Detailed Characterization of Novel Compounds

All solvents and reagents were used as obtained. For verification of chemical structures, 1H NMR spectra were recorded with a Varian Inova 500 NMR spectrometer and referenced to dimethyl sulfoxide. Chemical shifts are expressed in ppm. Mass spectra were measured with Waters Micromass ZQ using an ESI source coupled to a Waters 2525 HPLC system operating in reverse mode with a Waters Sunfire C18 5 μm, 4.6 × 50 mm² column. Purification of compounds was performed with either a Teledyne ISCO CombiFlash Rf system or a Waters Micromass ZQ preparative system. The purity was analyzed on an above-mentioned Waters LC—MS Symmetry (C18 column,4.6 × 50 mm², 5 μM) using a gradient of 5–95% methanol in water containing 0.035% trifluoroacetic acid (TFA). Detailed synthetic schemes and characterization data are available in Supplementary Chemical Synthesis Details and else-where.^{5 (link),6 (link)}