Xanthones from Tovomita pyrifolium

The wood of Tovomita pyrifolium (Guttiferae) contains the novel tovopyrifolins A [1,6-dihydroxy-7-methoxy-5-prenyl-6′,6′-dimethylpyrano (2′,3′:3,2)xanthone], B (1,5-dihydroxy-3,4-dimethoxyxanthone) and C (1,3,5-trihydroxy-2-methoxyxanthone) and also the known tovophyllins A and B [structure revised to 1,6-dihydroxy-5-prenyl-6′, 6′-dimethylpyrano(2′,3′:3,2)-6″,6″-dimethylpyrano(2″,3″:7,8)xanthone].     

Isoflavones from Lupinus angustifolius root

Two novel isoflavones, 5,7,2′-trihydroxy-6-(3,3-dimethylallyl)-[6″,6″-dimethylpyrano(2″,3″:4′,3′) ]-isoflavone and 5,2′,4′-trihydroxy-3′-(3,3-dimethylallyl)-[6″,6″-dimethylpyrano(2″,3″:7,6)]isoflavone, have been isolated from the roots of Lupinus angustifolius cv. Uniharvest. Structures were established by analysis of ¹³C NMR and other spectral data, and by chemical conversion of one of the compounds to a coumaronochromone.     

Minor xanthones from Rheedia gardneriana

8-Deoxygartanin and two new xanthones, 1,5-dihydroxy-6′,6′-dimethyl-2H-pyrano(2′,3′:3,2)-6″,6″-dimethyl-2H-pyrano(2″,3″:6,7)xanthone and 1,5,6-trihydroxy-6′,6′-dimethyl-2H-pyrano(2′,3′:3,2)-7-(3-methylprop-2-enyl)xanthone, have been isolated from the roots of Rheedia gardneriana. The latter of the two new xanthones has been assigned the trivial name 7-prenyljacareubin while the former has the structure erroneously assigned to pyranojacareubin reported from Garcinia densivenia. The correct identity of the G. densivenia xanthone has been shown to be rheediaxanthone-A.     

A chalcone and an isoflavone from Millettia pachycarpa seeds

Chemical examination of the seeds of Millettia pachycarpa has yielded a new prenylated isoflavone and a new prenylated chalcone in addition to the previously reported isoflavones 5-hydroxy-4′-methoxy-6″,6″-dimethylpyrano (2″,3″:7,8)isoflavone, 5,7,4′-trihydroxy-6,8-diprenylisoflavone, 5,7,3′,4′-tetrahydroxy-6,8-diprenyl-isoflavone and pomiferin.     

Structural confirmation of dihydrocinnamic acids from Adiscanthus fusciflorus by 13C NMR

In the wood of Adiscanthus fusciflorus six known alkaloids 4-methoxy-2-quinolone, 1-methyl-4-methoxy-2-quinolone, dictamine, skimmianine, γ-fagarine and N-methylflindersine and two new dihydrocinnamic acids 3-[2′,6′-dimethoxy-6″,6″-dimethylpyrano(2″,3″:4′, 3′)phenyl]-propionic acid and its methyl ester were identified. The structures of the dihydrocinnamic acid derivatives were confirmed by ¹³C NMR.     

New prenylated isoflavones and a prenylated dihydroflavonol from Millettia pachycarpa

Extraction of Millettia pachycarpa Benth. gave 5,7,4′-trihydroxy-6,8-diprenylisoflavone (1a), 5,7,4′-trihydroxy-6,3′-diprenylisoflavone (2a), 5,7,3′,4′-tetrahydroxy-6,8-diprenylisoflavone (3a) and (2R, 3R)-5,4′-dihydroxy-8-prenyl-6″,6″-dimethylpyrano[2″,3″: 7,6]-dihydroflavonol (4a) whose structures were established by chemical transformations and spectroscopic means. Pectolinarigenin and salvigenin were isolated from Buddleia macrostachya Benth.     

Phenolic compounds from Selaginella moellendorfii

Chemical investigation of the leaves and roots of Selaginella moellendorfii Hieron has resulted in the isolation and characterization of two new flavone glucosides, 7‐O‐(β‐glucopyranosyl(1→2)‐[β‐glucopyranosyl(1→6)]‐β‐glucopyranosyl)flavone‐3′,4′,5,7‐tetraol ( 1 ) and 7‐O‐(β‐glucopyranosyl(1→2)‐[β‐glucopyranosyl(1→6)]‐β‐glucopyranosyl)flavone‐4′,5,7‐triol ( 2 ), two new biflavonoids, 2,3‐dihydroflavone‐5,7,4′‐triol‐(3′→8″)‐flavone‐5″,6″,7″,4′′′‐tetraol ( 3 ) and 6‐methylflavone‐5,7,4′‐triol‐(3′→O→4′′′)‐6″‐methylflavone‐5″,7″‐diol ( 4 ), two new lignans, (7′E)‐3,5,3′,5′‐tetramethoxy‐8 : 4′‐oxyneolign‐7′‐ene‐4,9,9′‐triol ( 5 ) and 3,3′‐dimethoxylign‐8′‐ene‐4,4′,9‐triol ( 6 ), together with two known monolignans, four known lignans, and four known biflavonoids. Their structures were established by spectroscopic means and by comparison with literature values.     

Dibenzylbutyrolactone lignans from Piper cubeba

Six more lignans have been isolated from the hot petrol extract of Piper cubeba fruits. Of these, three compounds which have been isolated from a natural source for the first time were characterized as (2R,3R)-2-(5″-methoxy-3″,4″-methylenedi [(−)-cubebinone], (2R,3R)-2-(3″,4″-methylenedioxybenzyl)-3-(3′,4′,5′-trimethoxybenzyl)butyrolactone [(−)-isoyatein] and (2R,3R)-2-(3″,4″,5″-trimethoxybenzyl)-3-(3′,4′-dimethoxybenzyl)butyrolactone [(−)-di-O-methyl thujaplicatin methyl ether, i.e. (−)-thujaplicatin trimethyl ether]. The other three compounds were identified as (−)-yatein, (−)-cubebininolide and (2R,3R)-2-(3″,4″-methylenedioxybenzyl)-3-(3′,4′-dimethoxybenzyl) butyrolactone.     

3-Hydroxyisoflavanones from the stem bark of Dalbergia melanoxylon: Isolation,antimycobacterial evaluation and molecular docking studies

Two new 3-hydroxyisoflavanones, (S)-3,4′,5-trihydroxy-2′,7-dimethoxy-3′-prenylisoflavanone (trivial name kenusanone F 7-methyl ether) and (S)-3,5-dihydroxy-2′,7-dimethoxy-2″,2″-dimethylpyrano[5″,6″:3′,4′]isoflavanone (trivial name sophoronol-7-methyl ether) along with two known compounds (dalbergin and formononetin) were isolated from the stem bark of Dalbergia melanoxylon. The structures were elucidated using spectroscopic techniques. Kenusanone F 7-methyl ether showed activity against Mycobacterium tuberculosis, whereas both of the new compounds were inactive against the malaria parasite Plasmodium falciparum at 10 μg/ml. Docking studies showed that the new compounds kenusanone F 7-methyl ether and sophoronol-7-methyl ether have high affinity for the M. tuberculosis drug target INHA.     

Four isoflavanones from the stem bark of Platycelphium voënse

From the stem bark of Platycelphium voënse (Leguminosae) four new isoflavanones were isolated and characterized as (S)-5,7-dihydroxy-2′,4′-dimethoxy-3′-(3″-methylbut-2″-enyl)-isoflavanone (trivial name platyisoflavanone A), (±)-5,7,2′-trihydroxy-4′-methoxy-3′-(3″-methylbut-2″-enyl)-isoflavanone (platyisoflavanone B), 5,7-dihydroxy-4′-methoxy-2″-(2?-hydroxyisopropyl)-dihydrofurano-[4″,5″:3′,2′]-isoflavanone (platyisoflavanone C) and 5,7,2′,3″-tetrahydroxy-2″,2″-dimethyldihydropyrano-[5″,6″:3′,4′]-isoflavanone (platyisoflavanone D). In addition, the known isoflavanones, sophoraisoflavanone A and glyasperin F; the isoflavone, formononetin; two flavones, kumatakenin and isokaempferide; as well as two triterpenes, betulin and β-amyrin were identified. The structures were elucidated on the basis of spectroscopic evidence. Platyisoflavanone A showed antibacterial activity against Mycobacterium tuberculosis in the microplate alamar blue assay (MABA) with MIC = 23.7 μM, but also showed cytotoxicity (IC₅₀ = 21.1 μM) in the vero cell test.     

Thonningine-A and thonningine-B: two 3-phenylcoumarins from the seeds of Millettia thonningii

The seeds of Millettia thonningii have yielded four isoflavones and three 4-hydroxy-3-phenylcoumarins, of which two are novel. On the basis of spectral analyses the novel compounds have been identified as 4-hydroxy-5,8-dimethoxy-3-(3′,4′-methylenedioxy)phenyl-2″-isopropenylfurano (4″,5″:6,7)coumarin (thonningine-A) and 4-hydroxy-5,8-dimethoxy-3-(4′-methoxy)phenyl-2″-isopropenylfurano(4″, 5″: 6,7)coumarin (thonningine-B).     

Glabrachalcone,a chromenochalcone from Pongamia glabra seeds

Glabrachalcone, a new chromenochalcone has been isolated along with a known chromenochalcone from an ethanolic extract of the seed oil of Pongamia glabra. The structure of glabrachalcone has been established as 2′-hydroxy-2,4,5-trimethoxy-6″,6″-dimethylchromeno(4′,3′:2″,3″)chalcone on the basis of spectral evidence and was confirmed by synthesis.     

Les Flavonols d'Asclepias Syriaca

Eight flavonoids are present in the leaves of Asclepias syriaca. Three have been identified as quercetin, kaempferol, isorhamnetin; a structure of a fourth, 3,5,3′,4′-tetrahydroxy-7,8-(2″,2″-dimethyl-4″-methyl-5″,6″) pyranoflavone(I), has been established by study of its spectral properties (UV, IR, MS, NMR) and those of its acetate.     

Diarylpropanoids from Iryanthera polyneura

The trunk wood of Iryanthera polyneura Ducke (Myristicaceae) contains pinocembrin, 1-(2′,4′-dihydroxyphenyl)-3-(3″,4″-methylenedioxyphenyl)-propane, 1-(2′,4′-dihydroxy-3′-methylphenyl)-3-(2″-methoxy-4″, 5″-methylenedioxyphenyl)-propane and 4,2′,4′-trihydroxy-3-methoxydihydrochalcone.     

Diarylpropanes from the wood of Iryanthera grandis

Trunk wood of Iryanthera grandis contains 1(2′-hydroxy-4′,6′-dimethoxyphenyl)-3-(3″,4″-methylenedioxyphenyl)-propane and 1(2′-hydroxy-4′,6′-dimethoxyphenyl)-3-(3″-methoxy-4″-hydroxyphenyl)-propane, as well as three additional known diarylpropanes, a new flavan (±)-5,7-dimethoxy-4′-hydroxyflavan and the known (±)-7,4′-dihydroxy-3′-methoxyflavan.     

6′-substituted and 6′,6″-disubstituted derivatives of raffinose

The reaction of 6′-chloro-6′-deoxyraffinose deca-acetate with a variety of nucleophilic anions (Br^-,I^-,N^-₃) gave the corresponding 6′-substituted raffinoses. The 6′-azide was further converted into 6′-amino-6′-deoxyraffinose, isolated as its N-acetyl derivative, and silver fluoride-induced elimination of hydrogen iodide from the 6′-iodide gave the 6′-deoxy-5′-ene. Treatment of 6′-chloro-6′-deoxyraffinose and 6′,6″-dichloro-6′,6″-dideoxyraffinose with base afforded, respectively, 3′,6′-anhydro-and 3′,6′;3″,6″-dianhydro-raffinose in high yields. In addition, the dichloride was converted into 6′,6″-diazido-6′,6″-dideoxyraffinose.     

Coumarins from unripe fruits of Poncirus trifoliata

Petrol extracts of unripe fruits of Poncirus trifoliata L. were found to contain 7-geranyloxycoumarin, bergapten, imperatorin, 6-methoxy-7-geranyloxycoumarin and two new coumarins which were shown by chemical and spectroscopic means to be 7-(3′-methyl-2′,3′-epoxybutyloxy)-8-(3″-methyl-2″,3″-epoxybutyl)coumarin and 7-(3′-methyl-2′,3′-epoxybutyloxy)-8-(3″-methyl-2″-oxobutyl)coumarin respectively.     

Chemical modification of the nonreducing,terminal group of maltotriose

O-α-d-Galactopyranosyl-(1→4)-O-α-d-glucopyranosyl-(1→4)-d-glucopyranose (12) was prepared by inversion of configuration at C-4″ of 2,3,2′,3′,6′,2″,3″-hepta-O-acetyl-1,6-anhydro-4″,6″-di-O-methylsulfonyl-β-maltotriose (7), followed by O-deacylation, acetylation, acetolysis, and de-O-acetylation. The intermediate 7 was obtained by treatment of 1,6-anhydro-β-maltotriose (2) with benzal chloride in pyridine, followed by acetylation, removal of the benzylidene group, and methane-sulfonylation. Selective tritylation of 2 and subsequent acetylation afforded 2,3,2′,3′,6′,2″,3″,4″-octa-O-acetyl-1,6-anhydro-6″-O-trityl-β-maltotriose (6), which was O-detritylated and p-toluenesulfonylated to give 2,3,2′,3′,6′,2″,3″,4″-octa-O-acetyl-1,6-anhydro-6″-O-p-tolylsulfonyl-β-maltotriose (13). Nucleophilic displacement of 13 with thioacetate, iodide, bromide, chloride, and azide ions gave 6″-S-acetyl- (14), 6″-iodo- (15), 6″-bromo- (16), 6″-chloro- (19), and 6″-azido- (20) 1,6-anhydro-β-maltotriose octaacetates, respectively. 6″Deoxy- (18) and 6″-acetamido-6″-deoxy (21) derivatives of 1,6-anhydro-β-maltotriose decaacetates were also prepared from 15 and 16, and 20, respectively. Acetolysis of 14, 15, 16, 18, 19, and 21 afforded 1,2,3,6,2′,3′,6′,2″,3″,4″-deca-O-acetyl-6″-S-acetyl (22), -6″-iodo (23), -6″-bromo (24), -6″-deoxy (25), -6″-chloro (26), and -6″-acetamido-6′-deoxy (27) derivatives of α-maltotriose, respectively. O-Deacetylation of 24, 25, and 26 furnished 6″-bromo-(28), 6″-deoxy- (29), and 6″-chloro- (30) maltotrioses, respectively, which on acetylation gave the corresponding β-decaacetates.     

Quinoline alkaloids and cytotoxic lignans from Haplophyllum tuberculatum

Three quinoline alkaloids and two lignan lactones were isolated from Haplophyllum tuberculatum. Physicochemical and spectral evidence established the structures of two of the alkaloids as a new quinoldione, 3-(1′,1′-dimethylallyl)-3-(3″,3″-dimethylallyl)-1,2,3,4-tetrahydro-2,4-quinoldione and the known 4-(3′,3′-dimethylallyloxy)-3-(3″,3″-dimethylallyl)-2(1H)-quinolone. The former was shown to undergo facile [3,3]-sigmatotropic transformation into the latter. The remaining compounds were identified as the known Polygamain, kusunokinin and 1-methyl-2-n-nonyl-4(1H)-quinolone.     

Étude par R.M.N.-13C et -1h du (1→6)-β-d-glucane et des oligosaccharides linéaires et cycliques correspondants

The results of ¹H-n.m.r. and ¹³C-n.m.r. studies of linear and cyclic oligosaccharides in the series of gentiodextrins, both in their hydroxylated and acetylated form, were compared to those obtained for the corresponding natural or synthetic polysaccharide. The ¹³C-signals of each d-glucopyranose unit of acetylated oligosaccharides are more distinct than those of the parent hydroxylated compounds. In order to relate the change of the various signals with the degree of polymerization, gentiotriose undecaacetate, enriched in ¹³C at C-1″, was prepared, as well as gentiotetraose tetradecaacetate selectively labeled at C-1″ and C-1?. A (1→6)-β-d-glucan having a D.P. of ～10 was chemically prepared. During the course of the polycondensation, the 2,3,4,2′,3′,4′-hexa-O-acetyl-di-β-d-glucopyranosyl 1,6′:6,1′-di-anhydride, and the 2,3,4,2′,3′,4′,2″,3″,4″,2?,3?,4?-dodeca-O-acetyl-tetra-β-d-glucopyranosyl 1,6?:6,1?-tetraanhydride, respectively, were formed.