00394nas a2200121 4500008004100000022001400041245002300055210002200078260007500100300001400175100002400189856005900213 2009 eng d a0936-521400aLombardo's reagent0 aLombardos reagent aRUDIGERSTR 14, D-70469 STUTTGART, GERMANYbGEORG THIEME VERLAG KGcSEP a2545-25461 aChand, Hemender, R. uhttps://library.ncl.res.in/content/lombardos-reagent-001142nas a2200241 4500008004100000022001400041245007600055210006900131260010300200300001400303490000700317520025900324653000600583653002200589653003300611653002300644653002200667100002800689700002800717700002500745700002400770856010600794 2014 eng d a0376-469900aEfficient synthesis of 1,5-benzodiazepines catalyzed by bismuth nitrate0 aEfficient synthesis of 15benzodiazepines catalyzed by bismuth ni aANUSANDHAN BHAWAN, 2 RAFI MARG, NEW DELHI, 110001, INDIAbCOUNCIL SCIENTIFIC & INDUSTRIAL REScDEC a1561-15670 v533 a

An efficient method has been developed for the synthesis of biologically active 1,5-benzodiazepines in one-pot by reacting o-phenylenediamine and ketones catalyzed by bismuth nitrate pentahydrate at room temperature or under microwave irradiation.

10a110a5-benzodiazepines10abismuth nitrate pentahydrate10ao-Phenylenediamine10asynthetic methods1 aBhattacharya, Asish, K.1 aDange, Santoshkumar, S.1 aPolanki, Innaiah, K.1 aChand, Hemender, R. uhttps://library.ncl.res.in/content/efficient-synthesis-15-benzodiazepines-catalyzed-bismuth-nitrate-002257nas a2200181 4500008004100000245009700041210006900138260000800207300001000215490000700225520151700232653010901749100002801858700002401886700001801910700002601928856012101954 2015 eng d00aClerodane type diterpene as a novel antifungal agent from polyalthia longifolia var. pendula0 aClerodane type diterpene as a novel antifungal agent from polyal cFEB a1–70 v943 a

Bioactivity-guided chemical examination of methanolic extract of leaves of Polyalthia longifolia var. pendula led to the isolation of the active constituent, a diterpene 1 which was identified as 16α-hydroxycleroda-3,13(14)Z-dien-15,16-olide on the basis of its spectral data. Among the tested strains, diterpene 1 was found to exhibit antifungal activities having MIC90 values of 50.3, 100.6 and 201.2 μM against Candida albicans NCIM3557, Cryptococcus neoformans NCIM3542 (human pathogens) and Neurospora crassa NCIM870 (saprophyte), respectively. Initial, structure–activity-relationship (SAR) data generated by synthesizing some derivatives revealed that the double bond between C3–C4 and the free hydroxyl group at C16 are crucial for the antifungal activity of the diterpene 1. The mode of action of 1 in C. albicans is due to compromised cell membrane permeability and also probably due to disruption of cell wall structures. The red blood cell haemolysis of all the compounds (1–4) did not show any significant haemolysis and was found to be less than 15% for all the compounds when tested at highest concentration, i.e. 1200 μM. Interestingly, all the tested compounds inhibited Y–H transition in dimorphic C. albicans NCIM3557 at much lower concentration than their MIC90 values. Determination of ROS generation by diterpene 1 using DCFH-DA and DHR123 (dihydrorhodamine) staining of C. albicans NCIM3557 indicated production of intracellular ROS as a mechanism of antifungal activity.

10aDiterpene; Polyalthia longifolia; Isolation; Flash chromatography; Natural products; Antifungal activity1 aBhattacharya, Asish, K.1 aChand, Hemender, R.1 aJohn, Jyothis1 aDeshpande, Mukund, V. uhttps://library.ncl.res.in/content/clerodane-type-diterpene-novel-antifungal-agent-polyalthia-longifolia-var-pendula01683nas a2200217 4500008004100000022001400041245014000055210006900195260007500264300001200339490000600351520083800357653001801195653001501213653001601228653001301244653002601257100002401283700002801307856013001335 2016 eng d a2193-580700aDiastereoselective synthesis of beta-ether derivatives of artemisinin, an antimalarial drug: the effect of nitrile on stereoselectivity0 aDiastereoselective synthesis of betaether derivatives of artemis aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB a201-2060 v53 a

Malaria is a life-threatening disease affecting a major portion of the world's population with considerable loss of human life. Artemisinin, isolated from Artemisia annua, its oil- and water-soluble derivatives, and other known antimalarials are recommended for artemisinin combination therapy by the World Health Organization. We have established a method for the stereoselective synthesis of beta-ether derivatives of dihydroartemisinin in high yield and high diastereoselectivity. The reaction either in acetonitrile or dichloromethane/trichloroacetonitrile (6:1) mixtures at 0 degrees C or room temperature, respectively, furnished the antimalarial drugs artemether 3 or arteether 4 in high yield with a high diastereomeric ratio. The effect the nitrile has on the yield and stereoselectivity is mechanistically explained.

10aantimalarials10aarteethers10aartemisinin10anitriles10atrichloroacetimidates1 aChand, Hemender, R.1 aBhattacharya, Asish, K. uhttps://library.ncl.res.in/content/diastereoselective-synthesis-beta-ether-derivatives-artemisinin-antimalarial-drug-effect-001903nas a2200193 4500008004100000022001400041245016200055210006900217260000800286520116300294653001501457653001201472653001601484653001401500653001301514100002401527700002801551856013001579 2019 eng d a2193-580700aHemiketal-keto tautomerism in 2-deoxy-delta-lactones mediated by 2-lithiothiazole in solution state: a formal synthesis of DAH, Kamusol and their C-5 Epimers0 aHemiketalketo tautomerism in 2deoxydeltalactones mediated by 2li cOCT3 a

The reactions of 2-lithiothiazole on 3,4,6-tri-O-benzyl-2-deoxyglyconolactones have been studied, which resulted in the formation of two products, major (3,4,6-tri-O-benzyl-2-deoxy-1-(2-thiazolyl) glycal) and minor products 3,4,6-tri-O-benzyl-2-deoxy-1-(2-thiazolyl) glycal hemiketal. The hemiketal-keto tautomerism in solution was observed in the minor product. The tautomerism has been studied in various organic solvents and their ratios have been determined by H-1 NMR spectroscopy. The major product from the reaction of 2-lithiothiazole with 2-deoxygluconolactone was utilized for the synthesis of 3-deoxy-D-arabino-2-heptulosonic acid DAH 4 a and 3-deoxy-D-arabino-2-heptulopyranose commonly known natural product kamusol 6 a via acid catalyzed hydration followed by stereoselective methyl glycoside bond formation. Similarly, major product from 2-deoxygalactonolactone furnished 5-epi-DAH 4 b (C-5 epimer of 4 a) and 5-epi-kamusol 6 b (C-5 epimer of 6 a). The minor product has also been utilized for the synthesis of DAH 4 a, 5-epi-DAH 4 b, kamusol 6 a and 5-epi-kamusol 6 b through a common intermediate, alpha-methyl glycosylated product.

10ahemiketals10aKetones10atautomerism10athiazoles10aumpolung1 aChand, Hemender, R.1 aBhattacharya, Asish, K. uhttps://library.ncl.res.in/content/hemiketal-keto-tautomerism-2-deoxy-delta-lactones-mediated-2-lithiothiazole-solution-state01783nas a2200157 4500008004100000245014300041210006900184260000800253300001600261490000700277520113400284100002401418700002601442700002801468856012901496 2022 eng d00aGlycal mediated synthesis of piperidine alkaloids: fagomine, 4-epi-fagomine, 2-deoxynojirimycin, and an advanced intermediate, iminoglycal0 aGlycal mediated synthesis of piperidine alkaloids fagomine 4epif cNOV a33021-330310 v123 a

Glucal and galactal are transformed into 2-deoxyglycolactams, which are important building blocks in the synthesis of biologically active piperidine alkaloids, fagomine and 4-epi-fagomine. In one of the strategies, reduction of 2-deoxyglycolactam-N-Boc carbonyl by lithium triethylborohydride (Super-Hydride (R)) has been exploited to generate lactamol whereas reduction followed by dehydration was utilized as the other strategy to functionalize the C-1-C-2 bond in the iminosugar substrate. The strategies provide the formal synthesis of 2-deoxynojirimycin, nojirimycin and nojirimycin B. DFT studies were carried out to determine the reason for the failure of the formation of the 2-deoxygalactonojirimycin derivative. Further, DFT studies suggest that phenyl moieties of protecting groups and lone pairs of oxygen in carbamate group plays a vital role in deciphering the conformational space of the reaction intermediates and transition-state structures through cation-pi or cation-lone pair interactions. The influence of these interactions is more pronounced at low temperature when the entropy factor is small.

1 aChand, Hemender, R.1 aTiwari, Mritunjay, K.1 aBhattacharya, Asish, K. uhttps://library.ncl.res.in/content/glycal-mediated-synthesis-piperidine-alkaloids-fagomine-4-epi-fagomine-2-deoxynojirimycin