Indole ispyrroleAndbenzeneParallel compound, also known as benzopyrrole, chemical formula CeightHsevenN。Pyrrole and benzene have two types of combination, called indole and isoindole, respectively.Indole and indolehomologueandderivativeIt widely exists in nature, mainly in natural flower oil, such asJasmine Flower, bitter orange blossom, narcissus, fragrant magnolia, etc.
Smell: when indole is concentrated, it has a strong fecal odor, strong and lasting diffusion;Highly diluted solution has fragrance and can be used as perfume
Molecular structure data
Announce
edit
1. Molar refractive index: 38.52
2. Molar volume (cmthree/mol）：101.8
3. Isotonic specific volume (90.2K): 270.7
4. Surface tension (dyne/cm): 49.8
5. Polarization rate 15.27
Calculate chemical data
Announce
edit
1. Drainage parameter calculation reference value (XlogP): 0
2. Number of hydrogen bond donors: 1
3. Number of hydrogen bond receptors: 0
4. Number of rotatable chemical bonds: 0
5. Number of tautomers: 0
6. Topological molecular polar surface area: 15.8
7. Number of heavy atoms: 9
8. Surface charge: 0
9. Complexity: 101
10. Number of isotope atoms: 0
11. Determine the number of atomic structure centers: 0
12. Number of uncertain atomic structure centers: 0
13. Determine the number of chemical bond structural centers: 0
14. Number of indeterminate chemical bond structure centers: 0
15. Number of covalent bond units: 1
synthetic method
Announce
edit
1. The washing oil fraction is extracted in high temperature coal tar, which contains about 0.10% - 0.16% indole.Generally, it can be extracted from coal tar and wash oil fractions.The wash oil fraction is subjected to alkali washing and acid washing to obtain methyl naphthalene fraction, and then rectified in an efficient tower with 60 theoretical plates. The 225-256 ℃ fraction is cut out and fused with potassium hydroxide.The reaction is carried out at 170-240 ℃ for 2-4h, and stirred until foaming stops.Let it stand, let the lower layer of potassium indole out for cooling, and wash it with benzene at low temperature to remove oil after breaking.Then hydrolyze at 50-70 ℃ to obtain crude indole oil, distill it in a distillation tower with 20 theoretical plates, take the reflux ratio of 8-10:1, cut the distillate with tower top temperature of 170-256 ℃, cool it, crystallize, and centrifugally filter it to obtain refined indole.After pressing, the oil content is less than 3%, and the purified indole with purity of 99% is obtained by recrystallization with ethanol.
2. It is prepared by catalytic dehydrogenation of o-aminoethylbenzene.In the presence of aluminum nitrate (or aluminum oxide) in nitrogen flow, o-aminoethylbenzene is dehydrogenated and cyclized at 550 ℃, and dihydroindole is obtained by vacuum distillation.Then dehydrogenate at 640 ℃ to obtain indole.Other preparation methods include the reaction of o-nitrotoluene and oxalate to produce o-nitrophenylpyruvic acid and then produceα-Indole carboxylic acid is finally carbonized with lime to obtain the product;Indole was synthesized by heating aniline and acetylene at 600-650 ℃;Indole is synthesized from o-carboxyphenylglycine via 3-hydroxy-2-indole carboxylic acid and indole acid;Indolequinone was obtained by oxidizing static blue with concentrated nitric acid or chromic acid, and the latter was distilled with zinc powder to obtain indole.Indole can also be obtained by melting the mixture of nitrocinnamic acid and 10 parts of potassium hydroxide powder with iron filings.Fischer synthesis is the most common method for the synthesis of indole and its homologues.Under acidic conditions, aromatic hydrazones of ketones or aldehydes react to form indoles through rearrangement reaction similar to benzidine.
3. The 2-substituted or 3-substituted indole derivatives are obtained by heating and rearranging phenylhydrazone to eliminate one molecule of ammonia under acid catalysis.In practical operation, phenylhydrazone can often be obtained by heating and refluxing aldehyde or ketone with equivalent phenylhydrazine in acid, and it can be rearranged immediately under acid catalysis to eliminate ammonia to obtain indole compound.The commonly used catalysts are zinc chloride, boron trifluoride, polyphosphoric acid, etc. The commonly used acids are AcOH, HCl, trifluoroacetic acid, etc.
4. Indole without substituent at position 2 and 3 is generally synthesized from nitrobenzene derivatives in industry. Indole can be obtained from o-methyl, o-formyl, o-cyanoethyl, o-vinyl and nitrobenzene derivatives with hydrogen at position through corresponding methods.
S26：In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
After eye contact, immediately flush with plenty of water and seek medical advice;
S36/37/39：Wear suitable protective clothing, gloves and eye/face protection.
Wear appropriate protective clothing, gloves and eye/face protection;
S45：In case of accident or if you feel unwell, seek medical advice immediately (show the lable where possible).
In case of an accident or feeling unwell, seek medical advice immediately (show the label if possible);
S60：This material and/or its container must be disposed of as hazardous waste.
The substance and its container must be disposed of as hazardous waste;
S61：Avoid release to the environment. Refer to special instructions/Safety data sheets.
Avoid releasing into the environment, refer to special instructions/safety receipt instructions;
Risk terminology
Announce
edit
R20/21：Harmful by inhalation and in contact with skin.
Harmful by inhalation and in contact with skin;
R36：Irritating to eyes.
Irritating to eyes
preparation
Announce
edit
Indole and its homologues can be synthesized by many methods, of which the Fischer synthesis method is the most commonketoneoraldehydeThe aromatic hydrazones ofRearrangement reactionAnd made.In this reaction, the ketone used must have a first order carbon atom connected to the carbonyl group to get indole.Simple method:coal tar220 ℃~260 ℃ fraction, orisatinIt is prepared by reduction with zinc powder.[1]
Flavor use
Announce
edit
Natural products are widely contained inBitter neroli oil、Sweet orange oil、Lemon oil、White lemon oilCitrus oil, pomelo peel oil, jasmine oil and other essential oils can be widely used in jasmine, lilac, orange flower, gardenia, honeysuckle, lotus, narcissus, ylang ylang, grass orchid, white orchid and other flower fragrance.Extremely small amount can be used in chocolate, raspberry, strawberry, bitter orange, coffee, nuts, cheese, grape and fruit flavor compound and other essences.
derivative
Announce
edit
Indole derivatives are widely distributed in nature. Many natural compounds contain indole rings in their structures. Some indole derivatives are closely related to life activities, so indole is also a very importantHeterocyclic compound。
