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41.
James Elver Johnson Joanne A. Maia Karen Tan Abdolkarim Ghafouripour Patrice De Meester Shirley S. C. Chu 《Journal of heterocyclic chemistry》1986,23(6):1861-1868
O-Methyl-α-ketophenylacetohydroximoyl chloride ( 1 ) was prepared by the reaction of O-methyl-α-methoxyphenylacetohydroximoyl chloride ( 5 ) with N-bromosuccinimide and concentrated hydrobromic acid. Reaction of 1 with ethylenediamine gave 3-phenyl-5,6-dihydro-2(1H)-pyrazinone-O-methyloxime ( 6 ). 3-Phenyl-5,6-cyclohexano-5,6-dihydro-2(1H)-pyrazininone-O-methyloxime ( 7 ) was prepared by reaction of 1 with trans-1,2-diaminocyclohexane. The X-ray structure of 6 has been determined. The crystals are orthorhombic, space group Pbca with a = 10.264(3), b = 18.262(4), c = 23.530(4)Å, V = 4411(2)Å3, and Z = 16. The structure, which was refined to R = 0.038 using 1652 observed reflections, shows the amidoxime moiety to be the Z configuration. Reaction of benzohydroximoyl chloride with aziridine gave (Z)-aziridinylbenzaldoxime ( 16a ). Ultraviolet irradiation of a benzene solution of 16a gave a mixture of the Z and E isomers 16a and 16b . The E isomer 16b underwent thermal isomerization to 16a at 100°. Reaction of 16a with dimethyl sulfate in sodium hydroxide solution gave (Z)-O-methylaziridinylbenzaldoxime ( 17a ). Photoisomerization of a hexane solution of 17a gave a mixture of the Z and E isomers 17a and 17b which were separated by preparative glc. The isomers 17a and 17b are resistant to thermal Z = E isomerization. The mechanisms of thermal isomerization of benzamidoximes are discussed. 相似文献
42.
[reaction: see text] A protocol for the copper(II)-catalyzed etherification of aliphatic alcohols under mild and essentially neutral conditions is described. Air- and moisture-stable potassium alkenyl- and aryltrifluoroborate salts undergo cross-coupling with a variety of aliphatic primary and secondary alcohols and phenols, and are tolerant of a range of functional groups. The optimized conditions utilize catalytic copper(II) acetate with 4-(dimethylamino)pyridine as ligand in the presence of 4 A molecular sieves under an atmosphere of oxygen. 相似文献
43.
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The hexamolybdenum cluster complex [Mo6(3-Cl)8(O2CMe)6]2–, 1 was isolated as the Bu4N+ salt in 71% yield from the reaction of (Bu4N)2[Mo6(3-Cl)8Cl6] with AgO2CMe in CH2Cl2 solvent. The compound was characterized by single crystal X-ray diffraction analysis. The cluster contains an octahedral arrangement of six molybdenum atoms with eight chloride ligands bridging the eight trianglar faces and six carboxylate ligands terminally coordinated through one oxygen atom to each of the six molybdenum atoms. Crystal data: space group =P21/n,a=10.713(3)Å,b=14.43(1)Å,c=21.919(4)Å, =94.37(2)°,Z=2, 1965 reflections,R=0.036. 相似文献
46.
An organopalladium complex containing ortho-metalated (S)-(1-(dimethylamino)ethyl)naphthalene as the chiral auxiliary has been used to promote the asymmetric hydrophosphination reactions between diphenylphosphine and (E)- or (Z)-diphenyl-1-propenylphosphine in high regio- and stereoselectivities under mild conditions. Hydrophosphination of (Z)-diphenyl-1-propenylphosphine with diphenylphosphine gave (S)-(-)-prophos as the major product. Using the same chiral metal template, the corresponding hydrophosphination reaction with (E)-diphenyl-1-propenylphosphine gave (R)-(+)-prophos predominantly. The hydrophosphination reactions generated the asymmetric diphosphines as bidentate chelates on the chiral naphthylamine palladium templates. The template products obtained undergo cis-trans isomerization in solution to form an equilibrium mixture of regioisomers. X-ray analysis of the major template products obtained from the hydrophosphination of (Z)-diphenyl-1-propenylphosphine reveals that the two regioisomers are cocrystallized in a 1:1 ratio. The naphthylamine auxiliary could be removed chemoselectively from the template products by treatment with concentrated hydrochloric acid to form the corresponding optically pure neutral complexes [(R)- or (S)-(prophos)PdCl(2)]. Subsequently, the (R)- and (S)-dichloro complexes undergo ligand displacement with aqueous cyanide to generate the corresponding optically pure diphosphine ligands in high yields. Mechanistic pathways explaining the stereoselectivity of the chiral organopalladium template promoted hydrophosphination reactions are also proposed. 相似文献
47.
48.
聚丙烯纤维辐射接枝进展 总被引:1,自引:0,他引:1
本文对聚丙烯纤维的辐射接枝方法、特征和机理、以及其研究进展和表征进行了扼要综述。 相似文献
49.
Changlun Chen Di Xu Xiaoli Tan Xiangke Wang 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):227-233
The fate and transport of toxic metal ions and radionuclides in the environment is generally controlled by sorption reactions.
The extent of sorption of divalent metal cations is controlled by a number of factors including cosorbing or complexing. In
this work, the effects of pH, humic acid HA/Co(II) addition orders, ionic strength, concentration of HA, and foreign cations
on the Co(II) sorption on γ-Al2O3 in the presence of HA were investigated. The sorption isotherms of Co(II) on γ-Al2O3 in the absence and presence HA were also studied and described by using S-type sorption model. The experimental results showed
that the Co(II) sorption is strongly dependent on the pH values, concentration of HA, but independent of HA/Co(II) addition
orders, ionic strength, and foreign cations in the presence of HA under our experimental conditions. The results also indicated
that HA enhanced the Co(II) sorption at low pH, but reduced the Co(II) sorption at high pH. It was hypothesized that the significantly
positive influence of HA at low pH on the Co(II) sorption on γ-Al2O3 was attributed to strong surface binding of HA on γ-Al2O3 and subsequently the formation of ternary surface complexes such as ≡S-OOC-R-(COO−)
x
Co2−x
. Chemi-complexation may be the main mechanism of the Co(II) sorption on γ-Al2O3 in the presence of HA. 相似文献
50.
PhenNO—TTA—乳化剂OP荧光光度法测定微量铕 总被引:3,自引:0,他引:3
研究了Eu(Ⅲ)-PhenNO-TTA-乳化剂OP体系的荧光性质及其用于微量铕的测定。该体系具有良好的分析特性,最低检测限可达7.0×10^-14mol/L. 相似文献