A Convenient Route to Large-Scale Chemical Synthesis of <i>p</i>-Hydroxyphenylacetaldehyde Oxime and Its <i>p</i>-β-<scp>d</scp>-Glucopyranoside: Key Intermediates and Products in Plant Specialized Metabolism

Oximes are unrecognized chameleons in general and specialized plant metabolism. <i>E-</i> and <i>Z-p</i>-hydroxyphenylacetaldehyde oxime are key intermediates in the biosynthesis of the cyanogenic glucoside dhurrin produced in sorghum. Nevertheless, none of the geometrical oxime isomers accumulate in the plant. Herein, we report a convenient route to the chemical synthesis of <i>E-</i> and <i>Z-p</i>-hydroxyphenylacetaldehyde oxime and its biologically produced <i>p</i>-β-d-glucopyranoside using <i>p</i>-hydroxyphenylacetic acid as a starting material. This starting material is also available in radiolabeled forms. All reaction steps proceeded with excellent yield under mild conditions, operational facility, and scalability.