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Chan-Lam coupling is one of the most popular and easy methods to perform arylation of amines (N-arylations). This cross-coupling is generally performed by reacting aryl boronate derivatives with a variety of substrates involving nitrogen containing functional groups such as amines, amides, ureas, hydrazine, carbamates. This article summarizes the synthetic applications of this reaction and the efforts of scientists to develop novel and efficient methodologies for this reaction.

BackgroundCarica papaya is a well known medicinal plant used in the West and Asian countries to cope several diseases. Patients were advised to eat papaya fruit frequently during dengue fever epidemic in Pakistan by physicians. This study was conducted to establish Polyphenols, flavonoids and antioxidant potential profile of extracts of all major parts of the C. papaya with seven major solvents i.e. water, ethanol, methanol, n-butanol, dichloromethane, ethyl acetate, and n-hexane.ResultsTPC, TFC, antioxidant and antibacterial potential were determined using different aqueous and organic solvents in addition to the determination of trace element in leaves, pulp and peel of C. papaya. Total soluble phenolics and flavonoids were found in promising quantity (≈66 mg GAE/g) especially in case of methanol and ethanol extracts. Antioxidant activity using DPPH free radical scavenging assay indicated leaves, bark, roots and pulp extracts showed >75.0 % scavenging potential while leaves and pulp showed 84.9 and 80.9 % inhibition of peroxidation, respectively. Reducing power assay showed leaves, pulp and roots extracts active to reduce Fe3+ to Fe2+ ions. The antibacterial study showed pulp extract is the best to cope infectious action of bacteria.ConclusionThis study was conducted to test the medicinal profile of all parts of C. papaya by extracting secondary metabolites with organic and aqueous solvents. Ethanol and methanol both were found to be the best solvents of choice to extract natural products to get maximum medicinal benefits and could be used to medicinal formulation against different infectious diseases.Graphical abstractMedicinal evaluation of different parts of C. papaya.

Aziridine ring opening reactions have gained tremendous importance in the synthesis of nitrogen containing biologically active molecules. During recent years, a great effort has been put forward by scientists toward unique bond construction methodologies via ring opening of aziridines. In this regard, a wide range of chiral metal- and organo-catalyzed desymmetrization reactions of aziridines have been reported with carbon, sulfur, oxygen, nitrogen, halogen, and other nucleophiles. In this review, an outline of methodologies adopted by a number of scientists during 2013-2017 for aziridine ring opening reactions as well as their synthetic applications is described.

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The antioxidant activity and free radical scavenging capacity of the essential oil and three different extracts of wildly grown Mentha longifolia (M. longifolia) were studied. The essential oil from M. longifolia aerial parts was isolated by hydrodistillation technique using Clevenger-type apparatus. The extracts were prepared with three solvents of different polarity (n-hexane, dichloromethane, and methanol) using Soxhlet extractor. Maximum extract yield was obtained with methanol (12.6 g/100 g) while the minimum with dichloromethane (3.50 g/100 g). The essential oil content was found to be 1.07 g/100 g. A total of 19 constituents were identified in the M. longifolia oil using GC/MS. The main components detected were piperitenone oxide, piperitenone, germacrene D, borneol, and β-caryophyllene. The total phenolics (TP) and total flavonoids (TF) contents of the methanol extract of M. longifolia were found to be significantly higher than dichloromethane and hexane extracts. The dichloromethane and methanol extracts exhibited excellent antioxidant activity as assessed by 2,2′-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability, bleaching β-carotene, and inhibition of linoleic acid peroxidation assays. The essential oil and hexane extract showed comparatively weaker antioxidant and free radical scavenging activities. The results of the study have validated the medicinal and antioxidant potential of M. longifolia essential oil and extracts.