Letters in Organic Chemistry - Volume 18, Issue 11, 2021

Piperidine-based alkaloids are undoubtedly an important class of biologically active natural products. When a unique group, like trifluoromethyl (Tfm), is added to an active compound, it significantly ameliorates its bioactivity, bioavailability, physical, and chemical properties. Many fluorination and trifluoromethylation methods have been reported. In the present paper, we have shown that among all other trifluoromethylation pathways, the Mannich reaction has the great tendency to introduce the Tfm group in a saturated or aromatic heterocyclic compound. Applications of this reaction are elaborated in preparing several derivatives of piperidine-based alkaloids with trifluoromethyl at α-position. Furthermore, the substitution at C-4 and C-6 was successfully achieved with a variety of saturated and aromatic groups.

Rhodium-catalyzed hydrocarbon bond activation of N-heterocycles and decarboxylative Michael addition with coumarin-3-carboxylic acids has been well achieved. Various N-heterocycles substituted 3,4-dihydrocoumarin could be easily provided with excellent chemo- and regioselectivity in good to excellent yields. A class of functional groups on N-heterocycles and coumarin-3-carboxylic acids is compatible with this process. A stoichiometric amount of Zn(OAc)2 is necessary for the high yield of products.

A very convenient methodology to oxidize benzyl alcohols to benzaldehydes (9 examples, up to 95%) and secondary alcohols to ketones (8 examples, up to 99%) using trichloroisocyanuric acid in CH2Cl2 / MeCN (1:1) as co-solvent in the presence of water at room temperature is presented in this study.

Herein, an efficient and scalable synthesis of 2,4-diaryl substituted chromene [43-b] pyridine derivatives, using a multicomponent reaction strategy by microwave irradiation of 4-amino 2-oxo- 2H-chromene, aromatic aldehydes, and substituted anilines is described. This synthetic strategy was found to be very useful as it follows environment benign protocol. Also it gives a good outcome in terms of yield and requires a shorter reaction time.

Quinoxaline is a versatile heterocyclic moiety that posses almost all types of biological activities. The present work is a sincere attempt to review synthetic investigations of quinoxaline. A wide plethora of literature is available possessing different synthetic methods utilized for the synthesis of quinoxaline based scaffolds. The present review focuses on the various synthetic approaches of quinoxaline derivatives, which includes a summary of the advancement made over the past years in the synthesis of the quinoxaline nucleus and its derivatives. Some of these methods are mentioned in the review article associated with industrial applicability.

Coumarin is a heterocyclic scaffold and its derivatives, namely Schiff bases, esters, and hydrazides, etc., play an important role in the field of agrochemical and pharmaceutical industry due to its structure. Over the years, various biological activities like antifungal, antimicrobial, antiviral, anti-cancerous, anti-tumor, anti-inflammatory, anti-filarial, enzyme inhibitors, antiaflatoxigenic, analgesics, antioxidant and Oestrogenic, etc., have been analyzed. This review covers the latest literature and knowledge on the synthetic procedures for various coumarin and its derivatives, their biological and pharmacological applications.

series of new 1,2,3 triazoles hybrids were synthesized using a Cu-catalysed azide-alkyne cycloaddition reaction. Thus, a remarkable rapid click reaction of aryl azides with terminal alkynes at room temperature in DMF afforded new 4-((1-((1-(4-methoxy-3-nitrophenyl)-1H-1,2,3-triazol-4- yl)methyl)-1H-indol-3-yl)methylene)-3-methyl-1-phenyl-1H-pyrazol-5(4H)-ones in good to excellent yields. The reaction provides a safe, efficient and economic approach for the synthesis of various 1,2,3 triazoles. The reaction has many advantages like shorter reaction times, good yields of products and isolation of the products without the need for column chromatography. By using knoevenagel reaction under physical grinding with alkylating agents prepared various 1,2,3 triazoles.

The aim of this research work is to synthesise, study and analyse photocatalytic degradation, kinetics and microbial activity of new surfactant Copper (II) soya urea complex (CSU). Photocatalytic degradation has gained the attention of the scientific community throughout the world due to its multiple applications in environment, energy, wastewater treatment, pollution control, green chemistry, etc. Copper (II) soya urea complex has been synthesized and characterized through FT-IR, NMR, ESR studies. Present work deals with the study of photocatalytic degradation of Copper (II) soya urea complex by using ZnO as a semiconductor. This study employs a semiconductor catalyst using non-polar and non-aqueous solvent in photocatalytic degradation. The reaction rate is chosen as the photocatalytic activity, which has been governed by several factors. Antibacterial activities of the Copper (II) complex have also been studied against Staphylococcus aureus. Optical density (O.D.) was measured after different time intervals spectrophotometrically to measure the degradation of the complex. Mueller- Hinton agar medium was used for antimicrobial activity of synthesized compounds at different concentrations by disk/well diffusion susceptibility testing. Plot of 2+log O.D. (absorbance) versus time was plotted and found linear. The heterogeneous photocatalysis followed pseudo-first-order reaction kinetics. The present study suggests that Copper (II) soya urea (CSU) complex shows antibacterial activity against Staphylococcus aureus at different concentrations. The results were used to determine the rate of photocatalytic degradation of CSU complex. It has been found that the rate of degradation varies with different parameters like concentration of complex, amount of catalyst, light intensity, solvent polarity, etc. CSU complex derived from soyabean oil has been shown an inhibitory effect on the growth of S. aureus, which may cause skin disease.

This report describes an efficient and mild approach for the synthesis of Piperastrol and Enastron via a one-pot three-component cyclocondensation reaction employing ammonium sulfocyanate (NH4SCN) on gram scale in isopropyl alcohol–PEG 400 medium. In this reaction, ammonium sulfocyanate is not only the reacting component but also accelerates the rate of reaction to afford Biginelli compounds. High yields, short reaction time and easy workup procedure are the key advantages of the present protocol. Ammonium sulfocyanate is readily available, cheaper, safer and industrially acceptable inorganic salt.