O.[F:2][C:3]1[CH:8]=[CH:7][C:6]([CH2:9][C:10]([OH:12])=O)=[CH:5][CH:4]=1.CN(C)C=O.C(Cl)(=O)C([Cl:21])=O>C1(C)C=CC=CC=1>[F:2][C:3]1[CH:8]=[CH:7][C:6]([CH2:9][C:10]([Cl:21])=[O:12])=[CH:5][CH:4]=1Into a 1-L three-neck flask equipped with a mechanical stirrer, an addition funnel, and a nitrogen bubbler vented to a water scrubber was placed 60.0 g (0.389 mol) of 4-fluorophenylacetic acid, 0.18 g, 0.002 mol) of N,N-dimethylformamide and 250 g of toluene. The addition funnel was charged with 50.4 g (0.397 mol) of oxalyl chloride and added to the reaction mixture over a 10 minute period resulting in gas evolution (4.7° C. exotherm was observed). The reaction mixture was stirred at ambient temperature for 2.5 hours (gas evolution complete) and the head space of the reaction flask was sparged with nitrogen for 10 minutes before storing the material. HPLC assay of the solution indicated that 19.1 wt % of the solution was 4-fluoroacetyl chloride, thus affording a 99% yield. Purification of crude 4-fluorophenylacetyl chloride by vacuum distillation (57-58° C., 0.15 mm Hg) affords 4-fluorophenylacetyl chloride as a clear liquid in 90% yield.
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