# Cyclic Octamer Petroids: Simplified Isosters of Bioactive Fungal Cyclodepsipeptides
## 3 Experimental Section  
### Chemistry  
#### 3.1.1 General Methods  
Starting materials and reagents purchased from commercial suppliers were generally used without purification unless otherwise mentioned. HPLC analyses were performed on a JASCO LC-NET II/ADC equipped with a JASCO Model PU-2089 Plus Pump and a JASCO MD-2010 Plus UV-vis multiple wavelength detector set at 220 nm. The column used was a C\({}_{18}\) reversed-phase analytical column (Waters, Bondapak, 10 \(\mathrm{\SIUnitSymbolMicro m}\), 125 A, 3.9 mm \(\times\) 300 mm) run with linear gradients of ACN (0.1% TFA) into H\({}_{2}\)O (0.1% TFA) over 30 min, at a flow rate of 1.0 mL/min for the analytical runs. ESI-MS analysis in positive ion mode was performed using a Finnigan LCQ Deca ion trap mass spectrometer (ThermoFinnigan, San Jose, CA, USA) and the mass spectra were acquired and processed using the Xcalibur software provided by Thermo Finnigan. Samples were dissolved in 1:1 CH\({}_{3}\)OH/H\({}_{2}\)O, 0.1% formic acid and infused in the ESI source by using a syringe pump; the flow rate was 5 \(\mathrm{\SIUnitSymbolMicro m}\)/min. The capillary voltage was set at 4.0 V, the spray voltage at 5 kV and the tube lens offset at \(-\)40 V. The capillary temperature was 220 \({}^{\circ}\)C. Data were acquired in MS1 and MSn scanning modes. Zoom scan was used in these experiments. High-resolution mass spectra (HRMS) were recorded on a Bruker Solarix XR Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) equipped with a 7T magnet, using electrospray ionization (ESI). Yields refer to chromatographically and spectroscopically (\({}^{1}\)H- and \({}^{13}\)C NMR) pure materials. NMR spectra were recorded on a Bruker DRX 600 (\({}^{1}\)H at 600.13 MHz, \({}^{13}\)C at 150.90 MHz), Bruker DRX 400 (\({}^{1}\)H at 400.13 MHz, \({}^{13}\)C at 100.03 MHz), Bruker DRX 300 (\({}^{1}\)H at 300.13 MHz, \({}^{13}\)C at 75.03 MHz). Chemical shifts (\(\delta\)) are reported in ppm relative to the residual solvent peak (CHCl\({}_{3}\), \(\delta\) = 7.26; \({}^{13}\)CDCl\({}_{3}\), \(\delta\) = 77.00; C\({}_{2}\)DHCl\({}_{4}\), TCDE, \(\delta\) = 5.80) and the multiplicity of each signal is designated by the following abbreviations: s, singlet; d, doublet; dd, double doublet; t, triplet; sept, septet; m, multiplet; br, broad. 2D NMR experiments such as COSY, ROESY, HSQC and HMBC were performed for the full assignment of each signal. Coupling constants (_J_) are quoted in Hertz.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Number of Dead Larvae (\(\mathit{t}\) = 10)**} \\ \cline{2-7}
**Compound** & \multicolumn{6}{c}{**Time after Injection (h)**} \\ \cline{2-7}  & **1** & **6** & **24** & **72** & **120** & **168** \\ \hline vehicle & 0 & 0 & 0 & 0 & 0 & 0 \\
**5** & 0 & 0 & 0 & 2 & 2 & 2 \\
**6** & 0 & 0 & 0 & 1 & 2 & 2 \\
**7** & 0 & 0 & 0 & 2 & 2 & 2 \\
**8** & 0 & 0 & 0 & 1 & 1 & 1 \\ \hline \hline \end{tabular}  
* Each compound in DMSO was injected into 4 th-instar larvae (\(\mathit{ca}\) 0.9 g body weight) at a dose of 300 nmol/larva.  
\end{table}
Table 2: Toxicity of **5–8** against silkworms by haemolymph injection a.