Acta Cryst. (2012). E68, o54-o55 [ doi:10.1107/S1600536811051543 ]
Abstract: The title peptide [systematic name: 4-(butan-2-yl)-7,20-bis(1-hydroxyethyl)-10,23-bis(propan-2-yl)-12,25-dithia-3,6,9,16,19,22,27,28-octaazatricyclo[18.104.22.168,14]octacosa-1(26),11(28),13,24(27)-tetraene-2,5,8,15,18,21-hexone acetonitrile monosolvate], C32H48N8O8S2·CH3CN, an analogue of ascidiacyclamide (ASC) [cyclo(-Ile-Oxz-D-Val-Thz-)2], lies about a twofold rotation axis, so that the glycine (Gly) and isoleucine (Ile) residues are each disordered over two sites with equal occupancies. The acetonitrile molecule is also located on a twofold axis passing through the C and N atoms. In the peptide, the thiazole rings are faced to each other with a dihedral angle of 9.63 (15)° and intramolecular N-HO and O-HO hydrogen bonds are observed. A bifurcated N-H(O,O) hydrogen bond links the peptide molecules into a layer parallel to the ab plane.
Online 10 December 2011
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