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Fulltext Poly(N-vinylimidazole): A biocompatible and biodegradable functional polymer, metal-free, and highly recyclable heterogeneous catalyst for the mechanochemical synthesis of oximes

Gorjian H, Fahim H, Ghaffari Khaligh N

Turk J Chem, 2021;45(6):2007-2012.
PMID: 38144580 DOI: 10.3906/kim-2107-44

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.
Organocatalytic Synthesis of (Hetero)arylidene Malononitriles Using a More Sustainable, Greener, and Scalable Strategy

Johari S, Rafie Johan M, Ghaffari Khaligh N

Curr Org Synth, 2024 Jan 12.
PMID: 38231061 DOI: 10.2174/0115701794268766231108110816

AIM AND OBJECTIVE: The establishment of a green and sustainable Knoevenagel con-densation reaction in organic chemistry is still crucial. This work aimed to provide a newly de-veloped metal-free and halogen-free catalytic methodology for the synthesis of CS and (het-ero-)arylidene malononitriles in the laboratory and industrial scale. The Knoevenagel condensa-tion reaction of various carbonyl groups with malononitrile was investigated in ethanol, an eco-friendly medium, in the presence of seven nitrogen-based organocatalysts.
MATERIALS AND METHODS: A comparative study was conducted using two as-obtained and four commercially available nitrogen-based organocatalysts in Knoevenagel condensation reactions. The synthesis of CS gas (2-chlorobenzylidene malononitrile) using a closed catalytic system was optimized based on their efficiency and greener approach.
RESULTS: The conversion of 100% and excellent yields were obtained in a short time. The products could be crystallized directly from the reaction mixture. After separating pure products, the resi-due solution was employed directly in the next run without any concentration, activation, purification, or separation. Furthermore, the synthesis of 2-chlorobenzylidenemahmonitrile (CS) was carried out on a large scale using imidazole as a selected nitrogen-based catalyst, afforded crys-talline products with 95±2% yield in five consecutive runs.
CONCLUSION: Energy efficiency, cost saving, greener conditions, using only 5 mol% of organo-catalyst, high recyclability of catalyst, prevention of waste, recycling extractant by a rotary evaporator for non-crystallized products, demonstrated the potential commercial production of CS using imidazole in ethanol as an efficient and highly recyclable catalytic system.
Preparation and characterization of the encapsulated myrtle extract nanoliposome and nanoniosome without using cholesterol and toxic organic solvents: A comparative study

Gorjian H, Raftani Amiri Z, Mohammadzadeh Milani J, Ghaffari Khaligh N

Food Chem, 2021 Apr 16;342:128342.
PMID: 33092927 DOI: 10.1016/j.foodchem.2020.128342

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.
Fulltext Arene diazonium saccharin intermediates: a greener and cost-effective alternative method for the preparation of aryl iodide

Zaharani L, Ghaffari Khaligh N, Shahnavaz Z, Rafie Johan M

Turk J Chem, 2020;44(3):535-542.
PMID: 33488175 DOI: 10.3906/kim-2002-26

In the current protocol, the arene diazonium saccharin derivatives were initially produced from various substituted aromatic amines; subsequently, these intermediates were treated with a greener organic iodide for the preparation of the aryl iodide. We tried to choose low-cost, commercially available, biodegradable, recoverable, ecofriendly, and safe reagents and solvents. The arene diazonium saccharin intermediates could be stored in the liquid phase into a refrigerator for a long time with no significant loss activity. The outstanding merits of the current protocol (a) included the partial recovering of saccharin and tetraethylammonium salt, (b) reduce the use of solvents and the reaction steps due to eliminating separation and purification of intermediates, (c) good yield of the sterically hindered substrates, and (d) avoid the generation of heavy metal or corrosive waste.
Fulltext 4,4'-trimethylenedipiperidine as a nitrogen heterocycle solvent and/or catalyst: Liquid phase tandem Knoevenagel-Michael condensation

Zaharani L, Ghaffari Khaligh N, Gorjian H, Rafie Johan M

Turk J Chem, 2021;45(1):261-268.
PMID: 33679168 DOI: 10.3906/kim-2010-41

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.
Fulltext New protocols for the synthesis of 5-amino-7-(4-phenyl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate esters using an efficient additive

Ghaffari Khaligh N, Mihankhah T, Titinchi S, Shahnavaz Z, Rafie Johan M

Turk J Chem, 2020;44(4):1100-1109.
PMID: 33488215 DOI: 10.3906/kim-2005-6

This work introduces a new additive named 4,4'-trimethylenedipiperidine for the practical and ecofriendly preparation of ethyl 5-amino-7-(4-phenyl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate derivatives. This chemical is commercially available and easy to handle. It also possesses a low melting point and a broad liquid range temperature, high thermal stability, and good solubility in water. Based on green chemistry principles, the reaction was performed in a) a mixture of green solvents i.e. water and ethanol (1:1 v/v) at reflux temperature, and b) the additive was liquefied at 65 °C and the reaction was conducted in the liquid state of the additive. High yields of the desired triazolo-pyrimidines were obtained under both aforementioned conditions. Our results demonstrated that this additive, containing 2 Lewis base sites and able to act as an acceptor-donor hydrogen bonding group, is a novel and efficient alternative to piperidine, owing to its unique properties such as its reduced toxicity, nonflammable nature, nonvolatile state, broad liquid range temperature, high thermal stability, and ability to be safely handled. Furthermore, this additive could be completely recovered and exhibited high recyclability without any change in its chemical structure and no significant reduction in its activity. The current methodology has several advantages: (a) it avoids the use of hazardous materials, as well as toxic, volatile, and flammable solvents, (b) it does not entail tedious processes, harsh conditions, and the multistep preparation of catalysts, (c) it uses a metal-free and noncorrosive catalyst, and (d) reduces the generation of hazardous waste and simple work-up processes. The most important result of this study is that 4,4'-trimethylenedipiperidine can be a promising alternative for toxic, volatile, and flammable base reagents in organic synthesis owing to its unique properties.