Radiosynthesis of a Chloroacetanilide Herbicide (Acetochlor) and a Dichloroacetamide Safener for Herbicides (R-29148)

Article abstract of DOI:10.1002/jlcr.2580360207

2-Chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)acetamide (the chloroacetanilide herbicide acetochlor) and 3-(dichloroacetyl)-2,2,5-trimethyl-1,3-oxazolidine (the dichloroacetamide safener R-29148) are required at high specific activity for studies on their metabolism and mode of action. Acetochlor was obtained at 22 Ci/mmol in 71percent yield by reductive dehalogenation of iodoacetochlor with tritium gas in ethanol in the presence of palladium on carbon and triethylamine. <2,2-dimethyl-3H>R-29148 was prepared at 15 Ci/mmol by treating acetone and 1-amino-2-propanol in pentane with two equivalents of NaOH in tritiated water (i.e. hydroxide ion-catalyzed enolization of acetone) followed by dichloroacetyl chloride.Key words: acetochlor, chloroacetanilide, deuterium labeling, dichloroacetamide, herbicides, R-29148, safeners, tritiated water, tritium gas, tritium labeling