排序方式: 共有38条查询结果,搜索用时 15 毫秒
31.
Demirkiran O Topcu G Hussain J Ahmad VU Choudhary MI 《Magnetic resonance in chemistry : MRC》2011,49(10):673-677
Two new unusual monoterpene glycosides, (Z)-3,6-dimethyl-3-(β-D-O-glucosylmethylene)cyclohept-4-ene-1-one (1) and 3,6-dimethyl-3-(β-D-O-glucosylmethylene)cycloheptanone (2) have been isolated along with five known compounds, 3-hydroxy-4-methoxybenzoic acid, 6,7-dihydroxycoumarin, luteolin, apigenin 5-O-αl-L-rhamnoside, and pinocembrin-7-O-rutinoside from ethyl acetate extract of Euphorbia decipiens. The structures of the isolated compounds were elucidated by extensive 1D- and 2D-NMR, and mass spectroscopic analyses. 相似文献
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Yildiray Ozan 《Geometriae Dedicata》2004,108(1):131-140
Let X
0 be a topological component of a nonsingular real algebraic variety and i:X → X
C
is a nonsingular projective complexification of X. In this paper, we will study the homomorphism on homotopy groups induced by the inclusion map i:X
0 → X
C
and obtain several results using rational homotopy theory and other standard tools of homotopy theory. 相似文献
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Omer Andac Yildiray Topcu Veysel T. Yilmaz William T. A. Harrison 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):m14-m16
The structure of the title complex consists of isolated [Cd(C7H4NO3S)2(C4H11NO2)2] units. The Cd2+ cation lies on an inversion centre and is octahedrally coordinated by two N,O‐bidentate diethanolamine (dea) and two N‐bonded saccharinate (sac) ligands [saccharin is 1,2‐benzisothiazol‐3(2H)‐one 1,1‐dioxide]. The dea ligands constitute the equatorial plane of the octahedron, forming two five‐membered chelate rings around the CdII ion, while the sac ligands are localized at the axial positions. The Cd—Nsac, Cd—Ndea and Cd—Odea bond distances are 2.3879 (12), 2.3544 (14) and 2.3702 (13) Å, respectively. The H atoms of the free and coordinated hydroxyl groups of the dea ligands are involved in hydrogen bonding with the carbonyl and sulfonyl O atoms of the neighbouring sac ions, while the amine H atom forms a hydrogen bond with the free hydroxyl O atom. The individual molecules are held together by strong hydrogen bonds, forming an infinite three‐dimensional network. 相似文献
36.
Trans‐bis(ethanolamine)bis(saccharinato)mercury(II), [Hg(ea)2(sac)2], where ea and sac denote the ethanolamine molecule and the saccharinate anion, respectively, crystallizes in the triclinic space group P (No. 2) with a = 9.4651 (5), b = 10.4365 (5), c = 11.9314 (6) Å, α = 84.402 (1)° β = 78.313 (1)°, γ = 75.307 (1)°, Z = 2, V = 1115.11 (10) Å3. The structure consists of isolated [Hg(ea)2(sac)2] units in which the Hg(II) ion is octahedrally coordinated by two nitrogen and two oxygen atoms of two neutral ea ligands, and two nitrogen atoms of two sac ligands. The ea acts as a bidentate N‐ and O‐donor ligand and occupies the trans positions of the equatorial plane of the coordination octahedron forming a fivemembered chelate ring, while sac behaves as a monodentate N‐donor ligand occupying the axial positions. The average Hg‐Nsac and Hg‐Nea bond distances are 2.739 (3) and 2.114 (7) Å, respectively. The crystal exhibits extensive hydrogen bonds between the hydroxyl and amine hydrogen atoms of the ea ligands and the sulfonyl, carbonyl and amine groups of the sac ligands. 相似文献
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T. Kilic Ya. K. Yildiz A. C. Goren G. Tumen G. Topcu 《Chemistry of Natural Compounds》2003,39(5):453-456
Linearol, foliol, epicandicandiol, siderol and ent-7,18-dihydroxy-15,16-epoxykaurane have been investigated for antibacterial activity test. Highest activity of epicandicandiol has been determined against E-coli. 相似文献