Graduate Physical and Life Sciences PhD Chemistry Abstract ID 160 Evaluaon of human PDE4 inhibitors cilomilast and piclamilast as lead compounds for the treatment of human African trypanosomiasis (HAT). Emanuele Amata,1* Jennifer Woodring,1* Stefan O. Ochiana,1 Nicholas D. Bland,2 Alden Gustafson,2 Robert K. Campbell,2 and Michael P. Pollastri.1 1Northeastern University, Department of Chemistry and Chemical Biology, Hurg 102, 360 Hunngton Avenue, Boston, MA 02115. 2Marine Biological Laboratory, Josephine Bay Paul Center for Comparave Molecular Biology and Evoluon, 7 MBL Street, Woods Hole, MA 02543

ABSTRACT PICLAMILAST SAR STUDIES CILOMILAST SAR STUDIES Neglected tropical disease drug discovery requires applicaon of pragmac and Piclamilast is a cAMP‐specific human PDE4 inhibitor Cilomilast (Ariflo, SB‐207,499) is a drug which was efficient methods for development of new therapeuc agents. In the present work O used to treat respiratory inflammaon. Its structure Cl CN developed for the treatment of respiratory disorders we illustrate our target repurposing efforts for the essenal phosphodiesterase H 4 is closely related to that of cilomilast and rolipram. O such as asthma and Chronic Obstrucve Pulmonary (PDE) enzymes TbrPDEB1 and TbrPDEB2 of Trypanosoma brucei , the causave N O O Disease (COPD). It is orally acve and acts as a selecve agent for human African trypanosomiasis (HAT). OH O N O 5 Cl TbbPDEB1: IC50 = 4.65 μM H Phosphodiesterase‐4 inhibitor. TbbPDEB2: IC = 11.36 μM We have previously shown that the human PDE4 inhibitor piclamilast and some of 50 hPDE4 = 1 nM Cilomilast its analogues show modest inhibion of TbrPDEB1 and B2 and quickly kill the TbbPDEB1 IC50 = 6.595 μM hPDE4 IC50 = 120 nM bloodstream form of the subspecies T. brucei brucei. Here we describe our recent SYNTHESIS progress in understanding the SAR of the human PDE4 inhibitors piclamilast and SYNTHESIS cilomilast, tested against the parasic enzyme TbrPDEB1. Inhibitor design strategies 1. TFAA, t-BuOK MeO OH MeO CH3CN Ar B(OH)2 and compound syntheses will be reported. MeO rt MeO 1) LiBr, TMSCl O Br O Ar O R O R CN HO O 2) 1,1,3,3-Tetramethyldisiloxane O O 2. NBS, CH CN Pd(Ph ) , Na CO RBr, K2CO3 HO 3 HO Br PPh3, DEAD 3 4 2 3 rt Toluene Toluene/EtOH/H2O (4:1:1) 3) NaCN ACN, rt O O DMF, 60 °C rt 105oC O O

Triton-B BACKGROUND Cl ACN, reflux N N O O MeO MeO MeO •The Trypanosoma brucei genome codes for five different PDE isoforms B B Cl O R NH H O O O B N Cl 2 N N R CN R CN R CN •Two trypanosomal PDEs have been characterized (TbrPDEB1 and TbrPDEB2) O O R O O O NaH O n-BuLi N o NaCl Pd2(dba)3, Na2CO3 DIEA, NMP, 80 C N COOCH COOCH3 • o 3 PDEs in Trypanosoma brucei are 25‐30% homologous to human PDEs -78 C to rt Toluene/EtOH/H2O COOCH DMSO, H O 3 105oC O O 2 O O DME, reflux O •RNAi against TbrPDEB1 and B2 is lethal for bloodstream forms of T. brucei 150 °C B(OH) 2 1. mCPBA MeO MeO •The hPDE family has provided rich targets for human therapeuc approaches, and MeO CHCl3 MeO o 10 C to rt R NH2 H 1,2 N significant selecvity between PDE types as well O Br Cl Butyllithium O O O R S S N DIEA, NMP N Pd2(dba)3, Na2CO3 2. POCl3, TEA, CHCl3 N THF o MW, 1 hr, 250oC Toluene/EtOH/H2O MW, 1 hr, 100 C Si 105oC R CN R CN O O O O TARGET REPURPOSING O OH O O PHARMACOLOGICAL RESULTS H H R CN HgCl2, HClO4 LiOH O CH3OH, reflux THF, H2O, CH3OH 1 hour rt O S R CN R CN S O O H H O O O O O OH

PHARMACOLOGICAL RESULTS

R CN 3 3 Advantages of target repurposing O R1 • Homologs known to be “druggable” O R • Lead matter available without HTS 2 • Much data can be redirected from human to pathogen • Potential to engage development collaborations CONCLUSION • Potentially much faster and cheaper Here we described our ongoing target repurposing efforts focused on discovery of REFERENCES & ACKNOWLEDGEMENTS inhibitors of the essenal trypanosomal phosphodiesterase TbrPDEB1. This enzyme has Target repurposing entry point been implicated in virulence of Trypanosoma brucei, the causave agent of human 1. Oberholzer, M. et al. FASEB J., 2007, 21, 720-731. African trypanosomiasis (HAT). We outline the synthesis and biological evaluaon of 2. Laxman, S.; Beavo, J.A. Mol Interv. 2007, 7(4), 203-215. analogs of piclamilast and cilomilast, two human PDE4 inhibitors. Most analogs 3. Pollastri, M.P; Campbell, R.K. Future Med Chem 2011, 3,1307. synthesized displayed a poor inhibion profile with the notable excepon of Cilomilast 4. Ashton, J.M. et al. J. Med. Chem. 1994, 37, 1696-1703. (NEU‐491), the benzyl analogue of Cilomilast, namely compound NEU685 and Piclamilast. 5. Christensen, Siegfried B. et al. J. Med. Chem. 1998, 41, 821‐835. Our future work will be based on the structure acvity relaonship on both piclamilast and cilomilast, especially aimed at elucidaon of the importance of the Western region of This work was supported by NIH Award grant 7R01AI082577-02 Can these timelines be shortened? these analogs. and Northeastern University.