Electrochemical-Induced C-N Bond Formation: A New Method to Synthesis (Z)-Quinazolinone Oximes Using Primary Amines and Quinazolin-4(3H)-one.

A novel and highly selective electrochemical method for the synthesis of diverse quinazolinone oximes via direct electrooxidation of primary amines/C(sp2)-H functionalization of oximes has been developed. The reaction is conducted in an undivided cell under constant current conditions and is oxidant-free, open-air, and eco-friendly. Notably, the protocol shows good functional group tolerance, providing versatile quinazolinone oximes in good yields. Moreover, the mechanism is investigated through control experiments and cyclic voltammogram (CV) experiments.

Nine pairs of undescribed enantiomers from the resin of Styrax tonkinensis (Pierre) Craib ex Hart with anti-inflammatory activity.

Nine pairs of undescribed enantiomers, (±)-styraxoids A-I (1-9), were isolated from the resin of Styrax tonkinensis, and their structures were assigned by spectroscopic and computational methods. Compounds (±)-1 are a pair of degraded lignans, and the remaining compounds (±)-(2-9) are phenylpropanoid skeletons. Compounds (±)-8 and (±)-9 feature a 1,3-dioxolane moiety. The biological evaluation showed that both enantiomers of 1 could inhibit LPS-induced INOS and COX-2 in RAW264.7 cells in a dose-dependent manner.

8-O-ß-D-Glucopyranosyl-2-methylchromone, a new chromone glycoside from the Tibetan medicine plant of Swertia punicea Hemsl.

A new chromone glycoside, 8-O-ß-D-Glucopyranosyl-2-methylchromone (1), together with eight known compounds (2-9) were isolated from the Tibetan medicine plant of Swertia punicea. All compounds of this plant were reported for the first time. The structures of these metabolites were elucidated by analysis of their HR-ESI-MS, 1D and 2D NMR spectroscopic data and comparison with data reported in the literature. In vitro test, all compounds were evaluated for their anti-inflammatory activity through the determination of nitric oxide production. Compounds 1-2 were evaluated for cytotoxic activities against three human cancer cell lines (HeLa, MDA-MB-231 and A375) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. Furthermore, the chemotaxonomic significance of these compounds has also been described.

Structure Elucidation of Two New Norlignans from Anemone vitifolia and Their Anti-Inflammatory Activities.

Two new norlignans together with two known phenylpropanoids were isolated from the whole herb of Anemone vitifolia. All compounds were reported from this plant for the first time. The structures of these compounds were identified by comprehensive HR-ESI-MS, 1D and 2D NMR spectroscopic data analysis and comparison with literature data. Additionally, bioactivity study results showed that two new compounds have potential anti-inflammatory activity. The plausible biosynthetic pathway for these compounds were also speculated in this article.

Two new xanthone glycosides from Swertia punicea Hemsl. and their anti-inflammatory activity.

Two new xanthone glycosides (1-2), together with seven known analogues (3-9), were isolated from whole herb of Swertia punicea. The structures of these metabolites were established on the basis of detailed spectroscopic analysis and comparison with data reported in the literature. In an in vitro test, all isolates were evaluated for their anti-inflammatory activity. The results revealed that all of them showed significant anti-inflammatory activity with IC50 values ranging from 1.237 to 3.319 mM. Compounds 3, 4, and 5 (IC50 values in the range 1.237-1.987 mM) displayed more potent anti-inflammatory activity than the positive control, indomethacin (IC50 value of 2.004 mM).

Three new phenylacetamide glycosides from Dracocephalum tanguticum Maxim and their anti-hyperglycemic activity.

Three new phenylacetamide glycosides (1-3) together with one known phenylacetamide glycoside (4) and two known flavonoid glycosides (5-6) were isolated from whole plants of Dracocephalum tanguticum. The structure of all compounds were elucidated based on spectroscopic data analysis and comparison with data reported in related literature. Compounds (1-3) were evaluated for their anti-hyperglycemic and anti-fungal (Candida albicans) activities, the results revealed that all of them showed moderate activity with 3T3-L1 adipocytes glucose consumption rate of 20.80 ± 1.47%, 21.48 ± 2.44%, and 21.57 ± 1.35%, respectively at the final concentration of 25 µM. However, none of them showed obvious Candida albicans inhibitory activity.

Vasodilatory effect and structural-activity relationship of a group of iridoid glucosides from Phlomis likiangensis.

As a folk medicine, Phlomis likiangensis is traditionally used in China to activate collaterals and protect cardiovascular system. We hypothesized that the beneficial effects of Phlomis likiangensis may be related to vasodilatation. In the present study, twelve known iridoid glucosides (1-12) were isolated from Phlomis likiangensis. The vasodilatory effects and the underlying mechanisms of the main components (iridoid glucosides) of Phlomis likiangensis on rat aortic rings were investigated. The result showed that iridoid glucosides significantly increased the vasodilatation in rat aortic rings, which was abolished by removing the endothelium of the vessels or by eliminating the generation of nitric oxide. Finally, the structure-activity relationship of compounds 1-12 was also speculated. Our findings provide the first evidence that the iridoid glucosides of Phlomis likiangensis may be the pharmacodynamic basis for its traditional efficacy.

[Chemical constituents of Cassia siamea].

A total of ten compounds were isolated from the 90% Et OH extract of Cassia siamea by using various chormatographic techniques,and their structures were established as( 2' S)-2-( propan-2'-ol)-5,7-dihydroxy-benzopyran-4-one( 1),chrobisiamone( 2), 2-( 2'-hydroxypropyl)-5-methyl-7-hydroxychromone( 3), 2,5-dimethyl-7-hydroxychromone( 4), 2-methyl-5-acetonyl-7-hydroxychromone( 5),3-O-methylquercetin( 6),3,5,7,3',4'-pentahydroxyflavonone( 7),luteolin-5,3'-dimethylether( 8),4-( trans)-acetul-3,6,8-trihydroxy-3-methyl-dihydronapht halenone( 9) and 6-hydroxymellein( 10) based on the spectroscopic data.Compound 1 was a new compound,and 3,4,6,8 were isolated from this plant for the first time.

Commipholactam A, a cytotoxic sesquiterpenoidal lactam from Resina Commiphora.

Diverse terpenoids including a novel sesquiterpenoidal lactam, commipholactam A (1), and a structurally related new cadinane sesquiterpenoid, commiphorane H (2), a new eudesmane sesquiterpenoid, commiphorane I (4), a new guaiane sesquiterpenoid, commiphorane J (5), and two new nor-abietane diterpenoids, commiphoranes K1 and K2 (6 and 7) along with two known terpenoids (3 and 8), were isolated from Resina Commiphora. Their structures with absolute configurations were characterized by spectroscopic methods and calculated electronic circular dichroism (ECD). Notably, commipholactam A represents the first example of cadinane sesquiterpene alkaloids isolated from Resina Commiphora. Biological assessment toward human cancer cells showed that the IC50 values of 1 against HepG2 and A549 cells were 21.73 µM and 128.50 µM, respectively.

[A new naphthaldehyde derivative from Comastoma pulmonarium and its anti-tobacco mosaic virus (anti-TMV) activity].

A new naphthaldehyde derivative has been isolated from Comastoma pulmonarium by using various chromatographic techniques, including silica gel, Sephadex LH-20, MCI-gel resin and RP-HPLC. This compounds was determined as 5-methoxy-2-methyl-7-(2-oxopropyl)naphthalene-1-carbaldehyde(1) by NMR, MS, IR and UV spectra. This compound was also evaluated for its anti-tobacco mosaic virus (anti-TMV) activity. The result showed that it showed high anti-TMV activity with inhibition rate of 32.8%. The inhibition rate is close to that of positive control (ningnanmycin).

Biomimetic Synthesis of Macahydantoins A and B from Lepidium meyenii, and Structure Revision of Macahydantoin B as a Class of Thiohydantoin with a 4-Methyl-hexahydropyrrolo[1,2-c]imidazole Skeleton.

Phytochemical investigation on Lepidium meyenii led to the discovery of macahydantoin C (3), a new thiohydantoin with a 1,3-diazabicyclo[3.3.1]nonane core, the spectral properties of which indicate a potential structural misassignment of its previously reported analogue, macahydantoin B (2a). To probe this hypothesis, a concise, scalable, and biomimetic synthesis of the originally proposed 2a and its revised structure (2b) was efficiently accomplished using the modified Edman degradation as the key step from commercially available materials in 65% (three steps) and 52% (three steps) overall yields, respectively. These synthetic endeavors undoubtedly reassigned the structure of macahydantoin B as an unreported type of thiohydantoin featuring a 4-methyl-hexahydropyrrolo[1,2-c]imidazole scaffold.

Biomimetic Synthesis of Resveratrol Trimers Catalyzed by Horseradish Peroxidase.

Biotransformation of trans-resveratrol and synthetic (±)-ε-viniferin in aqueous acetone using horseradish peroxidase and hydrogen peroxide as oxidants resulted in the isolation of two new resveratrol trimers (3 and 4), one new resveratrol derivative (5) with a dihydrobenzofuran skeleton, together with two known stilbene trimers (6 and 7), and six known stilbene dimers (8-13). Their structures and relative configurations were identified through spectral analysis and possible formation mechanisms were also discussed. Among these oligomers, trimers 6 and 7 were obtained for the first time through direct transformation from resveratrol. Results indicated that this reaction is suitable for the preparation of resveratrol oligomers with a complex structure.

Four New Diterpene Glucosides from Perovskia atriplicifolia.

Four new diterpene glucosides, namely perovskiaditerpenosides A - D (1 - 4), were isolated from the BuOH extract of Perovskia atriplicifolia. Their structures were well elucidated by chemical methods and comprehensive spectroscopic analyses including MS, IR, and NMR (1D and 2D). The newly isolated compounds were screened for their cytotoxic activity against HepG2, NB4, HeLa, K562, MCF7, PC3, and HL60. The obtained results indicated that the new compounds possessed considerable cytotoxic activity.

(+)-Meyeniins A-C, Novel Hexahydroimidazo[1,5-c]thiazole Derivatives from the Tubers of Lepidium meyenii: Complete Structural Elucidation by Biomimetic Synthesis and Racemic Crystallization.

(+)-Meyeniins A-C (1-3), a novel class of sulfur-containing hexahydroimidazo[1,5-c]thiazole derivatives, were isolated from the tubers of Lepidium meyenii (maca) cultivated in Lijiang, Yunnan province, China. Guided by their biosynthetic hypothesis, a stereocontrolled biomimetic synthesis of meyeniins A-C and their individual enantiomers was efficiently accomplished by a combination of a condensation reaction and Edman degradation. The formation of high-quality crystals for X-ray crystallography occurred much more readily from a racemic mixture of (±)-meyeniin A than with the single enantiomer alone in this case. These extensive strategies, combined with circular dichroism (CD) spectra, allowed the complete structural assignments of (+)-meyeniins A-C. Among them, (+)-meyeniin A showed moderate selective cytotoxicities against the HL-60, A549 and MCF-7 human cell lines with IC50 values of 14.41, 32.22, and 33.14 µM, respectively. To some extent, these findings support traditional applications of maca as healthy nutritional supplements or functional foods for cancer prevention.

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.

Three new anthraquinones from the twigs of Cassia fistula and their bioactivities.

Three previously unreported anthraquinones, fistulaquinones A-C (1-3), together with three known ones (4-6) were isolated from the twigs of Cassia fistula. Their structures were determined by means of extensive NMR and MS spectroscopic analyses. All the isolated compounds were tested for their anti-tobacco mosaic virus (anti-TMV) activity, and compound 3 showed significant activity with inhibition rate of 34.5% at 20 µM concentration, even more potent than positive control. Additionally, compounds 1-6 exhibited moderate cytotoxicity with IC50 values ranging from 2.8 to 9.4 µM for some tested human tumor cell lines.

Three new xanthones from Swertia bimaculata and their anti-5α-reductase activity.

Three new xanthones (1-3), together with five known ones (4-8), were isolated from whole herb of Swertia bimaculata. Their structures were established on the basis of detailed spectroscopic analysis (1D- and 2D-NMR, HRESIMS, UV, and IR) and comparison with data reported in the literature. New isolates were evaluated for their anti-5α-reductase activity. The results revealed that all new compounds showed weak activity with reductase inhibitions of 40.5 ± 2.8, 38.6 ± 2.5, and 48.9 ± 3.0%, respectively.

Two new phenylpropanoids from Swertia atroviolacea and their anti-5α-reductase activity.

Two new phenylpropanoids (1-2), together with two known lignans (3-4), were isolated from whole herb of Swertia atroviolacea. The structures of the new metabolites were established on the basis of detailed spectroscopic analysis. Compounds 1 and 2 were evaluated for their anti-5α-reductase activity. The results revealed that 1 and 2 showed weak activity with reductase inhibitions of 45.6 ± 2.8% and 38.4 ± 2.5%, respectively.

Pregnane glycosides from the antidepressant active fraction of cultivated Cynanchum otophyllum.

Based on the bioactive screening results, four new pregnane glycosides, namely cynanotophyllosides A-D (1-4) were isolated from the anti-depressant active fraction of cultivated Cynanchum otophyllum, along with thirteen known compounds (5-17). The new compounds were characterized as qingyangshengenin 3-O-ß-D-glucopyranosyl-(1→4)-ß-D-cymaropyranosyl-(1→4)-ß-D-oleandropyranosyl-(1→4)-ß-D-cymaropyranosyl-(1→4)-ß-D-cymaropyranoside (1), qingyangshengenin-3-O-ß-D-glucopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→4)-ß-D-oleandropyranosyl-(1→4)-ß-D-cymaropyranosyl-(1→4)-α-L-cymaropyranosyl-(1→4)-ß-D-cymaropyranoside (2), caudatin-3-O-ß-D-glucopyranosyl-(1→4)-ß-D-thevetopyranosyl-(1→4)-ß-D-cymaropyranosyl-(1→4)-ß-D-digitoxopyranoside (3) caudatin-3-O-ß-D-glucopyranosyl -(1→4)-ß-D-thevetopyranosyl-(1→4)-ß-D-cymaropyranosyl-(1→4)-ß-D-cymaropyranoside (4), by detailed spectroscopic analysis and acidic hydrolysis.

Antiviral and Cytotoxic Isocoumarin Derivatives from an Endophytic Fungus Aspergillus oryzae.

Oryzaeins A-D (1-4), four new isocoumarin derivatives, along with five known ones (5-9) were isolated from solid cultures of an endophytic fungus Aspergillus oryzae. Their structures were elucidated by detailed spectroscopic analysis and by comparison with reported data of related derivatives. Among them, compounds 1 and 2 represent the first examples of isocoumarins possessing an unusual 2-oxopropyl group and a rare 3-hydroxypropyl group. Compounds 1 and 2 displayed moderate anti-tobacco mosaic virus activities with inhibition rates of 28.4% and 30.6%, respectively, at the concentration of 20 µM. The new compounds showed moderate inhibitory activities against several human tumor cell lines with IC50 values in the range of 2.8-8.8 µM. Supporting information available online at http://www.thieme-connect.de/products.