@article { ISI:000255318800025, title = {Amberlite-IR 120 catalyzed three-component synthesis of alpha-amino phosphonates in one-pot}, journal = {Tetrahedron Letters}, volume = {49}, number = {16}, year = {2008}, month = {APR}, pages = {2598-2601}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A simple, efficient, and environmentally benign method for a three-component reaction of an amine, an aldehyde or a ketone, and diethyl phosphite catalyzed by Amberlite-IR 120 resin has been developed to afford alpha-amino phosphonates in high yields and short reaction times under solvent-free reaction conditions. The major advantages of the present method are good yields, inexpensive, ecofriendly and reusable catalyst, mild and solvent-free reaction conditions and tolerance towards various functionalities present in the substrates. (c) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {aldehydes, alkyl phosphite, alpha-amino phosphonates, amines, ion-exchange resin, multi-component reaction}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2008.02.102}, author = {Bhattacharya, Asish K. and Rana, Kalpeshkumar C.} } @article { ISI:000270106700015, title = {Synthesis and in vitro study of 14-aryl-14H-dibenzo[a.j]xanthenes as cytotoxic agents}, journal = {Bioorganic \& Medicinal Chemistry Letters}, volume = {19}, number = {19}, year = {2009}, month = {OCT}, pages = {5590-5593}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A simple and expedient method for the synthesis of a series of 14-aryl-14H-dibenzo[a.j]xanthenes is described through a one-pot condensation of beta-naphthol with aryl aldehydes catalysed by TaCl(5) under solvent-free conventional heating. The major advantages of the present method are: high yields, less reaction time, solvent-free condition and easy purification of the products. The synthesized 14-aryl-14H-dibenzo[a.j]xanthenes were evaluated against a panel of six human cancer lines of different tissues. Synthesized compound 30 showed IC(50) of 37.9 and 41.3 mu M against Colo-205 and 502713, respectively, whereas 3g showed IC(50) of 41.9 mu M against Colo-205. (C) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {Aldehyde, beta-Naphthol, condensation, Cytotoxicity, One-pot reaction, Solvent-free, Tantalum(V) chloride, Xanthenes}, issn = {0960-894X}, doi = {10.1016/j.bmcl.2009.08.033}, author = {Bhattacharya, Asish K. and Rana, Kalpeshkumar C. and Mujahid, Mohammad and Sehar, Irum and Saxena, Ajit K.} } @article { ISI:000296752300019, title = {Design, synthesis and biological evaluation of peptidyl-vinylaminophosphonates as novel cysteine protease inhibitors}, journal = {Bioorganic \& Medicinal Chemistry}, volume = {19}, number = {23}, year = {2011}, month = {DEC}, pages = {7129-7135}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

We report herein, design and synthesis of vinylaminophosphonates, a novel class of compounds as possible cysteine protease inhibitors. The synthesis of vinylaminophosphonates has been accomplished employing Tsuji-Trost reaction as a key step. The synthesized compounds were assayed against papain, a model cysteine protease and some of our synthesized compounds showed IC50 values in the range of 30-54 mu M thereby suggesting that these chemical entities thus could constitute an interesting template for the design of potential novel protease inhibitors. (C) 2011 Elsevier Ltd. All rights reserved.

}, keywords = {Cysteine, Inhibitor design, Protease inhibitors, synthesis, Tsuji-Trost reaction, Vinylaminophosphonates}, issn = {0968-0896}, doi = {10.1016/j.bmc.2011.09.058}, author = {Bhattacharya, Asish K. and Rana, Kalpeshkumar C.} } @article { ISI:000292983400015, title = {Efficient synthesis of benzodiazepinyl phosphonates as clostripain inhibitors via FeCl3 catalyzed four-component reaction}, journal = {Organic \& Biomolecular Chemistry}, volume = {9}, number = {15}, year = {2011}, month = {OCT}, pages = {5407-5413}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A novel one-pot route for the synthesis of benzodiazepinyl phosphonates (BDPs) has been achieved. FeCl3 efficiently catalyzed four-component condensation of diamines, acetone and phosphites in the presence of molecular sieves to furnish BDPs as novel chemical entities with good yield. The synthesized BDPs have shown significant protease inhibition activity against clostripain, a disease model for gas gangrene, suggesting that these novel chemical entities could be further explored as cysteine protease inhibitors.

}, issn = {1477-0520}, doi = {10.1039/c0ob01102a}, author = {Bhattacharya, Asish K. and Rana, Kalpeshkumar C. and Raut, Dnyaneshwar S. and Mhaindarkar, Vaibhav P. and Khan, Mohammad Islam} } @article { ISI:000308042000010, title = {Efficient synthesis of a hydroxyethylamine (HEA) isostere and its alpha-aminophosphonate and phosphoramidate derivatives as potential anti-HIV agents}, journal = {Chemmedchem}, volume = {7}, number = {9}, year = {2012}, month = {SEP}, pages = {1601-1611}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

HIV protease is a promising drug target for AIDS therapy, and several potent HIV-1 protease inhibitors have been reported to date. Although existing inhibitors exhibit high selectivity, they have also been associated with severe side effects and the possible emergence of therapeutic resistance. As HIV protease cleaves the peptide bond via a tetrahedral intermediate, various transition-state models such as hydroxyethylamine (HEA) have been designed. We therefore pursued an efficient synthesis of an HEA isostere; this was performed with a novel one-pot reductiontransiminationreduction reaction sequence as a key step. a-Aminophosphonate and phosphoramidate derivatives of the HEA isostere were designed and synthesized, and all of the synthesized derivatives were assayed for their anti-HIV activities against wild-type and mutant HIV strains. Phosphoramidate derivative 15?a was found to be the most active of all synthesized compounds against the IIIB and RES056 strains. As phosphonates are known to exhibit physiological stability, good cell permeability, and other promising pharmacokinetic characteristics, our newly synthesized compounds have the potential as alternatives to existing therapeutics and diagnostics.

}, keywords = {a-aminophosphonates, antiviral agents, hydroxyethylamine isosteres, phosphoramidates, synthesis}, issn = {1860-7179}, doi = {10.1002/cmdc.201200271}, author = {Bhattacharya, Asish K. and Rana, Kalpeshkumar C. and Pannecouque, Christophe and De Clercq, Eric} } @article { ISI:000322358100002, title = {Antimycobacterial agent, (E)-phytol and lauric amide from the plant Lagascea mollis}, journal = {Indian Journal of Chemistry Section B-Organic Chemistry Including Medicinal Chemistry}, volume = {52}, number = {7}, year = {2013}, month = {JUL}, pages = {901-903}, publisher = {COUNCIL SCIENTIFIC \& INDUSTRIAL RES}, address = {ANUSANDHAN BHAWAN, 2 RAFI MARG, NEW DELHI, 110001, INDIA}, abstract = {

Chemical examination of aerial parts of the plant, Lagascea mollis has resulted in the isolation of two compounds, an acyclic diterpene alcohol which has been identified as (E)-phytol 1 and lauric amide 3. Their structures have been elucidated by spectral data and chemical transformations. This is the first report of isolation of both these compounds from this plant It is noteworthy that compound 1 has been found to be a potent antimycobacterial agent and thus, L. mollis could be exploited as an alternative source.

}, keywords = {amide, chemical transformation, diterpene, Lagascea mollis, structure elucidation}, issn = {0376-4699}, author = {Bhattacharya, Asish K. and Rana, Kalpeshkumar C.} } @article {47444, title = {Combating multi-drug resistant malaria parasite by inhibiting falcipain-2 and heme-polymerization: Artemisinin-peptidyl vinyl phosphonate hybrid molecules as new antimalarials}, journal = {European Journal of Medicinal Chemistry}, volume = {220}, year = {2021}, month = {AUG}, pages = {113454}, type = {Article}, abstract = {

Artemisinin-based combination therapies (ACTs) have been able to reduce the clinical and pathological malaria cases in endemic areas around the globe. However, recent reports have shown a progressive decline in malaria parasite clearance in South-east Asia after ACT treatment, thus envisaging a need for new artemisinin (ART) derivatives and combinations. To address the emergence of drug resistance to current antimalarials, here we report the synthesis of artemisinin-peptidyl vinyl phosphonate hybrid molecules that show superior efficacy than artemisinin alone against chloroquine-resistant as well as multidrug-resistant Plasmodium falciparum strains with EC50\ in pico-molar ranges. Further, the compounds effectively inhibited the survival of ring-stage parasite for laboratory-adapted artemisinin-resistant parasite lines as compared to artemisinin. These hybrid molecules showed complete parasite clearance in vivo using P. berghei mouse malaria model in comparison to artemisinin alone. Studies on the mode of action of hybrid molecules suggested that these artemisinin-peptidyl vinyl phosphonate hybrid molecules possessed dual activities: inhibited falcipain-2 (FP-2) activity, a P. falciparum cysteine protease involved in hemoglobin degradation, and also blocked the hemozoin formation in the food-vacuole, a step earlier shown to be blocked by artemisinin. Since these hybrid molecules blocked multiple steps of a pathway and showed synergistic efficacies, we believe that these lead compounds can be developed as effective antimalarials to prevent the spread of resistance to current antimalarials.

}, doi = {10.1016/j.ejmech.2021.113454}, author = {Aratikatla, Eswar K. and Kalamuddin, Md and Rana, Kalpeshkumar C. and Datta, Gaurav and Asad, Mohd and Sundararaman, Srividhya and Malhotra, Pawan and Mohmmed, Asif and Bhattacharya, Asish K.} }