1. Improving the Metal-Binding Efficiency of Heterocyclic Compounds Targeting
Metal Ion Dependent Enzyme of Hepatitis C Virus
Abdallah Malik Naanaa, Robert Chen, Rebecca Wong, & Dawn N. Ward Ph. D.
Department of Chemistry, Stevenson University, Stevenson, MD 21153
Abstract
Hepatitis C is a rising global health threat affecting 300 millionpeople worldwide. Hepatitis C directly
targets the liver, causing long term health effects, such as cirrhosis of the liver within 20 years. Currently
the most popular methods of treatmentfor HCV are pegylated interferon-α(PEG-IFN)and ribavirin
(RBV); and as a negative repercussion, this form of treatment is costly and presents pain and discomfort
to the patient, which results in reduced dosages or terminationof the treatment together. Development
for new treatments of HCV has been shifted toward inhibitingviral proteins, such as the crucialNS3
protein. NS3 protease requires zinc to bind for the protease to function properly, so the overall goal of
this project was to synthesize a compound that has a high affinity for metal ions, such as Zn2+. This
research focuses on the synthesis of a crossbreed cinnamicacid and UK-1 (a natural anti-cancer agent
with divalent metal ion binding abilities)to determine if the affinityfor the binding of metal ions has
increased. Verificationmethods such as, but not limitedto Infrared spectroscopy (IR) and Nuclear
magnetic resonance (NMR) will be used to validate the synthesis of our desired compound.
Introduction
• Hepatitis C virus is blood borne and affects more than 3% of individuals worldwide.
• Approximately80% of patients are chronic, leading to cirrhosis and hepatocellularcarcinoma.
• The virus is difficultto diagnose and has harmful effects to the body.
• Geneticallyvariable across all forms with a high RNA replicationrate.
• NS3 region of HCV is targeted, which needs Zn2+ ions for hydrolyticactivityand stabilization.
• The helicase region of the protein poses as a new target for inhibitors to generate novel therapies
Figure 1. The NS3 protease domain with two cofactors Figure 2. Structure of the HCV Genome
of Zn2+ ion (yellow) and NS4A protein (pink)
• A current method of inhibition is a combinationof Inferon-α (IFN-α) and ribavirin together (PR).
• This combination activates natural killer cells and macrophages to inhibit replication of the protein.
• Less than 41% of patients claim a beneficialeffect from treatmentand is expensive.
• Boceprevir can be used in triple therapy with PR to reduce timelineof therapy, but poses more side
effects and is very expensive as well.
Objectives
• To synthesize a structure that has an increased metal binding affinityover cinnamicacid inhibitors by
varying the heterocyclicgroups amongst the molecule.
• To determineif the desired compound will cyclize after addition of the amino compound.
Compound 1
• To determineif altering the heterocyclicgroups will increase the binding efficiencyto the zinc ion
found in the NS3 region of Hepatitis C.
Methods and Materials
Retrosynthesis
Scheme 1: Synthesis of a cinnamic acid derivative
Results
Results Cont.
Conclusions and Future Directions
Coupling between compound 4 and 6 was observed, supported by our percent yield (80%) and Rf
value that correlates to the presence of (Rebecca’s compound (make 5)).Based on 1H NMR, the peak at δ
9.0 suggests the presence of the amide.1H NMR also indicated ~16 H, while theoreticallyshould have 18
H present. This could be attributedto peaks being lost in the solvent peak (δ 7.0-7.5)or represents the
lost of functional groups, like the benzyloxy group, issues with the Cl3D, or the presence of enol-keto
tautomer for compound 6. Unfortunately, cyclizationof compound 6 was not observed. Based on TLC,
the Rf value for compound 1 correlatedstrongly to (Rebeccas compound (5)) and to compound 6. The IR
for compound 1 was inconclusive. Compound 1 needs to be further quantifiedbefore we can draw
further conclusions, but due to time constraints, this was not possible. Future directions would be to re-
submit compound 5, with modifiedreaction conditions to observe if cyclizationis possible, along with a
new synthesis route that would involve convertingour amine (3-hydroxylanthranilicacid ) with methyl
chloroformateto synthesize a 2o amide first and react that with compound 3. Effectivelybypassing
cumbersome steps and reducing the overall work load.
References
• Abian, O.; Vega, S.; Sancho, J.; Velazquez-Campoy, A. PLOS ONE 2013, 8, 1–10.
• DeFrancesco, R.; Migliaccio, G. Nature 2005, 438, 953–960.
• Gordon, C. P.; Keller, P. A. J. Med. Chem. 2005, 48, 1–20.
• Kim, D. Y.; Ahn, S. H.; Han, K.-H. Gut and Liver 2014, 8, 471–479.
• McHutchinson, J. G.; Patel, K. Hepatology 2002, 36, S245–S252.
• Tedbury, P. R.; Harris, M. J. Mol. Biol. 2007, 366, 1652–1660.
Acknowledgements
• Dr. Susan Gorman, Dean of the School of Sciences
• Stevenson University, Chemistry Department, Faculty and Staff
• Dr. Dawn Ward, Associate Professor of Organic Chemistry and Mentor
• University of Baltimore County (UMBC) for the utilizationof the NMR
• Previous research undergraduates Steven Sands, Brandon Smith, Rebecca Wong, Harriet Adutwum
IR of Compound 6 NMR of Compound 6
Compound
Rf Values
(3:97 Ethyl Acetate:
Dichloromethane)
IR Peaks
(cm-1)
2 0.29, 0.47, 0.70, 0.84
(Compound 2 was ran in 10:90
Ethyl Acetate: Hexane)
1664.04 (Ketone)
692.12/734.66(m-substitution)
1496.02/1581.04(aromatic ring)
1270.64 (ether)
3 0.94, 0.81 Left in Dorm, will fill on 11/30
4 0.41, 0.55, 0.62, 0.75, 0.81, 0.92 1682.32 (Ketone)
~700.00/732.00 (m-substitution)
3376.74(alcohol; very weak)
5 0.47 N/A
6 0.066, 0.45 700.00/745.63(m-substitution)
1453.75/1493.78(aromatic ring)
1690.00 (Ketone)
2928.77(Amide)
1 0.14, 0.44 Inconclusive
Table 1: Rf & IR values for synthesizedcompounds