| 摘要 |
<p>Preparation of (4,5)-trans-2-oxo-oxazolidine compounds of formula (I) comprises treatment of (4,5)-cis-2-oxo-oxazolidine compounds of formula (II) with strong base. R1 = alpha-amino acid side chain; R2 = alkyl; R3 = H, a protecting group (for amino, amido or urethane), or -C(O)-R4; R4 = alkyl, or one or more alpha-amino acids (linked via amide bonds). Also claimed are compounds obtained by the process. Preferably the base is an alkali- or alkaline earth- alkoxide, a lithium, sodium or potassium amide, an alkyl lithium compound or an alkyl magnesium halide (especially NaOMe or K-OCMe3). Reaction temperature is -20 to +80 degrees C. Solvent is toluene, tetrahydrofuran or an alcohol. A mixture of cis/trans isomers of 2-oxo-oxazolidine is used as starting material.</p> |
