Synthesis method of thioketone

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a synthesis method of 8-fluoro-5-methoxy-2H-[1, 2, 4] triazolo [4, 3-c] pyrimidine-3-thioketone, which comprises the following steps: (1) dissolving 5-fluoro-4-hydrazino-2-methoxypyrimidine in a solvent for later use; (2) putting hydrogen peroxide into a storage tank for later use; (3) putting carbon disulfide out of the storage tank for later use; (4) at a certain temperature, respectively pumping the 5-fluoro-4-hydrazino-2-methoxypyrimidine solution and carbon disulfide into the micro-channel reactor I by using a diaphragm metering pump, and completing the reaction; (5) pumping hydrogen peroxide into the micro-channel reactor II by using a diaphragm metering pump, and completing the oxidation reaction; and (6) centrifuging the reaction material liquid through a centrifugal machine to obtain a 8-fluoro-5-methoxy-2H-[1, 2, 4] triazolo [4, 3-c] pyrimidine-3-thioketone solution. The method has the advantages of simple operation steps, low risk, high equipment utilization rate, complete reaction, high product stability and high yield.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, specifically a method for synthesizing 8-fluoro-5-methoxy-2H-[1,2,4]triazolo[4,3-c]pyrimidine-3-thione . Background technique [0002] Flosulam is a triazolopyrimidine sulfonamide herbicide developed by Dow Agricultural Sciences Company of the United States. Its mechanism of action is to inhibit the synthesis of acetolactate synthase, thereby preventing the synthesis of related amino acids. Plants cannot synthesize proteins and die . Flusulam is a broad-spectrum herbicide with high efficiency and low toxicity for controlling broad-leaved weeds in post-emergence stem and leaf treatment. [0003] 8-Fluoro-5-methoxy-2H-[1,2,4]triazolo[4,3-c]pyrimidine-3-thione is an important intermediate in the synthesis of florasulam, and its synthesis reaction It is an oxidation reaction of one of the 18 hazardous processes under key supervision. In the past, 8-fluoro-5-methoxy-2H-[1,2,4]triazolo[4,...

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Problems solved by technology

[0003] 8-Fluoro-5-methoxy-2H-[1,2,4]triazolo[4,3-c]pyrimidine-3-thione is an important intermediate in the synthesis of florasulam, and its synthesis reaction It is an oxidation reaction of one of the 18 hazardous processes under key supervision. In the past, 8-fluoro-5-methoxy-2H-[1,2,4]triazolo[4,3-c]pyrimidine-3-thione The synthesis usually uses a kettle reaction, which is dangerous, has low utilization rate of equipment, incomplete reaction, poor product stability, and low yield, so it is not suitable for industrial production.

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