ISSN:
1572-8854
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract The crystal structure of the potent synthetic aza steroidal neuromuscular blocking agent 17aβ-(2-hydroxyethyl)-3β-pyrrolidino-17a-aza-D-homo-5-androstene dimethiodide (HS-626), (C27H48N2O)2+2I−, has been determined by the heavy-atom method and refined by block diagonal least squares toR o =0.044 for 3041 observed reflections andR=0.072 for 4313 reflections measured on a four-circle diffractometer in the ω/2θ scanning mode, employing Nb-filtered MoKα radiation. The crystals are orthorhombic,P212121,a=14.671(2),b=17.594(3),c=10.908(2) Å,Z=4. RingsA, C, andD-homo have chair conformations, ringB is a half-chair, and the pyrrolidine ringE has an envelope conformation. The N+---N+ distance of 10.33 Å is within the usual range associated with potent neuromuscular blocking. The hydroxyethyl side group appended to N+ (17a) forms part of an acetylcholine-like moiety which is observed to adopt thet,-g conformation commonly found in acetylcholine. This feature probably accounts for the dramatic increase in potency of HS-626 compared to similar drugs lacking this feature. Potential-energy calculations for the free HS-626 molecule indicate that the side chain may adopt a variety of conformations in the ranget, (+ g to− g).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01195717
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