Hydrogen bonds and preferred conformation of optically active amides

Preferred conformations and hydrogen bonds of [R]-N-benzylmandelamide 1, [S ]-N-(alpha -phenylglycinyl)acetamide 2, [S]-N-(alpha -phenylgiycinyl)tosyla mide 3, N-(N ' -benzyl-alpha -phenylglycinyl)acetamide 4, [S]-N-(N ' -benzy l-alpha -phenylglycinyl)tosylamide 5 and [N-(beta -benzoylpropyl)-N,N ' -di cyclohexyl]urea 6 are reported. The preferred conformation of 1-6 and hydro gen bonds were determined in solution by NMR and in the solid state by the X-ray diffraction analyses of 1-3, 5 and 6, and confirmed by ab-initio mole cular calculations [6-31G(d)]. (C) 2001 Elsevier Science B.V. All rights re served.