Fruit juice mediated multicomponent reaction for the synthesis of substituted isoxazoles and their in vitro bio-evaluation.

A simple, efficient and eco-friendly procedure for the synthesis of isoxazole derivatives (4a-4h) using one-pot three-component reaction between substituted aldehydes (1a), methyl acetoacetate (2a) and hydroxylamine hydrochloride (3a) has been achieved in presence of Cocos nucifera L. juice, Solanum lycopersicum L. juice and Citrus limetta juice respectively. The homogeneity of synthesized compounds was confirmed by melting point and thin layer chromatography. The synthesized compounds were characterized by using 1H NMR, FTIR and CHN analyses and evaluated for in vitro herbicidal activity against Raphanus sativus L. (Radish seeds). The compounds (4a-4h) were also screened for their fungicidal activity against Rhizoctonia solani and Colletotrichum gloeosporioides. Antibacterial activity was also tested against Erwinia carotovora and Xanthomonas citri. From bio-evaluation data, it was found that compound 4b was most active against Raphanus sativus L. (root) and Raphanus sativus L. (shoot) respectively. Compound 4b was also found most active against both the fungus viz. R. solani and C. gloeosporioides showing maximum percentage growth inhibition i.e. 90.00 against R. solani and 82.45 against C. gloeosporioides at 2000 µg/mL concentration. Compound 4 h has shown maximum inhibition zone i.e. 3.00-9.60 mm against Erwinia carotovora at 2000 µg/mL concentration. Maximum Xanthomonas citri growth was also inhibited by compound 4 h showing inhibition zone 1.00-5.00 mm at highest concentration.

A review on convenient synthesis of substituted coumarins using reuseable solid acid catalysts.

Due to growing concern about chemicals and their impact on the environment, cleaner reaction conditions are needed to be incorporated into chemical synthetic procedures. Recently, the use of heteropolyacid catalysts, mainly reuseable solid acid catalysts, has gained a leading role in organic synthesis due to their environmental and economic considerations and industrial utilization. The high catalytic activity, moisture sensitivity, reusability and inexpensive makes solid supported reagents attractive substituents to conventional Lewis acids. Nowadays synthesis of coumarins and their derivatives has attracted considerable attention from organic and medicinal chemists for many years as a large number of natural products contain this heterocyclic nucleus. In continuation with our investigations into the synthesis of substituted coumarins and due to several advantages of heterogeneous catalysts viz. cost-effective, no side products, high yield of desired products and no toxic waste material, here we report a new approach for the synthesis of substituted coumarins using solid acid catalysts.

One-pot three component synthesis of substituted dihydropyrimidinones using fruit juices as biocatalyst and their biological studies.

New and facile one-pot three component approach for the synthesis of substituted dihydropyrimidinones derivatives (4a-4h) from reaction of equimolar substituted aldehydes (1a-1h), methyl acetoacetate (2a) and urea (3a) in presence of nature derived catalyst viz. Cocos nucifera L. juice, Solanum lycopersicum L. juice and Citrus limetta juice, commonly known as coconut juice, tomato juice and musambi juice respectively, at room temperature has been carried out. All synthesized compounds were evaluated for in vitro herbicidal activity against Raphanus sativus L. (Radish seeds). The compounds (4a-4h) were also screened for their antifungal activity against Rhizoctonia solani and Colletotrichum gloeosporioides by poisoned food techniques method. Antibacterial activity was also studied against Erwinia cartovora and Xanthomonas citri by inhibition zone method. From activity data, it was found that compounds 4g and 4d were most active against Raphanus sativus L. (root) and Raphanus sativus L. (shoot) respectively. Compounds 4f and 4c was found most active against Rhizoctonia solani and Colletotrichum gloeosporioides fungus respectively at highest concentration. Compound 4g has shown maximum inhibition zone i.e. 1.00-5.50 mm against Erwinia cartovora at 2000 µg/mL concentration. Maximum Xanthomonas citrii growth was inhibited by compounds 4f showing inhibition zone 4.00-12.00 mm at highest concentration. Short reaction time, high yields, mild reaction condition and simple work-up are some merits of present methodology.