Abstract.M r = 262.3, orthorhombic, P21212~, Z = 8, a = 9.256(2), b = 10.154(2), c --27.420 (8)A, D c = 1.352 Mg m -3. R w = 0.039 for 1546 reflections with I > 2.5a(I), out of 3190 independent measurements. The benzyl group is a (pseudo-)axial substituent on the diketopiperazine ring and is folded above this ring in such a way that the overall distance is equal to the sum of the van der Waals values. The piperazine ring has a boat-like form. The molecules in the crystal occur as dimers formed through two hydrogen bridges. The geometry of the compound, also called cyclol-D-Phe-L-(yS) Pro-], is compared to cyclo (-D-Phe-L-Pro-).

No abstract

The piperidine ring in the title compound is in the chair conformation, whereas the diketopiperazine ring has a boat form. The benzyl group is axially positioned and folded above the diketopiperazine ring. No dimerisation is observed.

Der Piperidinring der Titelverbindung (I) liegt in der Sesselform, der Diketopiperazinring in der Bootform vor.