Geminal Systems 64.* N-Alkoxy-N-Chloroureas And N,N-Dialkoxyureas

Molecular and crystal structures of N-alkoxy-N-chloroureas and N,N-dialkoxyureas were studied together with those of N-alkoxyureas as reference compounds. N-Alkoxy-N-chloroureas were found to have an elongated N-Cl bond and a shortened N-O(Alk) bond due to the n(O(Alk))->sigma*(N-Cl) anomeric effect. Alcoholysis of N-alkoxy-N-chloro derivatives of urea, N'-arylureas, and carbamates in the presence of silver trifluoroacetate leads to sterically hindered N,N-dialkoxyureas, N,N-dialkoxy-N'-arylureas, and N,N-dialkoxycarbamates, respectively.