4-(Succinimido)-1-butane sulfonic acid as a Br?nsted acid catalyst for the synthesis of pyrano[4,3-b]pyran derivatives using thermal and ultrasonic irradiation

4-(Succinimido)-1-butane sulfonic acid was shown to be anefficient and reusable Br?nsted acid catalyst for the synthesis of pyrano[4,3-b]pyran derivatives using thermal and ultrasonic conditions. The c...     

Greener and practical synthesis of 4,4′-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s through a conventional heating and a mechanochemical procedure

A new catalytic application of 4,4′-trimethylenedipiperidine for the efficient synthesis of 4,4′-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s is developed. According to the principles of green chemistry, the reaction was performed by conventional and non-conventional processes: (a) in the refluxing ethanol using a catalytic amount of organocatalyst; (b) at room temperature in the presence of organocatalyst in a planetary ball mill under solvent-free conditions. The organocatalyst could be reused up to 10 runs, and a negligible reduction of catalytic activity was detected. A variety of substituted 4,4′-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s were obtained in good–to-excellent yields under eco-friendly conditions. 4,4′-Trimethylenedipiperidine is commercially available and easy to handle and storage, less toxic, non-flammable, as well as it shows high thermal stability and good solubility in water. The current methodology has merits including (a) wide substrate-scope and high yields of the desired products in the short reaction times, (b) avoiding the use of hazardous solvents and acidic and metal-containing catalysts, (c) minimize the generation of hazardous waste, and (d) simple workup process. Based on great potential as a promising organocatalyst, we hope it can be used as a greener alternative to piperidine for other organic transformations.     

温和条件下丁二酰亚胺-N-磺酸催化合成双吲哚甲烷和香豆素衍生物(英文)

A mild and simple procedure is described for the synthesis of bis(indolyl)methane and coumarin derivatives using succinimide-N-sulfonic acid as an efficient,cheap,and reusable catalyst under mild conditions.     

液-固相体系中以聚(N-乙烯基咪唑)为非均相碱性催化剂在超声波照射和无溶剂条件下催化不同醛和酮羟醛缩合(英文)

An ultrasound‐assisted aldol condensation reaction has been developed for a range of ketones with a variety of aromatic aldehydes using poly(N‐vinylimidazole) as a solid base catalyst in a liquid‐solid system. The catalyst can be recovered by simple filtration and reused at least 10 times without any significant reduction in its activity. The reaction is also amenable to the large scale, making the procedure potentially useful for industrial applications.     

A novel sublimable organic salt: Synthesis,characterization, thermal behavior,and catalytic activity for the synthesis of arylidene,heteroarylidene, and alkylidene malonates

A novel sublimable organic salt was synthesized, and its chemical structure was characterized by FTIR, 1D NMR, 2D NMR, and elemental analysis. In addition, the thermal phase transitions and thermal stability of new organic salt were investigated. The DSC and TGA results showed that the organic salt could convert into constituent molecules at?<?145 °C before decomposition temperature (T_dec.?~?200 °C) under atmospheric pressure without forming the liquid phase. Then, it was recondensed to regenerate the initial organic salt in the cool part of the vial. Therefore, it can be a promising organic salt towards the regeneration of spent catalyst from synthesis processes when the reaction mixture contains poorly volatile components and includes its use in gas-phase procedures. Also, the catalytic efficiency of new organic salt was investigated in the Knoevenagel condensation reaction. A variety of substituted arylidene and alkylidene malonates were isolated in 78–95% yield within six hours.? Under the optimized reaction conditions, the current catalytic procedure exhibited superiority compared to the mixed piperazine/acetic acid, piperidine/acetic acid, and piperidinium acetate. There were no significant changes in the new organic salt chemical structure and catalytic activity even after the 5th run. This work revealed the importance of the existence of simultaneous hydrogen bond acceptor/donor groups in our environmentally friendly catalyst to promote the Knoevenagel condensation reaction without the use of metal-containing catalysts.

     

An Overview of Recent Advances in the Synthesis of Organic Unsymmetrical Disulfides

Organic unsymmetrical disulfides have been extensively applied in various academic and industrial fields including intermediates in organic synthesis, agriculture, and food science, natural materials, biochemistry, pharmaceutical and medicine chemistry, polymers, material engineering, etc. They play a crucial role in the fabrication of various biological active sulfur heterocycles. Due to broad and extensive applications, many methods have been developed for the synthesis of unsymmetrical S−S and efforts have been made to improve some issues such as cost, energy efficiency, green chemistry, avoid or minimizing waste generation. Several outstanding review articles have been previously published highlighting the advances of S−S bond formation, in general, using various reagents under different conditions in the absence or presence of oxidants/catalysts. In 2020, a review paper was published by our group focusing on recent developments since 2014 in the synthesis of organic symmetrical disulfides. However, investigations on new catalytic methods are being regularly reported and new types of unsymmetrical disulfides are synthesized. The present overview has attempted to systematically summarize recent advances in the process of unsymmetrical S−S bond formation with a major focus since 2010, highlighting mechanistic considerations, substrate scope, advantages, and limitations. The patents are not studied in this overview.     

Application of nitrogen-rich porous organic polymer for the solid-phase synthesis of 2-amino-4H-benzo[b]pyran scaffolds using ball milling process

Molecular Diversity - This paper presents the efficient synthesis of 2-amino-4H-benzo[b]pyrans using mesoporous poly-melamine-formaldehyde as a polymeric heterogeneous catalyst. According to the...     

(Bbpy)(HSO_4)_2无卤素可重复使用 Brnsted 离子液体催化剂用于一锅法多组分合成非对称多氢喹啉衍生物（英文）

1,1'‐Butylenebispyridinium hydrogen sulfate is an efficient, halogen‐free and reusable Brnsted ionic liquid catalyst for the synthesis of ethyl‐4‐aryl/heteryl‐hexahydro‐trimehtyl‐5‐ oxoquino‐line‐3‐carboxylates by the one‐pot condensation of dimedone, aryl/heteryl aldehydes, ethyl aceto‐acetate, and ammonium acetate under solvent‐free conditions. This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The ionic liquid can be re‐cycled five times without significant loss of the catalytic activity.