## 2 Results  
Products were obtained via four reaction approaches, as shown in Scheme 1: Fisher's esterification (a); esterification using alkyl or aryl halides (b); the Mitsunobu reaction (c); and coupling reactions using PyBOP (benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate) (d) [11]. The analysis of \({}^{1}\)HNMR showed two aromatic hydrogens as singlets in \(\delta_{\rm H}\) from 7.20 to 7.36 ppm and signals of methoxy hydrogens in \(\delta_{\rm H}\) from 3.89 to 4.06 ppm. For the \({}^{13}\)CNMR, the common signals were \(\delta\)c from 165.7 to 166.7 ppm of C=O, signals in \(\delta\)c from 152.8 to 153.0 ppm and \(\delta\)c from 125.2 to 126.9 ppm, a signal at approximately a \(\delta\)c of 142.0 ppm, and a signal in \(\delta\)c from 106.7 to 107.0 ppm. In addition, the \({}^{13}\)CNMR spectrum shows signals in \(\delta\)c from 60.8 to 61.0 ppm and another signal with a chemical shift of \(\delta\)c from 56.0 to 56.4 ppm to carbons from methoxy1 groups. The compound 4-chloro-benzyl 3,4,5-trimethoxybenzoate (**9**) showed the following signals in the \({}^{1}\)H NMR: a multiplet to two hydrogens at \(\delta\) 7.37-7.36 (H-3\({}^{\prime}\)/, H-5\({}^{\prime}\)), another multiplet to two hydrogens at \(\delta\) 7.36-7.35, (H-2\({}^{\prime}\), H-6\({}^{\prime}\)), as well as a singlet to two hydrogens at \(\delta\) 5.31 (H-7\({}^{\prime}\)) and a singlet signal at 5.731 ppm (H-2, H-6). For the \({}^{13}\)C NMR, we obtained a signal at 134.6 (C-1\({}^{\prime}\)), a second signal at 134.2 (C-4\({}^{\prime}\)) with the presence of the halogen (C-Cl), a signal to two carbons at 129.5 (C-2\({}^{\prime}\), C-6\({}^{\prime}\)), another signal to two carbons at 128.7 (C-3\({}^{\prime}\), C-5\({}^{\prime}\)), and a signal at 66.0 from C-7\({}^{\prime}\). There were also signals from methoxy carbon (OCH\({}_{3}\)) at \(\delta\) 60.93 ppm and two methoxy carbons (2 OCH\({}_{3}\)) at \(\delta\) 56.28 ppm. For the compound 4-methylbenzyl 3,4,5-trimethoxybenzoate (**11**), the following \({}^{1}\)H NMR signals were obtained, referring to the aromatic substituent: a doublet to two protons at \(\delta\) 7.34 (\(d\), \(J\) = 8.0 Hz, H-3\({}^{\prime}\), H-5\({}^{\prime}\)), another doublet to two hydrogens at \(\delta\) 7.20 (\(d\), \(J\) = 8.4 Hz, H-2\({}^{\prime}\), H-6\({}^{\prime}\)), a singlet to two protons at \(\delta\) 5.32 (H-7\({}^{\prime}\)), and another singlet at \(\delta\) 2.36 (s, 3H, H-8\({}^{\prime}\)) referring to methyl hydrogens in the _para_ position of the aromatic ring, and a singlet signal at \(\delta\) 7.32 ppm (H-2, H-6). In the \({}^{13}\)C NMR, a signal at 138.1 (C-4\({}^{\prime}\)), another signal at 133.1 (C-1\({}^{\prime}\)), a signal to two carbons at 129.2 (C-3\({}^{\prime}\), C-5\({}^{\prime}\)), another signal to two carbons at 128.4 (C-2\({}^{\prime}\), C-6\({}^{\prime}\)), a signal at 66.7 (C-7\({}^{\prime}\)), and a signal at 21.3 referring to methyl in the  
Figure 1: Chemical structure of piplartine. para_ position. In addition, there were signs from methoxy carbon (OCH\({}_{3}\)) at \(\delta\) 60.85 ppm and two methoxy carbons (2 OCH\({}_{3}\)) at \(\delta\) 56.16 ppm. The analyses from IR spectroscopy showed common signals above 3000 cm\({}^{-1}\) (C-H sp2 stretch), signals at 1600 and 1475 cm\({}^{-1}\) from the aromatic ring, bands of carbonyl from 1740 to 1715, and 1300 to 1000 cm\({}^{-1}\) (C-O stretch). The methoxyls had signals from 1250 to 1040 cm\({}^{-1}\) (aryl ether stretch). The amides showed a band at approximately 3300 cm\({}^{-1}\) (-NH), except amide **18**, and a band from 1680 to 1630 cm\({}^{-1}\) of stretching C=O. The unpublished compounds were also analyzed by HRMS (FT-ICR) spectrometry [11]. The trypanacid effects of compounds **15**-**18** and **20** against _Trypanosoma cruzi_ (trypomastigote and epimastigote forms) are shown in Table 1.  
Cytotoxic evaluation of the 23 derivatives was performed in LLC-MK2 host cells submitted to the MTT (3,4,5-dimethiazol-2,5-diphenyltetrazolzoliumbromide) reduction assay.