PROCESS FOR OBTAINING BENZOXAZINES USEFUL FOR THE SYNTHESIS OF OFLOXACIN, LEVOFLOXACIN AND DERIVATIVES THEREOF.

摘要

Process for obtaining benzoxazines useful for the synthesis of ofloxacin, levofloxacin and derivatives thereof. The benzoxazines (I) wherein Xb is halogen and R1 is H, alkyl or alkylene up to 6 C atoms or aryl, may be obtained by cyclazation of a compound having the formula (II) by reaction with triphenylphosphin and azodicarboxylate of ethyl. The compounds of formula (II) may be obtained by reaction of a compound (III) with an appropriate epoxy. By using the appropriate chiral epoxy, the enantiomerically desired intermediate may be obtained, and consequently it is possible to selectively obtain the desired final product with the appropriate enantiomer form without having to go through a resolution step. The compounds (I) are valuable and key intermediates for the synthesis of antimicrobial agents such as floxacin and levofloxacin.