78920-10-2Relevant articles and documents
Simple route to synthesize (E)-3-propyl-4-oxo-2-butenoic acid esters through the Z isomer
Bolchi, Cristiano,Roda, Gabriella,Pallavicini, Marco
, p. 85 - 90 (2018)
Esters of 3-alkyl-4-oxo-2-butenoic acid, which are very important synthons, are not equally accessible in both E and Z configurations. The (Z)-isomers can be easily obtained from 3-alkyl-4-hydroxybutenolides, in turn prepared by aminoalkylation of aliphatic aldehydes with glyoxylic acid. The (E)-isomers, on the contrary, result from laborious procedures: the condensation of aldehydes with glyoxylic acid, followed by separation from γ-hydroxybutenolide by-product and esterification, or of aldehyde enamines with glyoxylic esters, followed by Z ester by-product conversion into γ-aminobutenolide and purification. Here, we describe a straightforward route to the title compounds, applied to methyl (E)-3-propyl-4-oxo-2-butenoate, avoiding any problematic by-product or isomer chromatographic separation: pentanal and glyoxylic acid are condensed to 3-propyl-4-hydroxybutenolide, which is converted to methyl (Z)-3-propyl-4-oxo-2-butenoate and then isomerized to E ester under acidic conditions.
PROCESS FOR THE PREPARATION OF BRIVARACETAM
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Paragraph 0099, (2021/06/26)
The present invention relates to a process for the preparation of brivaracetam, a compound of formula I and salts thereof. The present invention also relates to a compound of formula II and a compound of formula IIA, process for its preparation and conversion thereof to brivaracetam, the compound of formula I.
Asymmetric catalytic preparation method of brivaracetam
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Paragraph 0070-0072, (2020/11/12)
The invention discloses a preparation method of brivaracetam, which adopts cheap and accessible hydrogen as a hydrogen source, can implement asymmetric preparation of brivaracetam in a catalytic system with rhodium (I) as a metal center, and has the advantages of mild reaction conditions, simplicity, controllability, high yield, high enantioselectivity, environment friendliness, favorable atom economy, low cost and the like. In addition, the invention also provides the brivaracetam compound prepared by the method.