Synthesis of deuterium labeled plant ethylene precursor

Synthetic methods for the preparation of β-deuterium labeled 2-keto-4-methylbutyric acid were investigated. Vinyl chloride was first reacted with the ethyl oxalyl chloride moiety using aluminum chloride as condensing agent and the addition of methyl mercaptan followed. Deuterium labeling was achieved by using NaBD4 reduction in pyridine. (author)