Jing-Feng Zhao

Enantioselective Sequential Conjugate Addition−Allylation Reactions: A Concise Total Synthesis of (+)-Podophyllotoxin

A highly flexible and concise total synthesis of (+)-podophyllotoxin featured with an enantioselective sequential conjugate addition-allylation reaction was reported. Starting from commercially available 3,4,5-trimethoxycinnamic acid, this new route leads to (+)-podophyllotoxin 1 in only eight steps with 29% overall yield.

Efficient synthesis of β-amino-α,β-unsaturated carbonyl compounds

A versatile and high-yielding procedure for the synthesis of β-enamino esters and β-enaminones is presented: in the presence of tetraethyl orthosilicate, a number of highly functional β-enamino esters were obtained; this method provided an alternative for the formation of β-amino-α,β-unsaturated carbonyl compounds with mild and functional group compatible reaction conditions.

Copper-catalyzed arylation of o-bromoanilides: highly flexible synthesis of hexahydropyrroloindole alkaloids.

In the presence of catalytic amount of copper iodide, a remote amide-assisted intramolecular arylation followed by alkylation leads to a general and flexible synthetic method toward the synthesis of medicinally interesting hexahydropyrroloindole alkaloids.

Enantioselective total synthesis of (+)-brazilin, (−)-brazilein and (+)-brazilide A

An enantioselective strategy for the synthesis of (+)-brazilin, (-)-brazilein and (+)-brazilide A has been developed. A Lewis acid mediated lactonization established the novel fused bis-lactone core of brazilide A and finalized the first total synthesis of (+)-brazilide A.

Design, synthesis and aromatase inhibitory activities of novel indole-imidazole derivatives

A series of novel indole-imidazole derivatives have been prepared and evaluated in vitro on the aromatase inhibitory activities. The results suggested that proton or a small electron-withdrawing group at para-position of the phenyl ring would enhance the inhibitory activities and any bulky group should be avoided in order to keep a relative small volume for this kind of molecules.

Triterpenes from Tripterygium wilfordii Hook

Two new friedelane-type triterpenes, tripterfrielanons A (1) and B (2), along with six known triterpenoids, friedelin (3), canophyllal (4), canophyllalic acid (5), 3-oxo-29-hydroxyfriedelane (6), wilforlide A (7), wilforlide B (8), have been isolated from the EtOH extract of the roots of Tripterygium wilfordii Hook.f. Compounds 4, 5, 6 were isolated for the first time from this plant. The new triterpenes 1 and 2 exhibited mild cytotoxic activity against human Hela cell lines in vitro. The assay showed the IC50 of 1 and 2 were 8.5 and 25 μg/mL, respectively.

Two new phenyl esters from Litsea euosma

Two new phenyl esters, named as euosmoside A (1) and euosmoside B (2), have been isolated from the leaves and twigs of Litsea euosma. Their structures were elucidated on the basis of spectroscopic methods.

Novel cytotoxic chalcones from Litsea rubescens and Litsea pedunculata.

Two novel flavonoids with chalcone skeleton, together with seven known flavonoids, were isolated from the stem barks of Litsea rubescens and Litsea pedunculata. The structures of the new compounds were elucidated on the basis of spectral methods including IR, UV, 1D and 2D NMR. The new chalcones were found to contain the rare epoxy or ethylidenedioxy group. This is the first report on the presence of chalcone in the plant genus Litsea. The cytotoxic potential of two new chalcones was evaluated in vitro against three human tumor cell lines. Both new chalcones displayed potent cytotoxic activities against myeloid leukaemia (HL-60) and epidermoid carcinoma (A431) cell lines and more active than cisplatin (DDP). Interestingly, compound 1 exhibited cytotoxic activity against HL-60 with IC(50) value 2.1-fold more sensitive to DDP.

Flavonoids from Litsea chingpingensis

of Chemical Science and Teleology, Yunnan University, Kunming 650091, P. R. China, fax: 86 871 5035538, e-mail: xdyang120@hotmail.com; 2) College of Chemistry and Bio-Science, Yunnan Nationalities University, Kunming 650031, P. R. China; 3) College of Fundamental and Information Engineering, Yunnan Agricultural University, Kunming 650201, P. R. China. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 519-520, September-October, 2008. Original article submitted March 30, 2007.

A new C19-diterpenoid alkaloid, habaenine C, from Aconitum habaense

A new C19-diterpenoid alkaloid, habaenine C (1), together with the two known compounds vilmorrianine C and crassicauline A, were isolated from Aconitum habaense. The structure of the new compound was elucidated on the basis of spectral analysis, including 2D NMR spectroscopy.