共查询到20条相似文献,搜索用时 15 毫秒
1.
Janina Karolak-Wojciechowska Marian Mikołajczyk Andrzej Zatorski Katarzyna Kiec-Kononowicz Alfred Zejc 《Tetrahedron》1985,41(20):4593-4602
The crystal and molecular structures of the title isomeric compounds and , obtained by intramolecular N,S--dialkylation of 5,5-diphenyl-2-thiohydantoin with 1,2-dibro-moethane, have been determined from X-ray diffractometer data. 2,3-Dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one crystallizes in space group P212121 with a=11.376(3), b=12,255(5), c=8.434(3) Å and Z=4. Crystals of , containing one molecule of benzene, are monoclinic,space group P21/c with a=11.539(6), b=10.242(3), c=16.353(5) Å, β=95.45(5)° and Z=4. In both cases a planar geometry of the two fused five-membered heterocyclic rings was found. The selected bond lengths in and , as well as those analogous imidazothiazinones and , were used to calculate EHOSE (Harmonic Oscillation Stabilization Energy). The problem of stability and chemical reactivity of compounds to is also discussed. 相似文献
2.
Akihiko Sugie Hiromi Shimomura Junki Katsube Hisao Yamamoto 《Tetrahedron letters》1979,20(28):2607-2610
A stable PGI2 analog (methanoprostacyclin ) was synthesized starting from 5-norbornene-2,3-dicarboxylic anhydride. 相似文献
3.
A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [22](1,4)cyclophane (), providing syntheses of 5,7,8-trimethyl- [23](l,2,4)cyclophane (), a mixture of 5,8-dimethyl[24(1,2,4,5)cyclophane () and 5,7-dimethyl[24(1,2,3,5)cyclophane (, and-4-methyl[25](1,2,3,4,5)-cyclophane (). This route to completes a formal eight-step synthesis of [26](1,2,3,4,5,6)cyclophane (, superphane) with an overall yield of 17%. A Birch reduction of readily gave 12,15-dihydro-5,7,8-trimethyl[23](1,2,4)-cyclophane () in 85% yield. 相似文献
4.
Masato Mizutani Yuzuru Sanemitsu Yoshinao Tamaru Zen-ichi Yoshida 《Tetrahedron letters》1985,26(9):1237-1240
Selective transformation of 3-propargylthio-1,2,4-triazin-5(2H)-ones () to 6-methylene-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]-triazin-4-ones () and 3-methylene-2,3-dihydro-7H-thiazolo[3,2-b]-[1,2,4]triazin-7-ones () is performed under the conditions of Pd(II) salt or sodium hydroxide catalysis, respectively. 相似文献
5.
《Polyhedron》2001,20(9-10):1089-1095
6.
The tertiary phosphines R2PF2)n (R = C6H5 or C6H11; n = 2,3, or 4) react with M(CO)6 (M = Cr, Mo, W) to give R2PF2)nM(CO)5 in which the ligand is bonded to M through P alone. Similar bonding is found in some chloro-complexes of platinum and palladium. 相似文献
7.
Flash vacuum pyrolysis of functionalized tricyclo|5.2.1.02,3|decenone epoxide , and acetals and affords cyclopentadienone epoxide and acetals and , respectively. These epoxides are suitable precursors for the synthesis of (±) terrein. 相似文献
8.
G. Eulenberger 《Journal of solid state chemistry》1984,55(3):306-313
The new compound Tl6[Ge2Te6] was prepared by thermal synthesis from the elements. The material is triclinic, space group , with a = 9.471(2), b = 9.714(2), c = 10.389(2) Å, α = 89.39(1), β = 97.27(1), γ = 100.79(1)°, and Z = 2. The crystal structure was determined from single-crystal intensity data measured by means of an automated four-circle diffractometer and refined to an R value of 0.053 for 1831 observed reflections. Tl6[Ge2Te6] is characterized by Ge2Te6 units with GeGe bonds which are linked into a three-dimensional structure by Tl atoms coordinated to essentially six Te atoms. The most important mean distances are Å, Å, and Å. The lone 6s electron pairs of the thallium(I) atoms exhibit significant stereochemical activity. Tl6[Ge2Te6] represents a new structure type. 相似文献
9.
The structure of [Pt2Cl(CO) (μ-Ph2PCH2PPh2)2] [PF6] was determined by -ray methods and refined to = 0.082, using diffractometric intensities of 5646 independent reflections. The crystals are monoclinic, space group 21/, = 12.919(3), = 15.576(6), = 25.151(5)Å, β = 94.82(3)°, = 4. They are built of octahedral hexafluorophosphate anions and dinuclear platinum(I) cations. The latter contain PtCl and PtCO fragments linked to one another by a PtPt σ-bond and by two bridging bis(diphenylphosphino)methane ligands. The platinum atoms are in square planar environments and the dihedral angle between the two coordination planes is 40.1°. Selected bond lengths are: PtPt 2.620(1), PtCl 2.384(5), PtC 1.89(3) and PtP 2.291(5) – 2.308(5)Å. 相似文献
10.
Several aromatic compounds containing one or two C6F5S groups have been prepared by nucleophilic displacement reactions using CuSC6F5 in DMF solution. Aromatic iodine or bromine, rather than chlorine of fluorine is replaced by the SC6F5 group using CuSC6F5. A mechanism is postulated. New compounds prepared include -(C6F6F5S)2C6H4, - and -(C6F5S)2C6F4 and XC6H4SC6F5(X=C1, NO2, I, CH3, CO2C2H5). 相似文献
11.
Ronald E. Banks Ismail M. Farhat Roy Fields Robin G. Pritchard Mohamad M. Saleh 《Journal of fluorine chemistry》1985,28(3):325-340
The nitrosoarenes ArNO (Ar = C6H5, 2-MeC6H4, 2,4,6- Me3C6H2 and C6F5) have been condensed with 4-(dichloroamino)- tetrafluoropyridine to provide the azoxy-compounds pyFN()Ar (pyF = 2,3,5,6-tetrafluoro-4-pyridyl); de-oxygenation of the first three with triphenylphosphine or triethyl phosphite gave the corresponding azo-compounds, and the reverse reaction was achieved in the case of pyFNNC6H2Me3-2,4,6 using peroxytrifluoroacetic acid. Thermolysis of 4-azidotetrafluoropyridine in the presence of pentafluoronitrosobenzene provided the perfluorinated azoxy-compound pyFN()C6F5. X-Ray methods have been used to determine the molecular geometry of pyFN()C6H2Me3-2,4,6. 相似文献
12.
Peter B. Hitchcock Michael F. Lappert Pilar Terreros 《Journal of organometallic chemistry》1982,239(2):C26-C30
Treatment of [{Ir(COD)(μ-Cl)}2] with excess of the electron-rich olefin [Ar]2 (abbreviated as (LAr)2, Ar = C6H4Me-p or C6H4OMe-p) affords the ortho-metallated tricycle [)3], which for Ar = C6H4Me-p (Ia) with HCL yields [)2(LAr)]Cl (IV); X-ray data show that in IV there is an unexpectedly close Ir?C(o-aryl) contact (2;52(1) Å) involving the “free” LAr which compares with an IrC(o-aryl) distance of 2.09(3) Å in Ia or 2.07(3) Å in the ortho-metallated LAr ligand of complex IV. 相似文献
13.
Ta-jyh Lee 《Tetrahedron letters》1979,20(25):2297-2300
The title compound , a key intermediate for PGE2 elaboration, is readily available in nine steps from furfuryl alcohol. The crucial steps include the exclusive formation of from and the subsequent intramolecular Aldol condensation to . 相似文献
14.
Reactions between Ph3SnCH2SAr and 2-NO2C6H4SC? lead to the formation of 2-(ArSCH2-6-NO2C6H3SSC6H4NO2-2 via the [2,3]sigmatropic rearrangement of the S-arylthio-sulphonium ylides H2(Ar)SC6H4NO22. 相似文献
15.
Upasiri Samaraweera Subramaniam Sotheeswaran M. Uvais S. Sultanbawa 《Tetrahedron letters》1981,22(50):5083-5086
Calozeylanic acid has been isolated from the bark of three species: (= ), and . Its structure has been established as 2(R),3(R)-2,3-Dimetyl- 5-hydroxy-6-(3-methylbutanyl)-6-(3,7-dimethylocta-3,6-dienyl)-7-oxo-8- (2-carboxy-1-phenylethyl)-2,3,6,7-tetrahydrobenzo-4-pyrone. 相似文献
16.
The crystal structure of [HAlNCH(CH3)C6H5] 6· C6H14 has been determined by single crystal three-dimensional X-ray analysis. Block-matrix least-squares refinement led to conventional R factor of 0.08. The molecule is built up of a prismatic hexagonal framework, (AlN)6. Average AlN distances are 1.893(6) and 1.981(7) Å in the six-membered rings and in transverse bonds, respectively. Crystal data: hexagonal, space group P63, a 22.296(5), c 18.144(4) Å, V 7811.2 Å3, Z = 6, Dc 1.16 g cm?3. 相似文献
17.
()-5-Hydroxy-6--8,11,14--eicosatetraenoic acid (5-HETE) (1) and its enantiomer are readily available by a chemical synthesis from arachidonic acid which includes a chromatographic separation of diastereomeric urethanes (3) made from (±)-5-HETE methyl ester and the isocyanate 4 derived from dehydroabietylamine. 相似文献
18.
The syntheses of 5-methyl-5,8,9,14-tetrahydroindolo(2,3-)indolo (2,3-) quinolizin-6-one and 15-methyl-7,8,13,15-tetrahydroindolo ( 3,2-) indolo(2,3-)quinolizin-5-one from the photochemical cyclisation of i-methylene-2-(N-`methylindole-2'-carbonyl) 1,2,3,4-tetrahydro-B-carboline and 1-methylene-2- (N-`methylindole-3' carbonyl) 1,2,3,4,-tetrahydro-B-carboline are described. Attempts to prepare indolo(2,3-)isoquinolines from the photochemical cyclisation of 2-benzamidoindoles were unsuccessful. 相似文献
19.
The vapour phase reaction of ammonia and hexafluoroacetylacetone leads to the formation of the new β-keto-amine C5H3F6NO. Crystals of the compound are monoclinic, space group 21/, = 10.01(2), = 19.33(3), = 8.40(1) Å, β = 82.27(6)°; final R = 0.044. 相似文献
20.
The synthesis of an enantiomerically pure (5R, 6R)-carbapenem is described. The key step consists of a stereospecific C-C-coupling in 4-position of the lactam by means of cuprates. 相似文献