Manufacturing Process
1,3-Dioxo-1H-benz[de]isoquinoline-2(3H)-acetic acid:
1,8-Naphthalic acid anhydride (110 g, 0.556 mole), glycine (48 g, 0.64 mole)
and dimethylformamide (750 ml) are heated and stirred at reflux for 2 hr. The
homogeneous dark solution is cooled to about 100°C and 750 ml of hot water
is added slowly to the stirred solution. The reaction mixture is cooled and
allowed to stand in a refrigerator for 16 hr. The precipitate is collected and
recrystallized from ethanol, using decolorizing charcoal, to give the title
compound, MP: 271°-272°C.
In practice it is usually used as sodium salt.