Physical measurements: 1 H and C NMR spectra were recorded on BRUKER Biospin AVANCE-III FT-NMR HD-500 and JEOL 400 MHz spectrophotometer using CDCl3 as solvent. The peak values were obtained as ppm (δ) and referenced to tetramethylsilane (TMS) for 1 H NMR spectroscopy and the residual solvent signal for 13 C NMR spectroscopy. Data are reported as follows: chemical shifts in ppm, coupling constant J in Hz; multiplicity (s = singlet, bs = broad singlet, t = triplet, q = quartet, m = multiplet).