Resumo:
Chagas Disease (CD), a
n illness discovered by Carlos Chagas 11 5 years ago, remains a great
public health problem . It has been reported 30 thousand new cases annually and causing 14
thousand deaths during the same period of time . Currently, two drugs only are used in the
chemotherapy , benznidazol e (B Z) and nifurtimox (NF). T he former is the unique commercially
available in Brazil, but its major issue is a high treatment dropout rate around 20% due to
severe side effects and long periods of administration, in addition to its lack of efficacy in the
chronic phase of CD. In the search for new cand idates with potential trypanocidal effect , our
research group has been synthesizing several heterocyclic systems for their antiparasitic
evaluation. In this work, the aim is to synthesize and evaluate the trypanocidal activity of 9 new
1 aryl 3 --(methyl(4,5 dihydro 1 H imidazol 2 yl)) 4 --(4,5 dihydro 1 H imidazol 2 yl) 1 H
p yrazoles derivatives 1( a i )). Eighteen key intermediates were synthesized: 5 amine 1 aryl 4
cyane 3 --( 1 H pyrazoles 2( a i 1 aryl 4 cyane 3 --( 1 H pyrazoles
3( a c,e i )), 2 amine 1,1,3 tricyaneprop 2 en e 4 , isolated in 31 85% yields . Regard to synthesis
of the desired compounds 1(a i)i), eleven methodologies were evaluated in attempt to obtain 1a
and none of them generated this compound . However, when it was employed classical
methodology involving ethylenediamine (EDA) and carbon disulfide (CS 2 ), an unexpected
compound was obtained: 8 phenyl 2,3 dihydro 8 H imidazo[1,2 a ]pyrazolo[4,3 c ]pyridine 5
thiol 6a , in 29% yield From similar experimental procedure more three compounds were
obtained, 6(e,f,h) h), in 11 87% yields. All compounds had it structure confirmed by Fourier
Transform Infrared (FT IR) Spectroscopy, High Resolution Mass Spectrometry (HRMS), and
Nuclear Magnetic Resonance (NMR) analysis
