| abstract |
A novel process for preparing a compound of formula (E) comprising converting a compound of formula (J) to a compound of formula (E) using a Lewis acid, formula (J) and (E) wherein R2 is (C1-4)alkyl, (C1-3)alkoxy or phenyl optionally substituted by (C1-3)alkyl; and R3 and R4 which may be the same or different is each (C1-4)alkyl, allyl, benzyl or phenyl optionally substituted by (C1-3)alkyl or (C1-3)alkoxy, which may be used in an improved process to prepare antibacterial compounds of formula (I). |