを生成する官能基 - 金属交換、および求電子との反応が有効であることが示された<suP&gt; 9,10,11、およびN-保護アジリジンの最近レジオおよび立体選択的脱プロトンはまた12月15日に達成されている。ごく最近、パラジウムVedejs 16,17によって開発されているアジリジン官能化前駆体からのアリールアジリジンを形成するために、クロスカップリング法を触媒し、そして自分自身18。 ヘテロ原子置換アジリジンの化学的性質は、反応性、安定性19の魅惑的な質問を開きます。我々は、既存のアジリジン官能化反応と相補的な反応性を有する誘導体の広い範囲に前駆体を提供する可能性を提供しています小説官能基としてiodoaziridinesの準備に興味を持っています。 2012年には、アリール、N-BOC-iodoaziridines 20の第1の調製を報告し、そしてごく最近、N-TS-iodoaziridines 21置換アリールおよびアルキルの作成 ​​を報告した。 ACCEの方法カテゴリーのiodoaziridinesがdiiodomethyllithiumを使用して、最近ではdiiodoalkanes 22,23の調製に使用された試薬は、22,24 diiodomethylsilanes、ビニルヨウ25-27。この試薬 ​​のカルベノイドのような性質は、低温22,28の製造および使用を必要とします。 iodoaziridinesの調製にdiiodomethyllithiumの生成に使用される技術および条件は以下の通りである。 シリカクロマトグラフィー29のための選択の材料として浮上してきたが、N-Tsは-iodoaziridinesの精製には不向きであることが判明した。シリカゲルは、一般的に在庫状況により、効果的な分離を、有機化学でのフラッシュクロマトグラフィーに用いられる最初で唯一の固相材料である。しかしながら、シリカゲルの酸性の性質は、所望の材料の単離を防止する、精製の間に敏感な基材の分解を引き起こし得る。一方、他のSTationary相または改質シリカゲルクロマトグラフィー30に利用可能である、これらの異なる材料に標的分子の適合性を評価する方法はありませんでした。原因iodoaziridinesの敏感な性質のために、我々はここで示されている固定相21の配列に化合物の安定性を評価するためのプロトコルを確立しました。これは、敏感な官能基を有する化合物の広い範囲の合成に応用可能性を有する。以下のプロトコルは、アルキルおよび芳香族シス iodoaziridines高収率で両方のジアステレオ選択的合成を可能にする、N-TS iodoaziridinesへの効率的なアクセスを提供します。

<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

高度にジアステレオシスの準備- N-TSアルジミンとのdiiodomethyllithiumの反応を介してN-TS-iodoaziridinesが記載されている。 Diiodomethyllithiumは、THF /ジエチルエーテル混合物中、-78℃で、LiHMDSを有するジヨードメタンの脱プロトン化によって調製される 暗闇の中で。これらの条件は、生成されたLiCHI 2試薬の安定のために不可欠である。予め形成されたdiiodomethyllithium溶液にN-Tsをアルジミンのその後の滴下は、アミノ二ヨウ化物中間体は、単離されないが得られる。 0℃〜反応混合物の急速な温暖化が排他シス -ジアステレオでiodoaziridinesを得た環化を推進しています。反応物の添加及び環化段階は慎重な温度制御により、一つの反応フラスコ中で媒介される。 精製にiodoaziridinesの感受性に起因して、PUの適切な方法の評価rificationが必要です。カラムクロマトグラフィー用の固定相への感受性化合物の安定性を評価するためのプロトコルが記載されている。このメソッドは、新しいiodoaziridines、または他の潜在的に重要な新規化合物に適用することが好適である。そのため、この方法は、合成プロジェクトの範囲の用途を見出すことができる。手順は、まず、内部標準と比較して1 H NMR分光法による精製前の反応収率、、の評価が含まれます。不純な生成物混合物の部分は、次いで、フラッシュクロマトグラフィーで溶離液として適切な溶媒系中で、クロマトグラフィーのための適切な種々の固定相のスラリーに暴露される。濾過に続いてクロマトグラフィーを模倣するために30分間撹拌した後、サンプルを1 H NMR分光法によって分析される。各固定相について計算された収率は、次いで、最初に、粗反応混合物から得られたものと比較する。得られた結果は、tの定量的評価を提供彼異なる固定相への化合物の安定性;したがって、最適に選択することができます。適切な固定相は、優れた収率と純度の特定iodoaziridinesの分離を可能にしたように塩基性アルミナの選択は、アクティビティIVに変更。

手順は、 シスにより、電磁両立性を記載- （±）-2 -ヨード-3 - （4 -トリル）-1 - （4 -トリルスルホニル）アジリジンを単一ジアステレオ異性体として、優れた純度（ 図1）。精製の ​​前に、iodoaziridine生成物の収率59％を、1 H NMR分光法により算出した。しかし、このiodoaziridineは精製することが特に困難であり、シリカ上著しい分解を受けた。固定相スクリー...

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

シスのジアステレオ選択的ワンポット調製するためのプロトコル- N-TS-iodoaziridinesが記載されている。 diiodomethyllithium、N-TSアルジミンに加えて、アミノ宝石二ヨウiodoaziridines中間の環の生成が実証されている。また、迅速かつ定量的クロマトグラフィーによる精製のための最も適切な固定相を評価するためのプロトコルが含まれる。

クロマトグラフィーのための最適な固定相の定量的な選択を伴う合成とIodoaziridinesの精製

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 ビュー.  Imperial College London.  シスのジアステレオ選択的ワンポット調製するためのプロトコル- N-TS-iodoaziridinesが記載されている。 diiodomethyllithium、N-TSアルジミンに加えて、アミノ宝石二ヨウiodoaziridines中間の環の生成が実証されている。また、迅速かつ定量的クロマトグラフィーによる精製のための最も適切な固定相を評価するためのプロトコルが含まれ?...

ビデオ: 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.

オリゴペプチドの気相酸性度の決定

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

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.

ペプチド第三級アミドライブラリのスプリット·アンド·プールの合成とキャラクタリゼーション

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.

プログラムされた温度脱着ガスクロマトグラフィー - 電子捕獲型検出器による微量爆発性気体の定量的検出

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.

反応性多孔質材料を精製するための超臨界窒素処理

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.

定量的グライコミクスおよびプロテオミクス複合精製戦略

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.

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 ...

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 ...

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.

Photoredox触媒を用いた可視光媒介分散重合によるワームのようなミセルの簡便な合成

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.

2 &#39;末端を含むRNAのオリゴマーの固相合成のためのプロトコール<em&gt; O</em&gt;チオフェンメチル修飾と環状二色性によるキャラクタリゼーション

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.

合成とオリゴ ペプチドの質量分析

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