Method for preparing 2-chlorine-5 chloromethyl thiazole

Abstract

The invention relates to a method for preparing 2-chlorine-5 chloromethyl thiazole. The method comprises the following steps of: preparing 2-chlorine-5 chloromethyl thiazole by taking 2,3-dichloropropene, sodium sulfocyanate, sulfuryl chloride sulfuryl chloride and the like as main raw materials and changing a reaction solvent, reaction temperature and the like; purifying the product. An experimental result indicates that the method in which 2-chlorine-5 chloromethyl thiazole with the purity of 99% is prepared from 2,3-dichloropropene and sodium sulfocyanate through a one-pot process sequentially including substitution reaction, isomerization reaction and chlorination-cyclization reaction by taking methylbenzene as a solvent has the advantages of simple operation, few side reactions and high efficiency.

Description

Technical field:

[0001] The invention relates to a preparation method of 2-chloro-5-chloromethylthiazole, which belongs to the technical field of chemical intermediates. Background technique:

[0002] In the latest research on chemical pesticides, heterocyclic compounds occupy a major position. More than 90% of pesticide patents are heterocyclic compounds. In particular, thiazole compounds represented by thiamethoxam and chlorothialine have become one of the hot spots in the development of new pesticides at home and abroad due to their low dosage, broad spectrum, high efficiency, and no cross-resistance with other insecticides. . 2-Chloro-5-chloromethylthiazole, referred to as CCMT, is a white or slightly yellow crystal. When the temperature is higher than 25 ° C, it is a colorless to light yellow liquid. It is a key intermediate for the synthesis of chlorinated thiazole pesticides. A new generation of neonicotinoid insecticidal compounds such as methoxam, clothianidin, A...

Examples

preparation example Construction

[0029] The invention provides the preparation method of 2-chloro-5-chloromethylthiazole, comprising the following steps:

[0030] (a) Sodium thiocyanate and 2,3-dichloropropene are mixed in a solvent to obtain 1-thiocyano-2-chloropropene (2).

[0031] (b) subjecting (2) obtained in (a) above to high-temperature isomerization to generate 1-isothiocyanato-2-chloropropene (3).

[0032] (c) The (3) obtained in the above (b) is mixed with sulfuryl chloride in a solvent to obtain the compound 2-chloro-5-chloromethylthiazole.

[0033] (d) Purifying and purifying the 2-chloro-5-chloromethylthiazole produced in (c) above.

[0034]

Embodiment 1

[0037] Step 1. Substitution-isomerization reaction

[0038] Add 100g of sodium thiocyanate (1.23mol), 2.5g of tetrabutylammonium bromide, and 200mL of toluene into a 500mL three-necked flask, and slowly add 108g (0.97mol) of 2,3-dichloropropene dropwise under stirring. . Connect the condenser tube, condense and reflux in an 80°C oil bath for 4 hours, then directly heat up to 120°C for 3 hours (experimental phenomenon: from the original yellow liquid and white solid to dark brown liquid, after high temperature isomerization, it turns into black opaque liquid). After the reaction was completed and cooled, the solvent toluene was evaporated on a rotary evaporator to obtain 117.5 g of a black opaque product. The product and distilled toluene were analyzed by gas chromatography (gas phase conditions: 55°C for 2min, rising to 250°C at a rate of 20°C per minute), the product purity was 93%, and the yield was 81.3%. The distilled toluene contained about 9% of the product.

[0039]...

Technical field:

[0001] The invention relates to a preparation method of 2-chloro-5-chloromethylthiazole, which belongs to the technical field of chemical intermediates. Background technique:

[0002] In the latest research on chemical pesticides, heterocyclic compounds occupy a major position. More than 90% of pesticide patents are heterocyclic compounds. In particular, thiazole compounds represented by thiamethoxam and chlorothialine have become one of the hot spots in the development of new pesticides at home and abroad due to their low dosage, broad spectrum, high efficiency, and no cross-resistance with other insecticides. . 2-Chloro-5-chloromethylthiazole, referred to as CCMT, is a white or slightly yellow crystal. When the temperature is higher than 25 ° C, it is a colorless to light yellow liquid. It is a key intermediate for the synthesis of chlorinated thiazole pesticides. A new generation of neonicotinoid insecticidal compounds such as methoxam, clothianidin, A...

Examples

preparation example Construction

[0029] The invention provides the preparation method of 2-chloro-5-chloromethylthiazole, comprising the following steps:

[0030] (a) Sodium thiocyanate and 2,3-dichloropropene are mixed in a solvent to obtain 1-thiocyano-2-chloropropene (2).

[0031] (b) subjecting (2) obtained in (a) above to high-temperature isomerization to generate 1-isothiocyanato-2-chloropropene (3).

[0032] (c) The (3) obtained in the above (b) is mixed with sulfuryl chloride in a solvent to obtain the compound 2-chloro-5-chloromethylthiazole.

[0033] (d) Purifying and purifying the 2-chloro-5-chloromethylthiazole produced in (c) above.

[0034]

Embodiment 1

[0037] Step 1. Substitution-isomerization reaction

[0038] Add 100g of sodium thiocyanate (1.23mol), 2.5g of tetrabutylammonium bromide, and 200mL of toluene into a 500mL three-necked flask, and slowly add 108g (0.97mol) of 2,3-dichloropropene dropwise under stirring. . Connect the condenser tube, condense and reflux in an 80°C oil bath for 4 hours, then directly heat up to 120°C for 3 hours (experimental phenomenon: from the original yellow liquid and white solid to dark brown liquid, after high temperature isomerization, it turns into black opaque liquid). After the reaction was completed and cooled, the solvent toluene was evaporated on a rotary evaporator to obtain 117.5 g of a black opaque product. The product and distilled toluene were analyzed by gas chromatography (gas phase conditions: 55°C for 2min, rising to 250°C at a rate of 20°C per minute), the product purity was 93%, and the yield was 81.3%. The distilled toluene contained about 9% of the product.

[0039]...

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