Preparation method of 3-bromomethyl-2-halogeno-4-alkylsulfonylbenzoate

Abstract

The invention relates to the field of compound preparation and discloses a preparation method of 3-bromomethyl-2-halogeno-4-alkylsulfonylbenzoate. The preparation method comprises that a substrate compound and a bromate undergo a contact reaction in the presence of a reducing agent and an initiator. The method utilizes the bromate as a brominating agent and under action of a reducing agent, a desired product is obtained. The bromate and the reducing agent have low prices. The preparation method has the advantages of low cost and high yield and is suitable for large scale industrial production.

Description

technical field

[0001] The invention relates to the field of compound preparation, in particular to a preparation method of 3-bromomethyl-2-halo-4-alkylsulfonylbenzoate. Background technique

[0002] 3-Bromomethyl-2-halo-4-alkylsulfonyl benzoate is an intermediate for the preparation of the pesticide herbicide tembotrione.

[0003] WO2000021924A1 discloses a preparation method of 3-bromomethyl-2-chloro-4-methylsulfonylbenzoic acid methyl ester, the method is to use 3-methyl-2-chloro-4-methylsulfonylbenzoic acid Reaction of methyl ester with brominating agent NBS (N-bromosuccinimide) gives methyl 3-bromomethyl-2-chloro-4-methylsulfonylbenzoate. In addition, CN02817704.5 discloses a preparation method of 3-bromomethyl-2-chloro-4-methylsulfonylbenzoic acid, which uses the compound 3-methyl-2-chloro-4-methylsulfonate Acylbenzoic acid reacts with brominating agent NBS to give 3-bromomethyl-2-chloro-4-methylsulfonylbenzoic acid. In these bromination methods, although the yield ...

Examples

preparation example Construction

[0012] The present invention provides a kind of preparation method of 3-bromomethyl-2-halo-4-alkylsulfonyl benzoate shown in formula (1), wherein, the method comprises: in reducing agent and initiator Under the presence of, the compound shown in formula (2) is contacted with the compound shown in formula (3);

[0013]

[0014] In formula (2), R 1 for C 1 -C 7 The linear or branched hydrocarbon group, for example, can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl or n-hexyl. Preferably, R 1 for C 1 -C 3 The linear or branched chain hydrocarbon group, for example, can be methyl, ethyl or isopropyl.

[0015] In formula (2), R 3 is F, Cl or Br; preferably, R 3 is Cl or Br; more preferably, R 3 for Cl.

[0016] In formula (2), R 4 for C 1 -C 5 The alkyl group, for example, can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl or tert-pentyl; preferably land, R 4 for C 1 -C 3 The ...

Embodiment 1

[0048] This example is used to illustrate the preparation method of methyl 3-bromomethyl-2-chloro-4-methylsulfonylbenzoate.

[0049] Add 30g (0.112mol) methyl 2-chloro-3-methyl-4-methylsulfonylbenzoate and 120g chlorobenzene into a 500mL four-necked reaction flask; dissolve 25.6g (0.168mol) sodium bromate in In 100g of water, sodium bromate aqueous solution was obtained, and the obtained sodium bromate aqueous solution was added to a 500mL four-necked reaction flask; the temperature was raised to 85°C under stirring, and 0.93g (0.006mol) of azobisisobutyronitrile was added to a 500mL four-necked reaction flask In the reaction bottle; at 85°C, add 59g (0.224mol) of 40% sodium bisulfite aqueous solution dropwise while stirring, and the dropwise addition is completed in 3 hours; Stand to separate the layers, separate the water phase; add a small amount of sodium bisulfite aqueous solution to the organic phase to wash once, separate the water layer, recover the solvent from the or...

Embodiment 2

[0051] This example is used to illustrate the preparation method of ethyl 3-bromomethyl-2-chloro-4-methylsulfonylbenzoate.

[0052] Add 31.57g (0.112mol) ethyl 2-chloro-3-methyl-4-methylsulfonylbenzoate and 94.71g chlorobenzene into a 500mL four-necked reaction flask; add 17.07g (0.112mol) sodium bromate Dissolve in 39.83g of water to obtain aqueous sodium bromate solution, add the obtained aqueous sodium bromate solution into a 500mL four-necked reaction flask; heat up to 90°C while stirring, add 3.16g (0.019mol) of azobisisobutyronitrile into 500mL In a four-necked reaction flask; at 90°C, 70g (0.134mol) of 20% sodium bisulfite aqueous solution was added dropwise while stirring, and the addition was completed in 5 hours; Then stand still while hot and separate the water phase; add a small amount of sodium bisulfite aqueous solution to the organic phase to wash once, separate the water layer, recover the solvent from the organic phase under negative pressure, and recrystalliz...

technical field

[0001] The invention relates to the field of compound preparation, in particular to a preparation method of 3-bromomethyl-2-halo-4-alkylsulfonylbenzoate. Background technique

[0002] 3-Bromomethyl-2-halo-4-alkylsulfonyl benzoate is an intermediate for the preparation of the pesticide herbicide tembotrione.

[0003] WO2000021924A1 discloses a preparation method of 3-bromomethyl-2-chloro-4-methylsulfonylbenzoic acid methyl ester, the method is to use 3-methyl-2-chloro-4-methylsulfonylbenzoic acid Reaction of methyl ester with brominating agent NBS (N-bromosuccinimide) gives methyl 3-bromomethyl-2-chloro-4-methylsulfonylbenzoate. In addition, CN02817704.5 discloses a preparation method of 3-bromomethyl-2-chloro-4-methylsulfonylbenzoic acid, which uses the compound 3-methyl-2-chloro-4-methylsulfonate Acylbenzoic acid reacts with brominating agent NBS to give 3-bromomethyl-2-chloro-4-methylsulfonylbenzoic acid. In these bromination methods, although the yield ...

Examples

preparation example Construction

[0012] The present invention provides a kind of preparation method of 3-bromomethyl-2-halo-4-alkylsulfonyl benzoate shown in formula (1), wherein, the method comprises: in reducing agent and initiator Under the presence of, the compound shown in formula (2) is contacted with the compound shown in formula (3);

[0013]

[0014] In formula (2), R 1 for C 1 -C 7 The linear or branched hydrocarbon group, for example, can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl or n-hexyl. Preferably, R 1 for C 1 -C 3 The linear or branched chain hydrocarbon group, for example, can be methyl, ethyl or isopropyl.

[0015] In formula (2), R 3 is F, Cl or Br; preferably, R 3 is Cl or Br; more preferably, R 3 for Cl.

[0016] In formula (2), R 4 for C 1 -C 5 The alkyl group, for example, can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl or tert-pentyl; preferably land, R 4 for C 1 -C 3 The ...

Embodiment 1

[0048] This example is used to illustrate the preparation method of methyl 3-bromomethyl-2-chloro-4-methylsulfonylbenzoate.

[0049] Add 30g (0.112mol) methyl 2-chloro-3-methyl-4-methylsulfonylbenzoate and 120g chlorobenzene into a 500mL four-necked reaction flask; dissolve 25.6g (0.168mol) sodium bromate in In 100g of water, sodium bromate aqueous solution was obtained, and the obtained sodium bromate aqueous solution was added to a 500mL four-necked reaction flask; the temperature was raised to 85°C under stirring, and 0.93g (0.006mol) of azobisisobutyronitrile was added to a 500mL four-necked reaction flask In the reaction bottle; at 85°C, add 59g (0.224mol) of 40% sodium bisulfite aqueous solution dropwise while stirring, and the dropwise addition is completed in 3 hours; Stand to separate the layers, separate the water phase; add a small amount of sodium bisulfite aqueous solution to the organic phase to wash once, separate the water layer, recover the solvent from the or...

Embodiment 2

[0051] This example is used to illustrate the preparation method of ethyl 3-bromomethyl-2-chloro-4-methylsulfonylbenzoate.

[0052] Add 31.57g (0.112mol) ethyl 2-chloro-3-methyl-4-methylsulfonylbenzoate and 94.71g chlorobenzene into a 500mL four-necked reaction flask; add 17.07g (0.112mol) sodium bromate Dissolve in 39.83g of water to obtain aqueous sodium bromate solution, add the obtained aqueous sodium bromate solution into a 500mL four-necked reaction flask; heat up to 90°C while stirring, add 3.16g (0.019mol) of azobisisobutyronitrile into 500mL In a four-necked reaction flask; at 90°C, 70g (0.134mol) of 20% sodium bisulfite aqueous solution was added dropwise while stirring, and the addition was completed in 5 hours; Then stand still while hot and separate the water phase; add a small amount of sodium bisulfite aqueous solution to the organic phase to wash once, separate the water layer, recover the solvent from the organic phase under negative pressure, and recrystalliz...

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