Search

Nine new Daphniphyllum alkaloids (1–9) and 16 biosynthetically related known ones were obtained during the phytochemical investigation into a Nepalese plant, Daphniphyllum himalense. Structures were assigned to these compounds based on careful spectroscopic interpretation and NMR comparison with literature data. Deuteration of H2-16 in CD3OD due to quick keto-enol tautomerization was observed for both 2 and 3. The recently reported 3β-hydroxydaphniyunnine A was re-examined and its structure was revised to be 21-deoxymacropodumine D via X-ray diffraction analysis. All the isolates were screened preliminarily for their in vitro inhibitory effects against four kinases, PTP1B, aurora A, HDAC6 and IKK-β, and selective alkaloids exhibited weak activities at 20 μg mL−1.

The reaction of a variety of aldoximes with perfluoroalkanosulfonyl fluoride in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in dichloromethane smoothly generated the corresponding nitriles in 70%–95% yields.

The title compounds show moderate inhibitory activity against human HL-60 and A549 cancer cell lines.

A silver catalyzed coupling reaction using air as the terminal oxidant is developed for the synthesis of 1,4-diketones.

A new chemistry of hydrazines that is a copper-catalyzed radical reaction to synthesize vinyl sulfones from readily available N-tosylhydrazones has been described. The protocol provides a novel strategy for the synthesis of various vinyl sulfones including α, β-disubstituted ones and terminal ones. The advantages of the transformation include excellent E stereoselectivity, broad substrate scope, low cost of reagents, and convenient operation. A novel and efficient one-pot synthesis of alkynes from N-tosylhydrazones has been achieved. The studies provide important complementary approaches for the syntheses of vinyl sulfones and alkynes.

All products (III), (V), (VII), and (VIII) are E-isomers at the C-7 position, and no Z-isomers or other position substituted products can be detected.

Optimized conditions are developed for the preparation of the diketones (important substructures of natural products and pharmaceuticals) and for the simple, efficient, and regioselective formation of polysubstituted furans.

The novel protocol allows the highly regioselective synthesis of bifurans and bithiophenes in moderate to good yields under mild conditions.

The reaction proceeds with complete Markovnikov selectivity with no detectable formation of aldehydes or polymeric products.

An efficient IMesCl-catalyzed oxidative esterification of various aromatic and aliphatic aldehydes with alkyl halides and alkyl tosylates is presented.

Gold-catalyzed cycloisomerization reaction of acetylenylaziridines provides 2,5-disubstituted pyrroles in high yields. The presence of protic species accelerates the reaction rate and improves the yields of pyrrole products.

A simple, inexpensive, and green reaction permitting the synthesis of new C-6 arylsulfonylmethyl 4-aryl-3,4-dihydropyrimidinones in water by S-alkylation of 6-bromomethyl 3,4-dihydropyrimidinones 2 with benzenesulfinic acid anions 3 is reported. The required 6-bromomethyldihydropyrimidone precursors 2 were readily prepared using an organic solid brominating reagent.

Reactions of N-tosylimines with aziridines and electron-deficient unsaturated compounds in the presence of catalytic amount of NHC afforded unexpected tosyl group transfer products in good to high yields, which represent a new reaction pattern for imines as well as for catalysis of NHC.