Voacalgines AeE, new indole alkaloids from Voacanga grandifolia

Five new indole alkaloids, voacalgines A–E (1–5) consisting of a C-mavacurine type of skeleton with 2,3-dihydroxybenzoate moiety, a macroline-type of skeleton, or a macroline-type of skeleton with C6 unit, were isolated from the bark of Voacanga grandifolia. Their relative structures were determined by means of NMR data. Voacalgine A showed moderate cell growth inhibitory activities against HL-60 and HCT116 cells

Degradation rates and products of fluticasone propionate in alkaline solutions

The apparent degradation rate constant of fluticasone propionate (FLT) in 0.1 M NaOH:methanol=1:1 at 37 °C was previously reported to be 0.169±0.003 h−1, and four degradation products (products 1–4) were observed in the solution. The aims of the present study were to assess the degradation rates of FLT in other alkaline solutions and clarify the chemical structures of the four degradation products in order to obtain basic data for designing an enema for inflammatory bowel disease. The apparent degradation rate constants in 0.05 M NaOH and 0.1 M NaOH:CH3CN=1:1 were 0.472±0.013 h−1 and 0.154±0.000 h−1 (n=3), respectively. The chemical structures of products 1–4 in 0.1 M NaOH:methanol=1:1 were revealed by nuclear magnetic resonance (NMR) and mass spectrometry data. The chemical structure of products 2 was that the 17-position of the thioester moiety of FLT was substituted by a carboxylic acid. The degradation product in 0.1 M NaOH:CH3CN=1:1 was found to be product 2 based on 1H NMR data. The degradation product in 0.05 M NaOH was considered to be product 2 based on the retention time of HPLC. These results are useful for detecting the degradation products of FLT by enzymes of the intestinal bacterial flora in the large intestine after dosing FLT as an enema

Two novel tetracycles, cassibiphenols A and B from the flowers of Cassia siamea

Chemical investigation of the flowers of Cassia siamea (Leguminosae), resulted in the isolation of two novel tetracycles connecting 5-(2-hydroxypropyl)benzene-1,3-diol, cassibiphenols A (1) and B (2). The structures were elucidated by analysis of the 1D, 2D NMR, and HRMS spectra. Synthesis of a tetracyclic core of 1 and 2 led to determine the absolute configuration of 1 and C-12 of 2

Yohimbine-related Alkaloids from Tabernaemontana corymbosa

Five new yohimbine-type indole alkaloids were isolated from the leaves of Tabernaemontana corymbosa. Their structures were determined on the basis of the NMR and Circular Dichroism (CD) spectroscopy

Total Synthesis of A Novel Tetracyclic Alkaloid, Cassiarin F from the Flowers of Cassia siamea

A novel alkaloid, cassiarin F (1), which showed potent antiplasmodial activity against Plasmodium falciparum in vitro, was isolated from the flowers of Cassia siamea, and its structure was elucidated on the basis of 2D NMR analyses. A total synthesis of 1 was also achieved by employing the Suzuki coupling constructing biaryl unit, nucleophilic aromatic substitution, and Houben–Hoesch type ring construction as key steps

New Tricyclic Alkaloids, Cassiarins G, H, J, and K from Leaves of Cassia siamea

Four new alkaloids, cassiarins G, H, J, and K (1—4) which showed moderate antiplasmodial activity against Plasmodium falciparum 3D7, were isolated from the leaves of Cassia siamea (Leguminosae) and the structures of 1—4 were elucidated by 1D- and 2D-NMR analysis and X-ray crystallographic analysis