Process for the manufacture of spiro-linked pyrrolidine-2,5-dione derivatives

摘要

This invention relates to novel processes for the manufacture of spiro- linked pyrrolidine-2,5-diones of formula; ##STR1## which have a potent inhibitory activity on aldose reductase and are useful for reduction and prevention of chronic diabetic complications.P PThe invented processes are useful as improved and convenient method for a large scale manufacture.