Xyloccensin L.
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ABSTRACT:
SUBMITTER: Feng G
PROVIDER: S-EPMC3007225 | BioStudies | 2010-01-01
REPOSITORIES: biostudies
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Project description:The title compound, C19H22N2O3, {systematic name (1aR,4E,7aS,8E,10aS,10bR)-1a,5-dimethyl-8-[(pyrimidin-5-yl)-methylid-ene]-2,3,6,7,7a,8,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-9(1aH)-one} was obtained from the reaction of parthenolide [systematic name (1aR,7aS,10aS,10bR,E)-1a,5-dimethyl-8-methyl-ene-2,3,6,7,7a,8,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclodeca-[1,2-b]furan-9(1aH)-one] with 5-bromo-pyrimidine under Heck reaction conditions, and was identified as an E isomer. The mol-ecule possesses ten-, five- (lactone) and three-membered (epoxide) rings with a pyrimidine group as a substituent. The ten-membered ring displays an approximate chair-chair conformation, while the lactone ring shows a flattened envelope-type conformation. The dihedral angle between the pyrimidine moiety and the lactone ring system is 29.43?(7)°.
1000-01-01 | S-EPMC4719832 | BioStudies
Project description:The title compound, C21H25NO3 [systematic name: (1aR,4E,7aS,8E,10aS,10bR)-8-(2-amino-benzyl-idene)-1a,5-dimethyl-2,3,6,7,7a,8,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-9(1aH)-one], was synthesized by the reaction of parthenolide [systematic name (1aR,7aS,10aS,10bS,E)-1a,5-dimethyl-8-methyl-ene-2,3,6,7,7a,8,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-9(1aH)-one] with 2-iodo-aniline via Heck reaction conditions. The mol-ecule is composed of fused ten-, five- (lactone), and three-membered (epoxide) rings. The lactone ring shows a flattened envelope-type conformation (r.m.s. deviation from planarity = 0.0477?Å), and bears a 2-amino-benzyl-idene substituent that is disordered over two conformations [occupancy factors 0.901?(4) and 0.099?(4)]. The ten-membered ring has an approximate chair-chair conformation. The dihedral angle between the 2-amino-benzyl-idine moiety (major component) and the lactone ring (mean plane) is 59.93?(7)°. There are no conventional hydrogen bonds, but there are a number of weaker C-H?O-type inter-actions.
1000-01-01 | S-EPMC6218918 | BioStudies
Project description:THE TITLE COMPOUND [SYSTEMATIC NAME: (1S,3aS,4aR,4bS,5R,6aR,10aR,10bR,12aS)-1-(furan-3-yl)-5-hy-droxy-4b,7,7,10a,12a-penta-methyl-4b,5,6,6a,7,10a,10b,11,12,12a-deca-hydro-naphtho-[2,1-f]oxireno[2,3-d]isochromene-3,8(1H,3aH)-dione], C(26)H(32)O(6), which is a limonoid-type triterpene isolated from the seeds of X. moluccensis, crystallizes with three independent mol-ecules with very similar geometries in the asymmetric unit. In each mol-ecule, the four fused six-membered rings of the genudin core adopt distorted half-chair, chair, twist-boat and twisted half-chair conformations. In the crystal, inter-molecular O-H?O hydrogen bonds link the mol-ecules into helical chains propagated in [100]. Weak non-classical C-H?O contacts further consolidate the crystal packing.
2010-01-01 | S-EPMC3050298 | BioStudies
Project description:The title compound, C44H62O6S2 {systematic name: (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-5a,5b,8,8,11a-penta-methyl-1-(prop-1-en-2-yl)-3a-[(tos-yloxy)meth-yl]icosa-hydro-1H-cyclo-penta-[a]chrysen-9-yl 4-methyl-benzene-sulfonate}, was obtained by tosyl-ation of naturally occurring betulin. All the cyclo-hexane rings adopt chair conformations and the cyclo-pentane ring adopts a twisted envelope conformation, with the C atom bearing the tosyl-methyl substituent forming the flap. In the crystal, mol-ecules form a three-dimensional network through multiple weak C-H?O hydrogen bonds.
1000-01-01 | S-EPMC4158509 | BioStudies
Project description:THE TITLE COMPOUND (SYSTEMATIC NAME: methyl 2-{(1R,2R)-2-[(1aS,4S,4aS,8aS)-4-(furan-3-yl)-4a-methyl-8-methyl-ene-2-oxoocta-hydro-oxireno[2,3-d]isochromen-7-yl]-2,6,6-trimethyl-5-oxocyclo-hex-3-en-1-yl}acetate), C(27)H(32)O(7), was isolated from X. moluccensis seeds from Thailand. The conformations of the six-membered rings are distorted half-chair, chair and half-chair for the isolated cyclo-hexane, fused cyclo-hexane and lactone rings, respectively. In addition, the lactone ring bears in an equatorial orientation an essentially planar furan ring (r.m.s. deviation = 0.004?Å), which forms an angle of 63.87?(13)° with the mean plane defined by the ten atoms of the two fused six-membered rings (r.m.s. deviation = 0.213?Å). The absolute configuration was fixed on the basis of literature data.
1000-01-01 | S-EPMC3414995 | BioStudies
Project description:The title seco-dammarane triterpenoid, C(27)H(42)O(4) (systematic name: 3-{(3S,3aR,5aR,6S,7S,9aR,9bR)-6,9a,9b-trimethyl-3-[(R)-2-methyl-5-oxotetra-hydro-furan-2-yl]-7-(prop-1-en-2-yl)dodeca-hydro-1H-cyclo-penta-[a]naphthalen-6-yl}propanoic acid), has been isolated for the first time from the seeds of Aglaia forbesii. The mol-ecule has three fused rings and all rings are in trans-fused. The two cyclo-hexane rings are in standard chair conformations and the cyclo-pentane ring adopts an envelope conformation. Its absolute configuration was determined by the refinement of the Flack parameter to 0.26?(17). In the crystal, mol-ecules are linked into chains along [010] by O-H?O hydrogen bonds.
1000-01-01 | S-EPMC2984085 | BioStudies
Project description:THE TITLE MONOSUCCINATE DERIVATIVE OF MELAMPOMAGNOLIDE B [SYSTEMATIC NAME: 4-(((1aR,7aS,10aS,10bS,E)-1a-methyl-8-meth-yl-ene-9-oxo-1a,2,3,6,7,7a,8,9,10a,10b-deca-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-5-yl)meth-oxy)-4-oxo-butan-oic acid], C19H24O7, was obtained from the reaction of melampomagnolide B with succinic anhydride under nucleophilic addition reaction conditions. The mol-ecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings. The inter-nal double bond in the ten-membered ring has the cis geometry (i.e. it is the E isomer). The lactone ring has an envelope-type conformation, with the (chiral) C atom opposite the lactone O atoms as the flap atom. In the crystal, O-H?O hydrogen bonds link the mol-ecules into chains parallel to the b-axis direction.
1000-01-01 | S-EPMC3998419 | BioStudies
Project description:The title compound, C18H24N2O4·H2O {systematic name: (1aR,7aS,8R,10aS,10bS,E)-5-hy-droxy-methyl-8-[(1H-imidazol-1-yl)meth-yl]-1a-methyl-2,3,6,7,7a,8,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-9(1aH)-one monohydrate}, an imidazole derivative of melampomagnolide B was synthesized under Michael addition conditions. The mol-ecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings. The inter-nal double bond of the ten-membered ring identifies it as the cis or E isomer. The lactone ring has an envelope-type conformation, with the (chiral) C atom opposite the lactone O atoms as the flap atom. In the crystal, O-H?O, O-H?N and weak C-H?O hydrogen bonds link the mol-ecules (along with water) into sheets parallel to the bc plane.
2013-01-01 | S-EPMC3885019 | BioStudies
Project description:The crystal structures of three cyclo-penta-[c]furans with various substituents at the 4-, 5- and 6-positions of the ring system are reported, namely, (±)-(3aR,4S,5S,6aS)-4-methyl-5-phenyl-hexa-hydro-1H-cyclo-penta-[c]furan-4,5-diol, C14H18O3, (I), (±)-(3aR,4S,5S,6aS)-4-benz-yloxy-4-methyl-5-phenyl-hexa-hydro-1H-cyclo-penta-[c]furan-5-ol, C21H24O3, (II), and (±)-(1aR,1bS,4aR,5S,5aR)-5-benz-yloxy-5-methyl-5a-phenyl-hexa-hydro-2H-oxireno[2',3':3,4]cyclopenta-[1,2-c]furan, C21H22O3, (III). The dominant inter-action in (I) and (II) is an O-H?O hydrogen bond across the bicyclic 5,5-ring system between the non-functionalized hy-droxy group and the tetra-hydro-furan O atom, which appears to influence the envelope conformations of the fused five-membered rings, whereas in (III), the rings have different conformations. A weak intra-molecular C-H?O inter-action appears to influence the degree of tilt of the phenyl ring attached to the 5-position and is different in (I) compared to (II) and (III).
2016-01-01 | S-EPMC4704749 | BioStudies
Project description:THE TITLE COMPOUND [SYSTEMATIC NAME: (1S,3aS,4aR,4bS,5S,6R,6aR,10aR,10bR,12aS)-5,6-bis-(acet-yloxy)-1-(3-fur-yl)-1,5,6,6a,7,10a,10b,11,12,12a-deca-hydro-4b,7,7,10a,12a-penta-methyl-oxireno[c]phenanthro[1,2-d]pyran-3,8(3aH,4bH)-dione], C(30)H(36)O(9), is a limonoid-type triterpene isolated from Aglaia elaeagnoidea (A. Juss.) Benth. (Meliaceae) from Queensland, northern Australia. It contains the gedunin core of four trans-fused six-membered rings with an oxirane ring annelated to the fourth ring. A terminal 3-furyl unity and two acet-oxy groups in a mutual cis-disposition supplement the mol-ecule. A comparison between the gedunin cores of the title compound, the parent compound gedunin, and three further gedunin derivatives revealed considerable variations in their conformation stemming from the conformational lability of the first screw-boat ring and the third twist-boat ring. A sensitive measure for the third ring is one C-C-C-C torsion angle, which is 14.2?(2)° in the title compound, but varies in other cases from ca 20 to ca -40°. In the crystalline state, 6?-acetoxy-gedunin shows ten comparatively weak C-H?O inter-actions, with H?O distances in the range of 2.33-2.69?Å.
2009-01-01 | S-EPMC2977213 | BioStudies