Studies in the quinone field XLVI. Synthesis of thioethers and sulfones in the 5-hydroxyindole series
作者:F. A. Trofimov、N. G. Tsyshkova、A. N. Grinev、K. S. Shadurskii
DOI:10.1007/bf00759819
日期:1969.11
Microbial generation of (2R,3S)- and (2S,3S)-ethyl 2-benzamidomethyl-3-hydroxybutyrate, a key intermediate in the synthesis of (3S,1′R)-3-(1′-hydroxyethyl)azetidin-2-one
Microbial reduction of the carbonyl group of the substituted acetoacetate esters 3-6 affords directly, or after Ni-Raney desulfurization, the corresponding enantiomerically pure 3S carbinols of variable diastereoisomeric composition. These compounds are transformed into (3S,1'R)-3-(1'-hydroxyethyl)-azetidin-2-one, a useful intermediate in the synthesis of beta-lactam antibiotics.
Ethyl (R)-3-hydroxy-4-phenylthiobutyrate: Synthesis by the bakers' yeast reduction and use as a precursor of enantiomerically pure β-lactam
The bakers' yeast reduction of ethyl 3-oxo-4-phenylthiobutanoate gave ethyl (R)-3-hydroxy-4-phenylthiobutanoate with >99%ee. The resultant enantiomerically pure alcohol was easily transformed into β-lactam without loss of its enatiomeric purity via the oxamate derivative.
Method for the synthesis of 4-substituted acetoacetates
作者:Coos B. Troostwijk、Richard M. Kellogg
DOI:10.1039/c39770000932
日期:——
Ethyl 4-bromo-3-oxobutyrate can be converted with sodium hydride into the enolate salt and nucleophilic substitutions can thereafter be carried out at the 4-carbon atom.