Citation
Synthesis and Antimalarial Activities of a Diverse Set of Triazole-Containing Quinine Analogues

Material Information

Title:
Synthesis and Antimalarial Activities of a Diverse Set of Triazole-Containing Quinine Analogues
Creator:
Serrano, Juan C.
Copyright Date:
2014
Language:
English
Physical Description:
Undergraduate Honors Thesis

Thesis/Dissertation Information

Degree:
Bachelor's
Degree Grantor:
University of Florida
Committee Chair:
Dr. Charles D. Hall

Subjects

Subjects / Keywords:
Alkynes ( jstor )
Antimalarials ( jstor )
Azides ( jstor )
Click chemistry ( jstor )
Functional groups ( jstor )
In vitro fertilization ( jstor )
Malaria ( jstor )
Parasites ( jstor )
Sodium ( jstor )
Triazoles ( jstor )
antimalarial
click chemistry
parasite resistance
quinine
triazole

Notes

Abstract:
The search for antimalarial drugs with low parasite resistance is an ever increasing concern for global health. In this project we sought two goals: i) to select for a natural antimalarial drug that carries an effective track record for avoiding parasite resistance; ii) identify one which we could easily modify in order to improve its antimalarial activity. Quinine, the most abundant Cinchona alkaloid, was the only known antimalarial drug for over 300 years. In order to improve its activity to clinical levels of modern antimalarial drugs, we used the triazole functional group as a linker to other bioactive pharmacophores and various peptides. The use of a triazole functional group as a linker is becoming widely used in medicinal chemistry; studies show that incorporation of this heterocycle motif into a variety of drugs results in enhanced antimalarial properties compared to the parent drugs. To create these triazole-containing quinine analogues, we employed a ‘click chemistry’ approach by pairing an O-alkynequinine component to a variety of azides, hybridizing these two functional groups to create a 1-substituted triazole ring. Following the synthesis, triazole-containing quinine analogues were characterized and tested against the blood stage of P. falciparum strain 3D7 in vitro and their IC50 values determined compared to the parent drug. Many of the analogues show increased or retained potency against P. falciparum compared to quinine alone. Thus, hybridization to a triazole group could be a worthwhile route in developing potent modern antimalarials from natural drugs with low parasite resistance.
General Note:
Undergraduate Honors Thesis

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University of Florida Institutional Repository
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University of Florida
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Copyright Juan C. Serrano. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.

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i Synthesis and Antimalarial Activities of a Diverse Set of Triazole Containing Quinine Analogues Juan C. Serrano University of Florida Interdisciplinary Studies Department December 10 , 2014

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ii Acknowledgments I would like to thank Dr. Siva S. Panda and Mr. Khanh Ha for their mentorship, guidance, and continuing support both in my chemistry research and academic life. It was truly an honor to conduct research in the lab of the late Dr. Alan R. Katritzky, and I w holeheartedly believe his spirit lives on in the hundreds of students whom he mentored. Additionally, I would like to thank Dr. Dennis C. Hall for his support in this process, and all members of the Florida Center for Heterocyclic Compounds for their help .

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iii Table of Contents Chapter 1: Introduction ................................ ................................ ................................ .................... 1 1.1 Malaria prevalence and parasite drug resistance ................................ ................................ . 1 1.2 1,2,3 Triazoles use in antimalarial moieties ................................ ................................ ........ 3 Chapter 2: Results and Discussion ................................ ................................ ................................ ... 5 2.1 Preparation of triazole containing quinine analogues ................................ ............................ 5 2.2 in vitro antimalarial activity assay ................................ ................................ ......................... 8 Chapter 3 : Conclusion ................................ ................................ ................................ .................... 1 2 Chapter 4 : Experimental ................................ ................................ ................................ ................ 13 References ................................ ................................ ................................ ................................ ...... 25

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iv Abstract The search for antimalarial drugs with low parasite resistance is an ever increasing concern for global health. In this project we sought two goals : i) to select for a natural antimalarial drug that carries an effective track record for avoiding parasite r esistance ; ii) i de n tify one which we could easily modify in order to improve its antimalarial activity. Quinine, the most abundant Cinchona alkaloid, was the only known antimalarial drug for over 300 years. In order to improve its activity to clinical lev els of modern antimalarial drugs, we used the triazole functional group as a linker to other bioactive pharmacophores and various peptides. The use of a triazole functional group as a linker is becoming widely used in medicinal chemistry; studies show that incorporation of this heterocycle motif into a variety of drugs result s in enhanced antimalarial properties compared to the parent drug s . To create these triazole c ontaining quinine analogues, we alkyn equinine component to a variety of azides, hybridizing these two functional groups to create a 1 substituted triazole ring. Following the synthesis, triazole containing quinine analogues were characterized and tested against the blood stage of P. falciparu m strain 3D7 in vitro and their IC 50 values determined compared to the parent drug. Many of the analogues show increased or retained potency against P. falciparum compared to quinine alone. Thus, hybridization to a triazole group could be a worthwhile route in developing potent modern antimalarials from natural drugs with low parasite resistance. Keywords: antimalarial, quinine, triazole, click chemistry, parasite resistance.

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1 Chapter 1: I ntroduction 1.1 Malaria prevalence and parasite drug resistance Malaria is an incredibly devastating infectious disease with an annual mortality rate of over one million and a case mortality rate of 15 20% despite adequate treatment and access to facilities for intensive treatment. The disease is caused by protozoan pa rasites of the genus Plasmodium; in particular , P. falciparum is responsible for about 80% of all malaria cases a nd about 90% of deaths . 1 Once a P. falciparum infected mosquito bites a human, haploid sporozoi tes are injected into the bloodstream which travel to the liver and infect hepatocytes. After proliferating, the parasites exit the liver through the bloodstream as asexual merozoites which infect erythrocytes (Figure 1) . The mature forms of these parasites then alter the cell surface properties of erythrocytes which begin sticking to blood vessels, a process termed cytoadherence. This process res ults in obstruction of microcirculation within the human host and ultimately leads to multiple organ f ailure (Figure 2 ). 2 Most antimalarial drugs prevent t he proliferation of P. falciparum within blood cells by targeting the asexual blood stage cycl e of the parasite. More s pecifically within the parasite, the most exploited pathway is the sequestration and biocrystallization of toxic free heme. By i nhibiting Figure 2. Cytoadherence of an infected red blood cell. Figure 1. P. falciparum life cycle.

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2 hemozoin biocrystallization of free the subsequent free heme buildup disrupts membrane f unction and leads to cell lysis . 3 Targeting heme biocrystallization remains one of the most promising approaches for antimalar ial drug development . Degradation of toxic heme is an essential function necessary for survival of the parasite. Additionally, drugs target ing this pathway remain highly specific to the parasite. Finally and most importantly, most of these antimalarials ta rget the toxic species, free heme, rather than specific enzymes and thus , this target is outside of genetic control by the parasite. However, a recent rise in parasite resistance to modern antimalarial drugs has increased the demand to search evolutionary adaptations. Modern approaches to overcome parasite resistance include combination therapy with multiple drugs, developing analogues of existing drugs, or using drug r esistance reversers. 23 24 Molecular hybridization the design of new chemical entities by covalent fusion of two or more drugs, bioactive compounds, and/or pharmacophoric units has proven to be an attractive strategy since dual modes of action of the indivi dual hybrids could optimize antimalarial efficacy. 25 Yet this strategy has largely been abandoned despite the fact that modification of the Cinchona alkaloids was one of the most successful strategies employed for drug development. Moreover, recent studies reveal quinine conjugates with peptides, artemisinin units , or antibiotics show i mprovement or retention of antimalarial activ ity compared to the parent drug . 4 6 While the search for novel drug targets and new lead structures for the treatment of malaria is a critical venture, a complementary strategy is to utilize and further develop lead structures from nature wi th proven attractive properties . 7 8 Quinine, the most abundant Cinchona alkaloid, was the only known antimalarial drug for over 300 years and carries an impressive track record against P. falciparum . Its low susceptibility to parasite resistance may be due to a privileged natural structure

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3 which the parasite finds difficult to bypass. Thus, although abandoned as an antimalarial drug in should hold the key to the develo pment of effective antimalarial co mpounds with immunity to parasite resistance. 9 1.2 1,2,3 T riazoles use in antimalarial moieties T he use of a triazole functional group as a linker is becoming increasingly popular in medicinal chemistry, and many example s incorporating this heterocycle into a variety of drugs have appeared in the literature. 10 Recent studies reveal triazole containing furamidine and chloroquine analogues showed enhanced antimalarial activity compared to parent drug s . The use of a triazole ring to increase antimalarial activity has been shown to be an effective route for modif ication of known antimalarials. Recent studies demonstrate the use of triazole rings as linkers for drug hybrids, such as 7 chloroquinoline in lactam or isatin rings, 11 12 or as linkers to aryl groups in furamidine and chloroquine analogues. 13 14 These drug hybrids and analogues display increased or retained activity compared to the parent compound s , and it clearly shows that the triazole group plays a special ro le in enhancing the hemozoin formation inhibitory action of these drugs on P. falciparum. The exact mechanism of action has yet to be elucidated, although P. Singh et al. suggest that the increase in antimalarial activity may be attributed to either solubi lity enhancing properties of triazole rings or increase of heme binding. 11 In this thesis, I describe the modif ication of quinine by hybridizing it to various bioactive compounds and amino acids, using a triazole group as a linker, to increase its antimalarial activity while retaining its ability to avoid parasite resistance. By studying the substitution at 1,2,3 triazole on antimalarial activity, novel quinine analogues could be developed with increased potency for clinical use. While the molecular functionality of the triazole group is not explored in this study,

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4 we present a facile synthetic route using click chemistry t o synthesize triazole containing quinine analogues, taking advantage of the pharmacological activity enhancing property of triazoles, yet retaining quinines natural structure and low susceptibility to parasite resistance. However, the influence of the tria must be studied further , and it must be determined whether these analogues will be safe or adequate for further clinical application s .

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5 Chapter 2: Results and d iscussion The synthetic protocol utilized for the synthesis of desired hybrids invol ved well established Cu catalyzed click chemistry of alkynes 1a b with various azides according to the method pioneered by Sharpless 21 and Meldal. 22 The precursor alkynes were synthesized by the alkylation of quinine with an alkyne bromide species. Various azides of amino acids, aromatic amines and heterocyclic amines were synthesized using b enzotriazol 1 yl sulfonyl azide as azido t ransfer reagent and azido dipept i d es by follo wing previous reported method , or were commercially bought . 15 2. 1 Preparation of triazo le containing quinine analogues O propargylquinine 1a and O butyrylquinine 1b were prepared by alkylation of quinine by either propargyl bromide or 4 bromobut 1 yne in the presence of NaH in DMF at 0 for 24 h ( 70 80 % , Scheme 1 ) . 20 Presence of O propargylquinine or O butyrylquinine in the desired product was confirmed by the distinctive terminal alkyne carbon resona n ce at 60.1 ppm and 58.0 ppm, respectively. Scheme 1 Synthesis of O alkynequinine We prepared triazole containing quinine analogues 2 a e , 3a h , and 4a e by an azide alkyne 1,3 Huisgen cycloaddition of O alkynequinine 1a b with various azides in the presence of catalytic

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6 amount s of copper (II) sulfate pentahydrate and sodium ascorbate in ethanol:water (10:1) at room temperature for 24 48 h (Scheme s 2 and 3 ) . Scheme 2 H uisgen cycloaddition of O propargyl quinine with azido acids/dipeptides. Table 1. Preparation of quinine amino acid/dipeptide conjugates 2 a e . Entry Product R 1 R 2 Yield (%) m p ( o C) 1 2 a CH 3 72 189 191 2 2 b CH 2 Ph 74 122 124 3 2 c CH 2 CH(CH 3 ) 2 70 191 193 4 2 d CH(CH 3 ) 2 82 145 147 5 2 e H CH 2 CH(CH 3 ) 2 89 191 193

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7 Scheme 3 H uisgen cycloaddition of O propargyl quinine and O butyryl quinine with aryl azides. Table 2 . Preparation of quinine aryl conjugates 3 a h from O propargylquinine . Entry Product R Yield (%) m p ( o C) 1 3a 85 oil 2 3b 68 oil 3 3c 79 oil 4 3d 74 oil 5 3e 81 oil 6 3f 69 oil 7 3g 80 143 144 8 3h 70 oil

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8 Table 3 . Preparation of quinine aryl conjugates 4a e from O butyrylquinine. Entry Product R Yield (%) m p ( o C) 1 4a 85 oil 2 4b 74 123 124 3 4c 72 oil 4 4d 70 151 152 5 4e 66 oil 2.2 i n vitro antimalarial activity assay To determine whether the quinine analogues described retained antimalarial activity, compounds 2a e , 3a h , and 4a e as well as quinine itself , were tested against the blood stage of P. falciparum strain 3D7 in vitro. Table 1 gives the IC 50 values determined 72 h after compound addition. Quinine was highly potent (IC 50 = 77 nM), as expected. Compounds 2 a e , 3 a , and 3 f h were much less active (IC 50 s >1000 nM), with an approximately >15 fold decrease in potency compared to quinine ( Table 4 , F igure s 3 and 4 ) . Compound s 3b retained its potency in line with quinine with an IC 50 value of 902.9 nM. Compound 3c retained potency in line with quinine with an IC 50 value of 448.3 nM , while compounds 3b and 3 d e were somewhat less potent with IC 50 values ranging from 790 902.9 nM (Table 4, F igure 4 ) . Compounds 4a e displayed a significant increase in potency co mpared to quinine (approximate > 2 fold increase in potency) with IC 50 values ranging from 27.32 40.82 nM (Table 4, Figure 5) .

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9 Table 4 : In vitro antimalarial activities of compounds against the 3D7 strain of P. falciparum Entry Compound ID IC 50 1 Quinine 77 .0 0 nM 2 2a 41000 nM 3 2b 7700 nM 4 2c 58000 nM 5 2d 17000 nM 6 2e 12000 nM 7 3a 20164 nM 8 3b 902.9 nM 9 3c 448.3 nM 10 3d 790 nM 11 3e 885.3 nM 12 3f 2200 nM 13 3g 4800 nM 14 3h 3400 nM 15 4a 36.86 nM 16 4b 40.82 nM 17 4 c 27.32 nM 18 4d 40.19 nM 19 4e 30.02 nM

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10 Analysis of Table 4 and Figures 3 5 reveals a structure activity relationship (SAR) amongst the analogues. Compounds 4a e were all derived from O butyrylquinine 1b , suggesting the C 2 spacer between the hydroxyl group of quinine and the triazole group is essential for retaining or increasing potency of the analogue s . This can be seen by comparing each O butyrylquinine derivative with its complementary O propargylquinine derivative, whereby adding an additional carbon spacer in 4a e significantly increases the antimalarial activity o f the otherwise inactive compounds 3 a e , respectively. Additionally, con trary to prediction, amino acid and di peptide conjugated compounds 2a e did not display antimalarial activity. Whether this is due to the amino acids or di peptide structure or functionality, or because complementary analogues with C 2 spacers were not synthesized has yet to be explored. 77 41000 7700 58000 17000 12000 0 10000 20000 30000 40000 50000 60000 Quinine 2a 2b 2c 2d 2e IC50 (nM) Compound ID Figure 3. IC 50 s of quinine amino acid/dipeptide analogues .

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11 77 902.9 448.3 790 885.3 2200 4800 3400 0 1000 2000 3000 4000 5000 Quinine 3a 3b 3c 3d 3e 3f 3g 3h IC50 (nM) Compound ID 77 36.86 40.82 27.32 40.19 30.02 0 10 20 30 40 50 60 70 80 Quinine 4a 4b 4c 4d 4e IC50 (nM) Compound ID Figure 4. IC 50 s of quinine aryl analogues derived from O propargylquinine . *3a IC 50 value (20164 nM) extends beyond axis area. Figure 5. IC 50 s of quinine aryl analogues derived from O butyrylquinine.

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12 Chapter 3: Conclusion While discovering the exact mechanism of action through which substitution at the triazole group affects antimalarial activity against P. falciparum requires further studies, our study demonstrates that useful provides a simplistic scaffold for optimization of lead compounds 4a e , as well as the development of additional triazole containing quinine analogues. W e have developed an efficient method for the synthesis of triazole co ntaining quinine analogues via click chemistry. Some of these analogues show significant enhancement in in vitro anti malarial activity compared to quinine. Additional studies are needed to determine the

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13 Chapter 4: Experimental Melting points were determined on a capillary point apparatus equipped with a digital thermometer. NMR spectra were recorded in CDCl 3 or DMSO d 6 , on Mercury or Gemini NMR spectrometers operating at 300 MHz for 1 H (with TMS as an internal standard) and 75 MHz for 13 C . Elemental analyses were performed on a Carlo Erba EA1108 instrument. General procedure for the synthesi s of O alkynequinine conjugates 1a b Under N 2 atmosphere in a triple neck 250 mL round bottom flask, a solution of quinine (1 eq) was added below 20 °C to a NaH (2.2 eq) suspension in DMF over a period of 30 min. After cessation of H 2 evolution, the alkyne bromide (1.2 eq) was added dropwise over a period of 30 min, maintaining the temperature below 0 °C, followed by stirring at 10 °C. The re action was monitored by TLC and following completion (2 3 hr), was quenched by adding 18% HCl (2.5 mL) at 10 °C. After pouring the reaction mixture into a 250 mL Erlenmeyer flask, toluene (130 mL) and 5% NaOH (8 mL) were added, and using a separatory funne l, the product was extracted into the organic layer and washed with brine (2 × 75 mL). Activated carbon (5 g) was added to the separated organic layer, stirred for 1 hr and filtered. The clear filtrate was then evaporated to dryness. The product was recrys tallized using a Hexanes:EtOAc (9:1) mixture (50 mL) to obtain O alkynequinines 1a b as off white solids in 70 80 % yield. (1S,2R,4S,5R) 2 ((R) (But 3 yn 1 yloxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (1b). White power, 6.49 g, 17.2 mmol, 80% yield ; mp 155 157 o C; 1 H NMR (CDCl 3 ): 8.74 (d, J = 4.8 Hz, 1H), 8.01 (d, J = 9.4 Hz, 1H), 7.56 (d, J = 2.4 Hz, 1H), 7.35 7.23 (m, 2H), 5.81

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14 5.65 (m, 3H), 4.97 (d, J = 4.8 Hz, 1H), 3.90 (s, 3H), 3.61 3.48 (m, 1H), 3.29 3.10 (m, 3H), 2.81 2.70 (m, 2H), 2.4 1 2.30 (m, 1H), 1.89 1.70 (m, 4H), 1.65 1.51 (m, 3H), 1.29 1.14 (m, 2H); 13 C NMR (CDCl 3 ): 159.1, 157.3, 146.4, 143.9, 140.4, 137.0, 131.6, 126.0, 123.2, 116.8, 103.1, 82.3, 80.4, 72.5, 70.4, 58.0, 56.4, 55.9, 43.7, 43.3, 36.9, 28.4, 27.1, 20.0. HRMS (+ES I TOF) m/z for C 24 H 28 N 2 O 2 [M+1] + calcd. 376.2156, found 376.2150. General procedure for the synthesis of quinine analogues 2a e, 3a h , and 4a e To a stirred solution of O alkynequinine (1 eq) and the appropriate azide (2 eq) in 20 mL ethanol:water (10:1) was added in succession copper sulfate (0.055 eq) and sodium ascorbate (0.143 eq) at room temperature. The reaction was monitored by TLC and upon completion (24 48 hr), water (15 mL) was added to the reaction mixture. The product was then extracted with ch loroform (2 × 50 mL). The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure to afford triazole containing quini ne analogues 2a e , 3a h , and 4a e in 66 89 % yields . (S) 2 (4 (((R) (6 Methoxyquinolin 4 yl)((1S,2R,4S,5R) 5 vinylquinuclidin 2 yl)methoxy)methyl) 1H 1,2,3 triazol 1 yl)propanoic acid (2a). Light brown power , 183 mg, 0.38 mmol, 72% yield ; mp 189 191 o C; 1 H NMR (CDCl 3 ): 8.66 (d, J = 4.6 Hz, 1H), 7.99 (d, J = 9.2 Hz, 1H), 7.68 7.51 (m, 1H), 7.41 (s, 1H), 7.35 7.23 (m, 2H), 5.66 5.34 (m, 3H), 4.93 4.84 (m, 3H), 4.46 4.37 (m, 1H), 3.83 (s, 3H), 3.49 3.43 (m, 1H), 3.39 3.10 (m, 3H), 2.75 2.61 (m, 2H), 2.31 2.22 (m, 2H), 1.71 (d, J = 6.6 Hz, 3H), 1.41 1.39 (m, 2H), 1.25 1.19 (m, 2H); 13 C NMR (CDCl 3 ): 172.3, 159.4, 157.1, 145.9, 143.6, 142.0,

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15 141.1, 137.0, 132.4, 126.1, 122.9, 122.3, 117.1, 103.4, 82.5, 80.4, 71.9, 65.1, 58.0, 56.1, 43.2, 42.3, 36.4, 29.2, 27.0, 18.1. HRM S (+ESI TOF) m/z for C 26 H 31 N 5 O 4 [M+1] + calcd. 478.2449, found 478.2460. (S) 2 (4 (((R) (6 Methoxyquinolin 4 yl)((1S,2R,4S,5R) 5 vinylquinuclidin 2 yl)methoxy)methyl) 1H 1,2,3 triazol 1 yl) 3 phenylpropanoic acid (2b). Light brown power , 218 mg, 0.39 mmol, 74% yield ; mp 122 124 o C; 1 H NMR (CDCl 3 ): 8.67 (d, J = 4.4 Hz, 1H), 8.00 (d, J = 9.6 Hz, 1H), 7.42 7.17 (m, 9H), 5.70 5.59 (m, 1H), 4.96 4.84 (m, 3H), 4.46 4.37 (m, 1H), 4.51 (dd, J = 30.0, 12.0 Hz, 2H), 3.89 (s, 3H), 3.49 3.43 (m, 1H), 3.36 3.21 (m, 2H), 3.15 2.99 (m, 2H), 2.65 2.55 ( m, 2H), 2.28 2.20 (m, 2H), 1.72 1.21 (m, 5H); 13 C NMR (CDCl 3 ): 173.1, 159.4, 157.3, 146.3, 143.6, 142.1, 141.4, 138.3, 137.0, 132.4, 129.3, 127.1, 126.8, 125.9, 122.9, 122.0, 117.1, 104.6, 83.5, 80.4, 72.3, 68.3, 66.1, 58.0, 57.1, 43.6, 42.6, 36.4, 29.6, 27.0. HRMS (+ESI TOF) m/z for C 32 H 35 N 5 O 4 [M+1] + calcd. 554.2762, found 554.2787. (S) 2 (4 (((R) (6 methoxyquinolin 4 yl)((1S,2R,4S,5R) 5 vinylquinuclidin 2 yl)methoxy)methyl) 1H 1,2,3 triazol 1 yl) 4 methylpentanoic acid (2c). Light brown power , 194 mg, 0.37 mmol, 70% yield ; mp 191 193 o C; 1 H NMR (CDCl 3 ): 8.67 (d, J = 4.8 Hz, 1H), 7.99 (d, J = 9.4 Hz, 1H), 7.47 7.40 (m, 1H), 7.35 (s, 1H), 7.32 7.26 (m, 2H), 5.69 5.49 (m, 3H), 5.13 4.85 (m, 3H), 4.32 4.17 (m, 1H), 3.84 (s, 3H), 3.60 3.58 (m, 1H), 3.33 3. 06 (m, 3H), 2.78 2.67 (m, 2H), 2.37 2.25 (m, 2H), 2.01 1.66 (m,

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16 4H), 1.25 1.02 (m, 3H), 0.84 (d, J = 6.6 Hz, 3H), 0.78 (d, J = 6.6 Hz, 3H); 13 C NMR (CDCl 3 ): 175.2, 158.6, 158.4, 147.6, 144.6, 143.5, 142.7, 140.0, 131.9, 127.0, 123.6, 122.1, 117.8, 102.1, 82.5, 76.0, 71.3, 64.6, 62.8, 59.6, 56.3, 55.7, 43.3, 42.1, 38.7, 27.5, 25.1, 23.1, 21.4. HRMS (+ESI TOF) m/z for C 26 H 31 N 5 O 4 [M+1] + calcd. 520.2918, found 520.2930. (S) 2 (4 (((R) (6 methoxyquinolin 4 yl)((1S,2R,4S,5R) 5 vinylquinuclidin 2 yl)methoxy)methyl) 1H 1,2,3 triazol 1 yl) 3 methylbutanoic acid (2d). Light brown power, 228 mg, 0.44 mmol, 82% yield ; mp 145 147 o C; 1 H NMR (CDCl 3 ): 8.76 (d, J = 4.8 Hz, 1H), 8.20 (d, J = 9.6 Hz, 1H), 7.50 7.47 (m, 1H), 7.46 (s, 1H), 7.38 7.27 (m, 2H), 5.57 5.52 (m, 3H), 5.07 5.01 (m, 3H), 4.77 4.67 (m, 1H), 3.96 (s, 3H), 3.56 3.41 (m, 1H), 3.25 3.10 (m, 3H), 2.69 2.58 (m, 2H), 2.47 2.42 (m, 2H), 2.28 2.05 (m, 3H), 1.25 1.02 (m, 2H) 1.04 (d, J = 7.9 Hz, 3H), 0.95 (d, J = 7.9 Hz, 3H); 13 C NMR (CDCl 3 ): 175.1, 159.4, 158.4, 148.1, 144.5, 142.6, 142.7, 140.1, 132.3, 127.3, 123.6, 121.9, 117.1, 104.6, 82.0, 79.3, 70.3, 63.4, 59.1, 55.9, 53.7, 43.3, 41.1, 32.7, 28.5, 25.1, 19.2, 18.9. HRMS ( +ESI TOF) m/z for C 28 H 35 N 5 O 4 [M+1] + calcd. 506.2762, found 522.2711. (2 (4 (((R) (6 methoxyquinolin 4 yl)((1S,2R,4S,5R) 5 vinylquinuclidin 2 yl)methoxy)methyl) 1H 1,2,3 triazol 1 yl)acetyl) L leucine (2e). White power , 273 mg, 0.47 mmol, 89% yield ; mp 191 193 o C; 1 H NMR (CDCl 3 ): 8.77 (d, J = 4.6 Hz, 1H), 8.04 (d, J = 9.4 Hz, 1H), 7.53 7.49 (m, 1H), 7.37 (s, 1H), 7.35 7.25 (m, 2H), 5.69 5.58 (br s,

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17 1H), 5.55 5.59 (m. 1H), 5.29 5.24 (m, 2H), 5.01 4.81 (m, 4H), 4.26 4.17 (m, 1H), 3.86 (s, 3H), 3.44 3.24 (m, 1H), 3.21 3.06 (m, 3H), 2.84 2.74 (m, 2H), 2.60 2.50 (m, 2H), 2.20 2.01 (m, 2H), 1.71 1.48 (m, 2), 1.21 1.09 (m, 3H), 0.91 (d, J = 6.6 Hz, 3H), 0.89 (d, J = 6.6 Hz, 3H); 13 C NMR (CDCl 3 ): 174.9, 157.9, 156.9, 147.5, 145.6, 143.5, 142.6, 141.6, 131.5, 127.1, 123.6, 122.0, 118.1, 105.0, 81.6, 71.6, 70.9, 65.3, 62.9, 6 0.4, 59.5, 56.1, 55.5, 42.9, 41.1, 39.6, 32.3, 25.4, 22.9, 21.0. HRMS (+ESI TOF) m/z for C 31 H 40 N 6 O 5 [M+1] + calcd. 577.3133, found 577.3142. (1S,2R,4S,5R) 2 ((R) ((1 (2 chlorophenyl) 1H 1,2,3 triazol 4 yl)methoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (3a). Light y ellow oil, 233 mg, 0.45 mmol, 85% yield ; 1 H NMR (CDCl 3 ): 8.75 (d, J = 4.8 Hz, 1H), 8.04 (d, J = 9.4 Hz, 1H), 7.58 7.36 (m, 7H), 5.73 5.63 (m. 1H), 4.99 4.87 (m, 4H), 4.75 4.56 (m, 1H), 3.95 (s, 3H), 3.72 3.64 (m, 1H), 3.47 3.40 (m, 3H), 3.16 3.04 (m, 2H), 2.72 2.57 (m, 2H), 1.80 1.50 (m, 2H), 1.24 1.16 (m, 2H); 13 C NMR (C DCl 3 ): 160.1, 150.0, 148.5, 147.3, 145.1, 143.0, 136.5, 133.5, 132.6, 131.2, 130.2, 128.6, 126.2, 123.1, 122.5, 122.1, 119.6, 118.5, 103.1, 79.8, 68.2, 65.2, 55.5, 56.6, 43.6, 40.4, 38.9, 36.2, 23.1. HRMS (+ESI TOF) m/z for C 29 H 30 ClN 5 O 2 [M+1] + calcd. 516 .2161, found 516.2154. (1S,2R,4S,5R) 2 ((R) ((1 (4 chlorophenyl) 1H 1,2,3 triazol 4 yl)methoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (3b). Light y ellow oil , 187 mg, 0.36 mmol, 68% yield ; 1 H NMR (CDCl 3 ): 8.77 (d, J = 4.6 Hz, 1H), 8.03 (d, J = 9.8

PAGE 22

18 Hz, 1H), 7.68 7.36 (m, 7H), 5.77 5.65 (m. 1H), 4.99 4.90 (m, 3H), 4.73 4.60 (m, 2H), 3.96 (s, 3H), 3.73 3.64 (m, 1H), 3.49 3.45 (m, 3H), 3.21 3.00 (m, 2H), 2.77 2.64 (m, 2H), 1.84 1.50 (m, 2H), 1.26 1.18 (m, 2H); 13 C NMR (CDCl 3 ): 159.8, 149.8, 148 .2, 147.0, 145.6, 141.6, 135.3, 134.1, 130.8, 128.6, 125.9, 124.2, 122.5, 118.5, 115.9, 103.5, 80.1, 68.5, 67.1, 57.6, 56.4, 43.6, 41.5, 38.2, 36.2, 23.5. HRMS (+ESI TOF) m/z for C 29 H 30 ClN 5 O 2 [M+1] + calcd. 516.2161, found 516.2161. (1S,2R,4S,5R) 2 ((R) (6 methoxyquinolin 4 yl)((1 (4 methylbenzyl) 1H 1,2,3 triazol 4 yl)methoxy)methyl) 5 vinylquinuclidine (3c). Colorless oil , 214 mg, 0.42 mmol, 79% yield ; 1 H NMR (CDCl 3 ): 8.65 (d, J = 4.4 Hz, 1H), 8.00 (d, J = 9.8 Hz, 1H), 7.67 7.36 (m, 7H), 5.71 5.64 (m. 1H), 4.89 4.76 (m, 4H), 4.71 4.62 (m, 1H), 3.91 (s, 3H), 3.70 3.64 (m, 1H), 3.52 3.44 (m, 3H), 3.21 3.01 (m , 2H), 2.68 2.52 (m, 2H), 2.15 (s, 3H), 1.79 1.48 (m, 2H), 1.26 1.16 (m, 2H); 13 C NMR (CDCl 3 ): 160.1, 149.4, 147.8, 147.0, 145.4, 143.5, 138.6, 136.5, 133.8, 129.6, 125.9, 123.2, 121.3, 119.1, 115.9, 104.0, 80.0, 69.6, 67.0, 58.1, 56.4, 43.5, 42.6, 39.0, 36.6, 22.8, 21.8. HRMS (+ESI TOF) m/z for C 31 H 35 N 5 O 2 [M+1] + calcd. 510.2864, found 510.2884. (1S,2R,4S,5R) 2 ((R) ((1 benzyl 1H 1,2,3 triazol 4 yl)methoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (3d). Colorless oil, 202 mg, 0.39 mmol, 74% yield ; 1 H NMR (CDCl 3 ): 8.69 (d, J = 4.8 Hz, 1H), 8.00 (d, J = 9.6 Hz, 1H), 7.45 7.08 (m, 8H), 5.70 5.65 (m. 1H), 5.59 (s, 2H), 4.91 4.84 (m, 3H), 4.53 (dd, J = 28.8, 12.0 Hz, 2H), 3.91 (s,

PAGE 23

19 3H), 3.36 3.30 (m, 1H), 3.12 2.99 (m , 3H), 2.66 2.55 (m, 2H), 2.25 2.20 (m, 2H), 1.72 1.24 (m, 2H), 1.29 1.18 (m, 2H); 13 C NMR (CDCl 3 ): 157.9, 154.7, 147.4 144.7, 143.9, 141.2, 134.4, 131.7, 129.3, 128.1, 127.7, 126.3, 124.6, 122.6, 121.8, 114.6, 101.3, 79.1, 68.2, 62.5, 60.0, 57.6, 55.9, 43.0, 39.5, 37.9, 37.4, 24.0. HRMS (+ESI TOF) m/z for C 30 H 33 N 5 O 2 [M+1] + calcd. 512.2656, found 512.26 51. (1S,2R,4S,5R) 2 ((R) (6 methoxyquinolin 4 yl)((1 (3 phenylpropyl) 1H 1,2,3 triazol 4 yl)methoxy)methyl) 5 vinylquinuclidine (3e). Colorless oil , 226 mg, 0.43 mmol, 81% mmol ; 1 H NMR (CDCl 3 ): 8.71 (d, J = 4.8 Hz, 1H), 8.00 (d, J = 9.6 Hz, 1H), 7.55 7.28 (m, 8H), 5.70 5.65 (m. 1H), 4.97 4.87 (m, 4H), 4.74 4.56 (m, 3H), 3.91 (s, 3H), 3.73 3.60 (m, 1H), 3.52 3.42 (m, 3H), 3.25 2.91 (m, 4H), 2.70 2.56 (m, 4H), 1.80 1.51 (m, 2H), 1.29 1.1 8 (m, 2H); 13 C NMR (CDCl 3 ): 158.6, 149.3, 148.0, 145.0, 142.9, 141.3, 133.2, 131.9, 129.3, 128.2, 127.0, 126.3, 124.6, 123.5, 121.2, 117.2, 102.9, 79.0, 67.2, 67.5, 58.9, 57.4, 55.9, 43.2, 40.1, 37.9, 37.2, 32.6, 30.5, 23.5. HRMS (+ESI TOF) m/z for C 32 H 37 N 5 O 2 [M+1] + calcd. 524.3020, found 524.3023. (1S,2R,4S,5R) 2 ((R) ((1 (4 methoxyphenyl) 1H 1,2,3 triazol 4 yl)methoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (3f). Yellow oil , 188 mg, 0.37 mmol, 69% yield ; 1 H NMR (CDCl 3 ): 8.79 (d, J = 4.8 Hz, 1H), 8.02 (d, J = 9.4 Hz, 1H), 7.58 7.18 (m, 7H), 5.68 5.56 (m. 1H), 4.98 4.91 (m, 3H), 4.73 4.62 (m, 2H), 3.97 (s, 3H), 3.81 (s, 3H), 3.32 3.24 (m, 1H), 3.00 2.85 (m, 3H), 2.45

PAGE 24

20 2.40 (m, 2H), 2.10 1.85 (m, 2H), 1.62 1.45 (m, 4H); 13 C NMR (CDCl 3 ): 162.0, 159.2, 150.1, 146.8, 145.4, 143.0, 142.4, 140.9, 131.2, 128.6, 126.3, 123.0, 122.5, 122.0, 119.1, 117.5, 102.6, 81.5, 70.2, 69.2, 60.0, 59.5, 56.6, 44.6, 41.0, 39.6, 37.6, 25.1. HRMS (+ESI TOF) m/z for C 30 H 33 N 5 O 3 [M+1] + calcd. 512.2656, found 512.2678. (1S,2R,4S,5R) 2 ((R) ((1 ((1H benzo[d][1,2,3]triazol 1 yl)methyl) 1H 1,2,3 triazol 4 yl)methoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (3g). White solid , 228 mg, 0.43 mmol, 80% yield ; mp 143 144 o C; 1 H NMR (CDCl 3 ): 8.71 (d, J = 4.8 Hz, 1H), 8.00 (d, J = 9.6 Hz, 1H), 7.83 7.79 (m, 3H), 7.58 7.23 (m, 4H), 6.09 5.09 (m, 2H), 5.75 5.58 (m. 2H), 5.07 4.87 (m, 2H), 4.23 4.09 (m, 2H), 3.85 (s, 3H), 3.60 3.51 (m, 1H), 3.28 3.11 (m, 3H), 2.83 2.68 (m, 2H), 2.36 2.28 (m, 2H), 1.88 1.80 (m, 2H), 1.65 1.52 (m, 2H); 13 C NMR (CDCl 3 ): 159.8, 148.3, 146.2, 145.0, 143.6, 142.2, 140.9, 133.2, 130.6, 126.1, 125.3, 122.5, 122.2, 121.9, 120.5, 118.6, 116.5, 103.0, 81.5, 70.0, 69.1, 67.3, 59.9, 55.4, 44.2, 41.0, 36.6, 35.5 , 23.8. HRMS (+ESI TOF) m/z for C 30 H 32 N 8 O 2 [M+1] + calcd. 537.2646, found 537.2645. (1S,2R,4S,5R) 2 ((R) ((1 (2,2 dimethoxyethyl) 1H 1,2,3 triazol 4 yl)methoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (3h). Light Yellow oil , 184 mg, 0.37 mmol, 70% yield ; 1 H NMR (CDCl 3 ): 8.70 (d, J = 4.4 Hz, 1H), 8.00 (d, J = 9.8 Hz, 1H), 7.65 7.59 (m, 1H), 7.48 (s, 1H), 7.46 7.25 (m, 2H), 5.69 5.55 (m. 1H), 5.10 4.88 (m, 3H), 4.44 4.19 (m, 3H), 3.88 (s, 3H), 3.61 3.56 (m, 1H), 3.48 (s, 6H), 3.29 3.12 (m, 3H), 2.8 0 2.65

PAGE 25

21 (m, 2H), 2.36 2.25 (m, 2H), 1.80 1.45 (m, 4H); 13 C NMR (CDCl 3 ): 158.1, 148.0, 147.1, 144.6, 142.2, 140.9, 131.6, 130.6, 126.1, 124.3, 121.5, 118.0, 116.1, 102.5, 81.0, 69.5, 67.6, 59.4, 57.9, 55.4, 52.3, 42.9, 39.5, 29.5, 27.3, 22.8. HRMS (+ESI TO F) m/z for C 27 H 35 N 5 O 4 [M+1] + calcd. 494.2762, found 494.2776. (1S,2R,4S,5R) 2 ((R) (2 (1 (2 chlorophenyl) 1H 1,2,3 triazol 4 yl)ethoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (4a). Light y ellow oil, 240 mg, 0.45 mmol, 85% yield ; 1 H NMR (CDCl 3 ): 8.75 (d, J = 4.6 Hz, 1H), 8.04 (d, J = 9.4 Hz, 1H), 7.58 7.36 (m, 7H), 5.73 5.63 (m. 1H), 4.99 4.87 (m, 2H), 4.75 4.56 (m, 1H), 3.90 (s, 3H), 3.74 3.58 (m, 3H), 3.44 3.38 (m, 3H), 3.16 3.02 (m, 2H), 2.75 2.50 (m, 4H), 1.81 1.50 (m, 2H), 1.23 1.18 (m, 2H); 13 C NMR (C DCl 3 ): 158.6, 151.3, 148.5, 145.4, 143.0, 136.0, 135.9, 134.1, 132.4, 131.2, 129.6, 127.9, 125.8, 122.2, 121.9, 119.1, 117.5, 101.6.1, 79.8, 68.2, 65.2, 55.5, 56.6, 43.6, 40.4, 38.9, 36.2, 23.1. HRMS (+ESI TOF) m/z for C 30 H 32 ClN 5 O 2 [M+1] + calcd. 530.2317 , found 530.2332. (1S,2R,4S,5R) 2 ((R) (2 (1 (4 chlorophenyl) 1H 1,2,3 triazol 4 yl)ethoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (4b). Brown solid , 209 mg, 0.39 mmol, 74% yield ; mp 123 124 o C; 1 H NMR (CDCl 3 ): 8.61 (d, J = 4.8 Hz, 1H), 7.92 (d, J = 9.8 Hz, 1H), 7.51 7.19 (m, 8H), 5.72 5.63 (m. 2H), 4.97 4.89 (m, 2H), 3.84 (s, 3H), 3.60 3.56 (m, 1H), 3.15 3.01 (m, 4H), 2.75 2.60 (m, 2H), 2.32 2.29 (m, 2H), 1.83 1.50 (m, 4H), 1.46 1.29 (m, 3H); 13 C NMR (CDCl 3 ): 159.4,

PAGE 26

22 148.5, 147.0, 144.2, 142.2, 1 35.3, 134.6, 132.6, 130.2, 127.1, 124.3, 122.5, 120.6, 118.1, 110.1, 101.6, 79.9, 74.2, 67.5, 59.0, 57.9, 43.9, 39.8, 29.5, 27.4, 27.2, 22.7. HRMS (+ESI TOF) m/z for C 30 H 32 ClN 5 O 2 [M+1] + calcd. 530.2317, found 530.2326. (1S,2R,4S,5R) 2 ((R) (6 methoxyquinolin 4 yl)(2 (1 (p tolyl) 1H 1,2,3 triazol 4 yl)ethoxy)methyl) 5 vinylquinuclidine (4c). Yellow oil , 195 mg, 0.38 mmol,72% yield ; 1 H NMR (CDCl 3 ): 8.71 (d, J = 4.8 Hz, 1H), 8.01 (d, J = 9.8 Hz, 1H), 7.59 7.30 (m, 7H), 5.71 5.62 (m. 1H), 4.88 4.61 (m, 3H), 3.89 (s, 3H), 3.70 3.58 (m, 3H), 3.46 3.39 (m, 3H), 3.22 2.89 (m, 4H), 2.60 2.48 (m, 2H), 2.21 (s, 3H), 1.79 1.20 (m, 4H); 13 C NMR (CDCl 3 ): 158.9, 149.0, 147.8, 146.7, 145.1, 142.8, 138.6, 137.1, 131.9, 129.6, 125.9, 122.8, 121.4, 118.9, 115.9, 102.8, 78.9, 69.5, 67.0, 57.8, 56.7, 43.4, 41.9, 39.0, 36.6, 22.6, 21.6. HRMS (+ESI TOF) m/z for C 31 H 35 N 5 O 2 [M+1] + calcd. 510.2864, found 510.2847. (1S,2R,4S,5R) 2 ((R) (2 (1 benzyl 1H 1,2,3 triazol 4 yl)ethoxy)(6 methoxyquinolin 4 yl)methyl) 5 vinylquinuclidine (4d). Brown solid , 190 mg, 0.37 mmol, 70% yield ; mp 151 152 o C; 1 H NMR (CDCl 3 ): 8.58 (d, J = 4.8 Hz, 1H), 7.90 (d, J = 9.2 Hz, 1H), 7.51 7.18 (m, 9H), 5.71 5.62 (m. 4H), 5.22 4.89 (m, 2H), 3.82 (s, 3H), 3.62 3.57 (m, 1H), 3.16 3.06 (m, 4H), 2.70 2.61 (m, 2H), 2.32 2.27 (m, 2H), 1.82 1.48 (m, 4H), 1.45 1.29 (m, 3H); 13 C NMR (CDCl 3 ): 158.2, 149 .1, 148.0, 144.5, 142.2, 137.3, 133.8, 132.6, 130.0, 127.1, 126.2, 125.2, 122.8, 121.8, 120.9, 116.1, 102.6, 80.0, 76.8, 69.0, 58.0, 57.9, 44.5,

PAGE 27

23 39.9, 28.9, 27.7, 26.9, 22.7, 22.1. HRMS (+ESI TOF) m/z for C 31 H 35 N 5 O 2 [M+1] + calcd. 510.2864, found 510.2852. (1S,2R,4S,5R) 2 ((R) (6 methoxyquinolin 4 yl)(2 (1 (3 phenylpropyl) 1H 1,2,3 triazol 4 yl)ethoxy)methyl) 5 vinylquinuclidine (4e). Colorless oil , 189 mg, 0.35 mmol, 66% yield ; 1 H NMR (CDCl 3 ): 8.69 (d, J = 4.8 Hz, 1H), 8.00 (d, J = 9.4 Hz, 1H), 7.58 7.31 (m, 8H), 5.72 5.61 (m. 1H), 4.91 4.80 (m, 2H), 4.66 4.48 (m, 3H), 3.90 (s, 3H), 3.73 3.61 (m, 1H), 3.49 3.40 (m, 3H), 3.21 2.94 (m, 4H), 2.72 2.46 (m, 6H), 1.83 1.19 (m, 4H); 13 C NMR (CDCl 3 ): 159.1, 148.4, 148.0, 145.6, 143.2, 141.2, 133.2, 132.6, 129.0, 128.4, 128.0, 127.6, 125.0, 124.1, 122.6, 119.3, 102.4, 78.2, 67.1, 66.6, 58.3, 57.1, 55.9, 44.6, 40.1, 37.5, 35.7, 32.5, 29.0, 28.5, 23.1. HRMS (+ESI TOF) m/z for C 33 H 39 N 5 O 2 [M+1] + calcd. 538.3177, found 538.3196. Antimalarial activity assay Plasmodium falciparum strain 3D7 was cultured according to the method of Trager and Jensen 17 in an atmosphere of 5% CO 2 , 5% O 2 , and 90% N 2 in RPMI 1640 medium (Gibco, Grand Island, NY, USA) supplemented with 25 mM Hepes buffer (Sigma, Saint Louis, MO, USA), 25 mg/ L gentamicin (Gibco), 1 mM sodium pyruvate (Sigma), 50 mg/L hypoxanthine (Sigma), 2 g/L glucose (Sigma), 2.52 g/L sodium bicarbonate (Sigma), and 5 g/L Albumax 1 (Gibco). In vitro antimalarial activity was determined by the SYBR Green I method described by Smilkstein et al . 18 19 Stock solutions of each compound were prepared in DMSO at a concentration of 10 mM and threefold serial dilutions prepared in DMSO. Drugs were then diluted

PAGE 28

24 250 fold into culture medium in 96 well storage plates to create 2 × drug solutions. Drug solutions (50 µL/well) were transferred in quadruplicate to parasite cultures (50 µL) in 96 well black tissue culture plates for a total volume of 100 µL at 2% hematocrit, 0.2% parasitemia, and 0.2% DMSO nal concentrations. The plates were then incubated for 72 h at 37 °C. After incubation, 100 µL of lysis buffer containing 0.2 µL/mL SYBR Green I was added to each well. After incubation for 1 , NC, USA) plate reader with excitation and emission wavelengths of 497 and 520 nM, respectively. The 50% inhibitory concentrations (IC 50 s) were determined by nonlinear regression using a four parameter logistic equation (GraphPad Prism software, La Jolla, CA, USA).

PAGE 29

25 References (1) Dondorp, A. M.; Pongponratn, E.; White, N. J. Acta Trop. 2004 , 89 , 309 317. (2) Su, X.; Hayton, K.; Wellems, T. E. Nat. Rev. Genet. 2007 , 8 , 497 506. (3) Hempelmann, E. Parasitol. Res. 2007 , 100 , 671 676. ( 4 ) Panda, S. S.; Ibrahim, M. a; Küçükbay, H.; Meyers, M. J.; Sverdrup, F. M.; El Feky, S. a; Katritzky, A. R. Chem. Biol. Drug Des. 2013 , 82 , 361 366. (5 ) Panda, S. S.; Bajaj, K.; Meyers, M. J.; Sverdrup, F. M.; Katri tzky, A. R. Org. Biomol. Chem. 2012 , 10 , 8985 8993. (6 ) Walsh, J. J.; Coughlan, D.; Heneghan, N.; Gaynor, C.; Bell, A. Biorg. M ed. Chem. Lett. 2007 , 17 , 3599 3602. (7 ) Gamo, F. J.; Sanz, L. M.; Vidal, J.; de Cozar, C.; Alvarez, E.; Lavandera, J. L.; Vand erwall, D. E.; Green, D. V. S.; Kumar, V.; Hasan, S.; Brown, J. R.; Peishoff, C. E.; Cardon, L. R.; Garcia Bustos, J. F. Nature 2010 , 465 , 305 310. (8 ) Rottmann, M.; McNamara, C.; Yeung, B. K. S.; Lee, M. C. S.; Zou, B.; Russell, B.; Seitz, P.; Plouffe, D. M.; Dharia, N. V; Tan, J.; Cohen, S. B.; Spencer, K. R.; González Páez, G. E.; Lakshminarayana, S. B.; Goh, A.; Suwanarusk, R.; Jegla, T.; Schmitt, E. K.; Beck, H. P.; Brun, R.; Nosten, F.; Renia, L.; Dartois, V.; Keller, T. H.; Fidock, D. A.; Winzeler, E. A.; Diagana, T. T. Science 2010 , 329 , 1175 1180. (9 ) Kouznetsov, V. V.; Gómez Barrio, A. Eur. J. Med. Chem. 2009 , 44 , 3091 3113.

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2 6 (10 ) Kim, D. K.; Ki m, J.; Park, H. J. Biorg. Med. Chem. Lett. 2004 , 14 , 2401 2405. (11 ) Singh, P.; Singh, P.; Kumar, M.; Gut, J.; Rosenthal, P. J.; Kumar, K.; Kumar, V.; Mahajan, M. P.; Bisetty, K. Bioorg. Med. Chem. Lett. 2012 , 22 , 57 61. (12 ) Raj, R.; Singh, P.; Singh, P.; Gut, J.; Rosenthal, P. J.; Kumar, V. Eur. J. Med. Chem. 2013 , 62 , 590 596. (13 ) Berger, O.; Kaniti, a; van Ba, C. T.; Vial, H.; Ward, S. a; Biagini, G. a; Bray, P. G.; ChemMedChem 2011 , 6 , 2094 2108. (14 ) Manohar, S.; Khan, S. I.; Rawat, D. S. Chem. Biol. Drug Des. 2011 , 78 , 124 136. (15 ) J. Org. Chem. 2010 , 75 , 6532 6539. (16) Rennert R., Neundorf I., Beck Sickinger A.G. Nuclei c acid and peptide aptamers. In: Methods in Molecular Biology 2009, 535 (22), 389 403. (17) Trager, W.; Jensen, J. B. Science 1976 , 193 , 673 675. (1 8 ) Smilkstein, M.; Sriwilaijaroen, N.; Kelly, J. X.; Wilairat, P.; Riscoe, M. Antimicrob. Agents Chemother. 2004 , 48 , 1803 1806. (19 ) Winter, R. W.; Kelly, J. X.; Smilkstein, M. J.; Dodean, R.; Bagby, G. C.; Rathbun, R. K.; Levin, J. I.; Hinrichs, D.; Riscoe, M. K. Exp. Parasitol. 2006 , 114 , 47 56.

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27 (20) Ishii, Y.; Fujimoto, R.; Mikami, M.; Murakami, S.; Miki, Y.; Furukawa, Y. Org. Process Res. Dev. 2007 , 11 , 609 615. ( 21 ) Rostovtsev, V. V; Green, L. G.; Fokin, V. V; Sharpless, K. B. Angew. Chem. Int. Ed. Engl. 2002 , 41 , 2596 2599. ( 22 ) Tornøe, C. W.; Christensen, C.; Meldal, M. J. Org. Chem. 2002 , 67 , 3057 3064. (23) Morphy, R.; Rankovic, Z. J. Med. Chem. 2005 , 48 , 6523 6543. (24) Espinoza Fonseca, L. M. Bioorg. Med. Chem. 2006 , 14 , 896 897. (25) Meunier, B. Acc. Chem. Res. 2008 , 41 , 69 77.