4-Chloro-3,5-dinitrobenzoic acid

yellow crystals

4-Chloro-3,5-dinitrobenzoic-15N2 Acid is an intermediate in synthesizing Lodoxamide-15N2,d2 (L469367), a labelled form of Lodoxamide. It is an antiallergic drug that acts as a mast cell stabilizer. It is effective in the treatment of allergic conjunctivitis and in decreasing vascular permeability.

irritant

The synthesis of 4-Chloro-3,5-dinitrobenzoic acid is as follows:
4-chloro-benzoic acid  (20 g, 0.128 mol) was dissolved in H₂SO₄ (d = 1.835 g/mL, 300 mL) at80 C, and KNO₃ (66 g, 0.65 mol) was added. The reaction mixture was heated to 125 C using ahigh-pressure flask and kept for 2 h, after which the reaction was cooled to rt and poured onto ice.The yield of 4-Chloro-3,5-dinitrobenzoic acid was 28 g (89%) .

Crystallise the acid from EtOH/ H2O, EtOH or *C6H6. The 1:1 naphthalene complex (by fusing various ratios of ingredients and recrystallising from EtOH) has m 122o. [Beilstein 9 H 416, 9 III 1953, 9 IV 1360.]