One-step method for synthesizing 3,4-dimethylthiophene[2,3-b]thiophene

A technology of dimethylthiophene and 3-b, which is applied in the direction of organic chemistry, can solve the problems of many raw materials, complicated operation, and low overall yield, and achieve the effect of cheap raw materials, simple operation, and cost reduction

Active Publication Date: 2018-12-25
BINZHOU YUNENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Firstly, compound 1 is obtained by cyclization reaction with acetylacetone, ethyl bromoacetate and carbon disulfide; secondly, compound 1 is hydrolyzed to obtain compound 2; finally, compound 2 is obtained by decarboxylation reaction to obtain 3,4-dimethylthiophene[2,3-b ] and thiophene, the reaction process needs three steps, the raw materials involved are more, the operation is complicated, and the total yield is lower (less than 61%). Therefore, it is necessary to study a simpler and more efficient synthetic method

Method used

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  • One-step method for synthesizing 3,4-dimethylthiophene[2,3-b]thiophene

Examples

Experimental program
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Effect test

Embodiment 1

[0024] A method for synthesizing 3,4-dimethylthiophene[2,3-b]thiophene in one step, comprising the following steps:

[0025] 1) Mix thiophene[2,3-b]thiophene, nitromethane, sodium methoxide and 5% rhodium on carbon, feed nitrogen, raise the temperature to 130°C, pressurize to 5 atmospheres, and react for 17h; wherein thiophene[2 The consumption of ,3-b]thiophene, nitromethane and sodium methylate is 0.1mol, 3mol and 0.3mol respectively, and the consumption of rhodium carbon is 2% of the weight of thiophene[2,3-b]thiophene;

[0026] 2) After the reaction, the solid rhodium carbon was recovered by filtration, the filtrate was washed with water, and concentrated by distillation to obtain 16.16 g of excess substituted methane and solid 3,4-dimethylthiophene[2,3-b]thiophene, with a yield of 96.1%.

[0027] When recovering solid rhodium carbon, it can be reused after being washed with chloroform and then dried.

Embodiment 2

[0029] A method for synthesizing 3,4-dimethylthiophene[2,3-b]thiophene in one step, comprising the following steps:

[0030] 1) Mix thiophene[2,3-b]thiophene, nitromethane, potassium tert-butoxide and 5% rhodium on carbon, pass in argon, heat up to 150°C, pressurize to 8 atmospheres, and react for 25h; The molar dosages of thiophene[2,3-b]thiophene, nitromethane and potassium tert-butoxide are 0.1mol, 4.5mol and 0.7mol respectively, and the amount of rhodium carbon is 3.2% of the weight of thiophene[2,3-b]thiophene. %;

[0031] 2) After the reaction, the solid rhodium carbon was recovered by filtration, the filtrate was washed with water, and concentrated by distillation to obtain 16.68 g of excess substituted methane and solid 3,4-dimethylthiophene[2,3-b]thiophene, with a yield of 99.2%.

[0032] When recovering solid rhodium carbon, it can be reused after being washed with chloroform and then dried.

Embodiment 3

[0034] A method for synthesizing 3,4-dimethylthiophene[2,3-b]thiophene in one step, comprising the following steps:

[0035] 1) Mix thiophene[2,3-b]thiophene, methyl iodide, potassium tert-butoxide and 5% rhodium on carbon, pass in argon, heat up to 140°C, pressurize to 7 atmospheres, and react for 20 hours; where thiophene The molar dosages of [2,3-b]thiophene, nitromethane and sodium ethylate are 0.1mol, 5mol and 0.5mol respectively, and the rhodium carbon dosage is 3% of the weight of thiophene[2,3-b]thiophene;

[0036] 2) After the reaction, the solid rhodium carbon was recovered by filtration, the filtrate was washed with water, and concentrated by distillation to obtain 16.54 g of excess substituted methane and solid 3,4-dimethylthiophene[2,3-b]thiophene, with a yield of 98.3%.

[0037] When recovering solid rhodium carbon, it can be reused after being washed with chloroform and then dried.

[0038] 1. The influence of catalyst use times on the yield

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Abstract

The invention discloses a method for one-step synthesis of 3, 4-dimethylthieno[2, 3-b]thiophene. The method comprises 1) mixing thieno[2, 3-b]thiophene, substituted methane, an organic base and a catalyst, and carrying out a reaction process under conditions of pressure and protective gas, wherein the catalyst is rhodium carbon having rhodium content of 5wt%, and 2) separating and purifying the reaction system to obtain a product 3, 4-dimethylthieno[2, 3-b]thiophene. Under the pressure auxiliary condition, in the presence of the catalyst, under action of the organic base, groups at 3th and 4th sites of the thieno[2, 3-b]thiophene undergo a nucleophilic reaction to produce 3, 4-dimethylthieno[2, 3-b]thiophene. The reaction yield is 96% or more.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a method for synthesizing 3,4-dimethylthiophene[2,3-b]thiophene in one step. Background technique [0002] Thiophene (including thiophene and bithiophene) compounds are pure organic photosensitive dyes that can be used in dye-sensitized solar cells, and 3,4-dimethylthiophene [2,3-b] thiophene is the synthesis of such compounds important intermediates. Comel et al. [Journal of Heterocyclic Chemistry, 38(5), 1167-1171; 2001] disclose a method for synthesizing 3,4-dimethylthiophene[2,3-b]thiophene: [0003] [0004] Firstly, compound 1 is obtained by cyclization reaction with acetylacetone, ethyl bromoacetate and carbon disulfide; secondly, compound 1 is hydrolyzed to obtain compound 2; finally, compound 2 is obtained by decarboxylation reaction to obtain 3,4-dimethylthiophene[2,3-b ] and thiophene, the reaction process needs three steps, involving more raw...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): C07D495/04
CPCC07D495/04
Inventor王法云张立攀王永章建军罗蓓蓓郭青照任钊
OwnerBINZHOU YUNENG CHEM