Methanol d4

UV and IR spectra were recorded using a V-730 BIO spectrophotometer and an FT/IR-4200 spectrophotometer (JASCO, Tokyo, Japan), respectively. Optical rotations were determined using a P1020 polarimeter (JASCO, Tokyo, Japan). NMR spectra were measured using a JNM ECX-500 NMR and JNM ECX-600 NMR spectrometer (JEOL, Tokyo, Japan). ESI mass spectra were obtained using a Xevo G2-S QTOF (Waters, Milford, MA, USA).
Dimethyl sulfoxide (DMSO), 10× phosphate-buffered saline (PBS) and agar were purchased from FUJIFILM Wako Pure Chemical Corporation (Osaka, Japan). 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium (MTT) was purchased from Dojindo Molecular Technologies, Inc. (Kumamoto, Japan). Methanol-d₄ was purchased from Kanto Chemical Co., Inc. (Tokyo, Japan). Cisplatin was purchased from Sigma-Aldrich Co. LLC (St. Louis, MO, USA). TGF-β was purchased from BioLegend, Inc. (San Diego, CA, USA). Roswell Park Memorial Institute media (RPMI 1640) was purchased from Nacalai Tesque (Kyoto, Japan). Fetal bovine serum and penicillin-streptomycin were purchased from Gibco (Grand Island, NY, USA). Difco^TM potato dextrose broth (PDB) and Difco^TM potato dextrose agar (PDA) were purchased from Becton, Dickinson and Company (Franklin Lakes, NJ, USA).

Kinetic data were collected by recording the ¹H-NMR (400 MHz) spectra at 2- min intervals. Data were obtained at 70.0 °C under a N₂ flow of 400 L/h. Deuterated solvents were used for all measurements: Deuterium oxide, 99.9% D from Wako; methanol-d₄, 99.8% D from Kanto Chemical Co. Inc.; 1,4-dioxane-d₈, 99% D from Cambridge Isotope Laboratories, Inc.; and sodium deuteroxide, 40% wt. % in D₂O, 99.5% D from Sigma-Aldrich, Co. Parameters were set using the reaction solution at room temperature. Reactions were initiated by raising the temperature of the NMR machine. Spectral data were then recorded for at least one half-life. Hydrolysis experiments were repeated three times. Hydrolysis products were identified by comparison of the ¹H-NMR data with those of authentic samples, or by MS-ESI. Pseudo-first-order rate constants (k_obs) were evaluated by a linear least-squares fitting of a plot of the logarithm of reactant concentration versus time.