Synthesis and evaluation of nitrate derivatives of colchicine as anticancer agents

To search for more potent antitumor agent,a series of novel nitric oxide-donating colchicine(Col) derivatives(6a-f,8a and b) were synthesized by coupling nitrates with N-methyl colchiceinamide.Their cytotoxicity against four human cancer cell lines in vitro were evaluated by MTT assay.It was found that many of the derivatives displayed significant activity,particularly,compounds 6c,8a and 8b showed more potent cytotoxic activities than Col.     

Quantification of imatinib and related compounds using capillary electrophoresis-tandem mass spectrometry with field-amplified sample stacking

A quantification method for imatinib (IM), its major metabolite N-desmethyl imatinib (NDI), and a degradation by-product was developed using CE–MS combined with an online concentration technique. The use of multiple reaction monitoring (MRM)–MS/MS further improved the sensitivity of this technology. Liquid–liquid extraction (LLE) using tertiary butyl methyl ether yielded high recovery and reproducibility for the pretreatment of serum samples. The recovery rate exceeded 83% for all three analytes, and was 90% for IM. To improve quantification results, a conductivity-induced online analyte concentration technique, field-amplified sample stacking (FASS), was used. The S/N ratios were improved at least 10-fold when compared with conventional capillary zone electrophoresis. The detection limits were 0.2 ng/mL for IM, 0.4 ng/mL for NDI, and 4 ng/mL for the degradation by-product. These results are superior to those previously obtained by other reported methods. The new method was validated in terms of its selectivity, intra- and interday repeatability and accuracy, and sample storage stability, following the guidelines issued by the European Medicines Agency. Considering the convenient pretreatment procedure (LLE), superior sensitivity, and fast analysis speed (<15 min), this method can be useful in the determination of imatinib levels in blood.     

聚吡咯纳米线凝胶的模板制备及储能与电化学传感性能

以配位聚合物凝胶为模板, 构筑均一的聚吡咯纳米线网络, 聚合后经简单处理除去模板, 得到性能优异的聚吡咯凝胶. 结果表明, 模板法合成的聚吡咯凝胶为由均一纳米线组成的三维网络结构, 具有良好的力学性能、 较大的比表面积及优异的电化学特性, 在0.28 A/g电流密度下, 比电容可达450 F/g, 在2.8 A/g电流密度下充放电1000次, 比电容仍可保持88.6%. 聚吡咯纳米线网络凝胶经葡萄糖氧化酶负载后得到柔性传感电极, 对低浓度(0.2 mmol/L)的葡萄糖具有快速响应性能, 有望用于超级电容器及生物电化学传感器等领域.     

Asymmetric Michael Addition/Intramolecular Cyclization Catalyzed by Bifunctional Tertiary Amine–Squaramides: Construction of Chiral 2‐Amino‐4H‐chromene‐3‐Carbonitrile Derivatives

The efficient asymmetric Michael addition/intramolecular cyclization of malononitrile with dienones catalyzed by a chiral bifunctional tertiary amine–squaramide catalyst for the synthesis of chiral 2‐amino‐4H‐chromene‐3‐carbonitrile derivatives was developed. The corresponding products were obtained in good to excellent yields (up to 99 %) with excellent enantioselectivities (up to 98 % ee) for most of the bisarylidenecyclopentanones.     

1,3‐Dehydro‐o‐Carborane: Generation and Reaction with Arenes

Like the importance of benzyne, witnessed in modern arene chemistry for decades, 1,2‐dehydro‐o‐carborane (o‐carboryne), a three‐dimensional relative of benzyne, has been used as a synthon for generating a wide range of cage, carbon‐functionalized carboranes over the past 20 years. However, the selective B functionalization of the cage still represents a challenging task. Disclosed herein is the first example of 1,3‐dehydro‐o‐carborane featuring a cage C? B bond having multiple bonding characters, and is successfully generated by treatment of 3‐diazonium‐o‐carborane tetrafluoroborate with non‐nucleophilic bases. This presents a new methodology for simultaneous functionalization of both cage carbon and boron vertices.     

Regioselective Insertion of o‐Carborynes into the α‐CH Bond of Tertiary Amines: Synthesis of α‐Carboranylated Amines

o‐Carboryne can undergo α‐C? H bond insertion with tertiary amines, thus affording α‐carboranylated amines in very good regioselectivity and isolated yields. In this process, the nucleophilic addition of tertiary amines to the multiple bond of o‐carboryne generates a zwitterionic intermediate. An intramolecular proton transfer, followed by a nucleophilic attack leads to the formation of the final product. Thus, regioselectivity is highly dependent upon the acidity of α‐C? H proton of tertiary amines. This approach serves as an efficient methodology for the preparation of a series of 1‐aminoalkyl‐o‐carboranes.     

Improved and Efficient Synthesis of Pyrrolo[2,3,4‐kl]acridin‐1‐one Derivatives under Ultrasound Irradiation

A improved and efficient procedure for the synthesis of pyrrolo[2,3,4‐kl]acridin‐1‐one derivatives via the reaction of isatin and enaminone catalyzed by ceric ammonium nitrate under ultrasonic condition has been developed. Compared with the conventional methods, the remarkable advantages of this method are mild reaction conditions, operational simplicity, higher yield, and shorter reaction times.     

An Efficient Synthesis of Isoxazoles and Pyrazoles under Ultrasound Irradiation

A series of 5‐arylisoxazole and 5‐aryl‐1H‐pyrazole derivatives was synthesized by the reaction of 3‐(dimethylamino)‐1‐arylprop‐2‐en‐1‐one with hydroxylamine hydrochloride or hydrazine hydrate under ultrasound irradiation without using any catalyst. This method has the advantages of easier work‐up, mild reaction condition, high yields, shorter reaction time, and environmentally benign procedure.     

Convex Hamilton-Jacobi Equations Under Superlinear Growth Conditions on Data

Unbounded stochastic control problems may lead to Hamilton-Jacobi-Bellman equations whose Hamiltonians are not always defined, especially when the diffusion term is unbounded with respect to the control. We obtain existence and uniqueness of viscosity solutions growing at most like o(1+|x| ^p ) at infinity for such HJB equations and more generally for degenerate parabolic equations with a superlinear convex gradient nonlinearity. If the corresponding control problem has a bounded diffusion with respect to the control, then our results apply to a larger class of solutions, namely those growing like O(1+|x| ^p ) at infinity. This latter case encompasses some equations related to backward stochastic differential equations.