Formation of dihydrouracils via cyclization of N-substituted 3-thioureidopropanoic acids and facile desulfurization
Cyclization of N-3 substituted 3-thioureidopropanoic acids in isobutyric anhydride at high temperature resulted in the unexpected formation of N-3,N-1-substituted dihydrouracils, as confirmed by thorough spectroscopic characterization. A mechanism based on the identification of intermediates observed at lower reaction temperatures is proposed.
Delpiccolo, Carina M.L.,Albericio, Fernando,Schiksnis, Robert A.,Michelotti, Enrique L.