Bitter phenylpropanoid glycosides from Lilium speciosum var. rubrum

Seven bitter ferulic acid esters of sucrose have been isolated from Lilium speciosum var. rubrum. These compounds were identified as 3,6′-diferuloylsucrose, 4-acetyl-3,6′-diferuloylsucrose, 6-acetyl-3,6′-diferuloylsucrose, 4′-acetyl-3,6′-diferuloylsucrose, 4,6-diacetyl-3,6′-diferuloylsucrose, 6,3′-diacetyl-3,6′-diferuloylsucrose and 4,6,3′-triacetyl-3,6′-diferuloylsucrose on the basis of spectroscopic studies.     

Euclein: A new binaphthaquinone from Euclea pseudebenus

7-MethyljugIone, 8,8′-dihydroxy-4,4′-dimethoxy-6,6′-dimethyl-2,2′-binaphthyl-1,1′-quinone, 2-methylnaphthazarin, mamegakinone and euclein have been isolated from Euclea pseudebenus. Euclein is the 3,6′-dimer of 7-methyljuglone.     

Eucleolatin: A dimeric methylnaphthazarin from Euclea lanceolata

8,8′-Dihydroxy-4,4′-dimethoxy-6,6′-dimethyl-2,2′-binaphthyl-1,1′-quinone, 7-methyljuglone, 8′-hydroxydiospyrin, and eucleolatin have been isolated from the root bark of E. lanceolata. Eucleolatin is the 3,6′or 3,7′- dimer of 2-methylnaphthazarin.     

Some reactions of 1,6-di-O-p-tolylsulphonyl-D-mannitol and its derivatives

Nucleophilic displacement of 4,4′-di-O-mesyl-α,α-trehalose hexabenzoate occurred very readily to give, by a double inversion, the thermodynamically more stable 4,4′-di-iodide in 93% yield with overall retention of configuration. Reductive dehalogenation of the 4,4′-di-iodide with hydrazine hydrate—Raney nickel followed by debenzoylation afforded 4,4′-dideoxytrehalose in high, overall yield. Alternatively, treatment of trehalose with sulphuryl chloride afforded 4,6-dichloro-4,6-dideoxy-α-D-galactopyranosyl 4,6-dichloro-4,6-dideoxy-α-D-galactopyranoside, which underwent selective dehalogenation at the secondary positions on treatment with hydrazine hydrate—Raney nickel. Subsequent nucleophilic displacement of the primary chlorine substituents with sodium acetate in N,N-dimethylformamide gave, after deacetylation, 4,4′-dideoxy-α,α-trehalose. Repeated treatment of the 4,4′,6,6′-tetrachlorotrehalose derivative with hydrazine hydrate—Raney nickel gave 4,4′,6,6′-tetradeoxy-α,α-trehalose. An alternative route to the tetradeoxy derivative was via thiocyanate displacement of the 4,4′,6,6′-tetramethanesulphonate. The tetrathiocyanate, formed in poor yield, was desulphurized with Raney nickel to give the tetradeoxytrehalose. Treatment of 4,6-dichloro-4,6-dideoxy-α-D-galactopyranosyl 4,6-dichloro-4,6-dideoxy-α-D-galactopyranoside with methanolic sodium methoxide yielded, initially, 3,6-anhydro-4-chloro-4-deoxy-α-D-galactopyranosyl 4,6- dichloro-4,6-dideoxy-α-D-galactopyranoside which was transformed into the 3,6:3′,6′-dianhydro derivative. Reductive dechlorination of the dianhydride proceeded smoothly to give the 3,6:3′,6′-dianhydride of 4,4′-dideoxytrehalose.     

Coumarins from Amyris balsamifera

Two new coumarins have been isolated from the aerial parts of Amyris balsamifera. On the basis of spectral and chemical data, these have been identified as (R)-(+)-6-(2′-hydroxy-3′-methyl-3′-butenyl)-7-methoxycoumarin and balsamiferone, 7-hydroxy-3,6-bis (3′-methyl-2′-butenyl)-coumarin.     

Isolation and structural elucidation of cucurbitaxanthin a and b from pumpkin cucurbita maxima

Two new carotenoids, cucurbitaxanthin A [(3S,5R,6,R3′R)-3,6-epoxy-5,6-dihydro-β,β-carotene-5,3′-diol] and cucurbitaxanthin B [(3S,5R,6R,3′S,5′R,6′S)-3,6,5′,6′-diepoxy-5,6,5′,6′-tetrahydro-β-β-carotene-5,3′-diol] have been isolated from the pumpkin Cucurbita maxima.     

New water soluble flavone and xanthone glycosides from Hypericum canariense L.

The water soluble portion of the aerial parts of Hypericum canariense L. yielded after acetylation the 5,7,3′4′-tetra- and 7,3′4′-triacetates of a new flavonoid 5,7,3′,4′-tetrahydroxy-3-O-β-d-(methyl 2,3,4-triacetoxypyranuronyl)-quercetin, the 3′-acetate of a new flavonoid 3′-hydroxy-5,7,4′-trimethoxy-3-O-β-d-(methyl 2,3,4-triacetoxypyranuronyl)-quercetin, the 3′-acetate and the 3′5′-diacetate of the new flavonoid 5,3′dihydroxy-7,4′-dimethoxy-3-β-d-(methyl 2,3,4-triacetoxypyranuronyl)-quercetin, the xanthone derivative mangiferin 2′,3′,4′,6′-tetraacetate and the latter's new 1,3,6,7′-tetramethoxy, 1,3,6-trimethoxy-4-acetoxy and 1,7-diacetoxy-3,6-dimethoxy analogs.     

Helianthol a,a sesquiterpene alcohol from Helianthus tuberosus

A new sesquiterpene alcohol, helianthol A, was isolated from the aerial parts of Helianthus tuberosus. The structure of this compound has been established as (+)-2-methyl-6-[4-methyl-3′-cyclohexen-1′-(R)-yl]-3,6-heptadien-2-ol by chemical and spectroscopic methods.     

Flavonoids from Artemisia ludoviciana var. ludoviciana

Nineteen flavonoids were isolated from Artemisia ludoviciana var. ludoviciana, including a new 2′- hydroxy- 6-methoxyflavone, 5,7,2′,4′-tetrahydroxy-6,5′-dimethoxyflavone. The known compounds include quercetagetin 3,6,3′,4′-tetramethyl ether, eupatilin, 5,7-dihydroxy-3,6,8,4′-tetramethoxyflavone, luteolin 3′,4′-dimethyl ether, jaceosidin, 5,7,4′-trihydroxy-3,6-dimethoxyflavone, tricin, hispidulin, chrysoeriol, kaempferol 3-methyl ether, apigenin, axillarin, eupafolin, selagin and luteolin together with three flavones which were previously isolated for the first time from Artemisia frigida: 5,7,4′-trihydroxy-6, 3′,5′-trimethoxyflavone, 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone and 5,7,3′,4′-tetrahydroxy-6,5′- dimethoxyflavone.     

Non-polar flavonoids of perityle vaseyi (asteraceae)

Ten flavonoids have been isolated from a dichloromethane leafwash of Perityle vaseyi. Trace amounts of 7,4′-dimethylnaringenin were observed along with nine O-methylated flavonols. Two kaempferol, four 6-hydroxykaempferol and three 6-hydroxyquercetin O-methylated derivatives were identified. 5,7,4-Trihydroxy-3,6-dimethoxyflavone and 5,4′-dihydroxy-3,6,7-trimethoxyflavone were the major components.     

Flavonols of parthenium section bolophytum

Casticin (V), 5,7,3′,4′-tetrahydroxy-3,6-dimethoxyflavone-7-glycoside (I), 5,7,4′-trihydroxy-6-methoxyflavone-7-glycoside (hispidulin 7-glycoside) (IV), 5,4′-dihydroxy-3,6,7,3′-tetramethoxyflavone (VII) and 5,7-dihydroxy-3,6,3′,4′-tetramethoxyflavone (XII) were found, with the coumarin scopoletin (IX), in various combinations in the three species of Parthenium section Bolophytum. No infraspecific variation was detected in these calciphilic relicts.     

Algal carotenoids with novel end groups

The structures of three previously unidentified carotenoids from Eutreptiella gymnastica are reported. These include siphonein with defined n-2-trans-2-dodecenoic esterifying acid and assigned 3R(?), 3′R,6′R chirality, (3R)-3′,4′-anhydrodiatoxanthin and eutreptiellanone (3,6-epoxy-3′,4′,7′,8′-tetradehydro-5,6-dihydro-β,β-caroten-4-one) with probable 3S,5R,6S chirality.     

6-Hydroxy- and 6-methoxyflavonoids from Neurolaena lobata and N. macrocephala

Twelve flavonoids including one new sulfate were isolated from Neurolaena lobata, and six known flavonoids were obtained from N. macrocephala. The new compound isolated from N. lobata is 6-hydroxykaempferol 3-methyl ether 7-sulfate, and the known flavonoids are 6-hydroxykaempferol 3,7-di-dimethyl ether, 6-hydroxykaempferol, 3-methyl ether 7-glucoside, 6-hydroxykaempferol 7-glucoside, quercetagetin and its 7-glucoside, quercetagetin 3,6- and 3,7-dimethyl ethers, quercetagetin 3-methyl ether 7-glucoside and 7-sulfate, 6-hydroxyluteolin 3′-methyl ether and 6-hydroxyluteolin 7-glucoside. The known flavonoids identified from N. macrocephala are quercetagetin 3,6- and 3, 7-dimethyl ethers, quercetagetin 6-methyl ether 7-glucoside, quercetagetin 3,6-dimethyl ether 7-glucoside, quercetagetin 7-glucoside and quercetagetin 3-methyl ether 7-sulfate.     

Naringenin coumaroylglucosides from Mabea caudata

The fruits of Mabea caudata contain, besides 5,7,4′-trihydroxyflavanone (naringenin), naringenin 7-O-β-(3,6-di-p-coumaroylglucoside) and naringenin 7-O-β-(3-p-coumaroylglucoside).     

Flavonol glycosides in leaves of Spinacia oleracea

Besides spinatoside (3,6-dimethoxy-5,7,3′,4′-tetrahydroxyflavone 4′-O-β-D-glucopyranuronide), three new flavonol glycosides have now been isolated from the polar fractions of the methanolic extract of Spinacia oleracea. They have been identified as patuletin 3-O-β-D-glucopyranosyl-(1 → 6)-[β-D-apiofuranosyl-(1 → 2)]-β-D-glucopyranoside, patuletin 3-O-β-gentiobioside and spinacetin 3-O-β-gentiobioside, respectively.     

Complexes of 2,2′-bipyrimidine and 3,6-di(2-pyridyl)tetrazine

The synthesis, characterisation and cyclic voltam-metric behaviour of new complexes of 2,2′-bipyrimidine (bpm) with the metals rhodium, osmium, platinum, palladium and mercury and 3,6-di(2-pyridyl)- 1,2,4,6-sym-tetrezine (dpt) with nickel and ruthenium are described.     

The flavonoids of Cassia renigera stem bark

A new flavanone glycoside 5-hydroxy-6,7,3′,4′,5′-pentamethoxyflavanone 5-O-α-l-rhamnopyranoside along with quercetagetin 3,6-dimethyl ether and an anthraquinone glycoside have been isolated from the stem bark of Cassia renigera. The two flavonoids were characterized by spectral and chemical studies.     

The alkenic unreactivity of mono- and bi-cyclic derivatives of 3,6-dihydro-2-(methylthio)-2H-thiopyran S,S,S′,S′-tetraoxide

The inertness of the alkenic bond towards electrophilic additions in 3-exocyano-3-(methylthio)-2-thiabicyclo[2.2.1]hept-5-ene S,S,S′,S′-tetraoxide (5), 3,6-dihydro-2-(methylthio)-2H-thiopyran-2-carbonitrile S,S,S′,S′-tetraoxide (3), and 2-(acetamidomethyl)-3,6-dihydro-2-(methylthio)-2H-thiopyran S,S,S′,S′-tetraoxide (4) is attributed to the “supra-annular effect” and field effects. Conformational analysis of a pentadeuterated derivative of 4 (10) is reported. On the basis of the 220-MHz ¹H n.m.r.-spectral data of 10, the compound was concluded to adopt the ⁰H₂ conformation in chloroform solution.     

Methylated flavonols from Wyethia bolanderi and Balsamorhiza macrophylla

A leaf wash of Wyethia bolanderi afforded eight known methylated flavonols: santin, ermanin, jaceidin, 3,6-dimethoxyapigenin, kaempferide, isokaempferide, axillarin and quercetin 3-methyl ether. A leaf wash of Balsamorhiza macrophylla afforded six known methylated flavonols: centaureidin, quercetin 3,4′-dimethyl ether, axillarin, spinacetin, tamarexetin and quercetin 3-methyl ether. The chemotaxonomy of the two genera is discussed briefly.     

Chemistry of toxic range plants. Highly oxygenated flavonol methyl ethers from Gutierrezia microcephala

The perennial American desert shrub, Gutierrezia microcephala, contains 20 flavonol methyl ethers displaying nine different oxygenation patterns. These include 11 new flavonols: 5,7-dihydroxy-3,6,8,3′,4′,5′-hexamethoxyflavone, 5,7,4′-trihydroxy-3,6,8,3′,5′-pentamethoxyflavone, 5,7,3′-trihydroxy-3,6,8,4′,5′-pentamethoxyflavone, 5,7,2′,4′-tetrahydroxy-3,6,8,5′-tetramethoxyflavone, 5,7,3′,4′-tetrahydroxy-3,6,8-trimethoxyflavone, 5,7,8,3′,4′-pentahydroxy-3,6-dimethoxyflavone, 3,5,7,3′,4′-pentahydroxy-6,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,6,8-trimethoxyflavone, 5,7,8,4′-tetrahydroxy-3,3′-dimethoxyflavone, 5,7,8,3′,4′-pentahydroxy-3-methoxyflavone and 5,7,8,4′-tetrahydroxy-3-methoxyflavone. In addition, the following known flavonols were isolated: 5,7-dihydroxy-3,8,3′,4′,5′-pentamethoxyflavone, 5,7,4′-trihydroxy-3,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,8,3′-trimethoxyflavone, 5,7,3′,4′-tetrahydroxy-3,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,6,3′-trimethoxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone, 5,4′-dihydroxy-3,6,7,8,3′-pentamethoxyflavone, 5,7,4′-trihydroxy-3,6,8,3′-tetramethoxyflavone and 3,5,7,4′-tetrahydroxy-6,8,3′-trimethoxyflavone.