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

The reaction of N-(mesyloxy)phthalimides with secondary amines was examined . Transformations are accomplished by one-pot reactions to optionally affor d corresponding 2-ureidobenzamides, 2-ureidobenzoic acids, ethyl 2-ureidobe nzoates, or isatoic anhydrides, respectively. The mechanism of the acid-cat alyzed hydrolysis (or alcoholysis) of intermediate 2-ureidobenzamides to 2- ureidobenzoic acids (or esters) is discussed. A proton transfer mechanism i nvolving the ureido moiety as an internal acid catalyst is proposed. Interm ediate 2-ureidobenzoic acids undergo a further transformation to isatoic an hydrides. The utilization of the obtained 2-ureidobenzamides, 2-ureidobenzo ic acids, and ethyl 2-ureidobenzoates to prepare 3,1-benzoxazin-4-ones is d emonstrated.