Ravindra R. Kamble

Synthesis and antimicrobial studies of novel methylene bridged benzisoxazolyl imidazo[2,1-b][1,3,4]thiadiazole derivatives.

Novel methylene bridged benzisoxazolyl imidazo[2,1-b][1,3,4]thiadiazoles (3a-f) were synthesized from benzisoxazolyl-3-acetic acid and thiosemicarbazide. Reaction of 3 with bromine in glacial acetic acid in the presence of anhydrous sodium acetate yielded the corresponding 5-bromo derivatives (4a-f). While compound 3 furnished the 5-nitroso derivatives (5a-f) on refluxing with sodium nitrite solution. Thiocyanato derivatives (6a-f) were obtained by treating the imidazothiadiazole 3 with bromine and potassium thiocyanate in glacial acetic acid at room temperature. The structures of the newly synthesized compounds were confirmed by IR, NMR, mass and elemental analysis. All the compounds were screened for their antibacterial and antifungal activities. Some of the compounds displayed very good antibacterial and antifungal activity.

One-pot synthesis of pyrazoline derivatised carbazoles as antitubercular, anticancer agents, their DNA cleavage and antioxidant activities.

Novel tricyclic carbazoles 4a-k were synthesized in one-pot employing sydnone derivatives 3a-k as masked hydrazines by the ring transformation in presence of conc. HCl and cyclohexanone. The title compounds were screened for anti-tubercular, anti cancer, DNA cleavage, antioxidant activity. MIC, GI50, LC50, TGI were evaluated. The title compounds have exhibited significant antitubercular, DNA cleavage and antioxidant activities and partial anticancer activity.

Synthesis, characterization and in vitro anticancer evaluation of novel 1,2,4-triazolin-3-one derivatives

A series of novel 2-(4-chlorophenyl)-5-methyl-4-(2-amine/oxy-ethyl)-2,4-dihydro-[1,2,4]triazol-3-one (5a-t) were synthesized and in vitro anticancerous action of the resulting compounds was studied against NCI-60 Human Tumor Cell Line at a single high dose (10(-5) M) concentration for primary cytotoxicity assay. Among the tested compounds (5a-e, 5g-h, 5k, 5p), the compound 5g (NSC: 761736/1) was further evaluated for five dose criteria at five different minimal concentrations against the full panel of 60 human tumor cell lines which exhibited activity against Leukemia (GI50: 1.10 μM), Non-Small Cell Lung Cancer (GI50: 1.00 μM), Renal Cancer (GI50: 1.00 μM), Colon Cancer (GI50: 1.66 μM), CNS Cancer (GI50: 1.36 μM), Melanoma (GI50: 1.82 μM), Ovarian Cancer (GI50: 1.64 μM) and Breast Cancer (GI50: 1.69 μM).

An efficient one-pot cyclization of quinoline thiosemicarbazones to quinolines derivatized with 1,3,4-thiadiazole as anticancer and anti-tubercular agents

A series of 6,7,8-substituted thiosemicarbazones (2a–j) of 2-chloro-3-formyl-quinoline derivatives were cyclized to the title compounds (3a–j) using acetic anhydride. The structures of the final compounds (3a–j) were confirmed by elemental and spectral (IR, 1H NMR and MS) analysis. Some of the title compounds have shown promising anticancer and antitubercular activities.

Expedient synthesis of benzimidazoles using amides

In the present report an efficient, rapid, facile and inexpensive route for the synthesis of benzimidazoles using 1,2-arylenediamines and N,N-dimethylformamide in acidic medium under thermal/microwave condition is developed. This reaction was further explored with the different amides to afford a library of 2-substituted benzimidazoles. The advantage of the present synthetic method includes shorter reaction time, easy work up and excellent yields without using catalysts.

Synthesis of novel imidazo[2,1-b][1,3,4]thiadiazoles appended to sydnone as anticancer agents

A novel series of 3-aryl-4{6′-(6′′-substituted-coumarin-3′′-yl) imidazo[2,1-b][1,3,4]thiadiazol-2′-yl}-sydnones 5h–5s were synthesized and screened for their anticancer and DNA cleavage activities and analyzed for pharmacological parameters such as toxicity, drug-likeliness, and drug score for oral bioavailability. In vitro toxicity assay was carried out by assessing the survival E. coli AB1157 (wild type) cultures. Some of the compounds have shown significant anticancer activities also.

Synthesis of novel 2-(3′-aryl-sydnon-4′-ylidene)-5′-substituted-[1,3,4]-thiadiazolylamines and [1,3,4]-thiadiazol-2′-yl-3-oxo-[1,2,4]-triazoles as antimicrobial agents

The title compounds (3g–n) and (6g–n) were synthesized using 3-arylsydnones as synthons, and the structures were confirmed by IR, 1H NMR, FAB mass and CHN analysis. These compounds were evaluated for their antibacterial and the antifungal activities in terms of minimum inhibitory concentrations (MICs) against the bacterial strains E. coli, B. cereus, and the fungal strains A. niger, C. albicans. Some of the compounds have shown significant activities.

Synthetic utility of sydnones: synthesis of pyrazolines derivatized with 1,2,4-triazoles as antihyperglymic, antioxidant agents and their DNA cleavage study

Ring transformation of sydnone (1a–i) to 1,3,4-oxadiazoline-2-one (2a–i) was carried out using bromine in acetic anhydride. The compounds (2a–i) on heating with hydrazine hydrate gave 1,2,4-triazole (3a–i) in good yields. The structure of these unknown compounds was confirmed by IR, 1H NMR, MS and elemental analysis. Further, these compounds were evaluated for the extent of penetration into biological membranes (clogP) drug likeliness and finally drug score was calculated. The title compounds were also screened for their antihyperglycemic, DNA cleavage and antioxidant activity.

Polymer Synthesis and Processing

Polymer scientists have made an extensive research in the development of biodegradable polymers, which could find enormous applications in the area of medical science. Today, various biopolymers have been prepared and utilized in different biomedical applications. Despite the apparent proliferation of biopolymers in medical science, the science and technology of biopolymers is still in its early stages of development. Tremendous opportunities exist and will continue to exist for the penetration of biopolymers in every facet of medical science through intensive research and development. Therefore, this chapter addresses different polymerization methods and techniques employed for the preparation of biopolymers. The emphasis is on the general properties of biopolymers, synthetic protocols, and their biomedical applications. In order to make the useful biomedical devices from the polymers to meet the demands of medical science, various processing techniques employed for the development of devices have been discussed. Further, perspectives in this field have been highlighted and conclusions arrived at. The relevant literature was collected from different sources, including Google sites, books, and reviews.

Facile synthesis of novel quinoline derivatives as anticancer agents

Convenient and efficient synthesis of novel N-(4-acetyl-4,5-dihydro-5-(7,8,9-substituted-tetrazolo[1,5-a]-quinolin-4-yl)-1,3,4-thiadiazol-2-yl)acetamides 4a–j and their in vitro anticancer activity against two cell lines viz., human breast cancer cell line MCF7 and human cervix cancer cell line HeLa were carried out. GI50, LC50, TGI values were evaluated. Two of the compounds 4e and 4i with halogen substituent at 7th position of the target molecules have shown potent activity against human cervix cancer cell line HeLa. DNA cleavage studies revealed that most of these compounds show partial cleavage and few of them show complete cleavage of DNA.