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A new facile synthetic method for the preparation of α-sulfonylphosphonates based on the phosphorylation of carbanion derived from sulfones bearing an active methylene group was described. Condensation of the resulting sulfonyl phosphorus ylides with aldehyde or ketone in situ gives α,β-unsaturated sulfones with satisfactory yields. 相似文献
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A new synthetic method for the preparation of α-amino-substituted benzylphosphonic acids with moderate to good yields was developed by the following sequence of reactions. Diethyl phosphoramide was reacted with substituted benzaldehyde and triphenyl phosphite in the presence of catalytic amount of BF3·Et2O. Diphenyl α-(N-phosphorylamino)-substituted benzylphosphonates ( 1 ) thus obtained was then treated with hydrogen bromide in acetic acid to remove selectively the amino-protecting group with the formation of diphenyl α-amino-substituted benzylphosphonates ( 2 ), a key intermediate in phosphorus peptide synthesis, which was then successively hydrolyzed with hydrobromic acid to give corresponding hydrobromide of α-amino-substituted benzylphosphonates with excellent yields. The free aminophosphonic acid ( 3 ) was obatined from the latter by treatment with propylene oxide. 31P NMR studies demonstrated that a linear relationship exists in plotting δ versus δ constants of nuclear substituent in 1 series. The p-substituted compounds give, as a rule, higher value in 31P NMR spectra than those from meta- and ortho-substituents. 相似文献
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采用电弱统一标准模型(SM),分析了由参与电弱相互作用的各种混合圈构成的光子γ,中间玻色子Zo重整化链图传播子的构架方式,并完成了相关解析计算,进而获得了γ,Z0重整化混合圈链图传播子的解析计算结果.作者又将γ,Z0混合圈链图传播子Dγ(m-chain)(s),DZ(m-chain)(s)和DγZ(m-chain)(s)应用到粒子反应e■→f■中,精确计算了e■→f■反应总截面σSM(chain).通过与LEP实验组的实验观测值的比较,发现本文理论计算结果比最低(树图)阶的结果与实验吻合更好. 相似文献
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The Ã-ketoimidoyl chlorides resulted from the reaction of acyl chlorides with ethyl isocyanoacetate provides 2-acyl 5-ethoxyoxazoles in moderate yields via a base-induced intramolecular cyclization. 相似文献
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YUAN Cheng-Ye ZHAI Hai-Xiao LI Shu-SenShanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai S China 《中国化学》1996,(3)
During the etherification of 1,2-O-isopropylidene-4,6-di-O-benzyl myo-inositol, the specific regioselectivity on 3- or 5-hydroxyl group was showed to be determined by the nature of the O-alkylating agents used. As demonstrated by MM and MNDO calculation, the regioselectivity of the reaction mentioned can be rationalized by steric and/or electronic effect. 相似文献
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The preparation and infrared spectroscopic studies of coordination compounds of salicylaldoxime, 2-hydroxy-acetophenone oxime, 2-hydroxy-benzophenone oxime and 2-hydroxy-4-methoxy-benzophenone oxime with copper (II), nickel (II), cobalt (II) and iron (II) are described. The frequency of the C=N stretching vibration is usually higher in the complex than that in the ligand. The higher this frequency is, the larger the stability constant of the complex will be, but there is no quantitative relationship. In the case of complexes of salicylaldoxime with Cu (II), Ni (II), Co (II) and Fe (II), vO=N values are correlated linearly with the ionization potentials of the central metal ions. The frequency of the OH stretching vibration is closely related to the geometric configuration of the complex. Thus aromatic hydroxyoximes form coordination compounds with Co (II) and Fe (II) with cis configuration possessing six-membered hydrogen-bonded ring. This is indicated in the infrared spectra by the complete absence of the OH stretching band, or by the appearance of an extremely broad and flat band of very low intensity. However, Cu (II) or Ni (II) complex possesses trans configuration with five-membered hydrogen-bonded bridge showing characteristic OH absorption band in the infrared region. The voh's of complexes investigated are closely related to the polar nature of substituents on the benzene ring. By examining the spectra of 63Cu and 65Cu complexes with 2-hydroxy-4(5)-substituted benzophenone oximes in the far infrared region, the characteristic frequency of M-O and M-N were assigned for a series of aromatic hydroxyoxime-transition metal complexes. 相似文献
27.
YUAN Cheng-Ye ZHAI Hai-Xiao WENG Guan-HongShanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai China 《中国化学》1994,12(2):174-178
A new synthetic approach to 1,4,6-tri-O-benzyl myo-inositol was described on the basis of the regioselective benzylation of 1,2-O-isopropylidene-4,6-di-O-benzyl myo-inositol, subsequent acid hydrolysis, phosphorylation with tetrabenazylpyrophosphate and appropriate deprotec-tion. 相似文献
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通过水热法,在黑磷(BP)纳米片表面生长FeOOH纳米材料,制备出FeOOH/BP纳米复合材料。作为电化学析氧反应(OER)催化剂,该复合材料在20 mA·cm-2时的过电位仅为191 mV,Tafel斜率为49.9 mV dec-1;在循环1 000圈后,过电位仅仅增加了3 mV,且循环过程中元素价态不变,表现出优秀的稳定性。纳米FeOOH负载于BP表面,客观上能隔断氧气对BP的氧化,保护BP的载流子传导性能。同时,生长的FeOOH颗粒尺度小,结晶性弱,这有利于丰富其活性位点,增大活性面积。 相似文献