PROCESS FOR PRODUCING 1-SUBSTITUTED-2-PYRIDONE-3-CARBOXYLIC ACID DERIVATIVE

摘要

Disclosed are: a process for producing a 1-substituted-2-pyridone-3-carboxylic acid derivative which is an important intermediate for the production of a 2-pyridone-3-carbamoyl derivative that has a cannabinoid receptor agonist activity in a simple manner; and a process for producing the 2-pyridone-3-carbamoyl derivative in a simple manner. Specifically disclosed is a process for producing a compound represented by the general formula (II), which comprises: a step A for hydrolyzing a compound represented by the general formula (I); and a step (B) for adding an alcohol to the hydrolysate of the compound represented by the general formula (I) produced in the step A to produce a crystal of the compound represented by the general formula (II). (I) wherein R<SUP>1</SUP> represents an alkyl which may be substituted by a non-reactive substituent, or the like; R<SUP>2</SUP> and R<SUP>3</SUP> independently represent an alkyl or the like, or R<SUP>2</SUP> and R<SUP>3</SUP>, together with a carbon atom adjacent to R<SUP>2</SUP> and R<SUP>3</SUP>, may form a cycloalkene; R<SUP>4</SUP> represents a hydrogen atom or the like; and R<SUP>5</SUP> represents an alkyl. (II) wherein R<SUP>1</SUP>, R<SUP>2</SUP>, R<SUP>3</SUP> and R<SUP>4</SUP> are as defined above.