Nexus 870 ftir spectrometer

IR spectra were measured on a Nexus 870 FTIR spectrometer (Thermo Fisher Scientific, Waltham, MA, USA), and the absorption bands are expressed in cm⁻¹. The HRMS spectra were recorded on a high-resolution mass spectrometer equipped with electrospray (ESI) and nanospray sources, and a quadrupole-time of flight hybrid analyzer (Q-TOF Premier/nanoAquity, Waters, Milford, MA). ¹H NMR and 13 C NMR spectra were accomplished in CDCl₃ on a Bruker AV-300, AV-500 and DRX-600 NMR spectrometer (Billerica, MA, USA) using TMS as internal standard. Reactions and the resulted products were monitored by TLC which was carried out on TLC Silica gel 60 F254 Aluminium sheets from Merck KGaA, Darmstadt, Germany and visualised in UV light (254 nm). Silica gel (3 0 0–400 mesh) for column chromatography was purchased from Qingdao Marine Chemical Factory, China. The reagents (chemicals), all being of A.R. grade, were purchased from Shanghai Chemical Reagent Company (Shanghai, China) and Energy Chemical (Shanghai, China). Disproportionated rosin was provided by Zhongbang Chemicals Co., Ltd. (Zhaoqing, China), from which dehydroabietic acid (97%) was isolated according to the published method³⁸ .

Melting points were measured on an XT-4 apparatus (Taike Corp., Beijing, China) and were uncorrected. IR spetra were measured on a Nexus 870 FT-IR spectrometer (Thermo Fisher Scientific, Waltham, MA, USA), and the absorption bands were expressed in cm⁻¹. The HRMS spectra were recorded on a high-resolution mass spectrometer equipped with electrospray (ESI) and nanospray sources, and a quadrupole-time of flight hybrid analyzer (Q-TOF Premier/nanoAquity, Waters, Milford, MA, USA). ¹H and ¹³C NMR spectra were obtained in CDCl₃ on a Bruker DRX-600 NMR spectrometer (Billerica, MA, USA) using TMS as internal standard. Reactions and the resulted products were monitored by TLC which was carried out on TLC Silica gel 60 F₂₅₄ Aluminum sheets from Merck KGaA, Darmstadt, Germany, and visualized in UV light (254 nm). Silica gel (300–400 mesh) for column chromatography was purchased from Qingdao Marine Chemical Factory (Qingdao, China). The reagents (chemicals), all being of A.R. grade, were purchased from Shanghai Chemical Reagent Company (Shanghai, China) and Energy Chemical (Shanghai, China). Ursolic acid (95%) was bought from Jingzhu Biological Technology Co., Ltd. (Nanjing, China).

Melting points were measured on an XT-4 apparatus (Taike Corp., Beijing, China) and were uncorrected. IR spectra were measured on a Nexus 870 FT-IR spectrometer (Thermo Fisher Scientific, Waltham, MA, USA), and the absorption bands were expressed in cm⁻¹. The HRMS spectra were recorded on a high-resolution mass spectrometer equipped with electrospray (ESI) and nanospray sources, and a quadrupole time of flight hybrid analyser (Q-TOF Premier/nanoAquity, Waters, Milford, MA, USA). ¹H and ¹³C NMR spectra were obtained in CDCl₃ on Bruker AV-300, AV-500 (Billerica, MA, USA) and DRX-600 NMR spectrometers using TMS as internal standard. Reactions and the resulted products were monitored by TLC which was carried out on TLC Silica gel 60 F₂₅₄ Aluminium sheets from Merck KGaA, Darmstadt, Germany and visualised in UV light (254 nm). Silica gel (300 ∼ 400 mesh) for column chromatography was purchased from Qingdao Marine Chemical Factory, China. The reagents (chemicals), all being of A.R. grade, were purchased from Shanghai Chemical Reagent Company (Shanghai, China) and Energy Chemical (Shanghai, China). UA (95%) was bought from Jingzhu Biological Technology Co., Ltd. (Nanjing, China).