Unsubstituted N-arylcarbamate of title compound does not cyclize to the corresponding cyclic urea, with ROH liberation, under mild conditions (40° C). Substitution of the benzylic position by two methyl groups promotes slow cyclisation while N-methylation of the N-aryl carbamate has a more important effect. Relative cyclisation rates are in agreement with barrier heights obtained from ab initio calculations. The calculations also suggest that the ...
