Abstract: The present disclosure relates to a process for synthesis of mesotrione. The process comprises reacting 4-toluene sulfonyl chloride with alkali metal sulphite and alkali metal bicarbonate to obtain alkali metal toluene-4-sulfinate. The alkali metal toluene-4-sulfinate is reacted with alkali metal salt of monochloroacetic acid to obtain 4-methylsulfonyl toluene. Further, 4-methylsulfonyl toluene is nitrated to obtain 2-nitro-4-methylsulfonyl toluene. 2-nitro-4-methylsulfonyl toluene is oxidized and then halogenated to obtain 2-nitro-4-methylsulfonylbenzoyl halide. 2-nitro-4-methylsulfonylbenzoyl halide is reacted with alkali metal salt of 1,3-cyclohexanedione to obtain 3-(2-Nitro-4-methylsulfonylbenzoyloxy)cyclohexen-1-one which is reacted with base, a third fluid medium and cyanide ion source to obtain an amorphous mesotrione. The present disclosure also discloses the steps of converting the amorphous mesotrione to crystalline mesotrione having purity greater than 99%.

Abstract: The present disclosure relates to a process for synthesis of mesotrione. The process comprises reacting 4-toluene sulfonyl chloride with alkali metal sulphite and alkali metal bicarbonate to obtain alkali metal toluene-4-sulfinate. The alkali metal toluene-4-sulfinate is reacted with alkali metal salt of monochloroacetic acid to obtain 4-methylsulfonyl toluene. Further, 4-methylsulfonyl toluene is nitrated to obtain 2-nitro-4-methylsulfonyl toluene. 2-nitro-4-methylsulfonyl toluene is oxidized and then halogenated to obtain 2-nitro-4-methylsulfonylbenzoyl halide. 2-nitro-4-methylsulfonylbenzoyl halide is reacted with alkali metal salt of 1,3-cyclohexanedione to obtain 3-(2-Nitro-4-methylsulfonylbenzoyloxy)cyclohexen-1-one which is reacted with base, a third fluid medium and cyanide ion source to obtain an amorphous mesotrione. The present disclosure also discloses the steps of converting the amorphous mesotrione to crystalline mesotrione having purity greater than 99%.

Abstract: This invention relates to a process for the preparation of 5-amino-1-phenyl-3-cyano-4-trifluoromethyl sulphinyl pyrazoles as defined by Formula-I, wherein: R1=trifluoromethyl or trifluoromethoxy, and R2, R3=individually hydrogen, chlorine or bromine, the process comprising the step of oxidizing a compound of Formula-II, wherein: R1=trifluoromethyl or trifluoromethoxy, and R2, R3=individually hydrogen, chlorine or bromine, in a medium comprising at least one oxidizing agent and trichloro acetic acid, and/or the reactions product (s) of the at least one oxidizing agent and trichloro acetic acid, and at least one melting point depressant. The preferred pyrazole is Fipronil, preferably prepared using hydrogen peroxide and dichloro acetic acid at room temperature.

Abstract: This invention relates to a process for the preparation of 5-amino-1-phenyl-3-cyano-4-trifluoromethyl sulphinyl pyrazoles as defined by Formula-I, wherein: R1=trifluoromethyl or trifluoromethoxy, and R2, R3=individually hydrogen, chlorine or bromine, the process comprising the step of oxidizing a compound of Formula-II, wherein: R1=trifluoromethyl or trifluoromethoxy, and R2, R3=individually hydrogen, chlorine or bromine, in a medium comprising at least one oxidizing agent and trichloro acetic acid, and/or the reactions product (s) of the at least one oxidizing agent and trichloro acetic acid, and at least one melting point depressant. The preferred pyrazole is Fipronil, preferably prepared using hydrogen peroxide and dichloro acetic acid at room temperature.