A beta-sheet structure formed by C-H center dot center dot center dot O hydrogen bonds between the thiazole rings and amide bonds of a dimeric desoxazoline ascidiacyclamide analogue

Asano, A Taniguchi, T Sasaki, M Hasegawa, H Katsuya, Y Doi, M

A. Asano et al., A beta-sheet structure formed by C-H center dot center dot center dot O hydrogen bonds between the thiazole rings and amide bonds of a dimeric desoxazoline ascidiacyclamide analogue, ACT CRYST E, 57, 2001, pp. o834-o838

15

INGLESE

Article

Physical Chemistry/Chemical Physics

ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE

1600-5368 → ACNP

57

2001

9

o834 - o838

ISI

1600-5368(200109)57:<o834:ABSFBC>2.0.ZU;2-N

A dimeric analogue of desoxazoline ascidiacyclamide was synthesized to incr ease the conformational flexibility of the molecule. The overall structure of this compound, C72H112N16O16S4. 3C(3)H(7)NO .H2O, was relatively flat an d was classified neither as the folded nor squared form, which have been ob served in ascidiacyclamide analogues. Rather, a unique beta -sheet was form ed in the 48-membered ring with pseudo-twofold symmetry. This was stabilize d by hydrogen bonds including C-H . . .O interactions between thiazole and carbonyl O atoms. This is the first structure of an ascidiacyclamide analog ue to exhibit a flat conformation composed of a eta -sheet.