Chemical Properties
White to beige powder
Physical properties
Crystals of 3,5-dichlorobenzoic acid were obtained from a water/ethanol mixture, mp186–187℃(lit. l85–187℃). Crystallization of 3,5-Dichlorobenzoic acid occurred in the monoclinic centrosymmetric space group P21/n (No. 14) with a = 3.7812(3), b = 13.996(2), and c = 14.514(2) Å, β = 95.183(8); and Z = 4. Chlorine substituents of four dimeric molecules of 3,5-Dichlorobenzoic acid formed square channels, ca. 3.54 Å on a side, which run parallel to the crystallographic a axis.
Uses
3,5-Dichlorobenzoic acid is used in organic synthesis and pesticide and pharmaceutical intermediates. It can be used to synthesize 3,5-Dichloro-N-(4-hydroxyphenethyl)benzamide and (3,5-Dichlorophenyl)-(4-fluorophenyl)methanone.
Application
3,5-Dichlorobenzoic acid can be used as a pharmaceutical intermediate compound. Novel cyclopentquinoline and 3,5-dichlorobenzoic acid complexes possess antioxidant and neuroprotective effects, which can be used for the treatment of Alzheimer's disease. In addition, 3,5-Dichlorobenzoic acid has a stimulatory effect on skeletal muscle and can be used in the preparation of benzodiazepine derivatives for treating arrhythmias.
Definition
ChEBI: 3,5-dichlorobenzoic acid is a chlorobenzoic acid that is benzoic acid in which the ring hydrogens at positions 3 and 5 are substituted by chloro groups. It has a role as a herbicide and a metabolite. It is a chlorobenzoic acid and a dichlorobenzene. It derives from a benzoic acid. It is a conjugate acid of a 3,5-dichlorobenzoate.
Preparation
Synthesis of 3,5-dichlorobenzoic acid: 200 parts of ethanol is slowly added to a solution, heated to 70°C, of the diazonium salt prepared as described in Example 1 from 412 parts of 3,5-dichloroanthranilic acid; elimination of nitrogen immediately takes place with evolution of heat. The mixture is stirred for another 15 minutes and 350 parts (92% of theory) of 3,5-dichlorobenzoic acid having a melting point of 176° to 178°C is isolated as described in Example 1.
Synthesis Reference(s)
Journal of the American Chemical Society, 73, p. 455, 1951
DOI: 10.1021/ja01145a145
Purification Methods
Crystallise the acid from EtOH and sublime it in a vacuum. [Beilstein 9 IV 1008.] Aromatic acid impurities (to <0.05%) can be removed via the (±)--methylbenzylamine salt as described for 2,4-dichlorobenzoic acid [Ley & Yates Organic Process Research & Development 12 120 2008.]
