2,5,5-Trimethyl-2-oxazolin-4-one,its perchlorate,and α-acetoxyisobutyronitrile by acetylation of acetone cyanohydrin

Acetone cyanohydrin (1) yields on acylation and ring closure with anhydrides and perchloric acid. 2-oxazolin-4-onium perchlorates 5a, 5c or 5d. The same perchlorates (5a, 5b) may be obtained under similar conditions from acyloxy-nitriles (2) or -amides (4). Perchlorates 5 may be deprotonated in pyridine to 2-oxazolin-4-ones (6), but in aqueous solution they undergo ring opening to acyloxy-amides 4a.c.d. or to N-benzoyl-α-hydroxy-isobutyramide 7b.