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

Oximes are unrecognized\nchameleons in general and specialized plant\nmetabolism. <i>E-</i> and <i>Z-p</i>-hydroxyphenylacetaldehyde\noxime are key intermediates in the biosynthesis of the cyanogenic\nglucoside dhurrin produced in sorghum. Nevertheless, none of the geometrical oxime\nisomers accumulate in the plant. Herein, we report a convenient route\nto 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\nis also available in radiolabeled forms. All reaction steps proceeded\nwith excellent yield under mild conditions, operational facility,\nand scalability.