Phenylcarbamoylation of N-Acetyl-1,2,4-triazolium-4-aminides Revisited

The reaction of N-acetyl-1,2,4-triazolium-4-aminides (I, i.e. 1Aa-d) with phenyl isocyanate affords ring functionalized products (4a-d) rather than linear adducts (II).Analogous compounds are obtained from the triazolium-1aminide (1Ae) and the imidazolium congener (1Af).Twofold carbamoylation to give products of type (8) occurs on reaction of aminotriazolium salts (7A) in the presence of base.Azoliums having methyl at C(5) / (2) are inert throughout (B series).