Xi-Xian Jian

Five new norditerpenoid alkaloids from Aconitum sinomontanum.

Abstract From the roots of Aconitum sinomontanum, five new norditerpenoid alkaloids, sinomontanitines A (1) and B (2), sinomontanines A (3), B (4) and C (5), were isolated together with the known alkaloids lappaconitine (6) and ranaconitine (7), The structures of the new alkaloids were determined by spectral analysis.

Partial synthesis and biological evaluation of bisbenzylisoquinoline alkaloids derivatives: potential modulators of multidrug resistance in cancer

A series of new bisbenzylisoquinoline alkaloids was partially synthesized from tetrandrine and fangchinoline and evaluated for their ability to reverse P-glycoprotein-mediated multidrug resistance (MDR) in cancer cells. All the test compounds increased the intracellular accumulation rate of rhodamine 123 in MDR cells (Bel7402 and HCT8), and most exhibited more potent MDR-reversing activity relative to the reference compound verapamil. Compounds 8, 10, 13, and 14 enhanced intracellular accumulation of doxorubicin in Bel7402 and HCT8 cells.

New diterpenoid alkaloids from the roots of Delphinium tiantaishanense.

Four new diterpenoid alkaloids: tiantaishansine (1), tiantaishannine (2), tiantaishanmine (3), and tiantaishandine (4) have been isolated from the roots of Delphinium tiantaishan. Their structures were elucidated by chemical evidence and spectral analyses, including ESI-MS, HR-EI-MS, 1D- and 2D-NMR.

New C19-diterpenoid alkaloids from Aconitum hemsleyanum var leueanthus and Delphinium potaninii.

A new franchetine-type (leueandine 1) and two new lycoctonine-type [potanisines F (3) and G (5)] C19-diterpenoid alkaloids have been isolated from the roots of Aconitum hemsleyanum var. leueanthus and Delphinium potaninii, respectively, and their structures were established on the basis of spectral data.

Two new C19-DITERPENOID alkaloids from Aconitum kongboense

Two new C19-diterpenoid alkaloids, kongboentine A (1) and kongboentine B (3), were isolated from the roots of Aconitum kongboense Lauener and their structures were elucidated by spectral data.

Two New C19-Diterpenoid Alkaloids from Aconitum racemulosum Franch var. Pengzhouense

A new diterpenoid alkaloid, racemulotine (1), was isolated from the whole plants of Aconitum racemulosum Franch var. pengzhouense, and its structure was elucidated by 1D- and 2D-NMR spectra.

Studies on the relative reactivity of three hydroxyl groups in aconitine

The relative reactivity of three hydroxyl groups in aconitine toward acetylation, chlorination, sulfonylation, and oxidation has been studied in this paper. The reduction of C-3 ketone and C-15 ketone derivatives of aconitine was also investigated. It was found that (1) the relative reactivity of three hydroxyl groups toward acetylation, chlorination, and sulfonylation is 3-OH>13-OH>>15-OH; (2) 3-OH is much more reactive than 15-OH toward oxidation; and (3) reduction of the carbonyl group at C-3 with NaBH4 generated a pair of C-3 epimers, while the reduction products of the carbonyl group at C-15 depend largely on the specific reducing agent and the absolute configuration of 16-OCH3. When the substrate has 16β-OCH3, its carbonyl group at C-15 can be reduced with NaBH4 to yield exclusively the 15α-OH-containing product. Upon replacement of reducing agent NaBH4 with LiAlH4, the C-15 carbonyl group can be reduced to yield a pair of C-15 epimers. On the other hand, when the substrate has 16α-OCH3, C-15 carbonyl group can only be reduced to generate 15α-OH-containing product.

Diterpenoid alkaloids from Aconitum racemulosum Franch var. pengzhouense.

Abstract A new diterpenoid alkaloid, racemulotine (1), was isolated from the whole plants of Aconitum racemulosum Franch var. pengzhouense, and its structure was elucidated by 1D-and 2D-NMR spectra.

New C20-diterpenoid alkaloids from Aconitum vilmorrianum and structural revision of 2-O-acetylorochrine and orochrine.

Three new C20-diterpenoid alkaloids vilmorrianines E (1), F (2), and G (3) were isolated from the whole plants of Aconitum vilmorrianum, along with one artifact N-chloromethyl vilmorrianine E hydrochloride (4), as well as two known alkaloids hemsleyaconitines F (5) and G (6). The structures of 1–4 were established by HR-ESI-MS, 1D-, 2D-NMR (HMQC, HMBC, and NOESY), and single-crystal X-ray diffraction analysis. In addition, the structures of naturally occurring 2-O-acetylorochrine (7) and orochrine (8) were revised to be the known alkaloids heterophylloidine (9) and deacetyl heterophylloidine (10), respectively, on the basis of consideration of transannular effect and chemical correlations.

An O-to-N intramolecular acyl migration in C19-diterpenoid alkaloids

The O-acyl group at C-1 of two C19-diterpenoid alkaloids 2 and 5 was transferred to the secondary amine nitrogen to form amides 3 and 6 in the basic condition. This kind of O-to-N intramolecular acyl migration could be caused by the near distance between the nucleophilic nitrogen atom and the carbonyl group of the ester at C-1 in the C19-diterpenoid alkaloids, which is consistent with the conformation of rings A and E in the C19-diterpenoid alkaloids.