Method for producing 5-hydroxypiperidine-2-carboxylic acid

A method for producing the compound represented by the formula (8), the method comprising (i) the step 4 of:

• removing the ether protecting group from the hydroxyl group in the compound represented by the formula (7) below:
• wherein P represents an ether protecting group that is resistant to basic reaction conditions, R3 represents an alkyl group containing 1 to 4 carbon atoms, and A represents an alkyl group containing 1 to 10 carbon atoms, an aryl group containing 6 to 12 carbon atoms, an alkyloxy group containing 1 to 4 carbon atoms, or an aralkyloxy group containing 7 to 20 carbon atoms to synthesize the compound represented by the formula (8) below:
• wherein R3 represents an alkyl group containing 1 to 4 carbon atoms, and A represents an alkyl group containing 1 to 10 carbon atoms, an aryl group containing 6 to 12 carbon atoms, an alkyloxy group containing 1 to 4 carbon atoms, or an aralkyloxy group containing 7 to 20 carbon atoms.

A compound or a salt thereof, the compound represented by the formula (11a) below:

• wherein A′ represents an alkyl group containing 1 to 10 carbon atoms or an aryl group containing 6 to 12 carbon atoms
• or the formula (11b) below:
• wherein A′ represents an alkyl group containing 1 to 10 carbon atoms or an aryl group containing 6 to 12 carbon atoms.

A compound represented by the formula (8) below or a dicarboxylic acid salt thereof:

• wherein R3 represents an alkyl group containing 1 to 4 carbon atoms, and A represents an alkyl group containing 1 to 10 carbon atoms, an aryl group containing 6 to 12 carbon atoms, an alkyloxy group containing 1 to 4 carbon atoms, or an aralkyloxy group containing 7 to 20 carbon atoms,
• or a compound represented by the formula (7) below:
• wherein P represents an ether protecting group that is resistant to basic reaction conditions, R3 represents an alkyl group containing 1 to 4 carbon atoms, and A represents an alkyl group containing 1 to 10 carbon atoms, an aryl group containing 6 to 12 carbon atoms, an alkyloxy group containing 1 to 4 carbon atoms, or an aralkyloxy group containing 7 to 20 carbon atoms.