Metribuzin synthesis method

Abstract

The invention provides a novel metribuzin synthesis method which comprises the following steps: (1) adding 6-tert-butyl-4-amino-3-sulfydryl-1, 2, 4-triazine-5 (4H)-ketone into a certain amount of sulfuric acid in batches, and heating until the 6-tert-butyl-4-amino-3-sulfydryl-1, 2, 4-triazine-5 (4H)-ketone is completely dissolved and clarified; 2) cooling to a certain feeding temperature, adding acertain amount of methanol, controlling the temperature to a certain temperature, carrying out a heat preservation reaction for a period of time, and cooling the reaction material to a certain temperature for post-treatment; 3) dropwise adding a certain amount of water into the reaction material, and separating out a large amount of material, namely metribuzin sulfate; and 4) suspending the precipitated metribuzin sulfate in a certain amount of solvent, then adding alkali for neutralization, standing for layering, slowly cooling an organic phase for crystallization, and filtering to obtain high-purity metribuzin. The method is smooth in process, mild in condition and environmentally friendly, metribuzin with the purity of 98% or above can be directly obtained, and the yield can reach 85%or above.

Description

technical field

[0001] The present invention relates to the field of organic synthesis. Specifically, the present invention relates to a highly efficient method for synthesizing metrizone. Background technique

[0002] Mecitrione (6-tert-butyl-4-amino-3-mercapto-1,2,4-triazin-5(4H)-one) is a selective herbicide with high efficiency and low toxicity developed by German Bayer company , can be used in upland crops such as soybean and corn. At present, there are few reports on the synthesis process of metrizone with high content. Most of the studies on the synthesis process focus on methylating reagents. For example, CN1071181169 reports using methylating reagents such as methyl bromide and methyl iodide to synthesize metrizone. However, such methylating reagents are highly toxic, unsafe and environmentally friendly, and the country has explicitly restricted their use. CN103333129 reports the use of dimethyl sulfate as a methylating agent. However, dimethyl sulfate is also...

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