Synthesis of Pyridin-2(1H)-imines via the Transformation of Conjugated Ynones.

Conjugated ynones represent an important class of reactive species, useful synthetic intermediates, and synthons. However, the reactivity and synthetic applications of ynones are usually focused on the transformation of mono- or dual-functional groups. Herein, we developed a straightforward synthesis of pyridin-2(1H)-imines from the transformation of conjugated ynones. This cascade process probably began with a Michael addition of ynones and 2-aminopyridines, further underwent an intramolecular cyclization to generate the N,O-bidentate intermediates, and finally reacted with sulfonyl azides giving the pyridin-2(1H)-imines with accompanying loss of diazo.

New dammarane-type triterpenoid saponins from Panax notoginseng saponins.

BACKGROUND: Panax notoginseng saponin (PNS) is the extraction from the roots and rhizomes of Panax notoginseng (Burk.) F. H. Chen. PNS is the main bioactive component of Xuesaitong, Xueshuantong, and other Chinese patent medicines, which are all bestselling prescriptions in China to treat cardiocerebrovascular diseases. Notoginsenoside R1 and ginsenoside Rg1, Rd, Re, and Rb1 are the principal effective constituents of PNS, but a systematic research on the rare saponin compositions has not been conducted. OBJECTIVE: The objective of this study was to conduct a systematic chemical study on PNS and establish the HPLC fingerprint of PNS to provide scientific evidence in quality control. In addition, the cytotoxicity of the new compounds was tested. METHODS: Pure saponins from PNS were isolated by means of many chromatographic methods, and their structures were determined by extensive analyses of NMR and HR-ESI-MS studies. The fingerprint was established by HPLC-UV method. The cytotoxicity of the compounds was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5 -diphenyltetrazolium bromide assay. RESULTS AND CONCLUSION: Three new triterpenoid saponins (1-3) together with 25 known rare saponins (4-28) were isolated from PNS, except for the five main compounds (notoginsenoside R1 and ginsenoside Rg1, Rd, Re, and Rb1). In addition, the HPLC fingerprint of PNS was established, and the peaks of the isolated compounds were marked. The study of chemical constituents and fingerprint was useful for the quality control of PNS. The study on antitumor activities showed that new Compound 2 exhibited significant inhibitory activity against the tested cell lines.

Two pairs of bisabolane sesquiterpenoid stereoisomers, bisacurone D-G, from the rhizome of Curcuma longa L.

Phytochemical investigation of an extract of the rhizome of Curcuma longa L., resulted in the identification of four undescribed bisabolane sesquiterpenoids, namely as bisacurone D-G (1-4). With the aid of comprehensive spectroscopic techniques (NMR, IR, UV, MS), the structures of all isolated compounds were elucidated and subsequently screened for both anti-inflammatory and cytotoxic biological activities, Compounds 1 and 2 showed moderate inhibitory activity toward LPS-induced NO production on RAW 264.7 macrophages.

Structure elucidation and NMR assignment of two new eudesmane derivatives from Merremia yunnanensis.

Two new eudesmane derivatives, 1α,6ß,9ß-trihydroxy-eudesm-3-ene-1-O-ß-d-glucopyranoside (1) and 1α,6ß,9ß-trihydroxy-eudesm-3-ene-1-(6-cinnamoyl)-O-ß-d-glucopyranoside (2) were discovered from Merremia yunnanensis. The structures were elucidated by analysis of their spectroscopic data including HR-ESI-MS, 1D, and 2D NMR. It should be noted that this is the first report about structure elucidation and NMR assignment of compounds from M. yunnanensis.

Two new biphenyls from the stems of Garcinia tetralata.

Two new biphenyls (1 and 2) and three known xanthones (3-5) were isolated from the ethanol extract of the stems of Garcinia tetralata. Structural elucidations of 1-2 were elucidated by spectroscopic methods including extensive 1D- and 2D-nuclear magnetic resonance spectroscopy techniques. Compounds 1-2 showed anti-rotavirus activities with SI above 10.

Chemical constituents from the roots of Ampelopsis delavayana and their antibacterial activities.

Two new aromatic glycosides, 2-methylphenyl O-ß-d-xylopyranosyl-(1→6)-O-ß-d-glucopyranoside (1) and 2-methylphenyl O-α-arabinofuranosyl-(1→6)-O-ß-glucopyranoside (2), together with eight known compounds were isolated from the roots of Ampelopsis delavayana. Their structures were elucidated on the basis of extensive spectroscopic analysis. Furthermore, the in vitro antibacterial activities of 1 and 2 were investigated using serial twofold dilution in three bacteria including Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.

Diterpenoid alkaloids from the roots of Aconitum brachypodum Diels.

A new diterpenoid alkaloid, named bullatine H (1), along with 10 known diterpenoid alkaloids were isolated from the roots of Aconitum brachypodum Diels (Ranunculaceae). The structure of 1 was elucidated by analysis of its spectroscopic data. It should be noted that compound 1 is the first example with 11, 13-dioxygenated denudatine-type diterpenoid alkaloid isolated from Aconitum brachypodum.

Two new phenylpropanoid esters of rhamnose from Lagotis yunnanensis.

Two new phenylpropanoid esters of rhamnose, lagotoside B (1) and lagotoside C (2), together with three known compounds (3-5), were isolated from Lagotis yunnanensis. The structures of 1 and 2 were elucidated by spectroscopic methods. Compounds 3-5 have been obtained from this species for the first time.

Constituents of Lagotis yunnanensis.

The isolation from the ethanolic extract of Lagotis yunnanensis of the new compound lagotisoside A (1) and of 10 other constituents is reported.

[Studies on chemical constituents from the stems of Schisandra sphaerandra].

OBJECTIVE: To investigate the chemical constituents from the stems of Schisandra sphaerandra. METHOD: Compounds were isolated from ethanolic extract of the titled herb by silica gel column chromatography, and their structures were elucidated by physical and chemical evidences and spectroscopic analysis. RESULT: 12 compounds were obtained and identified as wuweizisu C (1), ganwuweizic acid (2), nigranoic acid (3), catechin (4), 2 alpha,24-dihytroxyursolic acid. (5), 3 beta-O-acetylursolic acid (6), ursolic acid (7), slyceryl 26-hydroxyhexacosanoate (8), slyceryl hexacosanoate (9), fat acids (10), beta-sitosterol (11), daucosterol (12), respectirely. CONCLUSION: Three pentacyclic triterpene carboxylic acid (5-7) were isolated from Schisandreae for the first time.

Cytotoxic 3,20-epoxy-ent-kaurane diterpenoids from Isodon eriocalyx var. laxiflora.

Four new ent-kaurane diterpenoids, laxiflorins J-M (1-4), along with maoecrystal A (5) and maoecrystal P (6), were isolated from the leaves of Isodon eriocalyx var. laxiflora. Their structures were determined by spectroscopic analyses. All the compounds were assayed for their cytotoxic effects on human tumor K562, A549, and T24 cell lines. Compounds 1 and 6 showed significant inhibitory effects on human tumor K562 and T24 cells, with IC(50) values less than 0.5 microg/mL. Compound 3 also demonstrated cytotoxic activities against all three types of human tumor cells, with IC(50) values in the range of 1-25 microg/mL.

Constituents of Clerodendrum bungei.

Two new compounds, 5-O-ethylcleroindicin D (1) and bungein A (2), together with 12 known compounds (3-14), were isolated from the aerial parts of the medicinal plant Clerodendrum bungei. The structures of 1 and 2 were elucidated as a perhydrobenzofuran derivative and a peroxide dimer by spectral and chemical evidence. Compounds 3-14 have been obtained from this species for the first time.

Cytotoxic ent-kaurane diterpenoids from Isodon eriocalyx var. laxiflora.

Three new ent-kaurane diterpenoids laxiflorin E (1), laxiflorin H (6) and laxiflorin I (8) were isolated from the leaves of Isodon eriocalyx var. laxiflora, along with nine known diterpenoids, eriocalyxin A (2), laxiflorin C (3), laxiflorin D (4), laxiflorin A (5), maoecrystal S (7), maoecrystal Q (9), eriocalyxin B (10), maoecrystal C (11) and enmelol (12). The structures of the new compounds were determined by spectroscopic methods. Compounds 1-5 are 6,7-seco-ent-kaurane-7,20-olide diterpenoids, and 6-12 belong to 7,20-epoxy-ent-kauranoids. The spectral data of enmelol (12) are reported here for the first time. Ten of these compounds were tested for their cytotoxicity toward K562 and T24 human tumor cells. Compounds 1, 3 and 10 showed significant inhibitory effects on K562 cells with IC50 values 0.077, 0.569 and 0.373 microg/mL, and compounds 1 and 10 also demonstrated significant inhibitory activities toward T24 cells with IC50 values 0.709 and 0.087 microg/mL. Compounds 8 and 11 also displayed inhibitory effect on both two kinds of cells with IC 50 value less than 6.5 microg/mL.

Abietane diterpenoids from Coleus xanthanthus.

Eight new abietane diterpenoids, coleon U 11-acetate (1), 16-acetoxycoleon U 11-acetate (2), and xanthanthusins F-K (3-8), together with five known analogues, coleon U (9), 16-O-acetylcoleon C (10), coleon U-quinone (11), 8alpha,9alpha-epoxycoleon U-quinone (12), and xanthanthusin E (13), were isolated from the aerial parts of Coleus xanthanthus. The structures of 1-8 were elucidated on the basis of spectral methods. Compounds 1, 5, and 11-13 were evaluated for their cytotoxicity against K562 human leukemia cells.

Diterpenoids from Isodon enanderianus.

Four ent-kauranoids, 6-epiangustifolin and enanderinanins F-H, as well as 11 known ent-kaurane diterpenoids, macrocalin B, xerophilusin A, trichorabdal A, trichorabdal B, effusin, angustifolin, longikaurin D, longikaurin F, enanderinanin B, xerophilusin G and shikokianin were isolated from the aerial parts of Isodon enanderianus. The new diterpenoids were identified as 6-epiangustifolin (11alpha-hydroxy-6alpha-methoxy-6,19-epoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide), enanderinanin F (19-acetoxy-6,20:6,11beta-diepoxy-6,7-seco-ent-kaur-16-en-15-one-1beta,7-olide), enanderinanin G (1beta,6beta,7beta-trihydroxy-19-acetoxy-16beta-methoxymethyl-7alpha,20-epoxy-ent-kaur-15-one) and enanderinanin H (6beta,7beta,14beta-trihydroxy-1alpha,11beta-acetonide-7alpha,20-epoxy-ent-kaur-16-en-15-one), respectively, on the basis of spectral data, especially by 2D NMR techniques. 6-Epiangustifolin showed significant cytotoxic activity against K562 cell.