Current Organic Synthesis - Volume 21, Issue 1, 2024

Aim: Organic Electro-optic (EO) materials have recently gained considerable attention owing to their advantages compared to inorganic EO materials. Among different kinds of organic EO materials, organic EO molecular glass exhibits desired prospect because of its high chromophore loading density and large macroscopic EO activity. Introduction: The objective of this study is to design and synthesize a novel organic EO molecular glass JMG utilizing julolidine moiety as the electron donor, thiophene moiety as the conjugated bridge, trifluoromethyl substituted tricyanofuran derivate (Ph-CF3-TCF) as the electron acceptor. Methods: The JMG’s structure was characterized through NMR and HRMS. The photophysical property, glass transition temperature, first hyperpolarizability (β) and dipole moment (μ) of JMG were determined through UV-vis spectra, DSC test and DFT calculation. Results: JMG’s Tg reached to 79°C and it can form high-quality optical film. The theoretical calculation shows that the first hyperpolarizability (β) and dipole moment (μ) of JMG were calculated to 730×10-³⁰ esu and 21.898 D. After connecting poling with the poling voltage of 49 V/μm at 90132;ƒ for 10 min, the highest EO coefficient (r33) of the poled JMG films reached to 147 pm/V. Conclusion: A novel julolidine-based NLO chromophore with two tert-butyldiphenylsilyl (TBDPS) groups was successfully prepared and characterized. TBDPS group is introduced as the film-forming group, and it also plays the role of isolation group, which can suppress the electrostatic interaction between chromophores, improve the poling efficiency and further enhance the EO activity. The excellent performances endow JMG with potential applications in device fabrication.

1, 2, 3-triazoles display enormous applications in the extensive fields of chemistry such as pharmaceuticals, ligands, conjectures, etc. Among these classes of compounds, the Nunsubstituted triazole emerges as a potent applicant for various fields of chemistry and therefore synthetic procedures for this molecular scaffold possess certain importance. Moreover, from an environmental perspective, metal-free organic synthesis gains tremendous attention as most of the metals are persistent in nature. In this review, we are going to discuss only the metal-free synthetic routes for the construction of N-unsubstituted 1,2,3-triazoles reported during the last decade.

The development of an active, selective, and long-term selective catalyst for the synthesis of biologically active heterocycles is still challenging. However, magnetic nanocatalysts have divergent applications like high efficiency, selectivity, consumption, and reusability. The current review explores a detailed survey of the latest information on synthetic methods of Pyrano [3, 2-c] chromene derivatives using different magnetic nanocatalysts. Numerous studies on the synthesis of these practical compounds have been stimulated by the special qualities and wide-ranging applications of pyrano coumarins and the nanoparticles were tested for their catalytic effectiveness in a one-pot, three-component reaction involving aldehydes, malononitrile, and 4-hydroxycoumarin for the synthesis of dihydropyrano [3, 2-c] chromenes (coumarins).

Background: Downy mildew is one of the major fungi causing significant economic losses to crops. The resistance of this fungus to current fungicides is increasing and new fungicides with a unique mode of action are needed. Objective: To find a novel pyrazole amide derivative as a potential fungicide. Methods: A series of pyrazole-5-carboxamide derivatives containing a diaryl ether were designed and synthesized by the Intermediate derivatization method (IDM). Their fungicidal activities against Pseudoperonospora cubensis (P. cubensis, cucumber downy mildew) were evaluated in the greenhouse. Results: Bioassays indicated that several compounds exhibited excellent fungicidal activity against P. cubensis in vivo. In particular, T24 (EC50 = 0.88 mg·L-1) had the highest activity compared with Dimethomorph and Fluazinam and other analogues. The relationship between the activity and the structure of these derivatives was analyzed, and an accurate and reliable three-dimensional quantitative structure-activity relationship (3D-QSAR) model was established to determine that electrostatic and steric fields had important effects on the improvement of fungicidal activity. Conclusion: The novel pyrazole-5-carboxamide derivative T24 can be considered a potential fungicide for P. cubensis control.

Introduction: L-proline is an efficient chiral small-molecule organocatalyst for the direct asymmetric aldol reaction between unmodified acetone and a variety of aldehydes. Methods: However, it is difficult to separate from the reaction medium for reuse. In this work, polyacrylic acid (PAA) supported The acylation reaction between L-hydroxyproline and PAA prepared lproline (P(AA-co-PA)) catalysts with various catalyst loadings. Fourier characterized them transforms infrared spectroscopy, nuclear magnetic resonance spectrum, gel permeation chromatography and thermogravimetry analysis. Results: These macromolecular catalysts were used to catalyze acetone and benzaldehydes' direct asymmetric aldol reaction. The influence of the catalyst structure on the catalytic performance was studied, and the reaction conditions were optimized. Conclusion: The results showed that P(AA-co-PA) with 50 mol% catalyst loading had excellent catalytic performance, much higher than that of L-proline and L-hydroxyproline. Its recovery was achieved by simple filtration. After being reused 7 times, its catalytic performance was still higher than that of L-proline.

Introduction: Seven new psoralen derivatives were synthesised by carbodiimide coupling to active carboxylic acid to amide formation in mild reaction conditions. Methods: The psoralen derivatives were produced through the condensation of seven different types of amine groups consisting of electron withdrawing groups and electron donating groups. Results: All the synthesised compounds were obtained with moderate to high yields. Structural characterization using ATR-FTIR, 1H NMR, 13C NMR, and HRMS has confirmed their structure. Moreover, in silico evaluation of the psoralen derivatives against the AChE enzyme was performed, and acetylcholinesterase inhibitory activity of psoralen derivatives was also conducted. Conclusion: Results from molecular docking show the potential of compound 12e as AChE inhibitors due to its highest binding energy value. It was further supported by the antiacetylcholinesterase activity of compound 12e, which has 91.69% inhibition, comparable to galantamine (94.12%). Furthermore, 100 ns run molecular dynamics (MD) simulation was used to refine docking results.

Background: Hydrated strontium perchlorate [Sr(ClO4)2.3H2O] acts as a very strong oxidizing and dehydrating agent. Until now, it could not be reported as a catalyst in dehydration mechanism-based organic synthetic reactions. Therefore, it is important to find whether it could be an effective catalyst for one-pot multicomponent reactions (MCRs). Objective: The main objective of the present work is the development of a novel process for the synthesis of 1,4-dihydropyrimidinones through the one-pot multicomponent strategy using hydrated Sr(ClO4)2 as a catalyst. Furthermore, it includes process optimization, stereoselectivity, and spectroscopic characterization of the synthesized compounds. Methods: Conventional and microwave-supported synthesis of 1,4-dihydropyrimidinones using 20 mol % of hydrated Sr(ClO4)2 catalyst via the one-pot solvent-free reaction was discovered as a new catalytic MCR methodology. The box-Behnken design approach and advanced analytical techniques were used for process optimization and reaction analysis. Results: The results confirmed that hydrated Sr(ClO4)2 works as an efficient catalyst for one-pot multicomponent organic synthesis under both conventional and microwave heating. It is an effective catalyst for laboratory synthesis of 1,4-dihydropyrimidinones stereoselectively with moderate to excellent yield without any undesirable effect. Microwave heating provided the desired product within 1-4 minutes. Moreover, this method provides easy isolation of the pure products simply by recrystallization, and without the use of a chromatographic purification method. Conclusion: The simplicity and neutrality of reaction conditions, easy post-reaction workup, higher satisfactory to excellent yield, effectiveness, the diversity of substrates, etc. render the hydrated Sr(ClO4)2 catalyst-based protocol for the stereoselective synthesis of 1,4-dihydropyrimidinones as a highly efficient method. Furthermore, it has been found to be safe un-der laboratory reaction conditions and no undesirable issues have been faced during the process

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