Amine‐induced lossen rearrangements of 3‐hydroxy‐5,6‐dihydrouracil and N ‐hydroxysuccinimide benzenesulfontes

The reaction of sodium succinohydroxamate with benzenesulfonyl chloride yielded 3‐benzene‐sulfonyloxy‐5,6‐dihydrouracil, 3 . Treatment of 3 with ammonia, aniline, t ‐butylamine or piperidine yielded a mixture of the requisite 1,2‐bis(ureido)ethane and 1‐curboxamido‐2‐imidazolidone. Acylation of N ‐hydroxysuccinimide with benzenesulfonyl chloride furnished N ‐benzenesulfonyl‐oxysuccinimide, 10. Aniline or t ‐butylamine were used as representative amines to demonstrate their capability of inducing a Lossen degradation on 10 to afford the corresponding β‐ ureido ‐propionamide.