The title compound, C(24)H(34)O(5), a fungal-transformed metabolite of the injecta-ble contraceptive medroxyprogesterone acetate, consists of four fused rings (A, B, C and D; steroid labelling). Ring A exists in a half-chair conformation while trans-fused rings B and C adopt chair conformations. The five-membered ring D adopts an envelope conformation with the C atom bound to the methyl group a...

The absolute configuration of the title compound, C16H24O, has been deduced from the chemical pathway. The six-membered ring has a roughly half-chair conformation with the quaternary C atom as the flap. The seven-membered ring displays a chair conformation. In the crystal, there is a weak C-H⋯O hydrogen bond between the methyl-ene group of the cyclo-propane ring and the carbonyl group of a scre...

C17H19O2N5 is monoclinic, P2(1)/n. Unit-cell dimensions at 293 K are a = 10.802(1), b = 24.085(2), c = 12.933(1)A, beta = 106.119(6) degrees, V = 3232.4(6)A3, Dx = 1.271 g/cm3, and Z = 8. The R value is 0.068 for 3017 observed reflections. There are two independent molecules in the asymmetric unit, denoted by A and B. In A, the dihedral angle between the adenine moiety and the phenyl ring is 73...

The new title thiadiazole compound, C(14)H(21)N(3)O(2)S, was semi-synthesized starting from 1-(4-methyl-cyclo-hex-3-en-yl)ethanone, a natural product isolated from Cedrus atlantica essential oil. The stereochemistry has been confirmed by single-crystal X-ray diffraction. The thia-diazo-line ring is roughly planar, although it may be regarded as having a half-chair conformation. The cyclo-hexeny...

The asymmetric unit of the title compound, (C(15)H(25)N(2)O(2))[FeCl(4)], contains a tetra-chloridoferrate(III) anion and a oxymatrinium cation [oxymatrine is (4R,7aS,13aR,13bR,13cS)-dodeca-hydro-1H,5H,10H-dipyrido[2,1-f:3',2',1'-ij][1,6]naphthyridin-10-one 4-oxide]. The conformation of oxymatrine is similar to that of matrine with one ring having a half-chair conformation, while the others hav...

In the title compound, C(33)H(31)Cl(2)NO(6), the five-membered ring displays an envelope conformation, whereas the two six-membered rings both exhibit a chair conformation. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope unit and the three C and one O atoms of the six-membered chair is 69.08 (4)°, and these two mean planes ar...

The title compound, C22H29NO4, a stemona alkaloid, is composed of two lactone rings (A and E), a six-membered ring (B), a pyrrole ring (C) and a seven-membered ring (D). The five-membered rings A and E exhibit envelope conformations (C atoms as flaps) while ring C is planar. Ring B exhibits a twist-chair conformation due to fusion with pyrrole ring C while ring D adopts a chair conformation. Th...

The asymmetric unit of the title compound, C(27)H(45)ClO, consists of two crystallographically independent mol-ecules. In both mol-ecules, the three cyclo-hexane rings in the steroid fused-ring systems adopt chair conformations, while the cyclo-pentane ring adopts a half-chair conformation in one mol-ecule and an envelope conformation in the other. In the crystal, the mol-ecules are linked into...

In the title compound, C(21)H(28)N(2)O(5) (systematic name: methyl 1,4a-dimethyl-7-nitro-9-oxo-6-propyl-amino-1,2,3,4,4a,9,10,10a-octa-hydro-phenanthrene-1-carboxyl-ate) the cyclo-hexane ring (A) and the central cyclo-hexene ring (B) exist at a trans ring junction, with the two methyl groups in the axial positions of the six-membered rings. Ring A has a chair conformation and ring B a half-chai...

The title compound, C(30)H(52)O(5)·2H(2)O, was degraded from pseudoginsenoside F11 which was extracted and seperated from Panax quinquefolium saponin. The three six-membered rings are in chair conformations. The five-membered ring is in an envelope conformation and the tetra-hydro-furan ring has a conformation inter-mediate between half-chair and envelope. In the crystal, inter-molecular O-H⋯O ...