title: (S)-Methyl 2-{(S)-2-[bis-(4-meth-oxy-phen-yl)methyl-idene-amino]-3-hy-droxy-propanamido}-3-methyl-butano-ate.
abstract: The title compound, C(24)H(30)N(2)O(6), a Schiff base, adopts an extended conformation in which the meth-oxy groups are essentially coplanar with the aromatic ring to which they are bonded (mean planes fitted through the non-H atoms of each methoxyphenyl group have r.m.s. deviations of 0.078 and 0.044 Å) and the angle between mean planes fitted through the aromatic rings is 87.57 (10)°. An intra-molecular N-H⋯N hydrogen bond keeps the imine and amide groups essentially coplanar. A mean plane fitted through these groups has an r.m.s. deviation of 0.0545 Å. Additional O-H⋯O hydrogen bonding parallel with the a axis links the mol-ecules into a hydrogen-bonded chain in the crystal. C-H⋯O and C-H⋯π inter-actions are found within the crystal packing. The compound has been assigned the S,S configuration on the basis of the chemical synthesis, which used pure homotopic l-amino acids, and we have no reason to believe that the compound has epimerized.
authors.affiliation: Department of Chemistry & Biochemistry, The University of Arizona, 1306 E University Boulevard, Tucson, AZ 85721, USA.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Keyari
authors.forename: Robin
authors.initials: R
authors.lastname: Polt
authors.forename: Gary S
authors.initials: GS
authors.lastname: Nichol