Microwave-Assisted Hydantoin Synthesis

Significance

A microwave-assisted solid-phase synthesis of hydantoin starting from various pre-loaded resins with N-protected amino acid has been developed. The resin-supported amino acids 2, which were prepared via suitable N-deprotection of the anchored amino acid of commercially available preloaded resin 1, reacted with an isocyanate in THF in a microwave reactor to give the corresponding polymer-supported ureas 3. Treatment of the intermediates 3 with Et₃N under microwave irradiation leads to nucleophilic attack on the ester allowing the ring-closing cleavage of the corresponding hydantoin products 4.