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A kind of preparation method of unsymmetrical azobenzene

An azobenzene and asymmetric technology, applied in the field of preparation of asymmetric azobenzene, can solve the problems of low yield of asymmetric azobenzene, limited types of substituent groups, complicated preparation process, etc. Commercialized, easy-to-use effects

Active Publication Date: 2020-05-19
HUAZHONG UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

But, consider above-mentioned asymmetric azobenzene preparation method comprehensively, find following deficiency: method (1) needs the prior preparation of diazonium salt and aromatic hydrocarbon can only be electron-rich phenols and aromatic amine compounds, so the synthesized The type of substituting groups on the asymmetric azobenzene obtained is greatly limited; the preparation process of method (2) is complex and the intermediate product nitrosophenol is easily oxidized in air and easily decomposed when exposed to light; method (3) requires Carried out under acid catalysis, and accompanied by a large amount of by-products such as benzidine, the yield of asymmetric azobenzene is low

Method used

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  • A kind of preparation method of unsymmetrical azobenzene
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  • A kind of preparation method of unsymmetrical azobenzene

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preparation example Construction

[0028] The invention provides a preparation method of asymmetric azobenzene, which comprises dissolving 6-chloro-2-carbonylbicyclo[3.1.0]hexane-6-carboxylate compounds in an organic solvent, adding aromatic hydrazine inorganic acid in sequence Salts and alkaline substances cause a ring-opening reaction to obtain unsymmetrical azobenzene after separation and purification. The structural formula of the 6-chloro-2-carbonylbicyclo[3.1.0]hexane-6-carboxylate compound is shown in formula (1):

[0029]

[0030] In formula (1), R 1 and R 2 each independently selected from a hydrogen atom, a halogen atom, an alkyl group, an aryl group or a substituted aryl group; wherein the aryl group is selected from benzene, naphthalene, biphenyl, anthracene, phenanthrene, furan, thiophene, indole, thiazole and benzene And thiazole, the substituted aromatic group has 1 to 5 substituting groups, and the substituting groups are selected from halogen atoms, hydroxyl groups, mercapto groups, cyano ...

Embodiment 1

[0046] Step (1): Dissolve 1642mg (20mmol) of 2-cyclopentenone and 2859mg (20mmol) of methyl dichloroacetate in N,N-dimethylformamide (100ml), and add 7820mg of cesium carbonate in batches under stirring (24mmol), react at room temperature for 48 hours. After the reaction, extracted with dichloromethane, washed with saturated brine to remove N,N-dimethylformamide, combined organic phases, dried over anhydrous sodium sulfate, filtered, concentrated by rotary evaporation under reduced pressure, and then separated by silica gel column method to obtain 2.94 g of methyl 6-chloro-2-carbonylbicyclo[3.1.0]hexane-6-carboxylate, the yield was 78%.

[0047]

[0048] 1 H NMR (400MHz, CDCl 3 )δ(ppm)3.73(s,3H),2.73(t,J=6.4Hz,1H),2.64(d,J=6.4Hz,1H),2.48–2.36(m,1H),2.27–2.11(m ,3H).

[0049] Step (2): 188mg (1mmol) of methyl 6-chloro-2-carbonylbicyclo[3.1.0]hexane-6-carboxylate obtained in step (1) was dissolved in 5ml of toluene in a reaction test tube equipped with magnetic stirring ...

Embodiment 2

[0053] Step (1) is identical with embodiment 1

[0054] Step (2): 188mg (1mmol) of 6-chloro-2-carbonylbicyclo[3.1.0]hexane-6-methyl carboxylate obtained in step (1) was dissolved in 5ml N , to N-dimethylformamide, add 174mg phenylhydrazine hydrochloride (1.2mmol) and 166mg potassium carbonate (1.2mmol) successively; the mixture was stirred and reacted at 120°C for 24 hours, after the reaction, saturated saline Washing, extraction with dichloromethane, combined organic phases, drying over anhydrous sodium sulfate, filtration, concentration under reduced pressure, and separation by silica gel column chromatography to obtain trans-3-formyl azobenzene 125 mg, yield 52 %.

[0055]

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Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of asymmetric azobenzene. The preparation method of the asymmetric azobenzene comprises the step of carrying out ring-opening-oxidizing reaction on a 6-chloro-carbonylbicyclo [3.1.0] hexane-6-formate compound and aromatic hydrazine in a suitable organic solvent to obtain the asymmetric azobenzene. The reaction needs to be carried out at a specific temperature, and after the reaction is finished, a product can be obtained by separation through methods including recrystallization, column chromatography and the like. The method has the characteristics of simple steps, simplicity and convenience in operation, low cost and the like, and a new way is provided for synthesis of the asymmetricazobenzene.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and more specifically relates to a preparation method of unsymmetrical azobenzene. Background technique [0002] As a ubiquitous basic structural skeleton, azobenzene compounds are widely used in dyes, pigments, food additives, drugs and other fields. In addition, asymmetric azobenzenes have been extensively studied as basic units of photosensitive materials due to their robustness and rapid and reversible conversion of cis-trans isomerism under ultraviolet and visible light. Regarding the synthesis of asymmetric azobenzene, the main methods are: (1) coupling reaction of aromatic diazonium salt with phenol, aniline, etc.; (2) Mills condensation reaction: firstly, nitroso is formed from phenol and nitroso in acidic medium A series of asymmetric azobenzenes were prepared by condensation reaction with aromatic amines; (3) Dehydrogenation of multi-substituted hydroazobenzenes was used to obtain asym...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C245/08C07C67/343C07C69/757
CPCC07C67/343C07C245/08C07C2602/18C07C69/757
Inventor 龚跃法姚瑞芳
Owner HUAZHONG UNIV OF SCI & TECH
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