Reactions of N-phenylaminoiminomethanesulfonic acid (PAIMSO), a stable trioxide of N-phenylthiourea, with Meldrum's acid, a cyclic diester, were carried out under various conditions. The desired product should be N-phenylamidino acetic acid which could cyclize to give a B-lactam. The reactions were carried out in aqueous solution as well as in different organic solvents. In aqueous solution, the main product was N-phenylurea, obtained through a nucleophilic displacement reaction between water and PAIMSO. In pyridine, two or three equivalents of PAIMSO may undergo condensation. No traces of an addition product were observed. This was also true for the reactions carried out in organic solvents under acidic conditions.



Included in

Chemistry Commons