Diethylamine

Isopropanol and and n-hexane were purchased from Fisher Scientific, Loughborough, UK. Diethylamine was obtained from VWR, Fontenay-sous-Bois, France. All chemicals were of analytical grade. The analytes were dissolved in Isopropanol (0.5 mg/mL). To achieve complete dissolution, the samples were put into an ultrasonic bath for five minutes.

(−)-Polyalthic acid (1) and kaurenoic acid (2) were isolated from the oleoresin of Copaifera reticulata Ducke, Fabaceae, as described in our previous studies (Çiçek et al. 2018 (link); Pfeifer Barbosa et al. 2019 (link)). N-Chlorosuccinimide (98%) and triphenylphosphine (ReagentPlus, 99%), sulphuric acid (puriss., analytical grade) and LC-MS grade formic acid were purchased from Sigma-Aldrich Co., St. Louis, MO, USA. Hydrochloric acid (25%, analytical grade) was obtained from Honeywell, Seelze, Germany, while sodium hydroxide solution (2N) was purchased from Carl Roth GmbH, Karlsruhe, Germany. Diethylamine (for synthesis), acetone (analytical grade), methanol (gradient grade or LC-MS grade) and water (LC-MS grade) as well as other analytical grade solvents used for purification were obtained from VWR International GmbH, Darmstadt, Germany. Solid phase extraction (SPE) columns (Chromabond SB 3 ml/500 mg) were obtained from Macherey-Nagel GmbH & Co. KG, Düren, Germany. Deuterated methanol (Lot P3021, 99.80%), deuterated DMSO (Lot S1051, 99.80%) and deuterated chloroform (Lot Q1981, 99.80%) for NMR spectroscopy were obtained from Eurisotop GmbH, Saarbrücken, Germany. Conventional 5-mm sample tubes were purchased from Rototec-Spintec GmbH, Griesheim, Germany.