Molecular arrangements in sphingolipids. Crystal structure of N-tetracosanoylphytosphingosine

Tetracosanoylphytosphingosine, which has been studied as a ceramide model compound, is triclinic (P1) with a = 6" 181, b = 4"929, c = 37.278A, ct = 90-96, fl = 91"30, 7, = 105"51 °. The two hydrocarbon chains point in opposite directions from the polar groups. The molecules cannot pack laterally when fully extended due to the space requirements of the polar groups. The chains form an angle of 101 °, thereby accommodating the polar groups in the apices of the V-shaped molecules. The molecules are linked together by one intraand three intermolecular hydrogen bonds. The chain packing is of the common triclinic type (TIP)