Structure of (20R)-5α-pregnano[3,4-c][1,2,5]oxadiazol-20-ol (HS1011)

Polymorphism in Dethoxyprone, a steroidal anesthetic. II. Crystal and molecular structure of 11?-dimethylamino-2?-ethoxy-3?-hydroxy-5?-pregnan-20-one (Dethoxyprone, form II)

“…Dethoxyprone is a fully saturated structure and most of the bond lengths are close to the expected values. The average C--C single bond lengths in rings A, B, C, and C ( This effect has been observed in other pregnane steroids, e.g., 4-pregnene-3,20-dione (Serantoni et al, 1975), 16-methyl-4-pregnene-3,20 dione (Weeks et al, 1976) and (20R)-5c~-Pregnano [3,4-c]-1', 2', 5'-oxadiazole-20-ol (Maes et al, 1992) which have angles hav- (12) 0.0498(9) 0.0365 (8) 0.0493 (9) 0.0022(6) -0.0078 (7) 0.0024(7) C (13) 0.0397 (7) 0.0368 (7) 0.0490 (8) 0.0045(6) 0.0034(6) 0.0032(6) C (14) 0.0474 (8) (1) 0.0662(9) 0.0398 (7) 0.0437 (7) 0,0037(6) -0.0115 (7) -0.0260 (7) 0(2) 0.0773(10) 0.0402 (7) 0.0578(8) 0.0053(6) 0.0112(7) -0.0075 (6) 0(3) 0.0694(9) 0.0476 (7) 0.0644(8) 0,0017(6) 0.0136 (7) 0.0104 (6) 0(20) 0,0923(12) 0.0395 (7) 0.0975(13) 0,0094 (7) -0.0159(11) 0.0060 (7) The expression used was: exp [-2~r2 ing corresponding values of 99.0(2), 99.1(3), and 99.4(1) ~ respectively. Conformational features of the molecule may be described in terms of (i) torsion angles (Table 6) and (ii) asymmetry parameters ( Table 7) .…”

Two Steroidal Epimers, (5β,17α)-Pregna-20-yno[3,4-c][1,2,5]oxadiazol-17-ol (the 5β-Epimer) and (5α,17α)-Pregna-20-yno[3,4-c][1,2,5]oxadiazol-17-ol (the 5α-Epimer)

“…The bond angles C2---C3--C4 and C3--C4---C5 for both epimers are somewhat larger than the average and the differences are associated with fusion of the oxadiazole rings. As with similar molecules (El Shora et al, 1984;Maes, Wyns, Lisgarten, Lisgarten & Palmer, 1992), there is a variation in CmC--C bond angles in the steroid nucleus depending on their environments; bond angles around quaternary, tertiary and secondary C atoms have the average values 109.4 (1), 111.4 (1) and 109.0 (1) °, respectively, for the 5/3-epimer, and 109.4 (1), 111.8 (1) and 109.1 (1) °, respectively, for the 5a-epimer. Conformational features of the molecules are described in terms of torsion angles (Table 2) and asymmetry parameters (Table 3).…”