Optical activity of oriented molecules. 5. .alpha.,.beta.-Unsaturated keto steroids

Abstract

Venkataram Prasad, 8. V.: Prashanth, D.; Balaram, P. international Symposium on Biomolecular Structure, Conformation, Function and Evolution, Madras, 1978, Abstract 130IH17. Reisse, J.; Ottinger, R,: Bickart, P.; Mislow, K. J. Am. Chem. Soc. 1978, 100,911-915. Mislow, K.; Raban. M. Top. Stereochem. 1967, 7, 1--38. Klotz, I. M.; Russo. S. F.: Hanlon, S.; Stake, M. A. J. Am. Chem. SOC. 1964, 86, 4774-4778. Abu Khaled, Md.; Urry, D. W.; Okamoto, K. Biochem. Biophys. Res. Commun. 1976, 72, 162-169. Avignon, M.; Huong, P. V.; Lascombe, J.; Marraud, M.; Neel, J. Biopoiymers 1969, 8, 69-89.Abstract: The CD (IC)'(;)) of a transition K k -N n of :in anisotropic solution is determined b) order coefficients g,,33, the tensor of rotation R;"". and its frequency dependence G;,Yhk: A t ' ( ; ) = \-' -,=, \" gi,l~R~""kG~;". For cholest-4-en-3-one. the l7$-substituted testosterones. Swandrost-I -en-3-oncs, and 53-androst-I -en-3-ones oriented in 11 liquid crystal matrix (cholesteryl chloride/cholcster).i laurate) it is shown that the information from the C D o f t h e anisotropic solution goes beyond t h a t obtained from the isotropic CD. E.g.. compound5 which have nearly identical C D hpectru in the isotropic state behave very differently in the oriented state. Furthermore. AtZ(l') depends on the I73 substitution. This can be explained b) 11 variation of the order parameter as ;I function of the length of the substituent: i.c.. for cholcst-4-en-3-one and the testosterones the order increases in the succession -OH. -0COCH3, -0COCH2CHj. -CH(CH3)CH$~H2CH2CH(CH3)2. The coordinates KplK + and K;: of the tcnsor of rotation arc estimated and ;in estimation of the contribution of thequadrupole transition moment is attempted

Synthesis and Comprehensive Structural and Chiroptical Characterization of Enones Derived from (−)-α-Santonin by Experiment and Theory

“…at 376 and 367 nm, respectively. This additional band, present in many spectra of the enones, was first remarked on by Kuball et al and termed the “preband”. − Based on the results of the extensive study of anisotropic circular dichroism (ACD) with enones as model compounds, they concluded that the sector and helicity rules can be used effectively provided that vibronic progressions of all possible conformers will be considered. ,, Otherwise, a different vibronic coupling caused by a variation in the surroundings of the chromophore may even induce the CE sign change. They have also stated that the enone helicity corresponds to the sign of the long wavelength part of the n → π* CE. , Such compliance is observed in enones 6 and 8 in which the preband CE is positive thus being in agreement with the Kirk rule.…”

Computing chiroptical properties with first‐principles theoretical methods: Background and illustrative examples

“…. Spectroscopic methods for measurements of anisotropic CD have also been reported 220–222. The CD measurements were performed in liquid crystals.…”