Novel 4-chloro-or-4-bromoresorcinol-based bicyclic phosphonates

<p>The reaction of 4-chloro- and 4-bromoresorcinol with 2-ethoxyvinylphosphonic acid dichloroanhydride has been investigated for the first time. It has been determined that the product of the reaction is the mixture of structural isomers of bicyclic phosphonates at the ratio of 9:1. The structure and composition of the compounds have been elucidated from <sup>1</sup>H, <sup>31</sup>P, and <sup>13</sup>C NMR spectroscopy, mass-spectrometry (MALDI-TOF), as well as elemental and X-ray analysis.</p>