A CuAAC/Ullmann C-C coupling tandem reaction: copper-catalyzed reactions of organic azides with N-(2-iodoaryl)propiolamides or 2-iodo-N-(prop-2-ynyl)benzenamines

A novel copper-catalyzed tandem reaction was developed by utilizing two famous copper-catalyzed reactions, CuAAC and Ullmann coupling. The trapping of the C-Cu intermediate produced in CuAAC led to further formation of an aryl C-C bond through intramolecular Ullmann C-C coupling.     

Heterobimetallic hexanuclear [Mn(ΙΙΙ)4Ln(ΙΙΙ)2] clusters: a rare Mn(ΙΙΙ)4Nd(ΙΙΙ)2 example exhibiting slow relaxation of magnetization

Reactions of lanthanide perchlorates and manganese acetate with Schiff-base ligand (H(4)L = 2-(((2-hydroxy-3-methoxyphenyl)methylene)amino)-2-(hydroxymethyl)-1,3-propanediol) in methanol in the presence of triethylamine yielded two hexanuclear heterometallic clusters of general formula [Mn(4)(ΙΙΙ)Ln(2)(ΙΙΙ)(H(2)L)(2)(HL)(2)(CH(3)COO)(4)(CH(3)O)(2)(CH(3)OH)(4)](ClO(4))(2)·6CH(3)OH [Ln = La(ΙΙΙ) (1), Nd(ΙΙΙ) (2)]. 1 and 2 are isostructural, with the metal centres consisting of a nonplanar [Mn(4)(ΙΙΙ)Ln(2)(ΙΙΙ)(μ(2)-O)(8)(μ(3)-OR)(2)](8+) core. Variable-temperature solid state magnetic susceptibilities measurements of 1 and 2 in the temperature 2-300 K were performed, indicating dominant antiferromagnetic exchange interactions between the metal centres in both compounds. Alternating current (ac) susceptibility data for 2 displays out-of-phase signal suggesting slow relaxation of magnetization whereas no out-of-phase signal is observed in 1, highlighting the incorporation of lighter lanthanide leads to SMM property.     

Investigation of brush-type chiral stationary phases based on O,O'-diaroyl tartardiamide and O,O'-bis-(arylcarbamoyl) tartardiamide

Four chiral organosilanes based on O,O'-dibenzoyl tartardiamide, O,O'-bis-(3,5-dimethylbenzoyl) tartardiamide, O,O'-bis-(phenylcarbamoyl) tartardiamide and O,O'-bis-[(3,5-dimethylphenyl)carbamoyl] tartardiamide were synthesized and immobilized on silica to afford corresponding brush-type chiral stationary phases (CSPs) with well-defined structures. Using 54 compounds containing a wide variety of structures as analytes, the enantioselectivities of the four CSPs were evaluated under normal-phase modes. 3,5-Dimethyl substituent in the aryl group was found to significantly affect the enantioselectivity of CSPs containing aryl ester moieties. Aryl carbamate moieties in CSPs were observed more beneficial for enantioseparation than aryl ester moieties. The additional hydrogen-bond donors (NH) present in the carbamate groups contributed greatly to the enantioselectivity of CSPs, which is contrary to the results that have been found in network-polymeric CSPs.     

Head-to-tail dimerization and organogelating properties of click peptidomimetics

Click triazole-based oligopeptides 1-3 were found to self-dimerize (K(dim) ≈ 10-680 M(-1)) in a head-to-tail fashion based on (1)H variable concentration, 2D, and H/D exchange NMR, VPO, CD, FT-IR studies and Gaussian 03 simulations. The dimerization constant K(dim) was shown to increase with increasing number of the amino acid units. Within the same oligomeric series, the K(dim) value is strongly affected by the size of the C-terminal end group. The tripeptides 2 are also excellent organogelators of aromatic solvents.     

Establishment of a search library about benzylisoquinoline alkaloids based on selective separation on the binaphthyl column and standard analysis on C18 column

A search library about benzylisoquinoline alkaloids was established based on preparation of alkaloid fractions from Rhizoma coptidis, Cortex phellodendri, and Rhizoma corydalis. In this work, two alkaloid fractions from each herbal medicine were first prepared based on selective separation on the “click” binaphthyl column. And then these alkaloid fractions were analyzed on C18 column by liquid chromatography coupled with tandem mass spectrometry. Many structure‐related compounds were included in these alkaloids fractions, which led to easy separation and good MS response in further work. Therefore, a search library of 52 benzylisoquinoline alkaloids was established, which included eight aporphine, 19 tetrahydroprotoberberine, two protopine, two benzyltetrahydroisoquinoline, and 21 protoberberine alkaloids. The information of the search library contained compound names, structures, retention times, accurate masses, fragmentation pathways of benzylisoquionline alkaloids, and their sources from three herbal medicines. Using such a library, the alkaloids, especially those trace and unknown components in some herbal medicine could be accurately and quickly identified. In addition, the distribution of benzylisoquinoline alkaloids in the herbal medicines could be also summarized by searching the source samples in the library.     

Synthesis of 3,4‐Dihalogenated Furan‐2‐(5 H)‐ones by Electrophilic Cyclization of 4‐Hydroxy‐2‐alkynoates

Functionalized 3,4‐dihalogenated furan‐2(5 H)‐ones can be readily prepared in moderate to good yields by treating 4‐hydroxy‐4‐arylbut‐2‐ynoate derivatives with ICl, IBr, and I₂. Both halogen atoms of the electrophile are incorporated in the product. The resulting halides can further afford polycyclic aromatic compounds using known palladium‐catalyzed coupling reactions.     

Diastereoselective Total Synthesis of (±)‐Schindilactone A,Part 2: Construction of the Fully Functionalized CDEFGH Ring System

The successful synthesis of the highly complex model compound ( 2 ) of the CEFGH ring system of schindilactone A ( 1 ) is described. Several synthetic methodologies were developed and applied to achieve this goal, including ring‐closing metathesis (RCM) and Co–thiourea‐catalyzed Pauson–Khand reactions. Furthermore, two independent approaches were developed for the construction of the GH ring of model compound 2 , the key steps of which included Pd–thiourea‐catalyzed carbonylative annulation, methylation, and sequential RCM/oxa‐Michael‐addition reactions. The chemistry developed herein has provided a greater understanding of the synthesis of schindilactone A ( 1 ) and its analogous compounds of the same family.     

Epoxy ether cleaving reactions catalyzed by supporting Lewis acidic ionic liquid

Lewis acidic ionic liquids were used to catalyze the reaction of epoxypropane with POCl₃.Considering the lower cost and catalytic activities,we concluded that[Et₃NH]Cl/AlCl₃ was the most attractive ionic liquid from an economical point of view.But it would be easily inactivated because of sensitive to water and air.Moreover,it could not be reused easily because of difficulty recovery in the reaction.However,supporting[Et₃NH]Cl/AlCl₃ catalyst could resolve above problems.Supporting[Et₃NH]Cl/ AlCl₃ catalyst could be separated by filter easily and reused 5 times in 98%yield.Furthermore,the catalyst was applicable to other epoxy ether cleaving reactions.     

西安市某辖区2～6岁儿童全血样品微量元素含量状况调查

摘要对西安市某辖区妇幼保健站及多家幼儿园920名2～6岁身体健康儿童的全血样品进行微量元素检测,统计得到该区域正常儿童微量元素的含量范围,为准确了解西安地区某区域2-6岁正常儿童体内微量元素正常含量提供了参考数据。