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181.
DaQingSHI JingCHEN QiYaZHUANG XiangShanWANG HongWenHU 《中国化学快报》2003,14(12):1242-1245
The condensation of aromatic aldehydes with acidic methylene compounds such as malononitrile, methyl cyanoacetate, cyanoacetamide, 5,5-dimethyl-1,3-cyclohexanedione,bartbituric acid and 2-thiobarbituric acid proceeded very efficiently in water in the presence of triethylbenzylammonium chloride (TEBA) and the products were isolated simply by filtration. 相似文献
182.
A novel two-step aldehyde homologation procedure for the preparation of methyl ketones has been developed, which involves the use of 1,1-dibromo-1-alkenes as precursors and zinc metal as mediator in near-critical water. 相似文献
183.
184.
Eric RaponiJean-Marc Pons 《Tetrahedron letters》2003,44(51):9193-9196
Silylketenes react under Kulinkovich conditions through two competitive pathways: alkene/ketene exchange versus nucleophilic addition. In both cases, the organotitanium intermediate reacts with an aldehyde to yield an adduct which can undergo an elimination to yield a vinylcyclopropanol or an α,β-unsaturated carbonyl compound. 相似文献
185.
A chloromethylated styrene-divinylbenzene copolymer support system functionalized with 4-benzaldehyde and 2-benzaldehyde was prepared.The degree of functionalization with aldehyde groups is well suited for the subsequent use of the products as Wittig reagents.The polymer bound aldehyde was reacted with Wittig reagents to give olefin groups grafted on styrene-divinylbenzene copolymers.The reactions were carried out in phase transfer catalysis conditions.A simple procedure for the calculation of the degree of functionalization and the statistical modeling of the structural repetitive unit of the copolymer are reported. 相似文献
186.
187.
首次使用气相色谱-质谱联用仪(GC-MS)对有机化合物重排反应进行了研究。苯基环氧化合物和α-氯代苯乙醇在气相色谱中发生重排反应,用质谱仪鉴定为其相应的羟基化合物。这种用GC-MS研究重排反应的方法在国内尚未见报道。此方法操作简便、反应迅速、产率高,为研究有机化合物的重排反应提供了一种新的方法。 相似文献
188.
189.
A simple, accurate and effective micellar electrokinetic capillary chromatography (MEKC) method for the separation and determination
of protocatechuic aldehyde (PA), danshensu (DSS), salvianolic acid B (SAB) and gallic acid (GA) in Chinese medicine 'SHUANGDAN'
granule was developed in this work. The separation was carried out in a 50.0 cm (42.0 cm to the detector) × 75 μm i.d. fused-silica
capillary using the optimum buffer solution containing 5.0 mM borate, 15 mM phosphate, 35 mM SDS and 10% (v/v) acetonitrile. The linear relationships between the concentration of the analytes and the corresponding peak areas were investigated,
and excellent linear behavior over the investigated concentration ranges was revealed (R2: 0.9985 for PA, 0.9994 for DSS, 0.9989 for SAB and 0.9991 for GA, respectively). The proposed method was successfully applied
to the determination of these four active components contained in 'SHUANGDAN' granule. The recoveries of these four components
were 97.6–101.2%, 97.6–100.5%, 96.9–101.6% and 97.6–102.9%, respectively. 相似文献
190.
边价连接性指数及其应用 总被引:5,自引:0,他引:5
基于邻接矩阵与边价 (fi)定义边价连接性指数 (mF) ,其中的0 F、1F及δmax与 85种链烷烃、72种脂肪族醛酮的沸点 (Tb)关联、得到良好的数学模型 :ln(783 -Tb) =6 4 95 0 6-0 0 5 1 1 3 0 F -0 0 6683 1F -0 0 1 1 80δmax(n =85 ) ,R =0 9984 ;ln(82 0 -Tb) =6 3 791 3 -0 0 3 0 3 5 0 F -0 0 71 661F +0 0 1 0 0 5δmax(n =72 ) ,R =0 9991。后一模型经Jackknife法检验具有总体稳健性。可以预示 ,该指数将在定量构效关系研究中成为重要参数 相似文献