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.
用于合成
氧氟沙星、
左氧氟沙星及其衍
生物的苯并噁嗪类化合物的制备方法。其中 Xb 为卤素,R₁ 为 H、6 个 C 原子以下的烷基或亚烷基或芳基的苯并噁嗪 (I) 可通过式 (II) 化合物与
三苯基膦和偶氮二
甲酸乙酯反应环氮化而获得。式(II)化合物可通过化合物(III)与适当的环氧反应获得。通过使用适当的手性
环氧化物,可以得到所需的对映体中间体,从而可以选择性地得到具有适当对映体形式的所需最终产物,而无需经过解析步骤。化合物 (I) 是合成
氟哌酸和
左氧氟沙星等抗菌剂的重要中间体。