Chemical Properties
4-Dimethylaminobenzaldehyde is white to off white crystalline powder
Uses
Used as derivitizing agent.
Uses
4-(Dimethylamino)benzaldehyde is used in Ehrlich's reagent for spectrophotometric determination of hydrazine as it reacts to form azo dyes. 4-(Dimethylamino)benzaldehyde is used for determination of u
rine bilirubin and porphobilinogen.
Uses
In the presence of oxygen, some bacteria, like E.coli, are able to split tryptophan into indole and alpha-aminopropionic acid. This reagent is for detecting the indole and identify the indole-positive and indole-negative microorganisms.
Uses
Forms colored condensation products (Schiff bases) with pyrroles1 and primary amines.2
Uses
In the presence of oxygen, some bacteria, like E. coli, are able to split tryptophan into indole and α-aminopropionic acid. This reagent is for detecting the indole and identifying the indole-positive and indole-negative microorganisms.
Uses
4-Dimethylaminobenzaldehyde is used to prepare colorful Schiff base adducts with amines, pyrroles and indoles. It is often used in the Ehrlich reaction, test for the presence of indoles in a sample containing alkaloids and determination of hydrazine.
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.]
