Features of Synthesis and Structure of Ethyl (2Z)-3-Hyclroxy-(2,3,4,5-tetrafluorophenyl)-propyl-2-enoate

摘要

The structure of key intermediates in the synthesis of fluoroquinolone antibiotics: diethyl (2,3,4,5-tetrafluorobenzoyl)malonate and ethyl (2Z)-3-hydroxy-(2,3,4,5-tetrafluorophenyl)prop-2-enoate was for first time studied using X-ray diffraction (XRD) and ~1H, ~(19)F NMR spectroscopy. In solution both the esters were shown to exist as a mixture of enol and ketone tautomeric forms with predominance of the latter. According to the XRD analysis, ethyl (2Z)-3-hydroxy-(2,3,4,5-tetrafluorophenyl)prop-2-enoate in the solid state exists entirely in the enol form.