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1.
o-Lithomethylphenyl isocyanide is reacted at ?78° with isocyanates and isothiocyanates to produce o-isocyanophenyl-acetamides and -acetothioamides . Isocyanides and are cyclized to indole-3-carboxamides and -3-thiocarboxamides via lithiathion, respectively. Isocyanides are also cyclized by Cu2O catalyst to produce 4,5-dihydro-1,3-benzodiazepin-4-ones with . 相似文献
2.
Pyrolysis of homoadamant-3-ene (), generated from 1-adamantylcarbene (), leads to the same three olefins (, , and ) that are produced from pyrolysis of 3-homoadamantyl acetate (). 相似文献
3.
is silylated, enolised with KH and converted by the addition of acid to a mixture of epimeric aldehydes and . Subsequent acetylation, oxydation and deacetylation of affords 6-Epi-gibberellin-A3 (). 相似文献
4.
C-Glycosides are stereoselectively formed by the titan-(IV)-catalysed addition of silyl enolethers to 2,4,6-tri-O-acyl-1-deoxy-D-erythro-hex-1-enopyran-3-uloses followed by elimination of the 4-acyloxy substituent. Cyclohexenyl silylether reacts with 2-acetoxy-3-keto-glycal derivative forming only one product . Thus, the reaction seems to be diastereospecific with respect to both new chiral centers of the product. 相似文献
5.
Regioselective Bayer-Villiger oxidation of 2-chloro-2-fluoroethyl-isopropyl ketone () gives isopropyl-3-chloro-3 fluoropropionate (). The dehalogenation of ester () with trimethylamine gives isopropyl-3-fluoropropenoate (). Ester cleavage by trimethylsilyl iodide, in the presence of cyclohexene oxide, gives -3-fluoropropenoic acid (). 相似文献
6.
During the hydrogenation of the Δ3(3a)-4-hydrindenones or on Pd or Ni, we observe a shift of the double bond to Δ3a(7a)-4-hydrindenones and . The absolute configuration established for ketones and shows that the reaction is a suprafacial process. By deuteriation experiments, we observe that the reaction is irreversible and occurs with a molecular hydrogen exchange. 相似文献
7.
The action of either cyanate or acetate ions on -3-mesyloxyflavanones led to the formation of flavones and aurones while the reaction with the respective S-nucleophiles (thiocyanate and thioacetate ions) resulted in -and -3-thiocyanato- and 3-acetylthioflavanones ( and ). The participation of the concurrent nucleophilic substitution, β-elimination and elimination with ring-contraction is dependent on the “hard-soft” character of the nucleophile and the increase of the “soft” character favours the displacement. 相似文献
8.
The 3d levels of gaseous Te2 have been studied by X-ray photoelectron spectroscopy. The binding energies are 580.14 ± 0.10 for the 3d level and 590.45 ≈ 0.10 eV for 3d. Comparison is made with the atomic binding energies of 581.33 (3d) and 591.64 eV (3d), computed using Desclaux's Dirac-Fock program, and with binding energies in ihe solid. The latter are ≈ 2.2 eV lower than those in Te2. 相似文献
9.
The preparation of -substituted-3-(4-fluorophenyl)indoles R = H, CH3, -Pr) and their direct formylation at the 2-position by Vilsmeier-Haack or Friedel-Crafts methodologies is described. 相似文献
10.
Chalcogenide glasses of the composition 0.7Ga2S3·0.27La2S3·0.03Nd2S3 doped by 3 mol% of Nd3+ were prepared. The absorption and emission spectra of these glasses were compared to those of commercial ED-2 3.1 wt.% Nd-doped silicate glass. The absorption intensities of Nd3+ in chalcogenide glass are higher than in silicate glass due to the increasing covalency of Nd3+ in these glasses. Because of the low phonon frequency of the chalcogenide glasses nonradiative relaxations from the 4F, 2H to the 4F are lower than in other oxide glasses and so fluorescence from this state is observed. 相似文献
11.
Wojciech Dmowski 《Journal of fluorine chemistry》1982,20(5):589-598
Acidic hydrolysis of 1-(o-methoxyphenyl)pentafluoropropene gave o-hydroxy-2,3,3,3-tetrafluoropropiophenone and o-methoxy-2,3,3,3-tetrafluoropropiophenone . Compound when treated with aqueous potassium hydroxide or methanolic sodium methoxide gave 3-fluoro-4-hydroxycoumarin . Structure of has been established by spectral means and some chemical reactions. The cyclisation mechanism of is discussed. 相似文献
12.
Adenosine cyclic 3′,5′-phosphoramidate was synthesized by reacting adenosine cyclic 3′,5′-phosphate with POCl3, in trimethyl phosphate for 1 h at O°C, followed by in situ treatment of the reaction mixture with a suspension of (NH4)2CO3 in anhydrous DMF or pyridine or DMF/pyridine mixture for 30 min at 25° C. Diastereoisomers (P)- and (P)- the relative quantities of which depended on the solvent of (NH4)2CO3 treatment, were separated by reversed phase partition chromatography. Hydrolysis of (RP)- and (SP)- proceeded with predominant (90% in 0.1 N HCl, 100% in 0.1 N NaOH) -P-O-C bond breaking. 相似文献
13.
An azaanalog of adamantene, 2-azaadamant-1-ene () and 4-azaprotoadamant-3-ene () were generated in the nonstatistical ratio via photolysis of 3-azidonoradamantane (). The highly strained and could not be isolable but were trapped by MeOH. Acidolysis of was also reported, and discussed in comparison with the photolysis. 相似文献
14.
Giovanni Fronza Claudio Fuganti Piero Grasselli Giuseppe Pedrocchi-Fantoni 《Tetrahedron letters》1981,22(50):5073-5076
The synthesis of the N-benzoyl derivatives of - (10),- (13) and - (-vancosamine) (12) 2,3,6-trideoxy-3--methyl-3-aminohexose from the (2,3) diol (1) prepared in fermenting bakers' yeast from α-methylcinnamaldehyde and acetaldehyde is reported 相似文献
15.
Refluxing the oximes () of naphtho-[1,8-bc] pyran-3(2H)-one and () of 3 (2H)-benzofuranone with alcoholic hydrogen chloride give the corresponding α-alkoxy-ketones , , and α-chloroketone respectively. This transformation appears to be related to the acid conversion of N-aryhydroxylamines to o. and p. substituted anilines (BAMBERGER réarrangement. 相似文献
16.
Gunda I. Georg 《Tetrahedron letters》1984,25(35):3779-3782
Addition of dianions of 3-hydroxybutyrates to benzylideneaniline results in direct formation of -3-(l-hydroxyethyl)-1,4-diphenyl-2-azetidinone with 95% diastereoselectivity. Inversion of the configuration at Cα, gives the desired -2-azetidinone in high yield. 相似文献
17.
A. Stanley Jones Michael J. McClean Hironichi Tanaka Richard T. Walker Jan Balzarini Erik De Clercq 《Tetrahedron》1985,41(24):5965-5972
Reaction of 2',3'-secouridine with acetone gave the 3',5'--isopropylidene derivative (1) which upon treatment with mesylchloride gave the 2'--mesyl compound (2). Replacement of the mesyl group of 2 with halide could be effected by reaction with a metal halide in DMF. The 3',5'--isopropylidene group was removed simultaneously to give a 2'-halogeno-2'-deoxy-2',3'-secouridine. 2',3'-Dichloro-2',3'-dideoxy-2',3'-secouridine upon treatment with base gave 6()-chloromethyl-2()-(uracil-1-yl)-1,4-dioxane in addition to O2,2'-anhydro-3'-chloro-3'-deoxy-2',3'-secouridine, as previously reported. 2',3'-Dichloro-2',3'-dideoxy-5'-0-trityl-2',3'-secouridine was converted to 2',3'-dichloro-2',3'-dideoxy-2',3'-secocytidine (16) a triazole derivative. Compound 16 was unstable and appeared to form O2,2'-anhydro-3'-chloro-3'-deoxy-2,3'-secocytidine upon standing at room temperature. 5-Vinyl- and 5-() (2-bromovinyl) uridine dialdehydes have been made, as well as a number of other 5-substituted 2',3'-secouridine derivatives. None of the compounds obtained showed significant activity against a number of virus strains or tumor cell lines, except for 5-()(2-bromovinyl) uridine dialdehyde, which was inhibitory to the growth of human lymphoblast (Raji, Namalva) cells at a concentration of 28 μ/ml. 相似文献
18.
Energy transfer from Bi3+ to Nd3+ is reported in germanate glass. It was found that the excitation range and intensities of the 4F → 4I, 4I emissions are increased several fold when excited through 1S0 → 3P1 absorption of Bi3+. It is shown that the energy transfer is nonradiative. The energy transfer probability and efficiency were calculated from the Bi3+ fluorescence decay rates and intensities. The Bi3+ → Nd3+ energy transfer may be utilized in Nd3+ glass laser. 相似文献
19.
Sigeru Torii Hideo Tanaka Norio Saitoh Takashi Siroi Michio Sasaoka Junzo Nokami 《Tetrahedron letters》1982,23(21):2187-2188
Synthesis of 3-chloromethyl-Δ3-cephems from 4-arenesulfonylthioazetidin-2-ones , derived from penicillins G and V, has been achieved by the electrolytic ene-type chlorination of in a CHC13-aqueous NaCl-H2SO4-(Pt electrodes) system and subsequent ring closure with NH3 in DMF. 相似文献
20.
Volker Batroff Wilhelm Flitsch Wilfried Lübisch Derek Leaver David Skinner 《Tetrahedron letters》1982,23(18):1947-1950
[2.2.3]Cyclazines are obtained in moderate yields by reaction of 3-pyrrolizines bearing conjugative substituents (Ph or CO2Me) with vinamidinium salts in the presence of strong bases. Syntheses of the previously unknown 2-phenyl-3-pyrrolizine and 1-methoxycarbonylcyclopenta [] [2.2.4] cyclazine are also described. 相似文献