Nmr as

Melting points were measured on an electro thermal digital melting point (Büchi, Germany) without calibration. ¹H-NMR spectra were recorded on Varian NMR AS and Varian Unity Inova 400 MHz NMR spectrometers. Chemical shifts were reported in parts per million (δ) units relative to the solvent peak. The ¹H NMR data were reported as peak multiplicities: s for singlet; d for doublet; t for triplet; q for quartet; and m for multiplet. Coupling constants were recorded in hertz (Hz). MS spectra were measured using Jeol JMS 700 high resolution mass spectrometer from the Korea Basic Science Institute (Daegu). Reagents were of commercial grade and were purchased from Sigma-Aldrich Co. (St. Louis, MI, USA), Merck (Darmstadt, Geramny), Duksan Pure Chemical Co (Ansan, Korea).

Ferulic acid, sulforhodamine B (SRB), (+/−)-verapamil hydrochloride and other reagents for synthesis were purchased from Sigma-Aldrich (St. Louis, MO, USA). [³H]-daumnomycin (16 Ci/mmol) was supplied by PerkinElmer Life and Analytical Sciences (Boston, MA, USA). The BD Gentest^TM ATPase assay kit and human P-glycoprotein membranes were commercially provided from BD Bioscience (Woburn, MA, USA). Paclitaxel (PTX) was obtained from Samyang Genex (Daejeon, Korea). All reagents and solvents were supplied as synthesis grades, cell culture grades and HPLC analysis grades. Melting points were measured on an electro-thermal digital melting point (Buchi, Essen, Germany) without calibration. ¹H NMR spectra were recorded on Varian NMR AS and Varian Unity Inova 400 MHz NMR spectrometers. Chemical shifts were reported in parts per million (d) units relative to the solvent peak. The ¹H NMR data were reported as peak multiplicities: s for singlet; d for doublet; t for triplet; and m for multiplet. Coupling constants were recorded in hertz. Mass spectra data was obtained on an Agilent 6220 Accurate-Mass time-of-flight liquid chromatography/mass spectrometry (TOF LC/MS). All the synthesized compounds have been registered as a patent (KR10-2013-0099676) by Prof. Hea-Young Park Choo and Ms So Yeon Lim since 2013.

Melting points were measured on an electro thermal digital melting point (Büchi, Germany) without calibration. ¹H-NMR spectra were recorded on Varian NMR AS and Varian Unity Inova 400 MHz NMR spectrometers. Chemical shifts were reported in parts per million (δ) units relative to the solvent peak. The ¹H NMR data were reported as peak multiplicities: s for singlet; d for doublet; t for triplet; q for quartet and m for multiplet. Coupling constants were recorded in Hertz (Hz). MS spectra were measured using a Jeol JMS 700 high resolution mass spectrometer from the Korea Basic Science Institute (Daegu). Reagents were of commercial grade and were purchased from Sigma-Aldrich Co., Merck, (St. Louis, MO, USA) and Duksan Pure Chemical Co., (Seoul, Korea).