A practical and facile synthesis of various coumarin derivatives was conducted using a liquid phase of 4,4'-trimethylenedipiperidine as a safe and greener dual-task reagent under catalyst-free and solvent-free conditions. This reagent is a commercially available solid and can be handled easily, having a liquid phase over a vast temperature range, high thermal stability, low toxicity, and good solubility in green solvents such as water and ethanol. It is worth mentioning that 4,4'-trimethylenedipiperidine could be completely recovered and regenerated after a simple process. The current method has other merits, including (a) minimizing the use of high-risk and toxic reagents and solvents; (b) the use of a secure and recoverable medium-organocatalyst instead of metal-based catalysts, (c) avoid tedious processes, harsh conditions, and a multi-step process for the preparation of catalysts, (d) transform phenol and salicyladehyde derivatives into the corresponding coumarin derivatives in good to high yields, (e) minimize hazardous waste generation. TMDP could be easily recovered and reused several times with no change in its activity. Furthermore, the current work demonstrated that the liquid phase of 4,4'-trimethylenedipiperidine can be a promising medium in organic reaction at higher temperatures due to its broad liquid range temperature, thermal stability, acceptor/donor hydrogen bond property, and other unique merits. New methodology for the synthesis of coumarines using liquid phase of TMDP under mild conditions.
Myrtus, commonly called myrtle, is a genus of flowering plants in the Myrtaceae family. This study aimed to review myrtle's pharmaceutical, food, and other uses. The pharmacological effects of myrtle for antioxidant, antibacterial, and anti-inflammatory activities, reduction of COVID-19 symptoms, anti-diabetic in the animal model, hepatoprotective in the rat model, antihypertensive, control of intestinal helminthiasis in mice model, inhibition of glucosyltransferase activity, protective effect on oxidative metabolism in the hypothyroidism model, and reducing the damage caused by skin burns are reviewed. In addition, the food uses of this plant such as improving the oxidative and microbial stability of products containing salmon, antimicrobial activity in meat and dairy products, flavoring in sea salt, microbial improvement of fresh fruits during post-harvest storage, animal nutrition, and bio-oil production are summarized.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s41110-023-00194-y.
The catalytic activity of poly(N-vinylimidazole), a biocompatible and biodegradable synthetic functional polymer, was investigated for the synthesis of oximes as an efficient, halogen-free, and reusable heterogeneous catalyst. The corresponding oximes were afforded in high to excellent yields at room temperature and in short times using the planetary ball mill technique. Some merits, such as the short reaction times and good yields for poorly active carbonyl compounds, and avoiding toxic, expensive, metal-containing catalysts, and hazardous and flammable solvents, can be mentioned for the current catalytic synthesis of the oximes. Furthermore, the heterogeneous organocatalyst could be easily separated after the reaction, and the regenerated catalyst was reused several times with no significant loss of its catalytic activity.
Nanoliposome and nanoniosome formulations containing myrtle extract were prepared without using cholesterol and toxic organic solvents for the first time. The formulations had different concentrations of lecithin (5, 7, and 9% w/w) and Hydrophilic-Lipophilic Balance (HLB) values (6.76, 8.40, and 9.59). The physicochemical characterization results showed a nearly spherical shape for the prepared nanosamples. The particle sizes, zeta potentials and encapsulation efficiencies for the prepared nanoliposomes and nanoniosomes were at a range of 260-293 nm and 224-520 nm; -33.16 to - 31.16 mV and - 33.3 to - 10.36 mV; and 68-73% and 79-83%, respectively. The formulated nanoniosomes showed better stability during storage time. Besides, the encapsulation efficiency and in vitro release rate of myrtle extract could be controlled by adjusting the lecithin concentration and HLB value. The release of myrtle extract from nanovesicles showed a pH-responsive character. The FTIR analysis confirmed that the myrtle extract was encapsulated in nanovesicles physically.
Liquid phase tandem Knoevenagel-Michael condensation of various aromatic and heteroaromatic aldehydes with barbituric acid or 2-thiobarbituric acid and malononitrile was studied in a one-pot three-component reaction. For the first time, TMDP was employed as a safe and efficient solvent and/or catalyst in the liquid and aqueous ethanol medium, respectively, for the practical and eco-friendly Knoevenagel-Michael condensation. The reactions were carried out by using greener procedures, including a) the use of TMDP as an N-heterocycle organocatalyst in a green medium including water and ethanol (1:1 v/v) at reflux temperature, and b) the use of TMDP as a dual solvent-catalyst at 65 °C in the absence of any solvent. High to excellent yields of the desired pyrano[2,3- d ]pyrimidinones were obtained under the two earlier mentioned conditions. The current methodologies have advantages, including (a) avoiding hazardous, toxic, volatile, and flammable materials and solvents, (b) avoiding tedious processes, harsh conditions, and multiple steps for the preparation of catalysts, (c) using a less toxic and noncorrosive catalyst, (d) minimizing hazardous waste generation and simple workup process, and (e) high recyclability of TMDP. Another important result of this work is that the TMDP can be a promising alternative for toxic, volatile, and flammable base reagents such as piperidine and triethylamine in liquid phase organic syntheses owing to its unique properties such as being less toxic, nonflammable, and nonvolatile, and having a low melting point, broad liquid range temperature, high thermal stability, and safe handling and storage.