A process for the preparation of derivatives of cyclobutene-3,4-dione

摘要

Cyclobuten-3,4-dione derivs. of formula (I), in which X and R1 can be various gps., y is 0-2, b and d are 0 or 1, e is 2-4 and c is 1-b, 2-b or 3-b, are made by reaction of a cpd. of formula (II) with 1,2-dimethoxy cyclobuten-3,4-dione by conventional methods, followed by reaction of the prod. with gaseous ammonia. The prod. is sepd. by filtration and purified by recrystallisation.