A kind of cu2+ catalyzes the method for preparing 2-amino-5-nitrothiophene compounds

A technology for the preparation of nitrothiophene and catalysis, applied in chemical instruments and methods, organic compound/hydride/coordination complex catalysts, catalytic reactions, etc., can solve the problem of high price of trifluoroacetic anhydride, limited large-scale production, Conditions are difficult to control and other problems, to achieve the effects of easy control of reaction temperature, simple and easy reaction operation, and mild reaction

Inactive Publication Date: 2018-09-14
UNIV OF SCI & TECH BEIJING
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  • Claims
  • Application Information

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Problems solved by technology

Among them, the nitric acid-sulfuric acid mixed acid method has the most reports, but there are defects such as strong oxidation and difficult control conditions; although the nitric acid-acetic anhydride method avoids the use of concentrated sulfuric acid, the strong oxidizing property of concentrated nitric acid still cannot avoid the easily oxidized groups on the aromatic ring. Oxidation of groups or atoms (such as sulfur atoms on thiophene rings); and trifluoroacetic anhydride is expensive, which limits large-scale production

Method used

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  • A kind of cu2+ catalyzes the method for preparing 2-amino-5-nitrothiophene compounds
  • A kind of cu2+ catalyzes the method for preparing 2-amino-5-nitrothiophene compounds
  • A kind of cu2+ catalyzes the method for preparing 2-amino-5-nitrothiophene compounds

Examples

Experimental program
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Effect test

Embodiment 1

[0029] a Cu 2+ Process for the catalytic preparation of 2-amino-3-cyano-5-nitrothiophene.

[0030] The preparation method is as follows:

[0031] (1) Acetic anhydride-Cu 2+ / NO 3 - The preparation of compound salt system: add acetic anhydride 23ml (0.25mol) and Cu(NO 3 ) 2· 3H 2 O (12.08g, 0.05mol), the temperature control is 0°C, after stirring for 30min, the acetic anhydride-Cu 2+ / NO 3 - compound salt system;

[0032] (2) Nitration reaction: the acetic anhydride-Cu prepared towards step (1) 2+ / NO 3 - Slowly add 2-benzamide-3-cyanothiophene (11.4g, 0.05mol) into the compound salt system of , control the temperature range to 0-10°C, stir until the reaction is complete, pour the reaction solution into a large amount of ice water, Filtration, collected containing Cu 2+ The filtrate is set aside, and a dark solid is obtained, which is dissolved in ethanol and then decolorized with activated carbon. After the activated carbon is filtered off, recrystallization is c...

Embodiment 2

[0036] a Cu 2+ Process for the catalytic preparation of 2-amino-3-acetyl-5-nitrothiophene.

[0037] The preparation method is as follows:

[0038] (1) Acetic anhydride-Cu 2+ / NO 3 - The preparation of compound salt system: with embodiment 1.

[0039] (2) Nitration reaction: the acetic anhydride-Cu prepared towards step (1) 2+ / NO 3 - Slowly add 2-acetylamino-3-acetylthiophene (9.15g, 0.05mol) into the compound salt system of the compound salt system, control the temperature range to 10°C, stir until the reaction is completed, pour the reaction solution into a large amount of ice water, filter, and collect Contains Cu 2+ The filtrate was set aside, and a yellow solid was obtained, which was dissolved in methanol solution and then decolorized with activated carbon. After the activated carbon was filtered off, recrystallization was continued with the above methanol solution, and dark yellow crystals were precipitated. After filtration and drying, 2-aminoacetyl-3- Acetyl-...

Embodiment 3

[0042] a Cu 2+ Process for the catalytic preparation of 2-acetamido-3-acetamide-5-nitrothiophene.

[0043] The preparation method is as follows:

[0044] (1) Acetic anhydride-Cu 2+ / NO 3 - Preparation of the compound salt system: add acetic anhydride 23ml (0.25mol), CuSO 4 (7.98g, 0.05mol) and KNO 3 (5.06g, 0.05mol), the temperature control is 0 ℃, and after stirring for 30min, the acetic anhydride-Cu 2+ / NO 3 - compound salt system;

[0045] (2) Nitration reaction: the acetic anhydride-Cu prepared towards step (1) 2+ / NO 3 - Slowly add 2-acetamido-3-acetamide thiophene (9.20g, 0.05mol) to the compound salt system, control the temperature range to 5°C, stir until the reaction is complete, pour the reaction solution into a large amount of ice water, filter, and collect Contains Cu 2+ The filtrate was set aside, and a yellow solid was obtained, which was dissolved in methanol solution and then decolorized with activated carbon. After the activated carbon was filtere...

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Abstract

The invention belongs to the field of organic synthesis and relates to a method for preparing a 2-amino-5-nitrothiophene compound from Cu<2+>. The method includes adding a 2-acylamino thiophene compound into an acetic anhydride-Cu<2+> / NO3<-> compound salt system, stirring, performing nitration to obtain a 2-acylamino-5-nitrothiophene compound, and subjecting the 2-acylamino-5-nitrothiophene compound to hydrolysis so as to obtain the 2-amino-5-nitrothiophene compound, namely a target product. The method for preparing the 2-amino-5-nitrothiophene compound from the Cu<2+> has the advantages that nitration is conducted in the acetic anhydride-Cu<2+> / NO3<-> compound salt system, mild reaction conditions, easiness in system reaction temperature control, little environmental pollution and high product purity are achieved, copper salt can be recycled after use, and accordingly the method is applicable to large-scale industrial production.

Description

technical field [0001] The invention belongs to the field of organic synthesis and relates to a Cu 2+ A method for catalytically preparing 2-amino-5-nitrothiophene compounds. Background technique [0002] Thiophene heterocyclic azo dyes are an important kind of thiophene heterocyclic azo dyes, and the azo component in thiophene heterocyclic azo dyes is 2-amino-5-nitrothiophene ring. The structural formula of thiophene heterocyclic azo dyes is as follows: [0003] [0004] Among them, R 1 for -CN, -COR, -CONH 2 , -COOR, or -COOH; R 2 and R 3 for -CH 3 ,-CH 2 CH 3 , or -CH 2 CH 2 CN. [0005] The 2-amino-5-nitrothiophene ring structural unit is a key intermediate of thiophene heterocyclic azo dyes, which is derived from the nitration reaction of 2-aminothiophene compounds. [0006] The nitration methods of compounds with aromatic ring structure are mainly nitric acid-sulfuric acid mixed acid method, nitric acid-acetic anhydride method and trifluoroacetic anhydri...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D333/44B01J31/28
CPCB01J31/28B01J2231/4283C07D333/44
Inventor 杨运旭董亚军
Owner UNIV OF SCI & TECH BEIJING
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