An environment-friendly Beckmann rearrangement: the diazotisation of ketoxime carbamates

The titled reaction was effected with iso-amyl nitrite or sodium nitrite, both in conc. H2SO4 at 0–25°C in excellent yields (55–98%). Apart from the mild temperatures employed, organic solvents and reagents can be avoided, and the by-products are CO2 and N2, so the conditions are environment-friendly.