tert-Butyl azidoformate () reacts with the conjugate bases of , , (R1 = R2 = CH3), and (R1 = CH3, R2 = H) to give products [, , , and , respectively] in addition to the expected N-(tert-butoxycarbonyl)indole derivatives. 相似文献
4″,5-Bis-O-(-butyldimethylsilyloxyacetyl)-23-O-(4-methylphenyloxythiocarbonyl)avermectin B2a gave on pyrolysis and deprotection avermectin Bla, while reduction with tri-n-butyltin hydride followed by deprotection afforded 22,23-dihydroavermectin Bla (ivermectin). 相似文献
Treatment of either 3--butyl-2-adamantanol or 2-isopropenyl-2-methyladamantane with acid in the presence of a reducing agent (hydrogen iodide or tri--hexylsilane) yielded 2--butyladamantane as the major or exclusive product. Both precursors gave the 2-- butyl-2-adamantyl cation at ?78°C in FSO3H-SbF5-SO2ClF. 相似文献
Metalation of the 2-position in indolines and tetrahydroquinolines is feasible via their fomamidine derivatives using -butyllithium. The N-methyl group in N-methylanilines is also metalated using this base. 相似文献
The preparation, isolation and purification of the title bromide (1) are described, and the application of 1 as a mechanistic probe is demonstrated in the metal—halogen interchange reaction with -butyllithium. 相似文献
(E)- and (Z)-1-benzenesulfonyl-4-trimethylsilyl-2-butenes (E/Z=9), prepared from 4-trimethylsilyl-1-buten-3-ol, -butyllithium and benzenesulfenyl chloride and oxidation of the intermediate (E)- and (Z)-1-benzenesulfinyl-4-trimethylsilyl-2-butenes with hydrogen peroxide, react with -butyllithium and then primary halides to give 4-benzenesulfonyl-1-trimethylsilyl-2-alkenes which are rapidly 1,4-debenzenesulfonyltrimethylsilated to (E)-1,3-alkadienes by tetra--butylammonium fluoride at O°C. 相似文献
3,3-Difluoroallyltrimethyltin was prepared by reaction of chlorodifluoromethane with the ylide reagent Ph3PCHCH2SnMe3-Difluoroallyllithium, which was generated by the reaction of -butyllithium with 3,3-difluoroallyltrimethyltin in THF at ?95°, was of very limited stability at that temperature. However, procedures and alternate incremental addition procedures allowed its application in the synthesis of 1,1-difluoroallylsilanes from chlorosilanes and of CH2CHCF2C(OH)-Et2 from 3-pentanone. 相似文献
Allyl 2-pyridyl sulfide or allyl phenyl sulfone on treatment with n-butyllithium in tetrahyrofuran followed by tri-n-butylstannylmethyl iodide () afforded directly the 1,3-diene in good yield. 相似文献
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
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
The energies of EPR transitions of 160Gd3+ in La(C2H5SO43 · 9D2O at 77.2 K are observed to be nonlinear functions of field at low fields. The + , + and ?, ? transition energies converge asymmetrically below 10 G and differ by only ≈ MHz at the lowest fields employed. 相似文献
Treatment of N-phenyl- a well as N-methyl-3-(tri-bar|n-butylstannyl)-propionamide with 2 equiv of bar|n-butyllithium in the presence of 1,4-diazabicyclo[2.2.2]octane at ?78°C in tetrahydrofuran produced the corresponding dilithio derivatives (homoenolate dianions) and respectively. Reaction with various electrophiles (1 equiv) gave the terminally substituted amides in good yields. 相似文献
Subsolidus phase relations of ternary oxide systems containing divalent Fe, Mg, or Ni, trivalent Al, Cr, or Fe, and tetravalent Ti are characterized by solid solutions at metal/oxygen ratios , , and . At low temperatures only compounds with cubic or hexagonal close-packed oxygen and uniform oxygen coordination remain stable in the crystal structures NaCl, spinel, ilmenite-α-Al2O3, TiO2. The pseudobrookite phases FeTi2O5, MgTi2O5, Al2TiO5, Fe2TiO5, the V3O5 structure phase Cr2TiO5, and the Andersson phases Cr2Tin?2O2n?1 (n = 4,6,7,8,9) decompose. Additional phases with close-packed oxygen as predicted by a simple structure model for metal/oxygen ratios , , and do not form but presumably are important for nonstoichiometric solid solutions. Most differences between systems containing transition metals and the MgOAl2O3TiO2 system can be attributed to crystal field effects. 相似文献
Crystal structures for the fluorite-related phases CaHf4O9) and Ca6Hf19O44 () have been determined from X-ray powder diffraction data. qf1 is monoclinic, , with a = 17.698 Å, b = 14.500Å, c = 12.021 Å, β = 119.47° and Z = 16. qf2 is rhombohedral, , with a = 12.058 Å, α = 98.31° and Z = 2.Both phases are superstructures derived from the defect fluorite structure by ordering of the cations and of the anion vacancies. The ordering is such that the calcium ions are always 8-coordinated by oxygen ions, while the hafnium ions may be 6-, 7-, or 8-coordinated. The closest approach of anion vacancies is a fluorite subcell vector, and in each structure vacancies with this separation form strings. 相似文献
Phosphorus pentafluoride was reported long ago to give adducts 2 PF5 ·5 NH3 (1) and nNH3·PF5 (n= 1 ? 4) (2). None of the compounds was characterised in detail. Repeating the reaction of PF5 and NH3 we found the adduct H3N·PF5, , in 8% yield besides (H2N) 2PF3 (3) and NH4PF6. However, HF and (F2P=N)3 gave in 41% yield. The 1H, 19F, and 31P n.m.r. spectra of exhibit 14NH, 14NPF(cis), and 14NP coupling. The x-ray structure determination shows almost perfect octahedral geometry at phosphorus with a PN bond length of 1.842 ā. Compound is soluble in water without decomposition. Treatment with NH3 leads to the anion H2NPF5?. Upon heating forms in good yield H2NPF4 and NH4PF6. Without a solvent and NH3 react to give (H2N) 2PF3. A mechanism for the ammonolysis of PF5 is proposed. 相似文献
The crystal structure of Na4SnS4 and Ba2SnS4 (α) were determined.Na4SnS4 crystallizes in tetragonal system, space group with parameters a = 7.837 Å, c = 6.950 Å, Z = 2 and Ba2SnS4 (α) in the monoclinic system, space group with a = 8.481 Å, b = 8.526 Å, c = 12.280 Å, β = 112.97° and Z = 4.In these compounds, the crystal structure is built up from discrete orthothiostannate tetrahedra SnS4. The structure of Ba2SnS4 (α) is modified K2SO4β type. 相似文献
In CFCl3, aziridines react with F2(6 %/N2, 20°C), COF2 (20 %/N2, 40°C) and CF3OF [1] (20 %/N2, 40°C).Substitution products are obtained : l-(aziridine)carbonyl fluorides and l-Fluoroaziridines In (Et)2O, aziridines react with COF2 (20 %/N2, 10°C) and we have the carbonyl fluorides . Products IV can be thermally decomposed into β fluoro isocyanates.In CFCl3, N substituted aziridines react with F2(6%/N2, 20°C) and with CF3OF [2] (20%/N2, 40°C). No reaction is observed with COF2in our conditions (5% to 25%/N2, 80°C to + 40°C).Addition products are obtained : N Fluoro amines β fluorinated , N Fluoro and NN difluoro amines β trifluoro methoxylated and .with R = SO2Ø, COØNO2, Cl. 相似文献
The atomic arrangement in the fluorite-related phase, Ca2Hf7O16, has been determined by powder X-ray diffraction. The unit cell is rhombohedral, , with a = 9.5273Å, α = 38.801°, and Z = 1, and its volume is times that of the fluorite subcell from which it is derived. The cations are ordered on the cation sites of the fluorite structure with the calcium ions segregated into discrete layers parallel to the (111) fluorite plane: there is some evidence that the formal anion vacancies are also ordered. 相似文献
Irradiation of 2,4,6-tri-(tert,-butyl)thiobenzaldehyde with some alkoxy-, alkylthio-, and phenyl-allenes - gave one stereoisomer of a (2+2)-cycloadduct, viz. thietane in high yields (75–95%). Ringclosure is in agreement with MNDO-calculations. 相似文献