RESUMEN
A palladium-catalyzed intramolecular Heck/aminocarbonylation of alkene-tethered iodobenzenes with nitro compounds has been developed for the synthesis of carbamoyl-substituted benzoheterocycles. Using Mo(CO)6 as a solid CO source, no external reductant or additives were needed in this procedure. Both nitroarenes and nitroalkanes were well tolerated. A range of carbamoyl-substituted dihydrobenzofurans and indolines were prepared in moderate to high yields.
RESUMEN
A visible-light-induced carbonylation of indoles with phenols for the synthesis of indole-3-carboxylates has been developed. The reaction proceeded via a radical carbonylation process in which elementary I2 was used as an effective photosensitive initiator and, thus, avoided the use of transition metal catalysts. A series of different aryl indole-3-carboxylates were prepared in moderate to good yields. The broad applicability of this methodology was further highlighted by the late-stage functionalization of several phenol-containing natural products and pharmaceuticals.
RESUMEN
Amide synthesis is one of the most important transformations in organic chemistry due to their ubiquitous presence in our daily life. In this communication, a palladium catalyzed cascade azidation/carbonylation of aryl halides for the synthesis of amides was developed. Both iodo- and bromobenzene derivatives were transformed to the corresponding amides using PdCl2 /xantphos as the catalyst system and sodium azide as the nitrogen-source. The reaction proceeds via a cascade azidation/carbonylation process. A range of alkyl and halogen substituted amides were prepared in moderate to good yields.
RESUMEN
OBJECTIVE: To establish a method for the determination of curculigoside in Curculigo orchioides, a species of crude medicine. METHOD: The methanol was used as the solvent of exatraction and the curculigoside was extracted from the crude medicine with the method of the ultrasonic vibration. Using Sep-Pak C18 cartridges to purify the solution, the curculigoside was detected by HPLC. Intersil ODS-3(150 mm x 4.6 mm, 5 microns) chromatographic column was used, mobile phase of methanol-water-ice acetic acid (45:80:1) and detect wavelength was set at UV 283 nm. RESULT: The average recovery was 99.2% for the determination of curculigoside, RSD = 1.7% (n = 5). The content range of the curculigoside for 6 kinds of different samples was from 0.11% to 0.35%. CONCLUSION: This method could be used to control the quality of crude medicine C. orchioides.
