[Constituents from Ranunculus ternatus and Their Inhibitory Effects on Multidrug-Resistant Tuberculosis].

Objective: To explore the chemical constituents of Ranunculus ternatus and their inhibitory effects on multidrug-resistant tuberculosis.

Methods: All compounds were separated by silica gel, Sephadex LH-20 column chromatography etc. Their structures were identified by NMR spectroscopy.

[Isolation and structural identification of flavonoids from Aurantii Fructus].

Aurantii Fructus is the dried and immature fruit of Citrus aurantium and its cultivars. To investigate the chemical constituents of Aurantii Fructus, the separation and purification of constituents were performed by column chromatography on silica gel LH-20, HW-40, ODS, PHPLC and PTLC. Fourteen flavonoids, including four flavone glycosides and ten polymethoxyflavones (PMFs) were isolated from the EtOAc fraction and Petroleum ether fraction of Aurantii Fructus and their structures were identified by physicochemical properties and spectral data (NMR and MS) as (2R) -and (2S)-6"-O-acetylprunin (1,2), naringenin-7-O-β-D-glucopyranside (3), 5,7,4'-trihydroxy-8,3'-dimethoxyflavone-3-O-6"-(3-hydroxyl-3-methylglutaroyl)-β-D-glucopyranoside(4), 4'-hydroxy-5,6, 7-trimethoxyflavone (5), natsudaidain (6), nobiletin (7), sinensetin (8), 5,6,7,4'-tetramethoxyflavone (9), 5,7,8,4'-tetramethoxyflavone (10), 3,5,6,7,8,3',4'-heptamethoxyflavone (11), tangeretin (12), 5-demethyl nobiletin (13), and 5-hydroxy-6,7,3', 4'-tetramethoxyflavone (14).

A simple, efficient Pd-catalyzed synthesis of N-sulfonylimines from organoboronic acids and tosylbenzimidoyl chlorides.

A simple and efficient synthesis of N-sulfonyl ketimines through a Pd-catalyzed cross-coupling reaction between organoboronic acids and tosylbenzimidoyl chlorides under mild conditions has been developed.

Palladium-catalyzed cross-coupling of stereospecific potassium cyclopropyl trifluoroborates with aryl bromides.

[reaction: see text] Stereospecific cyclopropanation of alkenylboronic esters of pinacol followed by in situ treatment with excess KHF(2) afforded the corresponding potassium cyclopropyl trifluoroborates in high yields, which then underwent Suzuki-Miyaura cross-coupling reactions with aryl bromides to give cyclopropyl-substituted arenes in good yields with retention of configuration. This promises to be a useful method for the synthesis of enantiomerically pure cyclopropanes.

A novel method for the construction of (z,e)- or (z,z)-conjugated alkadienyl carboxylates.

[reaction: see text] The stereocontrolled dehydrobromination of 1,2-dibromoethyl carboxylates giving (Z)-2-bromovinyl carboxylates could readily be approached by using DBU and a catalytic amount of hydroquinone as a base at -78 degrees C. The first investigation on the Suzuki-type cross-coupling of (Z)-2-bromovinyl carboxylates as electrophiles with stereodefined alkenylboronic acids provides a novel method for the construction of (Z,E)- or (Z,Z)-conjugated alkadienyl carboxylate moieties, which are often present in a range of natural products.

Remarkable co-catalysis by copper(I) oxide in the palladium catalyzed cross-coupling of arylboronic acids with ethyl bromoacetate.

Copper(I) oxide can effectively co-catalyze the Suzuki type cross-coupling reactions of arylboronic acids with ethyl bromoacetate. As an alternative protocol for introducing the methylenecarboxy group into functionalized molecules, this reaction occurs in the absence of highly toxic thallium compounds or special ligands and should be convenient and practical.

Efficient Suzuki-Type Cross-Coupling of Enantiomerically Pure Cyclopropylboronic Acids.

Optically active cyclopropanes (e.g. 1) can be prepared by the use of tartaric acid derivatives as chiral auxiliaries in the palladium-catalyzed cross-coupling of optically active cyclopropylboronic acids with electrophiles.