- Preparation method of triazolopyrimidine herbicide
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The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of a triazolopyrimidine herbicide. The preparation method specifically comprises thefollowing steps: a) reacting a compound with the structure represented by formula (I) with thiosemicarbazide, and then isomerizing under an alkaline condition to obtain a compound with the structurerepresented by formula (II); b) carrying out a diazotization reaction on the compound of the formula (II) and sodium nitrite, and then mixing and reacting with sodium hydrogen sulfite and chloride toobtain a compound with the structure represented by formula (III), wherein the chloride comprises copper chloride and/or cuprous chloride; and c) reacting the compound of the formula (III) with a compound with the structure represented by formula (IV) to obtain the triazolopyrimidine herbicide with the structure represented by formula (V). The preparation method provided by the invention has the advantages of mild reaction conditions, low safety risk and good environmental friendliness.
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- Method for preparing florasulam
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The invention discloses a method for preparing florasulam. The florasulam is obtained through a condensation reaction of 2-chlorosulfonyl-8-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine and 2,6-difluoroaniline, wherein the temperature of the condensation reaction is 10-50 DEG C; a molar ratio of the 2, 6-difluoroaniline to the 2-chlorosulfonyl-8-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidineis (1: 1) to (1.2: 1); the condensation reaction is carried out in the presence of dimethyl sulfide, N-chlorosuccinimide and 3-methylpyridine; and a molar ratio of the 2, 6-difluoroaniline to the dimethyl sulfide and a molar ratio of the 2, 6-difluoroaniline to the N-chlorosuccinimide are both (1: 0.3) to (1: 0.7). According to the method disclosed by the invention, a certain amount of the dimethyl sulfide and the N-chlorosuccinimide are adopted and participate in the reaction, so high reaction yield and high product purity can be obtained, production cost is low, reproducibility is good, andthe method is applicable to industrial production.
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Paragraph 0019-0032
(2019/12/25)
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- METHOD OF PREPARATION OF FLORASULAM
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The present disclosure concerns a method for preparing florasulam which involves treating a solution of 2,6-difluoroaniline in 1,2-propylene glycol with: a) sulfonyl chloride III and then b) a base to provide, after workup and isolation, florasulam (I) in yields of about 65-85%. The treatment of 2,6-difluoroaniline with sulfonyl chloride III and the base are conducted by controlled additions.
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Paragraph 0034
(2019/04/25)
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- PREPARATION OF N-ARYLARYLSULFONAMIDE COMPOUNDS
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N-(substituted aryl)[1,2,4]triazoloazinesulfonamide compounds, such as N-(2,6-difluorophenyl)-8-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide, were prepared at a good reaction rate and in good yield by the reaction of a chlorosulfonyl[1,2,4]triazoloazine compound, such as 2-chlorosulfonyl-8-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine, and an arylamine compound, such as 2,6-difluoroaniline, in an organic medium containing a relatively acidic alcohol, such as propylene glycol or 2,2,2-trifluoroethanol.
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Page/Page column 6
(2008/06/13)
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- Preparation of n-arylarylsulfonamide compounds
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N-(substituted aryl)?1,2,4!triazoloazinesulfonamide compounds, such as N-(2,6-difluorophenyl)-8-fluoro-5-methoxy?1,2,4!triazolo?1,5-c!pyrimidine-2-sulfonamide, were prepared at a good reaction rate and in good yield by the reaction of a chlorosulfonyl?1,2,4!triazoloazine compound, such as 2-chlorosulfonyl-8-fluoro-5-methoxy?1,2,4!triazolo?1,5-c!pyrimidine, and an arylamine compound, such as 2,6-difluoroaniline, in an organic medium containing a relatively acidic alcohol, such as propylene glycol or 2,2,2-trifluoroethanol.
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- Herbicidal compositions with increased crop safety
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Disclosed are herbicidal concentrate formulation compositions having reduced grass crop plant phytotoxicity comprising certain sulfonamide or sulfonylurea herbicides in admixture with a non-herbicidal organic or inorganic acid or mixture thereof in an amount sufficient to insure that during the post-emergent agricultural uses thereof in water diluted form the pH of the mixture is below about 5; also disclosed is the preparation of said compositions, aqueous formulations of said concentrate and the use of said formulations.
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- Herbicidal heterocyclic sulfonylurea compositions safened by herbicidal acids such as 2,4-D below a pH of 5
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Disclosed are herbicidal concentrate formulation compositions having reduced grass crop plant phytotoxicity comprising certain sulfonamide or sulfonylurea herbicides in admixture with a herbicidal organic acid from the group consisting of clopyralid, 2,4-D, 2,4-DP, dicamba, dichlorprop-P, fluroxypyr MCPA, MCPP, mecoprop-P, picloram, triclopyr or mixtures of said acids; also disclosed is the preparation of said compositions and the pre- and post-emergent agricultural uses thereof in water diluted form.
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