Heterosubstituted acetylenes XXVII: Synthesis of 4-amino-2-pyridones by the reaction of ynamines with styrylisocyanates

Abstract

Styrylisocyanates add to ynamines to give 4-amino-2 (1H) pyridones (III) by a 1,4-cycloaddition. Under the reaction conditions the 1:-adducts (III) are further N-acylated with a second mole of syrylisocyamate to urea derivatives (IV). These decompose upon heating into the parent compounds. N-, and O-methylation of III as well as IR, UV and NMR spectra confirm the proposed structures of the 1:1-and 1:2-adducts III and IV.