نتایج جستجو برای: membered rings
تعداد نتایج: 52672 فیلتر نتایج به سال:
The title compound, C(34)H(47)NO(12), is the norditerpenoid alkaloid aconifine isolated from the leaves and tubers of Aconitum karakolicum Rapaics. It has a lycoctonine carbon skeleton and contains four six-membered rings and two five-membered rings; its geometry is similar to that observed in other lycoctonine-type diterpenoid alkaloids. There are two intra-molecular O-H⋯O hydrogen bonds which...
The mol-ecular structure of the title compound, C(17)H(20)N(4)O(5), contains a central fused-ring system, comprised of six- and five-membered rings. This unit is linked by C(2) chains to two 2-oxo-1,3-oxazolidine five-membered rings. The central fused-ring system is essentially planar, with a maximum deviation of 0.008 (1) Å from the mean plane. Both oxazolidine five-membered rings are also nea...
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 title compound, C(19)H(32)O(4), was synthesized from γ-himachalene, wich was isolated from essential oils of Cedrus atlantica. The mol-ecule is built up from two fused six- and seven-membered rings. The six-membered ring has a screw-boat conformation, whereas the seven-membered ring displays a half-chair conformation; the dihedral angle between the mean planes of the rings is 61.99 (6)°.
The title compound, C(15)H(18)O(3), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methyl-ene-3,14-dioxatricyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The five-membered lactone ring has a twisted conformation, while the six- and five-membered rings display chair and envelope conf...
The title compound (also know as azorellanone), C(20)H(32)O(2), is built up from three fused carbocycles, one five-membered ring and two six-membered rings. The five membered-ring has an envelope conformation, whereas the six-membered rings have a distorted half-chair and a twist-boat conformation. In the crystal, mol-ecules are linked by O-H⋯O inter-actions into zigzag chains with graph-set no...
The title compound, C(24)H(32)O(8)S·C(3)H(6)O, features three six-membered and two five-membered rings. The six-membered rings adopt chair, boat and slightly distorted boat conformations whereas one five-membered ring adopts an approximate envelope conformation and the other a twist conformation. Disorder was modelled for the ethyl-thio group with the ethyl-C atoms resolved over three positions...
The title compound, C17H26Br2, was synthesized from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from fused six- and seven-membered rings and two appended three-memb...
The asymmetric unit in the crystal of the title compound, C(15)H(22)O(3), contains two independent mol-ecules with similar structures. Each mol-ecule contains two six-membered rings and one five-membered ring. The five-membered ring displays an envelope conformation with the C atom linking the epoxy group as the flap, while the two six-membered rings show half-chair conformations. The two indep...
IN THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND [SYSTEMATIC NAME: 2-(4b-fluoro-5-hy-droxy-4a,6a,8,8-tetra-methyl-2-oxo-2,4a,4b,5,6,6a,9a,10,10a,10b,11,12-dodeca-hydro-7,9-dioxa-penta-leno[2,1-a]phenanthren-6b-yl)-2-oxoethyl acetate], C(26)H(33)FO(7), the mol-ecules are connected by inter-molecular O-H⋯O hydrogen bonds into an infinite supra-molecular chain along the b axis. The mol-ecular framew...
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