NYSTED試薬

危険有害性情報のコード(GHS)

• 絵表示(GHS)

  

• 注意喚起語

  Danger

• 危険有害性情報

  H225：引火性の高い液体および蒸気

  H319：強い眼刺激

  H335：呼吸器への刺激のおそれ

  H336：眠気やめまいのおそれ

  H351：発がんのおそれの疑い

• 注意書き

  P201：使用前に取扱説明書を入手すること。

  P202：全ての安全注意を読み理解するまで取り扱わないこ と。

  P210：熱/火花/裸火/高温のもののような着火源から遠ざ けること。－禁煙。

  P233：容器を密閉しておくこと。

  P305+P351+P338：眼に入った場合：水で数分間注意深く洗うこと。次にコ ンタクトレンズを着用していて容易に外せる場合は外す こと。その後も洗浄を続けること。

  P308+P313：暴露または暴露の懸念がある場合：医師の診断/手当てを 受けること。

NYSTED試薬 価格

NYSTED試薬 化学特性,用途語,生産方法

• 化学的特性

  The Nysted reagent is a reagent used in organic synthesis for the methenylation of a carbonyl group. It was discovered in 1975 by Leonard N. Nysted in Chicago, Illinois. It was originally prepared by reacting dibromomethane and activated zinc in THF.
  A similar reagent is Tebbe's reagent.In the Nysted olefination, the Nysted reagent reacts with TiCl to methylenate a carbonyl group. The biggest problem with these reagents are that the reactivity has not been well documented. It is believed that the TiCl acts as a mediator in the reaction. Nysted reagent can methylenate different carbonyl groups in the presence of different mediators. For example, in the presence of BF•OEt, the reagent will methylenate aldehydes. On the other hand, in the presence of TiCl, TiCl or TiCl and BF•OEt, the reagent can methylenate ketones. Most commonly, it is used to methylenate ketones because of their general difficulty to methylenate due to crowding around the carbonyl group. The Nysted reagent is able to overcome the additional steric hinderance found in ketones, and more easily methylenate the carbonyl group.
  There is little research on Nysted reagent because of the hazards and high reactivity and the difficulty of keeping the reagent stable while it is in use. More specifically, it can form explosive peroxides when exposed to air and is extremely flammable. Also, it reacts violently with water. These make this reagent very dangerous to work with.

• 使用

  The cyclo-dibromo-di-m-methylene-(m-tetrahydrofuran)-trizinc is known as the Nysted reagent. This reagent is prepared by treatment of dibromomethane with activated zinc-lead couple or hydrogen chloride-activated zinc dust in THF. This reagent is useful for converting a carbonyl group into a methylene group, and such transformation is known as the Nysted methylenation or Nysted olefination. The study finds that this reagent is superior to the Tebbe reagent.

• 主な応用

  Useful reagent for the methylenation of ketones and α-ketols.
  Reactant for:
  Synthesis of amphidinolide T3 using a ring-closing metathesis and asymmetric dihydroxylation strategy
  Methylenation of carbonyl compounds
  Olefination reactions

• 反応性

  
  This commerically available reagent is capable of methyenylation alone or in concert with TiCl4. While information on the reactivity of the reagent exists, the mechanistic basis of its function has yet to be elucidated.

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