Three new flavonol C-glycosides from Sida cordifolia Linn

Three new flavonol C-glycosides: 3′-(3″,7″-dimethyl-2″,6″-octadiene)-8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucoside (1), 3′-(3″,7″-dimethyl-2″,6″-octadiene)-8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucosyl [1→4]-α-D-glucoside (2) and 6-(3″-methyl-2″-butene)-3′-methoxyl-8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucosyl [1→4]-β-D-glucoside (3) have been isolated from 80% ethanolic extract of the aerial parts of Sida cordifolia Linn followed by partitioning with ethyl acetate. Structures were established by chemical and spectroscopic methods.     

New Monoterpene-Substituted Dihydrochalcones from Piper aduncum

Five New unusual monoterpene-substituted dihydrochalcones, the adunctins A–E (1″S)-1-{2′-hydroxy-4′-methoxy-6′-[4″-methyl-1″-(1?-methylethyl)cyclohex-3″ -en-1″ -yloxy]phenyl}-3-phenylpropan-1-one ( 1 ), (5aR*,8R*,9aR*)-3-phenyl-1-[5′,8′,9′,9′a-tetrahydro-3′-hydroxy-1′-methoxy-8′-(1″-methylethyl)-5′-a-methyldibenzo-[b,d]furan-4′-yl]propan-1-one ( 2 ), (2′R*,4″S*)-1-{6′-hydroxy-4′-methoxy-4″-(1?-methylethyl)spiro[benzo[b]-furan-2′(3′H),1″ -cyclohex-2″ -en]-7′-yl}-3-phenylpropan-1-one ( 3 ), (2′R*,4″R*)-1-{6′-hydroxy-4′-methylethyl-4″-(1?-methylethyl)spiro[benzo[b]furan-2′(3′H),1″-cyclohex-2″-en]-7′-yl}-3-phenypropan-1-one ( 4 ), and (5′aR*,6′S*, 9′R*,9′aS*)-1-[5′a,6′,7′,8′,9′a-hexahydro-3′,6′-methoxy-6′-methyl-9′-(1″-methylethyl)dibenzo[b,d]-furan-4′-yl]-3-phenylpropan-1-one ( 5 ) were isolated from the leaves of Piper aduncum (Piperaceae) by preparative liquid chromatography. In addition, (?)-methyllindaretin ( 6 ), trans-phytol, and α-tocopherol ( = vitamin E) were also isolated and identified. The structures were elucidated by spectroscopic methods, including 1D- and 2D-NMR spectroscopy as well as single-crystal X-ray diffraction analysis. The antibacterial and cytotoxic potentials of the isolates were also investigated.     

Glycosylated constituents of iris fulva and Iris brevicaulis

The major constituents of leaf extracts of Iris fulva KER GAWL. comprised a known flavone C-glycoside, 5,4'-dihydroxy-7-methoxyflavone-6-C-(6?-O-(E)-p-coumaroyl-β-glucopyranosyl)(1?→2″)-β-glucopyranoside (1) and the new monoterpene glycoside, linalyl-6'-O-(3″-hydroxy-3″-methylglutaroyl)-β-D-glucopyranoside (2), both of which were prominent components of Iris brevicaulis RAF. leaf extracts. The structure of a new polyacylated sucrose derivative (3a) obtained from the rhizomes of I. fulva was elucidated as 3-O-(E)-p-coumaroyl-β-D-fructofuranosyl-(2?1')-[2″,4″,6″-tri-O-acetyl-β-D-glucopyranosyl-(1″→3')-(2',6'-di-O-acetyl-4'-O-(E)-p-coumaroyl-α-D-glucopyranoside)]. Selective hydrolysis of the 4″-O-acetyl moiety of the terminal β-glucopyranosyl residue of 3a occurred after several hours in solution giving 3-O-(E)-p-coumaroyl-β-D-fructofuranosyl-(2?1')-[2″,6″-di-O-acetyl-β-D-glucopyranosyl-(1″→3')-(2',6'-di-O-acetyl-4'-O-(E)-p-coumaroyl-α-D-glucopyranoside)] (3b), which subsequently underwent further deacetylation.     

Flavonoids from Tephrosia—VII : The constitution and absolute configuration of lupinifolin and lupinifolinol,two flavanones from Tephrosia lupinifolia Burch (DC)

The structure and absolute configuration of lupinifolin, (2S) - 4′,5 - dihydroxy - 8 - (3? - methyl - 2? - butenyl) - 2″, 2″ - dimethylpyrano[5″.6″ - g]flavanone, and lupinifolinol, (2R,3R) - 8 - (3? - methyl - 2? - butenyl) - 3,4′,5 - trihydroxy - 2″,2″ - dimethylpyrano[5″.6″ - g]flavanone, have been deduced from spectroscopic and chemical evidence.     

Two new xanthones from the stems of Garcinia cowa

Two new xanthones, 1,5,6-trihydroxy-3-methoxy-4-(3-hydroxyl-3-methylbutyl)xanthone (1) and 1,5-dihydroxy-3-methoxy-6',6'-dimethyl-2H-pyrano(2',3':6,7)-4-(3-methylbut-2-enyl)xanthone (2), have been isolated together with six known xanthones: 1,3,5-trihydroxy-6',6'-dimethyl-2H-pyrano(2',3':6,7)xanthone (3), dulxanthone A (4), 1,5,6-trihydroxy-3,7-dimethoxyxanthone (5), 1,7-dihydroxyxanthone (6), 1,3,5-trihydroxy-6-methoxyxanthone (7), 1,3,6,7-tetrahydroxyxanthone (8), from the stems of Garcinia cowa (Guttiferae).     

One-Pot Synthesis of Novel Spiro Pyrano[2,3-d][1,3]thiazolo[3,2-a]pyrimidine Derivatives

In a one-pot synthesis, 1′-methyl-2,3″-dioxo-5″-aryl-1,2,5a″,7″,8″,9a″-hexahydro-5″H,6″H-dispiro[indole-3,2′-pyrrolidine-3′,2″-pyrano[2,3-d][1,3]thiazolo[3,2-a]pyrimidine]-4′-carboxylic acid methyl ester was prepared via the sequential reaction of 4-aryl-octahydro-pyrano[2,3-d]pyrimidine-2-thione, dimethyl acetylenedicarboxylate (DMAD), and a mixture of isatin and sarcosine. All the novel spiro compounds, in moderate yields, were characterized thoroughly by infrared, NMR, mass spectromentry, and elemental analysis together with x-ray crystallographic analysis.     

A new fluorescent-colorimetric chemosensor for fluoride anion based on benzimidazolium salt

Two new benzimidazolium salts with the same cationic moiety and different anions 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium bromide and 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium hexafluorophosphate were prepared and characterized. The single crystal structure of 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium bromide was determined by X-ray single crystal diffraction. Particularly, anion recognition using 3-(2′-((8″-hydroxy-9″,10″-dioxo-9″,10″-dihydroanthracen-1″-yl)oxy)ethyl)-1-(pyridin-2?-ylmethyl)-1H-benzo[d]imidazol-3-ium hexafluorophosphate as a chemosensor was carried out via fluorescence and ultraviolet spectroscopy, ¹H NMR titrations, HRMS and IR spectra. The response of this chemosensor to fluoride anion can be observed through both remarkable fluorescence quenching and color change under visible light (from orange to purple). The results indicated that this chemosensor can distinguish fluoride anion from other anions via the instrument and naked eyes, and this is greatly convenient in practical operation.     

Reaction of thieno[2,3-b]pyridines with sodium hypochlorite: An unusual and stereoselective one-pot approach to dimeric pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridines

The oxidation of 3-aminothieno[2,3-b]pyridine-2-carboxamides with commercially available bleach leads to the formation of dimeric pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridines (7a,14a-diamino-7,14-bis(aryl)-7,7a,14,14a-tetrahydro-6H,13H-pyrido[3″″,2″″:4?,5?]thieno[2?,3?:4″,5″]pyrrolo-[3″,4″:3′,4′]pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridine-6,13-diones) in moderate yields (37–52%).     

Flavonoids from Tephrosia—IX : The structure of multijugin and multijuginol

The structures of two flavones, multijuginol and multijugin, isolated from Tephrosia multijuga Young, have been established as 5-methoxy-2?,2?-dimethyl-3?-hydroxy-tetrahydrofurano[5?,4?-b]-dihydrofurano[5″,4″-h]flavone and the 3?-O-acetate derivative, respectively by means of spectral evidence and chemical degradation reactions.     

Structural determination of flavonoids from Sophora flavescens

Eight flavonoids were isolated from Sophora flavescens. Among them, three prenylflavanones: (2S)-6[2(3-hydroxyisopropyl)-5-methyl-4-hexenyl]-5-methoxy-7,2', 4'-trihydroxyflavanone (1), (2S)-5, 4'-dimethoxy-8-lavandulyl-7, 2'-dihydroxy flavanone (2) and (2S)-8-(5-hydroxy-2-isopropenyl-5-methylhexyl)-7-methoxy-5,2', 4'-trihydroxyflavanone (3) are new compounds. Their chemical structures were determined by spectral methods including 2D NMR.     

Synthesis of new heteroaromatic nitrogen ligands: Pyrimido‐[4″,5″:4′,5′]‐thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidines and 1,2,3‐triazine[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]‐1,2,3‐triazines

An efficient one‐pot access for the synthesis of the previously unreported tetracyclic fused pyrimido‐[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidine ( 3 ) and 1,2,3‐triazine[4″,5″:4′,5′]thieno‐[3′,2′:4,5]thieno‐[3,2‐d]‐1,2,3‐triazine ( 5 ) heteroaromatic nitrogen ligands is described. The title compounds 3 and 5 were obtained from 3,4‐diaminothieno[2,3‐b]thiophene‐2,5‐dicarbonitrile and phosgeniminium chloride and sodium nitrite/HCl, respectively. Substituted condensed thieno[2,3‐b]thiophene derivatives 4 and 6 were synthesized by nucleophilic displacement of the chloroderivatives 3 and 5 .     

Synthesis of Star-Shaped Polystyrenes with Glucose in the Chain-End and Core

2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) was reacted with 4-ethylphenyl 2,3,4,6-tetra-O-acetyl-β-D -glucopyranoside using tert-butyl hydroperoxide and cobalt(II)acetate tetrahydrate in acetonitrile. The reaction provided 4-[1′-(2″,2″,6″,6″-tetramethyl-1″-piperidinyloxy)-ethyl]phenyl 2,3,4,6-tetra-O-acetyl-β-D -glucopyranoside, glycoconjugated initiator. Star-shaped polystyrene architectures in which glucose was covalently bonded in the core and chain-end were successfully prepared from the glycoconjugated initiator, styrene, and 1,4-divinylbenzene as starting materials.     

Xanthones with antiproliferative effects on prostate cancer cells from the stem bark of Garcinia xanthochymus

Investigations of the constituents of the stem barks of Garcinia xanthochymus have yielded two new compounds, garcinenones X (1) and Y (2), along with five known xanthones, 1,4,5,6-tetrahydroxy-7-(3-methylbut-2-enyl)xanthone (3), 1,4,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone (4), 1,4,5,6-tetrahydroxy-7,8-di(3-methylbut-2-enyl)xanthone (5), 1,3,5,6-tetrahydroxy-4,7,8-tri(3-methylbut-2-enyl)xanthone (6), and 1,5,6-trihydroxy-7,8-di(3-methylbut-2-enyl)-6',6'dimethylpyrano(2',3':3,4)xanthone (7). The structures of the compounds were determined by spectroscopic methods. The cell growth inhibitory activity of the isolated compounds against the PC-3 cell line was measured. Among them, compounds 2, 3, 5, and 6 exhibited significant inhibitory effects with IG50 values of 14.3, 15.5, 11.1, and 6.8 microM, respectively.     

Three Prenylated Isoflavones from Erythrina variegate

Two new prenylated isoflavones (erythrivarones A and B) were isolated from the stem bark of Erythrina variegata Linn, together with the known compound alpinumisoflavone (1). The structures of erythrivarones A and B were characterized as dihydroalpinumisoflavone (2) and 4′-hydroxy-[6″,6″-dimethyldihydropyrano(2″,3″:5,6)]-[6?,6?-dimethyldihydropyrano(2?,3?:7,8)]isoflavone (3), respectively, by means of spectroscopic analysis.     

New stilbenoids from Pholidota yunnanensis and their inhibitory effects on nitric oxide production

Six new stilbenoids, a (bibenzyldihydrophenanthrene) ether designated phoyunnanin D (1), a bis(dihydrophenanthrene) ether designated phoyunnanin E (2), and four stilbenes designated phoyunbene A-D (3-6), were isolated from the air-dried whole plant of Pholidota yunnanensis ROLFE. The new compounds were identified as 7-[2-(3-hydroxyphenethyl)-4-hydroxy-6-methoxyphenoxy]-4-hydroxy-2-methoxy-9,10-dihydrophenanthrene (1), 1-[(9,10-dihydro-4-hydroxy-2-methoxy-7-phenanthrenyl)oxy]-4,7-dihydroxy-2-methoxy-9,10-dihydrophenanthrene (2), trans-3,3'-dihydroxy-2',4',5-trimethoxystilbene (3), trans-3,4'-dihydroxy-2',3',5-trimethoxystilbene (4), trans-3,3'-dihydroxy-2',5-dimethoxystilbene (5), and trans-3-hydroxy-2',3',5-trimethoxystilbene (6) based on spectroscopic evidence. Furthermore, the inhibitory effects of compounds 1-6 on nitric oxide production in a murine macrophage-like cell line (RAW 264.7) activated by lipopolysaccharide and interferon-gamma were examined.     

Synthesis,Characterization and Reactions of 4‐Hydrazino‐2‐methylpyrimidino[4′5′:4,5]thiazolo[3,2‐a]benzimidazole

4‐Hydrazino‐2‐methylpyrimidino[4′,5′:4,5]thiazolo[3,2‐a]benzimidazole ( 4 ) was obtained from hydrazinolysis of the 4‐chloro derivative 3 with hydrazine hydrate. The hydrazino derivative 4 was further cyclized to the corresponding pyrazole 5 , pyrazolone 6 and 5‐methyl‐1,2,4‐triazolo[1″,5″:3′,4′]pyrimidino[5′,6′:5,4]‐thiazolo[3,2‐a]benzimidazole ( 9 ) and 5‐methy‐1,2,4‐triazolo[4″,3″:3′,4′]pyrimidino[5′,6′:5,4]thiazolo‐[3,2‐a]benzimidazole ( 10 ), respectively. The triazolo derivative 10 was isomerized to the triazolo derivative 9 under a variety of reaction conditions.     

Rapid Access for the Synthesis of 1‐N‐Methyl‐spiro[2.3′]oxindole‐spiro[3.7″] (3″‐Aryl)‐5″‐methyl‐3″,3a″,4″,5″,6″,7″‐hexahydro‐2H‐pyrazolo[4,3‐c]pyridine‐4‐aryl‐pyrrolidines Through Sequential 1,3‐Dipolar Cycloaddition and Annulation

The 1,3‐dipolar cycloaddition of an azomethine ylide, generated from isatin and sarcosine by a decarboxylative route with various p‐substituted 3,5 bis(aryl methylidene)N‐methyl‐4‐piperidinones in refluxing methanol, proceeded regioselectively to give novel dispiroheterocycles. The product on subsequent annulation with hydrazine hydrate afforded 1‐N‐methyl‐spiro[2.3′]oxindole‐spiro[3.7″](3″‐aryl)‐5″‐methyl‐3″,3a″,4″,5″,6″,7″‐hexahydro‐2H‐pyrazolo[4,3‐c]pyridine‐4‐aryl‐pyrrolidines in good yield.     

The Diels-Alder Reactivity of 2,2′-Ethylidenebis[3,5-dimethylfuran] and Exploratory Chemistry of the Mono-adducts

In the presence of Me₃Al, 1-cyanovinyl acetate added to 2,2′-ethylidenebis[3,5-dimethylfuran] ( 1 ) to give a 20:10:1:1 mixture of mono-adducts 4,5,6 , and 7 resulting from the same regiocontrol (‘para’ orienting effect of the 5-methyl substituent in 1 ). The additions of a second equiv. of dienophile to 4–7 were very slow reactions. The major mono-adducts 4 (solid) and 5 (liquid) have 2-exo-carbonitrile groups. The molecular structure of 4 (1RS,1′RS,2SR,4SR)-2-exo-cyano-4-[1-(3,5-dimethylfuran-2-yl)ethyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl acetate) was determined by X-ray single-crystal radiocrystallography. Mono-adducts 4 and 5 were saponified into the corresponding 7-oxanorbornenones 8 and 9 which were converted with high stereoselectivity into (1RS,1′SR,4RS,5RS,6RS)-4-[1-(3,5-dimethyl furan-2-yl)ethyl]-6-exo-methoxy-1,5-endo-dimethyl-7-oxabicyclo [2.2.1]heptan-2-one dimethyl acetal ( 12 ) and its (1′RS-stereoisomer 12a , respectively. Acetal hydrolysis of 12a followed by treatment with (t-Bu)Me₂SiOSO₂CF₃ led to silylation and pinacol rearrangement with the formation of (1RS,1′RS,5RS,6RS)-4-[(tert-butyl)dimethy lsilyloxy]-1-(3,5-dimethylfuran-2-yl)ethyl]-5-methoxy-6-methyl-3-methylidene- 2-oxabicyclo[2.2.1]heptane ( 16 ). In the presence of Me₃Al, dimethyl acetylenedicarboxylate added to 12 giving a major adduct 19 which was hydroborated and oxidized into (1RS,1′RS,2″RS,3″RS,4SR,4″RS,5 SR,6SR)-dimethyl 5-exo-hydroxy-4,6-endo-dimethyl-1-[1-(3-exo,5,5-trimeth oxy-2-endo,4-dimethyl-7-oxabicyclo[2.2.1]hept-2-yl)ethyl]-7-oxabicyclo [2.2.1]hept-2-ene-2,3-dicarboxylate ( 20 ). Acetylation of alcohol 20 followed by C?C bond cleavage afforded (1′RS,1″SR,2RS,2′″SR,3RS, 3″SR,4RS,4″SR,5RS)-dimethyl {3-acetoxy-2,3,4,5-tetrahydro-2,4-dimethyl-5-[1-(3-exo,5,5-trimethoxy ?2-endo,4-dimethyl-7-oxabicyclo[2.2.1]hept-1-yl)-ethyl]furan-2,5-diyl} bis[glyoxylate] ( 24 ).     

Facile Syntheses of 3′,4′-Methylenedioxy- 2″,2″-dimethylpyrano-[5″,6″:7,8]-flavoneand (±)-Ponganone III,Two Pyranoflavanoids

Facile syntheses of two naturally occurring pyranoflavanoids, 3′,4′-methylenedioxy-2″,2″-dimethylpyrano-[5″,6″:7,8]-flavone (1) and (±)-ponganone III (2), have been achieved through the key intermediate chromene 6 by a DDQ-induced oxidative cyclization.     

Two new compounds from Dendrobium candidum

Two new compounds were isolated from the stems of Dendrobium candidum: (R)-3,4-dihydroxy-5,4',alpha-trimethoxybibenzyl (1), named dendrocandin A; and 4-[2-[(2S,3S)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-hydroxymethyl-8-methoxy-2,3-dihydrobenzo[1,4]dioxin-6-yl]ethyl]-1-methoxyl benzene (2), dendrocandin B. Five previously known bibenzyls were also identified: 4,4'-dihydroxy-3,5-dimethoxybibenzyl (3), 3,4-dihydroxy-5,4'-dimethoxybibenzyl (4), 3-O-methylgigantol (5), dendrophenol (6), and gigantol (7).