Rotameric conformations

VCD and IR Absorption Maxima, VCD Bias, Solubility and C -Cg Rotameric Conformational Distribution for the Amino Acids and... 

The presence of two OH groups separated from the nitrogen atom by a distance of 7-8 angstrom units is a common feature of all active compounds. We had hypothesized previously that the beta rotameric form of DA, as typified by A-6.7-DTN, was the preferred conformation. However, we recently reported that dipropyl A-5.6-DTN was a potent DA. agonist (10) and, thus, the rotameric conformation may be of secondary importance. 

Figure 8 Conformational polymorphism in crystalline Ru6C(CO)17 the projections in the equatorial planes of the cluster evidence the difference in the rotameric conformation of the tricarbonyl units on the two apices, and in the pattern of terminal, bridging, and semi-bridging COs around the molecular equator [45],...

In more recent work the o.r.d, and c.d. of 34 steroidal azides were reported . An octant rule similar to that of carbonyl was proposed, but the analysis of the results in terms of this rule was not successful. This failure was ascribed to free rotation of the chromophore in the steroidal azides, so that very many rotameric conformations are accessible. 

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