Tert-butyl 5-fluoro-2-nitrophenylcarbamate → N2-(tert-Butoxycarbonyl)-4-fluoro-1,2-phenylenediamine

Participants

Reaction Conditions

Reaction Steps

A slurry of Raney nickel (W.R. Grace 2800, 30.6 g calc. dry weight) was added to a 2-gallon Parr stirred pressure reactor containing THF (3 L). tert-Butyl 5-fluoro-2-nitrophenylcarbamate (102 g) was added. The vessel was sealed, purged, and pressurized to about 30 psig with hydrogen. The mixture was vigorously stirred at ambient temperature (20° C.) while hydrogen was supplied on-demand at 30 psig. After stirring for 16 h, the vessel was vented and purged with nitrogen. The product mixture was filtered to remove the catalyst using THF (1 L) to rinse the reactor and catalyst cake. The solvent was removed under vacuum. Heptane (510 mL) was added and the mixture was heated to 50° C. for 1 h, then cooled slowly to 0° C. The solids were filtered and washed with cold heptanes (100 mL) and dried under vacuum at 50° C. (76.7 g of product isolated, 87% pure, 73% yield).

Provenance & Evidence