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Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
野心的なエチルN-ニトロソカルバメートアニオン:アルキル化と熱安定性の実験的および計算的研究
Vladimir Benin1, Piotr Kaszynski, J George Radziszewski
1Organic Materials Research Group Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.
Journal of the American Chemical Society
|November 21, 2002
まとめ
N-ニトロスウレタンテトラブチラモニウム塩のアルキル化により,3つのレジオアイソマーが得られ,その比率は電極性に依存する. 熱分解経路と安定性は,運動学的および計算学的研究を通じて明らかにされました.
科学分野:
- 有機化学 オーガニック・ケミストリー
- コンピューティング・ケミストリー
- 反応メカニズム 反応メカニズム
背景:
- N-ニトロスウレタンテトラブチラモニウム塩は,有機合成における潜在的な応用がある反応性のある種である.
- アルキル化N-ニトロソウレタン誘導体の地域選択性および分解経路を理解することは,反応結果を制御するために極めて重要です.
- 以前の研究では,関連化合物のアルキル化が調査されていますが,様々な電離性を持つN-ニトロズウレタンテトラブチラモニウム塩の包括的な分析は欠けています.
研究 の 目的:
- N-ニトロソウレタンテトラブチラモニウム塩のアルキル化を,異なる電ophilesで調査する.
- 電気ファイルの構造と溶媒が,結果として生成される地域イソメアの比率に及ぼす影響を決定する.
- アルキル化製品と母塩の熱分解機構と運動学を解明する.
主な方法:
- (1) H NMRスペクトロスコピーは,二塩ロメタン-d2およびアセトニトリル-d3溶液中のアルキル化反応を研究するために使用されました.
- 鍵となる中間物質の熱分解のための第一次流動学と活性化パラメータを決定した.
- 反応機構と移行状態を分析するために,MP2 (fc)/6-31+G (d) /MP2 (fc)/6-31G (d) レベルでのガス相理論計算を行った.
主要な成果:
- アルキル化により,N-アルキル-N-ニトロソウレタン,アゾキシ,O-アルキルディアゾートという3つのレジオアイソマーが生成され,その比率は電極性に依存するが,溶媒に依存しない.
- 原塩とO-アルキル誘導体は,熱的不安定性を示し,単分子過程でエチル炭酸に分解した.
- 計算的研究は,分解のための4つの中心の移行状態を持つ協調したメカニズムを支持し,実験的観測と一致する安定性の順序を予測しました.
結論:
- N-ニトロスウレタンテトラブチラモニウム塩アルキル化の地域選択性は,主に電愛体の性質によって支配されます.
- 熱分解経路は,塩とO-アルキル誘導体の単分子プロセスを含み,速度を決定する明確なステップがあります.
- 理論的な計算は,反応機構,移行状態,および研究された化合物の相対的な安定性に関する貴重な洞察を提供します.
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