4-Dimethylaminobenzaldehyde

Chemical properties

4-Dimethylaminobenzaldehyde is white to off white crystalline powder

The Uses of 4-Dimethylaminobenzaldehyde

4-Dimethylaminobenzaldehyde is a versatile reagent for the synthesis of Schiff bases, which are colorful condensation products formed with amines, pyrroles, and indoles. It plays a crucial role in the Ehrlich reaction, a test for indole presence in alkaloid-containing samples, and in the determination of hydrazine through the formation of azo dyes. This compound is instrumental in identifying indole-positive and indole-negative microorganisms, such as E.coli, which can metabolize tryptophan into indole. Additionally, 4-Dimethylaminobenzaldehyde is utilized in the spectrophotometric analysis of urine bilirubin and porphobilinogen, making it an essential tool in both organic synthesis and biochemical detection.

What are the applications of Application

4-(Dimethylamino)benzaldehyde is a reagent for indole, pyrrole, and amine assay

Definition

4-Dimethylaminobenzaldehyde is a mamber of the class of benzaldehydes carrying a dimethylamino substituent at position 4. Used as an indicator for detection of indoles and hydrazine.

Synthesis Reference(s)

Journal of Heterocyclic Chemistry, 26, p. 1563, 1989
Organic Syntheses, Coll. Vol. 4, p. 331, 1963
Tetrahedron Letters, 30, p. 287, 1989 DOI: 10.1016/S0040-4039(00)95181-5

General Description

Kovac′s reagent for indoles is a solution of 4-(dimethylamino)benzaldehyde and hydrochloric acid in n-butanol.

Biochem/physiol Actions

Kovac′s reagent detects the indole and aids in identifying the indole-positive and indole-negative microorganisms. E. coli can split tryptophan into indole and α-aminopropionic acid in the presence of the enzyme tryptophanase. p-Aminobenzaldehyde present in the reagent reacts with indole to form a cherry-red complex, that is soluble in alcohol, ether, and chloroform. It is recommended to use glucose free media and peptone with a high tryptophan content for the test.

Purification Methods

Crystallise DMAB from water, hexane, or from EtOH (2mL/g), after charcoal treatment, by adding excess of water. Alternatively dissolve it in aqueous acetic acid, filter, and precipitate it with ammonia. Finally recrystallise it from EtOH. It is used for the detection of pyrroles [Iyer et al. J Org Chem 59 6038 1994]. [Beilstein 14 IV 51.]

Hazard

4-Dimethylaminobenzaldehyde is a strong eye irritant, may cause allergic skin reactions on contact and is harmful if swallowed. It caused general anaesthesia, somnolence and ataxia in oral and intraperitoneal lethal dose studies in mice.