Ethylamine → N-Ethyl-3-nitro PABA

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1.85 g of 4-fluoro-3-nitrobenzoic acid (10 mmol) in 25 mL of MeOH is added 20 mL of ethylamine (2.0M in THF). The resulting yellow solution is stirred at 75° C. for 5 h then at RT for 48 h. The solvent is removed under reduced pressure, then water is added to the residue. The resulting orange suspension is acidified with 2N aqueous HCl and the yellow precipitate is collected by filtration, washed with water and dried in vacuo to give 4-ethylamino-3-nitro-benzoic acid: mp=233-236° C.; 1H-NMR (DMSO-d6) δ 12.83 (s, 1H), 8.61 (d, J=1.84, 1H), 8.49 (m, 1H), 7.97 (dd, 1H), 7.12 (d, J=9.2, 1H), 3.46 (m, 2H), 1.23 (t, 3H); [M−1]−=209.

Provenance & Evidence