A Recent Update on the Visible Light-promoted Organic Transformations - A Mini-review.

Visible light-induced reactions are a rapidly developing and powerful technique to promote organic transformations. They provide green and sustainable chemistry and have recently received increasing attention from chemists due to their wide application in organic synthesis. Light energy is eco-friendly, cheap, green, and inexhaustible with potential industrial and pharmaceutical applications. In this review, the most recent advances in visible light-induced reactions (2021-till date) have been highlighted.

Recent Advances in N-Heterocycles for COVID-19 Treatment - A Mini Review.

Severe emergencies occurred across the globe, beginning with the outbreak of SARSCoV in 2002, followed by MERS-CoV in 2012. In December 2019, an acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in Wuhan, China as the agent responsible for the recent COVID-19 pandemic outbreak. The virus rapidly spread throughout the world due to its high transmissibility, leading to enormous health problems and complexities. The COVID-19 pandemic has affected public health, the weak persons were severely affected by this virus. To stop the disease from spreading further, effective remedies are the need of the hour. Although SARS-CoV-2 vaccination campaigns are being carried out all over the globe, several new SARS-CoV-2 variants have emerged, and each has caused a wave of infections, highlighting an urgent need for therapeutics targeting SARS-CoV-2. Heterocyclic compounds have been explored extensively for a very long time for their biological activities, namely, anti-inflammatory, antimalarial, antitubercular, anticancer, antiviral, antimicrobial, antidiabetic, and many more bio-activities. Through this review, the author has tried to report the heterocyclic compounds synthesized all over the world over the last 2 years to fight against the SARS CoV-2 coronaviruses. The heterocyclic motifs mentioned in the review can serve as important resources for the development of COVID-19 treatment methods.

Ionic Liquids: Environment-Friendly Greener Solvents for Organic Synthesis.

Constituted by ions, ionic liquids (ILs) are evolving as greener solvents for many organic syntheses. Due to their high solvent power and low volatility, ionic liquids are serving as an environment-friendly substitute to conventional volatile organic solvents. The present review introduces ionic liquids as an insight into the diverse recent applications of ILs in organic synthesis.

Synthesis of some thiophene, imidazole and pyridine derivatives exhibiting good anti-inflammatory and analgesic activities.

A series of thiophene derivatives 1a-d & 2a-c were synthesized by condensation of 5-nitro-2-thiophene carboxaldehyde with mono and diamines respectively. Various imidazole derivatives 3a-c were obtained by condensing 4-(2-ethylamino)-1H-imidazole with 4-acetylpyridine, 2-acetylpyridine and 4-acetylbenzonitrile respectively. Pyridine derivatives 4a-e were synthesized by condensing 2-hydrazino-pyridine with various carbonyl compounds; 5a-c by condensing 2, 6-pyridine dicarbonyl dichloride with various aryl sulfonylhydrazides; 6, 7 by condensing 2, 6-dialdehyde pyridine with 2-hydrazinopyridine and anthranilonitrile respectively and compound 8 by condensing 2, 5-thiophene dialdehyde with hydrazinopyridine. All the compounds were characterized by IR, (1)HNMR, Mass spectra and elemental analysis. Compounds 1a-d; 2a-c; 3a-c; 4a-e; 5a-c, 6, 7 and 8 were screened for anti-inflammatory and analgesic activities. Compounds 1b and 2c exhibited good anti-inflammatory (26.5% and 33.4% at 50mg/kg p.o. respectively) and 3a, 3c good analgesic (100% and 75% at 100 mg/kg p.o. respectively) activities.

Synthesis of biologically active N-methyl derivatives of amidines and cyclized five-membered products of amidines with oxalyl chloride.

A series of substituted N-methylisonicotinamidine (2a-f), N-methylpyrazine-2-carboxamidine (2g-i) derivatives were synthesized by reaction of amidine derivatives (1a-i) with methyl iodide in presence of triethylamine. Five-membered condensed dihydroimidazolylbenzenesulfonamide derivatives (3a-i) were obtained by the reaction of amidine derivatives (1a-i) with acylating agent oxalyl chloride. All the compounds, i.e. 2a-i and 3a-i were purified by crystallization. Structures of all the synthesized compounds are supported by correct IR, (1)H NMR, mass spectral and analytical data. Anti-inflammatory activity evaluation was carried out using carrageenan-induced paw oedema assay and compounds 2e, 3a and 3d exhibited good anti-inflammatory activity (44%, 31% and 37% activity at 50 mg/kg p.o., respectively). Analgesic activity evaluation was carried out using acetic acid writhing assay and compounds 2a and 3f gave 75% activity each at 100 mg/kg p.o.; on the other hand compounds 3a and 3d exhibited 60% analgesic activity each at 50 mg/kg p.o. Compounds 3a and 3d exhibited good anti-inflammatory and analgesic activities.

One pot synthesis of pyrimidine and bispyrimidine derivatives and their evaluation for anti-inflammatory and analgesic activities.

A number of pyrimidine derivatives (1-10) have been synthesized by condensation of 4-isothiocyanato-4-methylpentan-2-one with furfurylamine, histamine, 1-(3-aminopropyl)imidazole, 1-(3-aminopropyl)-2-pyrrolidinone, 2-aminobenzonitrile and 3-isothiocyanatobutanal with 1-(3-aminopropyl)-2-pyrrolidinone and 2-hydrazinopyridine under different reaction conditions. Various bispyrimidine derivatives (11-15) were obtained by condensation of 4-isothiocyanato-4-methylpentan-2-one with 2,4,8,10-tetraoxaspiro[5,5]undecane3,9-dipropamine (11'), 1,4-bis(3-aminopropyl)piperazine (13'), 3,5-diamino 1,2,4-triazole (15') and 3-isothiocyanatobutanal with 2,4,8,10-tetraoxaspiro[5,5]undecane 3,9-dipropamine, 1,4-bis(3-aminopropyl)piperazine. All these compounds were characterized by correct FT-IR, (1)H NMR, MS and elemental analysis. These compounds were screened for anti-inflammatory and analgesic activities. Anti-inflammatory activity of 3 is comparable while analgesic activity was found to be better than that of standard drug.

Synthesis, anti-inflammatory and analgesic activity evaluation of some amidine and hydrazone derivatives.

A number of amidine derivatives (3a-i) were synthesized by condensation of cyanopyridine and cyanopyrazine with sulfonylhydrazides in the presence of sodium methoxide. 2-Acetylpyridine and 4-acetylpyridine were condensed with sulfonylhydrazides by microwave irradiation in solid phase to give corresponding hydrazones (5a-d). Indole-3-carboxaldehyde was condensed with sulfonylhydrazides by refluxing in acetic acid to give corresponding condensation product (5e and f). All the compounds, that is, 3a-i and 5a-f were purified by crystallization or by column chromatography. Structures of all the synthesized compounds are supported by correct IR, (1)H NMR, mass spectral and analytical data. Anti-inflammatory activity evaluation was carried out using carrageenin-induced paw oedema assay and compounds 3e,f and 5e exhibited good anti-inflammatory activity, that is 52%, 37% and 38% at 50 mg/kg po, respectively. Analgesic activity evaluation was carried out using acetic acid writhing assay and compounds 3a,c,e and 5f showed good analgesic activity, that is, 50%, 50%, 50% and 60% at 50 mg/kg po, respectively.