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A hydrogen bonded dimer having an unprecedented 16-membered ring is identified during the study of several different types of (2-cyanoethyl)urea derivatives. The process of hydrogen bonding is essential for the production of structured assemblies of molecules. Hydrogen bonded-dimes are always made up of minimum of cyclic eight arrays of atoms.

A better procedure in the generation of enantiomerically pure amino acid ester isocyanates is presented. The new method no longer calls for the use of gaseous phosgene, high temperature conditions and very high hydronium ion concentrations. A solution of phosgene in toluene replaces gaseous toluene and removes the hydrogen chloride in solution. The isocyanate derived from amino acid ester hydrochloride and pyridine precursors is purified by aqueous extraction at freezing point followed by Kugelrohr distillation.

Intramolecular hydrogen bonding plays a key role in the conformation of oligoureas. The urea derivatives are obtained by an iterative process that involves the conjugate addition of a primary amine to acrylonitrile, followed by reaction with an isocyanate then by reduction of the nitrile group to form a primary amine. Spectroscopic studies reveal significant intramolecular hydrogen bonding of the NH group with the carbonyl oxygen. Moreover, N-alkyl and aryl substituents exert a strong influence on the orientation of the carbonyl groups. This conformational control makes oligoureas potentially useful as molecular scaffoldings or oligoamine backbones.

The synthesis of a two-stranded parallel beta-sheet, in which the dipeptide strands are attached to a a diurea molecular scaffold, is described. The synthesis involves the sequential treatment of diamine with peptide isocyanates, followed by aminolysis of the methyl ester groups with methylamine. Nuclear Overhauser effect and chemical shift studies showed that the artificial beta-sheets adopt a parallel conformation in chloroform solution.