絞り込み

16590

広告

18年の医療事故は377件 手術が最多 (毎日新聞)

医療事故発生報告件数 患者の予期せぬ死亡を扱う医療事故調査制度で、日本医療安全調査機構は、2018年に「死亡事故が発生し、院内調査が必要」として届け出があったの...

  1. 第2回「認知症バリアフリー」に関する懇談...
  2. 史上最年少のプロ入りを前に 囲碁の仲邑菫...
  3. 新規コンテンツページ - (1242)
  4. 刑事ドラマや仁きょう映画の名脇役 織本順...

ニュース一覧

Mechanical Stabilization of Helical Chirality in a Macrocyclic Oligothiophene.

著者 Weiland KJ , Brandl T , Atz K , Prescimone A , Häussinger D , Solomek T , Mayor M
J Am Chem Soc.2019 Jan 11 ; ():.
この記事をPubMed上で見るPubMedで表示
この記事をGoogle翻訳上で見る Google翻訳で開く

スターを付ける スターを付ける     (2view , 0users)

Full Text Sources

We introduce a design principle to stabilize helically chiral structures from an achiral tetrasubstituted [2.2]paracyclophane by integrating it into a macrocycle. The [2.2]paracyclophane introduces a three-dimensional perturbation into a nearly planar macrocyclic oligothio-phene. The resulting helical structure is stabilized by two bulky substituents installed on the [2.2]paracyclophane unit. The increased enantiomerization barrier enabled the separation of both enantiomers. The synthesis of the target helical macrocycle 1 involves a sequence of halogenation and cross-coupling steps and a high-dilution strategy to close the macrocycle. Substituents tuning the energy of the enantiomerization process can be introduced in the last steps of the synthesis. The chiral target compound 1 was fully characterized by NMR spectroscopy and mass spectrometry. The absolute configurations of the isolated enantiomers were assigned by comparing the data of circular dichroism spectroscopy with TD-DFT calculations. The enantiomerization dynamics was studied by dynamic HPLC, variable temperature 2D exchange spectroscopy and supported by quantum-chemical calculations.
PMID: 30632363 [PubMed - as supplied by publisher]
印刷用ページを開く Endnote用テキストダウンロード