Process for Producing Chromone Compound

摘要

A process for producing a nitrochromone compound represented by the formula (5):
wherein R 10 is as defined below; which comprises reacting a dicarboxylic acid compound represented by formula (4'):
wherein R 10 and R 20 are the same or different and independently represent a hydrogen atom or a C 1-6 alkyl group and the wavy line indicates that this compound is the E- or Z-isomer or a mixture of them, with chlorosulfonic acid.