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Preparation method of 2-aminothiazole

An aminothiazole, boric acid technology, applied in chemical instruments and methods, physical/chemical process catalysts, metal/metal oxide/metal hydroxide catalysts, etc., can solve the problems of poor color, low product yield and purity, etc. Achieve the effect of reducing side reactions, improving product yield and purity, and avoiding discoloration or even deterioration

Active Publication Date: 2022-08-05
INST OF CHEM ENG GUANGDONG ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the existing 2-aminothiazole synthesis method that needs recrystallization, and the product yield and purity are low, and the defect and deficiency of poor color provide a kind of preparation method of 2-aminothiazole, by adopting boric acid-boric acid Salt composite catalyst enables thiourea and chloroacetal acetal to be synthesized in a heterogeneous one-pot method, which simplifies the synthesis process, and the reaction is mild and easy to control, reducing the occurrence of side reactions, and subsequent recrystallization is not required, and the yield is achieved. Purity, improvement of color

Method used

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  • Preparation method of 2-aminothiazole

Examples

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Effect test

Embodiment 1

[0041] A preparation method of 2-aminothiazole, comprising the steps:

[0042]S1. Mix 6.51g boric acid (99%) and 21.17g sodium tetraborate (99%) with a mortar and grind to powder to prepare a composite catalyst,

[0043] The prepared catalyst, 176.33g of thiourea (99%) and 265g of chloroacetaldehyde dimethyl acetal (98%) were added to a 500mL three-necked round-bottomed flask with magnetic stirring, connected with a thermometer and a condenser, and the reaction temperature was controlled at 90°C for 8h, to obtain the reaction product;

[0044] S2. connect underpressure distillation apparatus after the reaction finishes, set 65 ℃ of underpressure distillations to distill out by-product methanol, to distillate without distillate distillation, the reaction flask is moved in the freezing tank, and 145g 25% ammonia water is added dropwise while freezing, dripping The process temperature is kept below 40 °C, and a large number of white crystals (such as figure 1 After the dropwise...

Embodiment 2

[0048] A preparation method of 2-aminothiazole, comprising the steps:

[0049] S1. Mix 6.51 g of boric acid (99%) and 14.51 g of sodium metaborate tetrahydrate (99%) with a mortar and grind to powder to obtain a composite catalyst,

[0050] The prepared catalyst, 192.35g thiourea (99%) and 265g chloroacetaldehyde dimethyl acetal (98%) were added to a 500mL three-necked round bottom flask with magnetic stirring, connected with a thermometer and a condenser, and the reaction temperature was controlled at 90°C for 8h.

[0051] S2. connect underpressure distillation apparatus after the reaction finishes, set 65 ℃ of underpressure distillations to distill out by-product methanol, to distillate without distillate distillation, the reaction flask is moved in the freezing tank, and 145g 25% ammonia water is added dropwise while freezing, dripping The process temperature was kept below 40°C, a large number of white crystals were precipitated during the dropwise addition, pH=9.5 after t...

Embodiment 3

[0055] A preparation method of 2-aminothiazole, comprising the steps:

[0056] S1. Mix 5.21g of boric acid (99%) and 25.42g of sodium tetraborate (99%) with a mortar and grind to powder to obtain a composite catalyst. The obtained catalyst, 176.33g of thiourea (99%) and 324.67g of Chloroacetaldehyde diethyl acetal (98%) was added into a 500 mL three-necked round bottom flask with magnetic stirring, connected with a thermometer and a condenser, and the reaction temperature was controlled at 100°C for 8 hours.

[0057] S2. connect underpressure distillation apparatus after the reaction finishes, set 70 ℃ of underpressure distillations to distill out by-product ethanol, to distillate without distillate, the reaction flask is moved in the freezing tank, 290g 30% ammonia water is added dropwise while freezing, dripping The process temperature was kept below 40 °C, a large number of white crystals were precipitated during the dropwise addition, pH=10.1 after the dropwise addition of...

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Abstract

The invention discloses a preparation method of 2-aminothiazole, and belongs to the field of fine chemical engineering. The preparation method of the 2-aminothiazole comprises the following steps: S1, fully reacting thiourea, chloroacetaldehyde acetal and a boric acid-borate composite catalyst at 90-110 DEG C by a solvent-free one-pot method to obtain a reaction product; and S2, removing by-products in the reaction product, adjusting the pH value to 9-10, separating out at 0-10 DEG C, filtering to obtain crystals, and purifying and drying the crystals to obtain the 2-aminothiazole. According to the method, thiourea and chloroacetaldehyde acetal which cannot be subjected to mutual dissolution reaction can be subjected to out-phase reaction to generate 2-aminothiazole under the solvent-free condition by adopting the boric acid-borate composite catalyst, the product yield and purity are improved, the yield can be improved to 95% or above from 75%-80% in the prior art, and the purity is improved to 97%-99% from 80%-90%. In addition, color change and even deterioration of the 2-aminothiazole are avoided through specific pH control, and white 2-aminothiazole can be obtained.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, and more particularly, to a preparation method of 2-aminothiazole. Background technique [0002] 2-Aminothiazole is an important fine chemical and is widely used in various fields. For example, the more traditional application is as a drug intermediate to synthesize anticancer drugs with drug or physiological activity; as an additive, it is used in PCB browning solution. Among them; used as a coupling component in azo dyes. Among them, high-purity 2-aminothiazole is used as an additive in photoresist, and its wide application also represents its broad market demand. [0003] Among the existing 2-aminothiazole synthesis methods, one is that the chloroacetaldehyde aqueous solution and thiourea are reacted and synthesized to obtain 2-aminothiazole. This method has severe reaction, many by-products, low yield and purity, and poor color. Recrystallization is required, and the other is One is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D277/40B01J23/04B01J21/02
CPCC07D277/40B01J21/02B01J23/04Y02P20/584
Inventor 张小春吴正旭陈伟健翁行尚杨宗美赵鹏庄学文
Owner INST OF CHEM ENG GUANGDONG ACAD OF SCI
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