Single Step Conversion of Chiral Carnitine and Derivatives into (<i>S</i>)- and (<i>R</i>)-β-Substituted-γ-Butyrolactones
作者:Giuseppina Calvisi、Roberto Catini、Wilma Chiariotti、Fabio Giannessi、Sandra Muck、Maria Tinti、Francesco De Angelis
DOI:10.1055/s-1997-686
日期:——
This paper describes an efficient single step transformation of chiral carnitine and carnitine derivatives into stereoisomerically pure (S)- and (R)-β-substituted-γ-butyrolactones, obtained by intramolecular nucleophilic displacement. (S)- Or (R)-carnitine and (R)-aminocarnitine inner salts give β-hydroxy-γ-butyrolactone and β-amino-γ-butyrolactone respectively (82% and 77%) with the same configuration as the starting material. (R)-Acetylaminocarnitine inner salt gives (R)-β-acetylamino-γ-butyrolactone (90%), while (R)-acetylcarnitine gives 2(5H)-furanone under the same reaction conditions (77%, via cyclization and subsequent elimination reaction). (R)-N-Benzyloxycarnitineamide gives a mixture of pyrrolidinone (11%) and furanoyl imidate (50%) derivatives. The direct transformation of wast (S)-carnitine into the valuable (S)-β-hydroxy-γ-butyrolactone or (after acetylation) into the precious 2(5H)-furanone is of particular interest.
本文介绍了通过分子内亲核置换将手性肉碱和肉碱衍生物高效地一步转化为立体异构纯(S)-和(R)-δ-取代-δ³-丁内酯的方法。(S)-或(R)-肉碱和(R)-氨基肉碱内盐分别得到δ-羟基-δ³-丁内酯和δ-氨基-δ³-丁内酯(82%和 77%),其构型与起始原料相同。(在相同的反应条件下,(R)-乙酰基氨基肉碱内盐可以得到(R)-δ-乙酰氨基-δ-丁内酯(90%),而(R)-乙酰基肉碱通过环化和随后的消除反应可以得到 2(5H)-呋喃酮(77%)。(R)-N-苄氧基肉碱酰胺可以得到吡咯烷酮(11%)和呋喃酰亚胺酯(50%)衍生物的混合物。废(S)-卡尼汀直接转化为有价值的(S)-δ-羟基-δ-丁内酯或(乙酰化后)转化为珍贵的 2(5H)-呋喃酮特别令人感兴趣。