Novel 2- and 5-azido-N-(diphenylcarbamoyl)proline methyl esters. Examples of a novel proline oxidation.

The crystal structures of two azido-substituted proline derivatives are reported. Racemic 2-azido-1-(diphenyl-carbamoyl)proline methyl ester, (I), C19H19N5O3, is resolved upon crystallization from methylene chloride-diethyl ether. The azido moieties are nonlinear with N--N--N angles of 173 (1) and 170.3 (2) degrees for (I) and (II) [cis-5-azido-N-(diphenylcarbamoyl)proline methyl ester, C19H19N5O3], respectively. Close intramolecular contacts between the carbonyl O atom of the amide and the central N atom of the azido group are found. The contact distances between N7 and O14 are 2.780 (14) and 2.815 (2) A for (I) and (II), respectively.