Imidazolium-Based Phosphinite Ionic Liquid (IL-OPPh2) as Reusable Catalyst and Solvent for the Knoevenagel Condensation Reaction

A task-specific ionic liquid (IL, OPPh₂) that bears a phosphinite weak Lewis base group in an imidazolium cation was found to efficiently catalyze the Knoevenagel condensation of arylaldehydes with malononitrile, dimethyl(diethyl)malonate, and ethyl cyanoacetate. This IL plays a dual role as both the reaction media and also catalyst, and it can be easily recovered and reused in several runs. Satisfactory results were obtained with good yields, short reaction time, and simplicity in the experimental procedure. A variety of coumarin derivatives were synthesized in this procedure.     

Microbial reduction of coumarin, psoralen, and xanthyletin by Glomerella cingulata

Microbial transformation of coumarin, psoralen, and xanthyletin was performed with the fungus Glomerella cingulata. The main reaction pathways involved reduction at α,β-unsaturated δ-lactone ring on coumarin analogue. Coumarin was metabolized by G. cingulata to give the corresponding reduced acid, hydrocoumaric acid. In the biotransformation of psoralen, two reduced metabolites, 6,7-furano-hydrocoumaric acid, and 6,7-furano-o-hydrocoumaryl alcohol were isolated from the incubation of psoralen. Xanthyletin was converted to reduced products 9,9-dimethyl-6,7-pyrano-hydrocoumaric acid and 9,9-dimethyl-6,7-pyrano-o-hydrocoumaryl alcohol by G. cingulata. The structures of the new compounds were characterized using spectroscopic techniques. In addition, all of compounds including methyl ester derivatives of the metabolites were tested for the β-secretase (BACE1) inhibitory activity in vitro. 6,7-Furano-hydrocoumaric acid methyl ester was shown to possess BACE1 inhibitory activity, and an IC₅₀ value was 0.84 ± 0.06 mM.     

Synthesis and electrochemical properties of crown ether functionalized coumarin substituted cobalt and copper phthalocyanines

The synthesis of novel 6,7-[15-crown-5]-3-[p-(3,4-dicyanophenoxy)phenyl]coumarin (1)/6,7-[15-crown-5]-3-[p-(2,3-dicyanophenoxy)phenyl]coumarin (2) and their peripherally/non-peripherally cobalt and copper phthalocyanine complexes (3-6) have been prepared and characterized by elementel analysis, ¹H-NMR, MALDI-TOF, FT-IR and UV-Vis spectral data. Fluorescence intensity changes of compound 1 and 2 have been determined by addition of Na⁺ or K⁺ ions at 25 °C in THF. The effect of substitution type on the redox and aggregation behaviour of the compounds was investigated by voltammetry and in situ spectroelectrochemistry.     

β-环糊精和遥爪聚合物C-PDMAEMA的包结行为

以香豆素二硫化物(C-S-S-C)/三丁基膦(Bu3P)复合体系为链转移剂,甲基丙烯酸-N,N-二甲氨基乙酯(DMAEMA)为单体,偶氮二异丁腈(AIBN)为引发剂制备了末端为香豆素光响应基元的双亲性遥爪聚合物(C-PDMAEMA).用傅里叶变换红外(FTIR)光谱仪、凝胶渗透色谱(GPC)、核磁共振氢谱(1H-NMR)等对该聚合物进行了结构表征.并用紫外-可见吸收光谱和荧光光谱及光二聚反应考察了β-环糊精与香豆素端基的包结络合行为.研究表明:β-环糊精与香豆素端基足以1∶1形式进行包结,其包结常数K=(1.270+0.062)x104 L·mol-1;光二聚反应实验表明该包结络合作用处于一快速平衡中,其对香豆素端基光二聚反应的影响甚微.