Process for Preparing Tetrahydropyran-4-Carboxylic Acid Compound

A process for preparing a tetrahydropyran-4-carboxylic acid ester represented by the formula (4):

• wherein R1 represents a hydrocarbon group,
• which comprises reacting tetrahydropyran-4-carboxylic acid represented by the formula (1):
• with an alcohol represented by the formula (3):
• R1OH (3)
• wherein R1 has the same meaning as defined above, in the presence of an acid.

A process for preparing a tetrahydropyran-4-carboxylic acid amide compound represented by the formula (6):

• wherein R2 and R3 each represent a hydrogen atom, a hydrocarbon group, an alkoxyl group, an aryloxyl group or an amino group;
• provided that the case where both of R2 and R3 are amino groups is excluded;
• incidentally, R2 and R3 may form a ring by binding to each other, and the ring may contain at least one hetero atom selected from an oxygen atom, a nitrogen atom and a sulfur atom,
• which comprises reacting a tetrahydropyran-4-carboxylic acid halide represented by the formula (5):
• wherein X has the same meaning as defined above, with an amine compound represented by the formula (7):
• R2R3NH (7)
• wherein R2 and R3 has the same meaning as defined above.