Green synthesis of bis-coumarin derivatives using Fe(SD)3 as a catalyst and investigation of their biological activities

A convenient, practical, green, and environmentally friendly method was developed for the synthesis of biscoumarins and corresponding tetrakis products from the reaction of 4-hydroxycoumarin and various aldehydes. The bis-coumarins were synthesized in high yield under mild reaction conditions. Products were obtained in the presence of in situ prepared Fe(SD)₃ [Iron(III) dodecyl sulfate] as a combined Lewis acid–surfactant catalyst (LASC) in water in short reaction times. Also, the antibacterial activity of compounds was screened against Pseudomonas aeruginosa and Escherichia coli as Gram-negative bacteria and Micrococcus luteus and Staphylococcus aureus as Gram-positive bacterial strains. Products 3g , 3k–l were most active than cefotaxime against E. coli and also compounds 3c and 3g were most active than cefotaxime against S. aureus.     

对苯二甲醛双缩硫代氨基脲的合成与晶体结构

对苯二甲醛双缩硫代氨基脲的合成与晶体结构;杀菌活性     

Corrosion Inhibition of Mild Steel in Hydrochloric Acid Environment Using Terephthaldehyde Based on Schiff Base: Gravimetric,Thermodynamic, and Computational Studies

Using traditional weight-loss tests, as well as different electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy), we investigated the corrosion-inhibition performance of 2,2′-(1,4-phenylenebis(methanylylidene)) bis(N-(3-methoxyphenyl) hydrazinecarbothioamide) (PMBMH) as an inhibitor for mild steel in a 1 M hydrochloric acid solution. The maximum protection efficacy of 0.0005 M of PMBMH was 95%. Due to the creation of a protective adsorption layer instead of the adsorbed H₂O molecules and acidic chloride ions, the existence of the investigated inhibitor reduced the corrosion rate and increased the inhibitory efficacy. The inhibition efficiency increased as the inhibitor concentration increased, but it decreased as the temperature increased. The PMBMH adsorption mode followed the Langmuir adsorption isotherm, with high adsorption-inhibition activity. Furthermore, the value of the ∆Gadso indicated that PMBMH contributed to the physical and chemical adsorption onto the mild-steel surface. Moreover, density functional theory (DFT) helped in the calculation of the quantum chemical parameters for finding the correlation between the inhibition activity and the molecular structure. The experimental and theoretical findings in this investigation are in good agreement.     

9，9’-（1，4-亚苯基）十四氢-二-吖啶-1，1＇,8，8’-四酮缩双季戊四醇的合成

利用1，3-环己二酮和1，4-苯二甲醛为原料，在微酸介质中通过羟醛缩合和脱水反应，合成了9，9’-（1，4-亚苯基）-2H，2’H，3H，3’H，4H，4’H，5H，5H’，6H，6’H，7H，7’H，9H，9’H-十四氢-二-吖啶-1，1’，8，8＇-四酮（化合物Ⅰ）。提出了化合物Ⅰ生成的反应机理。将化合物Ⅰ与季戊四醇在Ⅰ，催化下反应，生成了目标化合物9，9’-（1，4-亚苯基）-2H，2’H，3H，3’H，4H，4’H，5H，5H’，6H，6’H，7H，7’H，9H，9’H-十四氢-二-吖啶-1，1’，8，8’-四酮缩双季戊四醇（化合物Ⅱ），收率为40％。产物和中间体用IR、^1H NMR、MS和元素分析进行了结构表征。在含有螺环单元的化合物Ⅱ^1H NMR中，亚甲基中的8个氢由于受手性轴和苯环的影响而裂分成8重峰。对影响反应的因素特别是副产物生成的原因进行了探讨     

9,9-(′1,4-亚苯基)十四氢-二-吖啶-1,1,′8,8′-四酮缩双季戊四醇的合成

利用1,3-环己二酮和1,4-苯二甲醛为原料,在微酸介质中通过羟醛缩合和脱水反应,合成了9,9′-(1,4-亚苯基)-2H,2′H,3H,3′H,4H,4′H,5H,5H,′6H,6′H,7H,7′H,9H,9′H-十四氢-二-吖啶-1,1,′8,8′-四酮(化合物Ⅰ)。提出了化合物Ⅰ生成的反应机理。将化合物Ⅰ与季戊四醇在I2催化下反应,生成了目标化合物9,9-(′1,4-亚苯基)-2H,2′H,3H,3′H,4H,4′H,5H,5H,′6H,6′H,7H,7′H,9H,9′H-十四氢-二-吖啶-1,1,′8,8′-四酮缩双季戊四醇(化合物Ⅱ),收率为40%。产物和中间体用IR1、H NMR、MS和元素分析进行了结构表征。在含有螺环单元的化合物Ⅱ1H NMR中,亚甲基中的8个氢由于受手性轴和苯环的影响而裂分成8重峰。对影响反应的因素特别是副产物生成的原因进行了探讨