| abstract |
Disclosed is a process for preparing a β-lactam compound represented by the formula:n n wherein R¹ represents a hydroxy-substituted lower alkyl group or an amino group each of which may be protected; R² represents a hydrogen atom or an ester residue; X represents a methylene group which may be substituted by a lower alkyl group, a sulfur atom or a group represented by the formula: -A-CH₂- where A represents a sulfur atom, an oxygen atom or a methylene group; and Y is either a W which represents an active ester residue of a hydroxyl group, or a R⁴ which is an organic group, nor a salt thereof, which comprises the steps of treating a corresponding 1-aza-3-thia-bicycloalkane compound represented by the formula:n n or a salt thereof with a base in the presence of a desulfurizing agent and then reacting the resulting compound with an active esterifying agent of hydroxyl group and, if appropriate, further treating the β-lactam compound obtained with a R⁴-SH compound. |