Acylketen‐S,S‐ und Acylketen‐S,N‐acetale als Bausteine für Heterocyclen: 5‐Cyanopyrimidine

Acylketene S,S‐ and Acylketene S,N‐acetals as Buildingsets for Heterocycles: 5‐Cyanopyrimidines Acylketene S,S‐acetals 1 react with amidines, guanidine or S‐alkylisothioureas in the presence of triethylamine to give 4‐methylthio‐5‐cyanopyrimidines 4–6. 4‐Anilino‐5‐cyanopyrimidines 7 have been synthesized from the acylketene‐S,N‐acetals 2 under similiar conditions. The treatment of 1 with guanidine and acetamidine, respectively, in alcoholic sodium ethoxide solution yields 4‐ethoxy‐5‐cyanopyrimidines 10. The i.r.‐ and 1H‐n.m.r.‐spectra of the synthesized compounds are discussed.