Microwave synthesizing method for 2, 3, 3-trimethyl -3H-indole and its derivatives

A technology of microwave synthesis and derivatives, applied in 2 fields, can solve problems such as complicated process, polluted environment, large amount of ketone, etc., and achieve the effect of shortening reaction time and reducing pollution

Inactive Publication Date: 2009-09-30
JIANGXI SCI & TECH NORMAL UNIV
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  • Abstract
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Problems solved by technology

The two-step synthesis method needs to obtain the intermediate phenylhydrazone first, and then carry out the ring-closing reaction. The process is complicated, involves a large amount of organic solvents, produces waste acid, and pollutes the environment; although the one-step method simplifies the reaction steps, it also has a long reaction time. The yield is low, and the amount of ketone is large, etc.

Method used

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  • Microwave synthesizing method for 2, 3, 3-trimethyl -3H-indole and its derivatives

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Experimental program
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Effect test

Embodiment 1

[0011] A kind of synthetic method of 2,3,3-trimethyl-3H-indole is:

[0012] Mix phenylhydrazine (34g), methyl isobutyl ketone (70g) and glacial acetic acid (300mL), place in an open container, reflux, microwave radiation (800W), 20-30min. After the reaction, the solution was concentrated, cooled, diluted with (100 mL) ethyl acetate, neutralized with saturated NaHCO3 solution to neutral pH=7-8, separated into layers, the organic layer was concentrated to dryness and the crude product 47.9 g was separated by a flash column (Developer polar ethyl acetate / petroleum ether=1:5) and concentrated to obtain 2,3,3-trimethyl-3H-indole (45.1 g, 90.3%).

[0013] IR(KBr): 3065, 2974, 2928, 2860, 1635, 1589, 1463, 1419, 749cm -1

[0014] 1 H NMR (CDCl 3 , 400MHz): δ: 7.45-7.43 (1H, d), 7.21-7.16 (2H, m), 7.10-7.07 (1H, m), 2.177 (3H, s), 1.19 (6H, s). 13 C NMR (CDCl 3 , 100MHz) δ: 187.3, 153.23, 145.15, 127.03, 124.545, 120.72, 119.37, 53.04, 21.38, 14.83.

Embodiment 2

[0016] A kind of synthetic method of 2,3,3-trimethyl-3H-indole is:

[0017] Mix phenylhydrazine (34g), methyl isobutyl ketone (42g) and glacial acetic acid (300mL), place in a sealed container, reflux, microwave radiation (800W), 25-45min. After the reaction was complete, the solution was concentrated, cooled, diluted with (100 mL) ethyl acetate, washed with saturated NaHCO 3 The solution was neutralized to neutral pH=7-8, separated, the organic layer was concentrated to dryness, and the crude product 48.5g was separated by a flash column (developing agent polar ethyl acetate / petroleum ether=1:5), concentrated to obtain 2,3,3-Trimethyl-3H-indole 44.9g, yield 90%.

[0018] IR (KBr): 3062, 2962, 2906, 2860, 1635, 1567, 1453, 1407, 737cm -1

[0019] 1 H NMR (CDCl 3 , 400MHz): δ: 7.54-7.52 (1H, d), 7.31-7.26 (2H, m), 7.20-7.16 (1H, m), 2.27 (3H, s), 1.28 (6H, s). 13 C NMR (CDCl 3 , 100MHz) δ: 188.09, 153.58, 145.60, 127.58, 125.10, 121.32, 119.84, 53.58, 23.09, 15.44.

Embodiment 3

[0021] A kind of synthetic method of 5-bromo-2,3,3-trimethyl-3H-indole is:

[0022] Mix p-bromophenylhydrazine (37g), methyl isobutyl ketone (43g) and glacial acetic acid (200mL) in an open container, reflux, microwave radiation (800W), 15-30min. After the reaction, the solution was concentrated, cooled, diluted with (100 mL) dichloromethane, washed with saturated NaHCO 3 The solution was neutralized to neutral pH=7-8, and the layers were separated. There were several layers of concentrated and dried crude product 44g, separated by a flash column (developing agent polar ethyl acetate / petroleum ether=1:5), concentrated to obtain 42.3 g of 5-bromo-2,3,3-trimethyl-3H-indole, yield 89.2%.

[0023] IR (KBr): 3066, 2974, 2916, 2860, 1873, 1713, 1645, 1567, 1453, 873, 817cm -1

[0024] 1 H NMR (CDCl 3 , 400MHz): δ: 8.17 (1H, s), 8.03 (1H, d), 7.65 (1H, d), 2.54 (3H, s), 1.44 (6H, s). 13 C NMR (CDCl 3 , 100MHz) δ: 188.62, 152.48, 147.76, 130.66, 124.87, 121.22, 116.70, 54.12, 2...

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Abstract

A microwave synthesizing method for 2, 3, 3-trimethyl -3H-indole and its derivatives, which indicates dissolving phenyl hydrazine or phenyl hydrazine derivates together with methyl isopropyl ketone with the molar ratio of 1:1-1:20 in acetic acid, putting the solution into a reaction container, irradiating with microwave for 2-45 minutes at 200-850W, finishing the reaction in short minute and severing the solution after concentrated and cooled down with conventional method. This microwave synthesizing method employs microwave heating, and the fire power and time show inverse ratio when microwave acts. Compared to existing technology which needs several hours to more than ten hours, this invention considerably shorten the time of reaction, the acetic acid during the reaction can be recovered and reused and there adds no other organic solvent and catalyse ache which reduces the pollution of the environment.

Description

technical field [0001] The invention relates to a microwave synthesis method of 2,3,3-trimethyl-3H-indole and its derivatives. Background technique [0002] 2,3,3-Trimethyl-3H-indole is an important intermediate in the synthesis of photochromic substances and conjugated cyanine cationic dyes. 2,3,3-trimethyl-3H-indocyanine dyes have the advantages of high fluorescence quantum yield, large tunable range of absorption wavelength, easy synthesis of near-infrared fluorescent dyes, and relatively good stability. Fluorescent probes have been used in frontier fields of life sciences such as biochips, DNA sequencing, fluorescent immunoassay, clinical diagnostic analysis and treatment. [0003] Currently used to prepare 2,3,3-trimethyl-3H-indole synthetic route, the most important method is the Fisher indole synthesis method, HugoIlly and Lance Funderburk in 1968, with methyl isopropyl ketone Using hydrazone as raw material, 2,3,3-trimethyl-3H-indole was synthesized under the condi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D209/08B01J19/12
Inventor 肖强谢汐阳如春丁海新肖伟洪
Owner JIANGXI SCI & TECH NORMAL UNIV
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