6a,7-Dehydro-2-hydroxy-4,5-dioxonoraporphine and Other Alkaloids from Monocyclanthus vignei: ¹³C-nmr Studies on 4,5-Dioxoaporphines

Abstract

The new and unusually substituted 4,5-dioxonoraporphine 1 was isolated, among other aporphines and phenanthrene-type alkaloids, from Monocyclanthus vignei. The 13Cnmr spectra of 4,5-dioxoaporphines were studied for the first time.In the course of our phytochemical investigations on tropical plants, we studied the constituents of Monocyclanthus vignei Keay. This plant of the Annonaceae grows endemically in West Africa (1).From the basic fraction of the MeOH extract the individual alkaloids 1-12, reticuline, and N-feruloyltyramine were isolated by chromatographic procedures.The approximate concentrations of these compounds are summarized in Table 1.The structures given mainly result from spectroscopic studies. Compounds 1, 3, 9, and possibly, 10-12 represent new genuine natural products.Compounds 1 and 2 show electron spectra and eims typical for 4,5-dioxoaporphines (9). The eims of 2 exhibits significant ions at [M + 14]+ and [M -14]+ caused by intermolecular methyl transfer. The position of the only hydroxy substituent in 1 at C-2 is indicated by the «-coupling between H-l and H-3.Because no BC-nmr data of 4,5-dioxoaporphines have yet been published, we studied the BC nmr of 1 and 2. In this study are included their methylation products 13 and 14 and the dioxoaporphines 15 and 16, available to us from other sources (10,11). Due to poor solubility in the usual solvents, all spectra were run in pyridinet/5. The assignments presented in Table 2 are based on heteronuclear lJ-and 2,iJ-COSY measurements.

Establishment of HPLC-DAD-MS Fingerprint of Fresh Houttuynia cordata

“…Their purities were shown to be higher than 96% by HPLC analysis, and their structures were elucidated by comparison their spectroscopic data (ESI-MS, 1 H-and 13 C-NMR, HMBC, HMQC and H-H COSY) with references. 17,[28][29][30][31][32][33][34][35][36] The detailed procedures for isolation and spectrometric identification of these compounds will be reported in another paper. Plant Materials Samples of fresh H. cordata were collected from the cultivation areas in Sichuan, Guangdong provinces and retailers in Hong Kong of China.…”

Chromone and Phenanthrene Alkaloids from Dennettia tripetala.

“…Compound 3 is a known phenanthrene alkaloid named stephenanthrine previously isolated from Stephania tetrandra (Menispermaceae) 13) and from Monocyclanthus vignei (Annonaceae) 14) and the compound 4 is argentinine that has been isolated for the first time in Aristolochia argentina 15) of the Aristolochiaceae family and more recently in the genus Annona, 16) Enantia, 17) Guatteria, 18,19) Monocyclanthus, 14) Monodora, 20) Oxymitra, 21) Phaeanthus 22) and Popowia 23) of the Annonaceae family, as well as in Stephania 13) of the Menispermaceae family. From a taxonomic point of view, it is interesting to note that this is the first report on the isolation of phenanthrene alkaloids from the genus Dennettia, which increase the number of genus belonging to the Annonaceae family with this class of compounds.…”

Chemical Constituents From the Stem Bark of Zanthoxylum Scandens

“…Five aromatic protons of the spectrum closely resembled those of other 7,8,9,10,11-unsubstituted dioxoaporphine. 11,12 Therefore, the methylenedioxy group had to be on ring A. The singlet at δ 8.04 (1H, s) was ascribed to H-7 while H-8, H-9, H-10 and H-11 appeared as a complex ABCX coupling system.…”