What is indole?
Indole is a compound in which pyrrole is connected in parallel with benzene. Also known as benzopyrrole. There are two ways to combine them, called indole and isoindole. Indole and its homologues and derivatives are widely found in nature, mainly in natural flower oils such as jasmine, bitter orange flower, daffodil, fragrant orchid, and the like.
For example, indole was firstly degraded by indigo; indole and its homologs were also found in coal tar; essential oils (such as jasmine essential oils) also contained indole; feces contained 3-methyl indole; many anthraquinones were indole Derivatives; an essential amino acid of the animal, tryptophan is a derivative of indole; certain physiologically active natural substances, such as alkaloids, auxins, etc., are derivatives of indole.
Indole is an imine which has a weak basicity; the double bond of a heterocyclic ring generally does not undergo an addition reaction; under the action of a strong acid, a dimerization and a tripolymerization can occur; under special conditions, an aromatic electrophilic substitution can be performed. In the reaction, hydrogen at the 3-position is preferentially substituted, and if reacted with a sulfonyl chloride, 3-chloroindole can be obtained. A variety of reactions can also occur at the 3-position, such as the formation of Grignard reagents, condensation with aldehydes, and Mannich reactions.
How to make indole?
Indole and its homologues can be synthesized by a variety of methods, among which Fischer synthesis is most common, and it is prepared by using a ketone or an aldehyde aromatic oxime to act under acidic conditions and undergo a rearrangement reaction.
In this reaction, the ketone used must have a primary carbon atom attached to the carbonyl group to give indole. Simple preparation method: it can be obtained by distilling off the 220° to 260° fraction of coal tar or by reducing the magenta with zinc powder.
What is the main use of indole?
Natural products are widely contained in essential oils such as bitter orange blossom oil, sweet orange oil, lemon oil, lime oil, citrus oil, pomelo oil, and jasmine oil.
Can be widely used in jasmine, lilac, orange blossom, medlar, honeysuckle, lotus, daffodil, ylang-ylang, grass orchid, white orchid and other floral flavors. Very small amounts can be used in flavors such as chocolate, raspberry, strawberry, bitter orange, coffee, nuts, cheese, grapes and fruity complexes.
It can also be used to formulate flavors such as cheese, citrus, coffee, nuts, grapes, strawberries, raspberries, chocolate, assorted fruits, jasmine and lily.
The above is a brief introduction to the definition of indole, manufacturing methods, uses, if you have any ideas, please contact us!