Synthesis and Properties of N,N′-Disubstituted Ureas and Their Isosteric Analogs Containing Polycyclic Fragments: XIV. N-[(Adamantan-1-yl)(phenyl)methyl]-N′-substituted Ureas and Symmetrical Bis-ureas

A procedure has been developed for the synthesis of rac-1-[isocyanato(phenyl)methyl]adamantane from rac-2-(adamantan-1-yl)-2-phenylacetic acid in 95% yield. The reactions of rac-1-[isocyanato(phenyl)methyl]adamantane with aliphatic diamines and trans-4-[(4-aminocyclohexyl)oxy]benzoic acid afforded a series of N,N′-disubstituted ureas in 60–91% yields, and its hydrolysis in the presence of a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene gave 94% of symmetrical N,N′-bis[(adamantan-1-yl)(phenyl)methyl]urea. The structure of rac-2-(adamantan-1-yl)-2-phenylacetic acid was confirmed by X-ray analysis of its single crystal.