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Publications 2008

Below is the list of Scientific Communications Published by Tripathi Research Group in 2008

  1. An efficient chemoselective etherification of phenols in polyfunctional aromatic compounds. Pandey, Jyoti; Mishra, Mridul; Bisht, Surendra Singh; Sharma, Anindra; Tripathi, Rama P.. Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Tetrahedron Letters (2008), 49(4), 695-698. Publisher: Elsevier Ltd., CODEN: TELEAY ISSN: 0040-4039. Journal written in English. CAN 148:308009 AN 2008:26236 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    A simple and efficient chemoselective alkylation of phenols in polyfunctional arom. compds. with different alkyl halides in the presence of K2CO3/TBAB is reported. The method is successful with various hydroxy arom. acids or oximes possessing other functional groups.

  2. D-Glucosamine, a natural amino sugar as organocatalyst for an ecofriendly direct aldol reaction of ketones with aromatic aldehydes in water. Singh, Nimisha; Pandey, Jyoti; Tripathi, R. P.. Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Catalysis Communications (2008), 9(5), 743-746. Publisher: Elsevier B.V., CODEN: CCAOAC ISSN: 1566-7367. Journal written in English. AN 2008:198189 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    D-Glucosamine, one of the important sugars of natural origin catalyzes direct aldol reaction of different arom. aldehydes with acyclic or cyclic ketones. Diastereo- and enantioselection varies with the substituent on the benzene ring of the arom. aldehydes used.

  3. Preparation and reactions of sugar azides with alkynes: synthesis of sugar triazoles as antitubercular agents. Singh, Biswajit Kumar; Yadav, Amit Kumar; Kumar, Brijesh; Gaikwad, A.; Sinha, Sudhir Kumar; Chaturvedi, Vinita; Tripathi, Rama Pati. Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Carbohydrate Research (2008), 343(7), 1153-1162. Publisher: Elsevier Ltd., CODEN: CRBRAT ISSN: 0008-6215. Journal written in English. CAN 149:79814 AN 2008:489852 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    5-Azido-5-deoxy-xylo-, ribo-, and arabinofuranoses were prepd. by the reaction of the resp. 5-O-(methanesulfonyl) or p-toluenesulfonyl derivs. with NaN3 in DMF. The intermediate 5-azido-5-deoxy glycofuranoses on 1,3-cycloaddn. with different alkynes in the presence of CuSO4 and sodium ascorbate gave the corresponding sugar triazoles in very good yields. The synthesized sugar triazoles were evaluated for their antitubercular activity against Mycobacterium tuberculosis H37Rv, where one of the compds. displayed mild antitubercular activity in vitro with MIC 12.5 mg/mL.

  4. Aldol reaction of b -C-glycosylic ketones: synthesis of C-(E)-cinnamoyl glycosylic compounds as precursors for new biologically active C-glycosides. Bisht, Surendra Singh; Pandey, Jyoti; Sharma, Anindra; Tripathi, Rama Pati. Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Carbohydrate Research (2008), 343(9), 1399-1406. Publisher: Elsevier Ltd., CODEN: CRBRAT ISSN: 0008-6215. Journal written in English. CAN 149:224462 AN 2008:668472 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    A series of b-C-glycosylic ketones were prepd. starting from -glucose, -xylose, -mannose, and cellobiose. The b-C-glycosylic ketones on aldol condensation with different arom. aldehydes in the presence of a suitable organocatalyst led to the formation of resp. C-(E)-cinnamoyl glycosides stereoselectively in good yields as precursors for the synthesis of biol. active compds.

  5. NAD+-dependent DNA ligase: a novel target waiting for the right inhibitor. Dwivedi, Namrata; Dube, Divya; Pandey, Jyoti; Singh, Biswajit; Kukshal, Vandna; Ramachandran, Ravishankar; Tripathi, Rama Pati. Medicinal & Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Medicinal Research Reviews (2008), 28(4), 545-568. Publisher: John Wiley & Sons, Inc., CODEN: MRREDD ISSN: 0198-6325. Journal; General Review written in English. CAN 149:214872 AN 2008:831549 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    A review. DNA ligases (EC.6.5.1.1) are key enzymes that catalyze the formation of phosphodiester bonds at single stranded or double stranded breaks between adjacent 5′ phosphoryl and 3′ hydroxyl groups of DNA. These enzymes are important for survival because they are involved in major cellular processes like DNA replication/repair and recombination. DNA ligases can be classified into two groups on the basis of their cofactor specificities. NAD+-dependent DNA ligases are present in bacteria, some entomopox viruses and mimi virus while ATP-dependent DNA ligases are ubiquitous. The former have recently been drawing a lot of attention as novel targets for antibiotics to overcome current drug resistance issues. Currently a diverse range of inhibitors have been identified. There are several issues to be addressed in the quest for optimized inhibitors of the enzyme. In the first part of the review we summarize current structural work on these enzymes. Subsequently we describe the currently available classes of inhibitors. We also address modalities to improve the specificity and potencies of new inhibitors identified using protein structure based rational approaches. In conclusion, NAD+-dependent ligases show great promise and represent a novel drug target whose time has come.

  6. NAD+-dependent DNA ligase (Rv3014c) from M. tuberculosis: Strategies for inhibitor design. Dube, Divya; Kukshal, Vandna; Srivastava, Sandeep Kumar; Tripathi, Rama Pati; Ramachandran, Ravishankar. Molecular and Structural Biology Division, Central Drug Research Institute, Lucknow, India. Medicinal Chemistry Research (2008), 17(2/7), 189-198. Publisher: Birkhaeuser Boston, CODEN: MCREEB ISSN: 1054-2523. Journal written in English. CAN 149:396529 AN 2008:899386 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    NAD+-dependent DNA ligases (LigA) are essential enzymes found only in bacteria and some virus species. This makes them attractive drug targets. Based on the crystal structure of the NAD+ binding domain of the M. tuberculosis enzyme (MtuLigA) and virtual screening, we have earlier identified several novel classes of inhibitors for this enzyme. These inhibitors bind to the adenylation domain and compete with the cofactor NAD+. Recently, we identified that the BRCT domain is essential for the enzyme activity of MtuLigA. We have used virtual screening to identify compds. from the CAP database that should potentially bind to the BRCT domain. These will now be evaluated as inhibitors of the enzyme with a novel mechanism of action. Challenges faced in designing specific and potent inhibitors of the enzyme which can distinguish between the human ATP-dependent ligase and MtuLigA are addnl. discussed in this report. Proposed strategies for the design of potent inhibitors with desired properties are also outlined.

  7. Synthesis and antitubercular activity of nucleoside analogs based on L-ascorbic acid and bases. Tripathi, R. P.; Dwivedi, Namrata; Singh, Nimisha; Misra, Mridul. Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Medicinal Chemistry Research (2008), 17(2/7), 53-61. Publisher: Birkhaeuser Boston, CODEN: MCREEB ISSN: 1054-2523. Journal written in English. CAN 149:402604 AN 2008:899388 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    5,6-O-isopropylidene-2,3-di-O-Me ascorbic acid, obtained by reaction of acetone with ascorbic acid followed by methylation with Me iodide, on 1,8-Diazabicyclo[5.4.0]undec-7-ene-catalyzed elimination of acetone moiety led to the formation of resp. 2,3-di-O-Me didehydro-L-ascorbic acid in good yield. The latter, on methanesulfonylation with methanesulfonyl chloride and subsequent reaction of the crude methanesulfonyloxy deriv. with imidazole, benzimidazole, and adenine resulted in the corresponding tetronolactonyl nucleoside analogs I, II, and III. I on reaction with benzyl amine led to the N-benzylated teramyl nucleoside analog, while compds. II and III did not react under similar conditions. All the synthesized compds. were evaluated for their antitubercular activity against M. tuberculosis H37Ra and H37Rv, exhibiting a min. inhibitory concn. (MIC) of more than 12.5 mg/mL.

  8. Synthesis of azatricyclodiones & octahydro-benzo[f]isoindoles and their antimicrobial evaluation. Saxena, Nisha; Singh, Nimisha; Mishra, Mridul; Shiva Keshava, G. B.; Shukla, Praveen Kumar; Tripathi, Rama Pati. Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Journal of Enzyme Inhibition and Medicinal Chemistry (2008), 23(4), 476-482. Publisher: Informa Healthcare, CODEN: JEIMAZ ISSN: 1475-6366. Journal written in English. CAN 149:355623 AN 2008:910756 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    A series of azatricyclodiones and octahydro-benzo[f]isoindoles have been synthesized by (4+2) Diels-Alder cycloaddn. of maleimides with furfuryl amine. Reaction of azatricyclodiones with isocyanates led to the resp. ureides. All of the compds. were screened against a no. of bacteria and fungi. Compds. I (R = H) displayed moderate antitubercular activity while two compds. I (R = H, Me) inhibited the fungal growth at 25 mg/mL.

  9. Leishmania donovani pteridine reductase 1: Biochemical properties and structure-modeling studies. Kumar, Pranav; Kumar, Ashutosh; Verma, Shyam Sundar; Dwivedi, Namrata; Singh, Nasib; Siddiqi, Mohammad Imran; Tripathi, Rama Pati; Dube, Anuradha; Singh, Neeloo. Drug Target Discovery and Development, Chattat Manzil, Central Drug Research Institute, Lucknow, India. Experimental Parasitology (2008), 120(1), 73-79. Publisher: Elsevier Inc., CODEN: EXPAAA ISSN: 0014-4894. Journal written in English. AN 2008:971187 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    Pteridine reductase 1 (PTR1, EC 1.5.1.33) is a NADPH dependent short-chain reductase (SDR) responsible for the salvage of pterins in the protozoan parasite Leishmania. This enzyme acts as a metabolic bypass for drugs targeting dihydrofolate reductase, therefore, for successful antifolate chemotherapy to be developed against Leishmania, it must target both enzyme activities. Based on homol. model drawn on recombinant pteridine reductase isolated from a clin. isolate of L. donovani, we carried out mol. modeling and docking studies with two compds. of dihydrofolate reductase specificity showing promising antileishmanial activity in vitro. Both the inhibitors appeared to fit well in the active pocket revealing the tight binding of the carboxylic acid Et ester group of pyridine moiety to pteridine reductase and identify the important interactions necessary to assist the structure based development of novel pteridine reductase inhibitors.

  10. Recent development on catalytic reductive amination and applications. Tripathi, Rama P.; Verma, Shyam S.; Pandey, Jyoti; Tiwari, Vinod K. Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, India. Current Organic Chemistry (2008), 12(13), 1093-1115. Publisher: Bentham Science Publishers Ltd., CODEN: CORCFE ISSN: 1385-2728. Journal written in English. AN 2008:1130912 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    Reductive amination is one of the most useful and versatile methods for the prepn. of amines in chem. and biol. The present review focuses on the development of catalytic reductive amination from beginning to recent ones, where we have attempted to thoroughly illustrate an account of utility of various reagents including organocatalyst, sym. and asym. (Ru, Rh, Ir) complexes, boron, tin or silicon reagents etc for enantio- and/or chemoselective reactions under different reaction conditions with emphasis on the yields of the reaction products and stability of the reagents used. Emerging applications of this reaction for the development of chiral ligands, pharmacol. active mols., combinatorial scaffold, and key step in the total synthesis of some interesting natural products is also reviewed briefly.

  11. Pharmacokinetics and excretion of the novel anti-tuberculosis compound 1,2:5,6-di-O-isopropylidene-3-O-(phenyl cyclopropyl methanonyl)-a -D-glucofuranose (S-001-14) after oral doses in rats: development of a sensitive and reproducible high performance liquid chromatography-UV method for the determination of the test compound in rat serum. Lal, Jawahar; Tripathi, Rama Pati; Gupta, Ram Chandra. Pharmacokinetics and Metabolism Division, Central Drug Research Institute, Lucknow, India. Arzneimittel Forschung (2008), 58(8), 410-418. Publisher: Editio Cantor Verlag, CODEN: ARZNAD ISSN: 0004-4172. Journal written in English. CAN 149:548179 AN 2008:1171353 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    A sensitive and reproducible high performance liq. chromatog. (HPLC)-UV method for the detn. of the novel anti-tuberculosis compd. 1,2:5,6-di-O-isopropylidene-3-O-(Ph cyclopropyl methanonyl)-a-D-glucofuranose (S-001-14) has been developed and validated in rat serum, urine and feces. Following extn. with hexane at alk. pH, samples were sepd. on a reverse phase C18 column and quantified using UV detection at 267 nm. The mobile phase was 70% acetonitrile in ammonium acetate buffer (10 nmol/L, pH 6.0) with a flow rate of 1.0 mL/min. The method was used to det. the pharmacokinetics and excretion of S-001-14 after oral doses in rats. Linearity was satisfactory over the concn. range of 5-500 ng/mL (r2, >0.99). Recoveries were >90% and were consistent throughout the calibration range. The precision and accuracy were acceptable as indicated by relative std. deviation ranging from 2.72 to 9.54%, bias values ranging from 1.62 to 12.05%. Moreover, S-001-14 was stable in rat serum after being subjected to three freeze-thaw cycles and for 30 days on storage at -60°C. The method was used to det. the serum concn.-time profiles for S-001-14 after oral doses of 4, 100 and 200 mg/kg in rats. A linear pharmacokinetics was found in rats at 100 and 200 mg/kg doses with a long elimination half-life (.apprx.24 h), wide distribution and bioavailability of .apprx.13%. The excretion study after the 100 mg/kg oral dose revealed that S-001-14 was excreted in urine (0.002 ± 0.001%) and feces (15.6 ± 3.5%).

  12. Synthesis of 2-sulfanyl-6-methyl-1,4-dihydropyrimidines as a new class of antifilarial agents. Singh, B. K.; Mishra, Mridul; Saxena, Nisha; Yadav, G. P.; Maulik, P. R.; Sahoo, M. K.; Gaur, R. L.; Murthy, P. K.; Tripathi, R. P.. Medicinal and Process Chemistry Division, Central Drug Research Institute, Uttar Pradesh, India. European Journal of Medicinal Chemistry (2008), 43(12), 2717-2723. Publisher: Elsevier Masson SAS, CODEN: EJMCA5 ISSN: 0223-5234. Journal written in English. AN 2008:1462465 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R))

    Abstract

    A series of 2-sulfanyl-6-methyl-1,4-dihydropyrimidines (8-21) were synthesized in good yields by alkylation of 5-methyl-6-phenyl-2-thioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid Et esters (2-7) with different alkyl or aralkyl halides in the presence of a combination of anhyd. K2CO3 and catalytic amt. of tetra-Bu ammonium bromide. The title compds. were evaluated for their antifilarial activity against adult parasites of human lymphatic filarial parasite Brugia malayi (sub-periodic strain) in vitro and in vivo at various concns. One of the compds. (18) showed promising antifilarial activity.

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