One-pot reactions of N-(mesyloxy)phthalimides with secondary amines to 2-ureidobenzamides, 2-ureidobenzoic acids, ethyl 2-ureidobenzoates, or isatoic anhydrides

The reaction of N-(mesyloxy)phthalimides with secondary amines was studied. Transformations were performed by one-reactions to optionally provide corresponding 2-ureidobenzamides, 2-ureidobenzoic acids, ethyl 2-ureidobenzoates, or isatoic anhydrides, respectively. A proton transfer mechanism involving the ureido moiety as an internal acid catalyst is suggested. Intermediate 2-ureidobenzoic acids underwent a further transformation to isatoic anhydrides.