Vijaykumar P. Rasal

Synthesis and antimicrobial studies on novel sulfonamides containing 4-azidomethyl coumarin.

A series of new and novel coumarin-6-sulfonamides with a free C4-azidomethyl group have been synthesized as antimicrobials in three steps starting from 7-methyl-4-bromomethylcoumarin 1. The reaction of 1 with chlorosulfonic acid was found to yield the corresponding 6-sulfonylchloride 2, which when treated with sodium azide led to intermediate 3. The title sulfonamides 5a-y were obtained from the reaction of 3 with various aromatic amines 4 in refluxing benzene. The chemical structures of the compounds were elucidated by IR, NMR and LC-MS spectral data. All the synthesized compounds have been screened for their in vitro anti-bacterial and anti-fungal activities. Some of the compounds have been found to be active against both bacterial species at a concentration of 1 microg/mL.

Microwave assisted synthesis of dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-ones; synthesis, in vitro antimicrobial and anticancer activities of novel coumarin substituted dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-ones.

The present article describes the synthesis of dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-one (2a-h) under microwave irradiation. The product was obtained in excellent yield (74-94%) in a shorter reaction time (2 min). These molecules (2a, b) further reacted with various substituted 4-bromomethylcoumarins (3a-f) to yield a new series of coumarin substituted dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-ones (4a-h). The structure of all the synthesized compounds were confirmed by spectral studies and screened for their in vitro antibacterial activity against three Gram-positive bacteria viz., Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans and three Gram-negative bacteria viz., Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and antifungal activity against Candida albicans, Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, Fusarium oxysporum, Penicillium chrysogenum and anticancer activity against Daltons Ascitic Lymphoma (DAL) cell line. In general, all the compounds possessed better antifungal properties than antibacterial properties. The coumarin substituted dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-one (4g) (R = i-Pr, R₁ = 6-Cl) was found to be the most potent cytotoxic compound (88%) against Daltons Ascitic Lymphoma cell line at the concentration of 100 μg/mL.

The Synthesis and Biological Evaluation of Regioisomeric Benzothiazolyl Coumarins

Various 4-aryloxymethylcoumarins have been obtained by the r.t. allylic substitution with formylphenols. These have been further reacted with o-aminothiophenol resulting in the formation of a benzothiazole skeleton. These compounds have been synthesised with a view to study their potential as microbial growth inhibitors. Comparative studies on the spectral and antimicrobial activities have also been carried out.

Synthetic and Biological Studies on 4-Aryloxymethyl Coumarinyl Thiazolidinones

A series of new thiazolidinonyl -4-aryloxymethylcoumarins ( 4a–h ) have been synthesized from 4-Bromomethylcoumarins ( 1a–b ) and 4-aryliminomethyl-phenols ( 2a–d ). Structures of all the new compounds are elucidated by elemental analyses, IR, 1 H NMR, and mass spectral data. All these compounds have been subjected to in-vitro antimicrobial and in-vivo anti-inflammatory screening.

Synthesis, antimicrobial and DNA cleavage studies of some 4-aryloxymethylcoumarins obtained by reaction of 4-bromomethylcoumarins with bidentate nucleophiles

Symmetrical bidentate nucleophiles such as resorcinol have been made to react with 4-bromomethylcoumarins in a cascaded manner to obtain mono and bis-4-aryloxymethylcoumarins by a room temperature allylic nucleophilic displacement. Unsymmetrical nucleophiles such as 3-acetylaminophenol and 3-diethylaminophenol have been used to generate 4-aryloxymethylcoumarins. All the compounds have been analyzed by spectral methods and subjected to preliminary antibacterial, antifungal and DNA cleavage studies. The results showed that the compounds bearing methoxy, chloro and bromo substituents at C6-position of coumarin showed higher activity.Graphical AbstractSymmetrical bidentate nucleophiles such as resorcinol, and unsymmetrical nucleophiles, 3-acetylaminophenol and 3-diethylaminophenol have been made to react with 4-bromomethylcoumarins in a cascaded manner to obtain corresponding 4-aryloxymethylcoumarins. All the compounds have been analyzed by spectral methods and subjected to preliminary antibacterial, antifungal and DNA cleavage studies.

Efficacy of chemopreventive agent, Dipteracanthus prostratus, on 1,2-dimethylhydrazine induced colon carcinogenesis

Aim: The aim of this study was to evaluate the effect of Dipteracanthus prostratus extracts on 1,2-dimethyl hydrazine (DMH) induced colon cancer in rats. Materials and Methods: To achieve this objective DMH model was selected to evaluate the effect of D. prostratus extracts on colon cancer. The study was carried out on 48 male Wistar rats divided into six groups. Group I served as a control. Groups II and III served as a positive control received ethanolic extract (500 mg/kg) and aqueous extract (500 mg/kg), respectively. Group IV served as a tumor bearing group received (20 mg/kg) DMH. Groups V and VI served as a treatment group received DMH (20 mg/kg) + ethanolic extract (500 mg/kg) and aqueous extract (500 mg/kg), respectively. Lipid peroxidation (LPO) was studied by measuring the formation of thiobarbituric acid reactive substances, catalase (CAT), glutathione peroxidase (GP X ), and reduced glutathione (GSH) in the liver and colonic tissues of DMH administered rats. Results: (1) Decreased levels of LPO in the colonic tissues; (2) decreased activities of antioxidant enzymes LPO, CAT, GP X , and GSH levels in the tissues on DMH treatment. D. prostratus supplementation during the entire period stages of carcinogenesis significantly reversed these activities. Conclusion: These results indicate that D. prostratus may be a potential chemopreventive agent against DMH induced colon cancer.