A series of E and Z-isomers of 3-（4＇-substituted benzylidene）-indolin-2-one derivatives were synthesized and separated. Based on their 1H NMR characterization, an unusual counterintuitive deshielding phenomenon for the protons presenting in the shielding zone of phenyl ring was observed and analyzed for the first time.
Twenty-seven flavonoids, including 10 isoflavones, 9 flavanones, 3 dihydrochalcones, 3 flavonols and 2 flavans, were isolated from the whole plant of Tibetan medicine Oxytropis falcate Bunge. Structure elucidation was conducted by extensive spectroscopic analysis, including MS, NMR and CD spectra. Twelve compounds were obtained from this plant for the first time, among which 10 compounds were obtained from the genus of Oxytropis for the first time.
