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1.
The surprising formation of C22H32N2S2 from the title compound 1 at 45°C involves the interaction of the basic adamantanethione S-methylide () with its acidic precursor , in the course of which the anion undergoes electrocyclic ring opening; the acid and base functions offer the clue to a prolific chemistry of the thiadiazoline and the thiocarbonyl ylide . 相似文献
2.
The reactions (I) Hg2Cl2(s) + Br2(g) and (II) HgCl2(s) + HgBr2(s) have been investigated by an X-ray method. Both the reactions yield two forms of the mixed halide HgClBr, designated as α-HgClBr and β-HgClBr. The cell parameters of the two are as follows:α-HgClBr: , , , z = 4, ? = 5.91 g/cm3. The powder pattern and cell parameters are similar to that of HgCl2. Therefore it is probable that the chlorine atoms, in the linear halogenHghalogen molecules of HgCl2 structure have been replaced by bromines, and since the radius of the bromine atom is larger than that of chlorine, the lattice is larger in this case.β-HgClBr: , , , z = 4, ? = 5.40. These parameters are the same as those reported in the literature for β-Hg(ClBr)2, and its X-ray powder pattern is similar to HgCl2. Therefore this phase also has linear halogenHghalogen molecules but the distribution of Cl and Br atoms is perhaps random.Heating the products (I) and (II) up to the melting point increases the amount of α phase and decreases the β phase, whereas crystallization increases the β phase. DTA study has supported the X-ray findings. 相似文献
3.
The vinylbromides and are allowed to react ith AgBF4 and AgPF6 in the presence of various olefins in CH2Cl2 as the solvent. Except for the reaction of cyclopentene with all other olefins used, react with vinyl cation to form the cycloaddition products , and in high yields. 相似文献
4.
A synthesis of -4,5,15,16-tetramethyl[22] (5,8) phenalenophane-1,12-diene () is described as well as its transformation via a radical abstraction process to an enantiomeric mixture of the Cope rearrangement product . 相似文献
5.
The crystal structure of Ca6Eu2Na2(PO4)6F2 has been determined by single crystal X-ray diffraction. The unit cell constants are and the space group is . The structure was refined by normal full matrix least squares techniques. The final value of the refinement indicator is R = 0.065, based on 419 reflections.The structure of Ca6Eu2Na2(PO4)6F2 contains disordered cations in both the triangle and column positions. The occupation of the six triangle sites is and and of the four column sites , and . 相似文献
6.
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
7.
Irradiation of thioxanthenethione with the alkyl- and alkoxysubstituted butatrienes a-d gives the thietanes a-d the cyclobutanethione is formed as a byproduct. Free radical addition of iC3H7SH to a predominantly occurs via terminal attack of the thiyl radical on the π-system. 相似文献
8.
Optical absorption and emission spectra are reported for single crystals of the cubic elpasolite Cs2NaSmCl6. The variable temperature spectra obtained at high resolution are assigned using energies and relative intensities. Transitions from the ground level, 6H to cystal fi levels of 6H-, 6F-, 4G-, 4F,, 4I, and 6P, are located and characterized. Intensity calculations are reported for magnetic dipole allowed transitions. The dominance of vibronic intensity in 6H→6F - and 6P, transitions is accounted for qualitatively through the ligand polarization model involving quadrupole metal (Sm3+)-ligand (Cl?) interaction mechanisms. The Eu″(6H)→E′(6H) Eu′(6F) no-phonon transition is postulated to be pure electric quadrupole allowed. The ground state magnetic moment is determined to be very small from magnetic circular dichroism (MCD) spectra.This study has led to the assignment of nearly all of the crystal field levels in the visible and IR region for Cs2NaSmCl6. A total of 27 such levels were identified, 17 from no-phonon transitions and the rest from vibronic transitions. The magnetic dipole intensity calculated using intermediate coupling Oh wavefunctions along with a crystal field analysis of the splitting pattern was used in the assignment of the levels. Vibronic bands were observed for all transitions and their vibrational symmetries were tentatively assigned. MCD data were used to determine the magnet moment of the ground state. 相似文献
9.
The production of I(2P) in the photolysis of CH2I2 has been studied optoacoustically at excitation wavelengths between 365.5 and 247.5 nm. Bands found at 32200 and 47000 cm?1 correlate with I(2P) whilst those at 34700 and 40100 cm?1, which correlate with I(2P), give final 2P/2P ratios of 1.75 and 1.1, respectively, after curve crossing. 相似文献
10.
T. Tanaka N. Okamura K. Bannai A. Hazato S. Sugiura K. Manabe S. Kurozumi 《Tetrahedron letters》1985,26(45):5575-5578
(5)-Prostaglandin E2 methyl ester was synthesized from ()-4--butyldimethylsiloxy-2-cyclopentenone by 2-alkenyloxycarbonylation of the organocopper conjugate-addition adduct followed by intramolecular palladium-catalyzed decarboxylative 2-alkenylation. A ()-2-butenylated cyclopentanone derivative was obtained from either 2-[()- or ()-2-butenyloxy-carbonyl]cyclopentanone derivative under the similar reaction condition. 相似文献
11.
Kiyoshi Bannai Takeshi Toru Takeo Ba Toshio Tanaka Noriaki Okamura Kenzo Watanabe Seizi Kurozumi 《Tetrahedron letters》1981,22(15):1417-1420
Stable analogues of PGI2, 7-hydroxy- and 7-acetoxy-PGI2, were synthesized from protected PGI2 methyl ester via sulfoxides , through stereocontrolled sulfoxide-sulfenate rearrangement. 相似文献
12.
Richard D. Chambers Colin G.P. Jones Michael J. Silvester David B. Speight 《Journal of fluorine chemistry》1984,25(1):47-56
Base-catalysed additions of alcohols to F-2-butyne (1) give mainly products of -addition while -addition predominates in uncatalysed additions of alcohols carried out in a diluent. The stereochemistry of addition of diethylamine is very dependent on the solvent used and - or -addition may predominate. Stepwise and concerted mechanisms are advanced to account for these observations. Nucleophilic addition of sulphur to (1) gives F-tetramethylthiophene (68%) and hydration gives CF3CH2COCF3 (91%). 相似文献
13.
The relative photoionization cross section of Kr2 was determined from 900 to 970 A at a resolution of 0.15 A. Complex molecular autoionization structure is observed throughout the spectrum and has been analyzed in part in terms of Rydberg states converging to the A2Σ+u and B2Π states of the ion. 相似文献
14.
The title compounds were readily prepared in one-pot by phase-transfer reaction of a methanol adduct of 2-(-methyl)-- propene with acetamidine or benzamidine in the presence of aqueous sodium hydroxide in CH2Cl2. Various 5-trifluoromethyl- pyrimidines were also synthesized nucleophilic substitution of the 4-fluorine of the title compounds. 相似文献
15.
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
16.
Junzo Nokami Toshio Ono Shoji Wakabayashi Atsuo Hazato Seizi Kurozumi 《Tetrahedron letters》1985,26(16):1985-1988
PGJ2 analogues, the title compound () and its related derivatives (, ), were synthesized the three-component coupling process involving 1,4-addition reaction of phenylsulfinylallylic carbanion (′) to cyclopentenone derivative () followed by trapping the generated enolate with aldehyde (). 相似文献
17.
Syntheses of the labile ketone are described. Bromine rapidly converts to a deep blue substance, C26H20O, for which the heptacyclic structure is uniquely established. 相似文献
18.
-2-Chlorostilbene undergoes uncatalyzed LiAlH4 reduction giving phenanthrene and -stilbene. An electron transfer radical mechanism is proposed. LiAlH4 induced isomerization of -stilbene produces -stilbene. 相似文献
19.
An intense EPR spectrum observed in UV-irradiated solid Kr/CF3OF solutions at 10 K shows anisotropic hyperfine interactions of a single unpaired electron with one nuclear spin of and (using isotopically enriched 83Kr) two equivalent spins of . The spectrum is attributed to the linear radical KrFKr having a 2Σu ground state. 相似文献
20.
Previous (1) work on ternary chalcopyrite solid solution formation has shown that the difference in end point axial ratios () is an important factor in determining the extent of mutual solubility. It was concluded that when complete solid solubility will not occur. In this work it is shown that complete solid solution formation in the systems AgAlS2AgInS2 (), AgGaS2AgInS2 () and AgAlSe2AgInSe2 () does occur. This shows that the value of as an upper limit for solid solution formation can be approached closely. 相似文献