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A straightforward protocol for the direct conversion of readily available coumarin‐3‐carboxylic acids to the corresponding 3‐iodocoumarins is described herein. Heating acetonitrile solution of coumarin‐3‐carboxylic acids, molecular iodine and potassium hydrogen phosphate resulted in the decarboxylative iodination of coumarin‐3‐carboxylic acids via radical mechanism. Various electron rich and electron poor coumarin‐3‐carboxylic acids were compatible with the established reaction conditions and consequently afforded the corresponding 3‐iodocoumarins in (46–93 %) reaction yields with minimum purification efforts. The formed products serve as valuable precursors to streamline more complex organic compounds incorporating coumarin core. [ABSTRACT FROM AUTHOR]

Plant-derived compounds and their extracts are known to exhibit chemo preventive (antimicrobial, antioxidant and other) activities. The levels of such chemo preventive compounds vary depending on environmental factors, including the regions where they grow. Described in this study are: (i) a phytochemical analysis of the two plants grown in the desert environment of Qatar, viz., Anastatica hierochuntica and Aerva javanica; (ii) the antibacterial, antifungal and antioxidant activities of various solvent extracts of these plants; (iii) a report on the isolation of several pure compounds from these plants. The phytochemical screening indicated the presence of glycosides, tannins, flavonoids, terpenoids, saponins, phenol and anthraquinones in various extracts of each of the plants. Antibacterial and antioxidant activities were studied using agar diffusion and DPPH methods, respectively. The extracts of Anastatica hierochuntica as well as Aerva javanica inhibit the growth of both gram-positive and gram-negative bacterial species. Various extracts of the two plants also exhibited higher or similar antioxidant activities as those of the standard antioxidants, α-tocopherol and ascorbic acid. The extracts of these plants were further purified by HPLC and characterized by IR and NMR techniques. This process has led to identification of β-sitosterol, campesterol and methyl-9-(4-(3,4-dihydroxy-1′-methyl-5′-oxocyclohexyl)-2-hydroxycyclohexyl)nonanoate from Anastatica hierochuntica, and lupenone, betulinic acid, lupeol acetate and persinoside A and B from Aerva javanica. The results reported herein suggests that Anastatica hierochuntica and Aerva javanica are potent sources of phytomedicines. [ABSTRACT FROM AUTHOR]

A new protocol for the synthesis of thieno[3,2- c ]coumarins is disclosed. In this method, a 3-formyl-2-oxo-2 H -chromene-4-thiolate anion is generated in situ by treatment of 4-chloro-3-formylcoumarin with sodium sulfide. This chromene-4-thiolate undergoes an l -proline-catalyzed substitution/Knoevenagel cascade with various α-halo ketones to afford the desired thienocoumarins in moderate to good isolated yields. This protocol eliminates the need for stoichiometric amounts of inorganic bases and the use of foul-smelling thiols. The reaction conditions tolerate a variety of α-halo ketones. [ABSTRACT FROM AUTHOR]

Over the last decades, molecularly imprinted polymers (MIPs) have emerged as selective synthetic receptors that have a selective binding site for specific analytes/target molecules. MIPs are synthetic analogues to the natural biological antigen–antibody system. Owing to the advantages they exhibit, such as high stability, simple synthetic procedure, and cost-effectiveness, MIPs have been widely used as receptors/sensors for the detection and monitoring of a variety of analytes. Moreover, integrating electrochemical sensors with MIPs offers a promising approach and demonstrates greater potential over traditional MIPs. In this review, we have compiled the methods and techniques for the production of MIP-based electrochemical sensors along with the applications of reported MIP sensors for a variety of analytes. A comprehensive in-depth analysis of recent trends reported on picomolar (pM/10−12 M)) and beyond picomolar concentration LOD (≥pM) achieved using MIPs sensors is reported. Finally, we discuss the challenges faced and put forward future perspectives along with our conclusion. [ABSTRACT FROM AUTHOR]

Acacia ehrenbergiana (Hayne), also known as Salam, is a highly drought resistant shrub distributed in North and East Africa, and the Arabian Peninsula. The plant is gathered for its gum and fiber, and is an important legume species for indigenous populations. In this study, the phytochemical analysis, antibacterial, and antioxidant properties of various alcoholic and aqueous extracts of Acacia ehrenbergiana grown in Qatar were investigated. The qualitative phytochemical screening of this species exhibited the presence of glycosides, tannins, flavonoids, terpenoids, saponins, phenol, and anthraquinones in various extracts. The agar diffusion method was performed to check the antibacterial activity. The acetone and ethanol extracts showed 85% antibacterial activity of the control against Gram-negative E. coli, while the acetone extract had 65% activity against the Bacillus Gram-positive species. The highest activity against Staphylococcus aureus was 65% for the butanol extract. The antioxidant capacities were evaluated by the DPPH method. Various extracts exhibited antioxidant activities similar to or higher than standard antioxidants, with the highest percent inhibition of 95% for the acetone and ethanol extracts. The acetone extracts were further purified by reverse phase combiflash chromatography followed by HPLC. Three of the pure compounds isolated were subjected to MS, FTIR, and NMR spectral analysis and were found to be stigmasterol, spinasterol, and theogallin. In conclusion, the observed antibacterial and antioxidant activities as well as the presence of secondary metabolites with potential medicinal activities makes Acacia ehrenbergiana a potent valuable endemic medicinal plant. [ABSTRACT FROM AUTHOR]