Method for manufacturing 3-(alkylsulfonyl)pyridine-2-carboxylic acid

A method for producing a compound represented by formula (7) or a salt thereof, comprising:

• a step of allowing a compound represented by formula (4):
• wherein X represents a halogen atom, and Y represents a halogen atom, to react with a compound represented by formula (5):
• R1SM1 (5)
• wherein R1 represents a C1-8 straight-chain alkyl group, and M1 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (1-S):
• wherein R1 and X are as defined above;
• a step of allowing the compound represented by formula (1-S) to react with a compound represented by formula (2):
• R2SM2 (2)
• wherein R2 represents a C1-8 straight-chain alkyl group, and M2 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (3-S):
• wherein R1, R2, and X are as defined above;
• a step of allowing the compound represented by formula (3-S) to react with hydrogen peroxide in the presence of a tungsten catalyst and an acid to give a compound represented by formula (6-S):
• wherein X and R2 are as defined above;
• and
• a step of reducing the compound represented by formula (6-S) or a salt thereof in the presence of a base and a heterogeneous transition metal catalyst to give a compound represented by formula (7) or a salt thereof:
• wherein R2 is as defined above.

A method for producing a compound represented by formula (6-S) or a salt thereof, comprising:

• a step of allowing a compound represented by formula (1-S):
• wherein R1 represents a C1-8 straight-chain alkyl group, and X represents a halogen atom,
• to react with a compound represented by formula (2):
• R2SM2 (2)
• wherein R2 represents a C1-8 straight-chain alkyl group, and M2 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (3-S):
• wherein R1, R2, and X are as defined above;
• and
• a step of allowing the compound represented by formula (3-S) to react with hydrogen peroxide in the presence of a tungsten catalyst and an acid to give a compound represented by formula (6-S) or a salt thereof:
• wherein X and R2 are as defined above.

A method for producing a compound represented by formula (6-S) or a salt thereof, comprising:

• a step of allowing a compound represented by formula (4):
• wherein X represents a halogen atom, and Y represents a halogen atom, to react with a compound represented by formula (5):
• R1SM1 (5)
• wherein R1 represents a C1-8 straight-chain alkyl group, and M1 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (1-S):
• wherein R1 and X are as defined above;
• a step of allowing the compound represented by formula (1-S) to react with a compound represented by formula (2):
• R2SM2 (2)
• wherein R2 represents a C1-8 straight-chain alkyl group, and M2 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (3-S):
• wherein R1, R2, and X are as defined above;
• and
• a step of allowing the compound represented by formula (3-S) to react with hydrogen peroxide in the presence of a tungsten catalyst and an acid to give a compound represented by formula (6-S):
• wherein X and R2 are as defined above.

A method for producing a compound represented by formula (3-S), comprising allowing a compound represented by formula (1-S):

• wherein R1 represents a C1-8 straight-chain alkyl group, and X represents a halogen atom,
• to react with a compound represented by formula (2):
• R2SM2 (2)
• wherein R2 represents a C1-8 straight-chain alkyl group, and M2 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (3-S):
• wherein R1, R2, and X are as defined above.

A method for producing a compound represented by formula (3-S), comprising:

• a step of allowing a compound represented by formula (4):
• wherein X represents a halogen atom, and Y represents a halogen atom,
• to react with a compound represented by formula (5):
• R1SM1 (5)
• wherein R1 represents a C1-8 straight-chain alkyl group, and M1 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (1-S):
• wherein R1 and X are as defined above;
• and
• a step of allowing the compound represented by formula (1-S) to react with a compound represented by formula (2):
• R2SM2 (2)
• wherein R2 represents a C1-8 straight-chain alkyl group, and M2 represents a hydrogen atom or an alkali metal,
• to give a compound represented by formula (3-S):
• wherein R1, R2, and X are as defined above.