...A general term for the condensation reaction of compounds with a carbonyl group, such as aldehydes, ketones, and esters, that have a hydrogen atom at the α-position of the carbonyl group (active methylene compounds). It was named after the German organic chemist L. Claisen (1851-1930), who first reported it in 1881. It usually refers to reactions involving esters. The reaction is carried out in a solvent system in which a catalytic amount of sodium is added to alcohol. For example, two molecules of ethyl acetate condense in ethyl alcohol in the presence of a catalytic amount of sodium ethylate NaOCH 2 CH 3 to produce acetoacetic ester. ... *Some of the terminology that mentions "Claisen, L." is listed below. Source | Heibonsha World Encyclopedia 2nd Edition | Information |
…アルデヒド,ケトン,エステルなどのカルボニル基のα位に水素が存在する化合物(活性メチレン化合物)とカルボニル基を有する化合物の縮合反応の総称。1881年ドイツの有機化学者クライゼンL.Claisen(1851‐1930)によって最初に報告されたので,この名が付けられた。通常,エステルが関与する場合の反応をいうことが多い。触媒量のナトリウムをアルコールに加えた溶媒系中で反応が行われる。たとえば,酢酸エチルは触媒量のナトリウムエチラートNaOCH2CH3の存在下,エチルアルコール中で2分子縮合し,アセト酢酸エステルを生成する。… ※「Claisen,L.」について言及している用語解説の一部を掲載しています。 出典|株式会社平凡社世界大百科事典 第2版について | 情報 |
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