STRUCTURES OF 2 MALONAMIDE DERIVATIVES AS MODELS OF NYLONS N,3 AND OFPEPTIDOMIMETIC COMPOUNDS

We have synthesized and analyzed by X-ray diffraction two malonamide d erivatives of the type RNHCOCH2CONHR', with R = R' = phenyl or propyl. We have compared their structure with other known compounds of the sa me family. In all cases the planes of the peptide groups are approxima tely perpendicular, as a result of the fact that the two psi torsion a ngles about the carbonyl-methylene bonds are in the range 100-150-degr ees. An intramolecular hydrogen bond is never found. Due to this confo rmation, a network of hydrogen bonds oriented in two directions in spa ce is formed, a situation also found in n,3 nylons. The propyl derivat ive is thus an excellent model for these types of nylons. These result s also allow a better understanding of malonamide conformation in pept idomimetic compounds.