| abstract |
The present invention provides an industrially advantageous, simple, and efficient process for producing a key intermediate of a benzo[b][1,4]diazepine-2,4-dione compound, which is a therapeutic medicine for arrhythmia. n The present invention relates to a process for producing a compound represented by formula (1),n nwherein each of R 1 , R 2 , R 3 and R 4 , which may be the same or different, represents a hydrogen atom or a lower alkyl group, the process including deprotecting a protective group (R 5 ) of a compound represented by formula (2),n nwherein R 1 , R 2 , R 3 and R 4 are as defined above, and R 5 represents a protective group of a hydroxy group. |