Obliquin derivatives and other constituents from Australian Helichrysum species

The investigation of three Australian Helichrysum species afforded in addition to known compounds three new obliquin derivatives, eight cinnamic acid derivatives, a tremetone derivative, a styrene derivative, two lignans, two caryophyllene derivatives and an azulene. The structures were elucidated by highfield ¹H NMR.     

Germacrene derivatives and other sesquiterpenes from Senecio species and Lordhowea insularis

From Senecio galpinii six new highly oxygenated germacrene derivatives were isolated, while S. coronatus afforded in addition to known cacalol derivatives two new ones. This species also contained a rare tricyclic sesquiterpene angelate, so far only isolated from one species. From the aerial parts of S. pleistocephalus an angelate derived from cadinene was isolated, while Lordhowea insularis (Benth.) B. Nord. afforded farnesyl angelate, which was reported previously. The structures were elucidicated mainly by high field ¹H NMR spectroscopy.     

Cuauthemone sesquiterpenoids from Blumea alata

The investigation of five Blumea species afforded, in addition to known compounds, several cuauthemone derivatives, most of them being 7,11-epoxides, some thymol derivatives, an eremophilane epoxide and a himachalane diol. From Pterocaulon virgatum a further himachalane derivative was isolated. The structures were elucidated by spectroscopic methods and in part by partial synthesis.     

Further glaucolides from south african Vernonia species

The investigation of three South African Vernonia species afforded minute amounts of five new glaucolides, two monoepoxides and three diepoxides. The structures were elucidated by ¹H NMR spectroscopy. The roots of Vernonia sutherlandii contain, in addition to vernonataloide, bergamotene and santalene, minute amounts of the corresponding acetoxy derivatives.     

Neue sesquiterpenlactone und nerolidol-derivate aus Ursinia-arten

The aerial parts of U. anethoides afforded, in addition to new nerolidol derivatives, a new germacranolide. The structure could only be elucidated by formation of the corresponding pyrazoline derivative and by comparison of the ¹H NMR data with those of similar pyrazolines. The aerial parts of U. alpina also contain a new nerolidol derivative and, in addition to the known 9β-hydroxycostunolide, a new eudesmanolide. The roots of all species contain furanosesquiterpenes, which are also present in related genera.     

Caryophyllane derivatives from Pulicaria scabra

The investigation of Pulicaria scabra afforded in addition to known compounds seven new caryophyllane derivatives, three of them etherified with a caryophyllane derivative and one esterified with a caryophyllane derived alcohol. The structures were elucidated by high field ¹H NMR spectroscopy. The chemistry of this species is similar to that of P. dysenterica but differs from that of the other genera of the subtribe Inulinae.     

Neue pyron-derivate aus Helichrysum-arten

The investigation of five further Helichrysum species afforded in addition to known compounds nine α-pyrone derivatives all also being phloroglucinol derivatives. Furthermore, a new toxol derivative has been isolated. The structures were elucidated by extensive NMR studies and by some chemical transformations. The chemotaxonomic situation is discussed briefly.     

Neue labdan-derivate aus Aristeguietia buddleaefolia

The aerial parts of Aristeguietia buddleaefolia afforded, in addition to known compounds, three new diterpenes, all being 12, 13-E-abienol derivatives. A further diterpene turned out to be jhanidiol-18-O-acetate, isolated earlier from an Ageratina species. Furthermore two derivatives of hydroxy dihydroconiferyl alcohol are present. The structures were elucidated by spectroscopic methods and by some chemical transformations.     

Kinetin inhibition of h-uracil and C-leucine incorporation by tobacco cells in suspension culture

The rate of ¹⁴C-leucine and ³H-uracil incorporation by tobacco cells (Nicotiana tabaccum var. Samsun N.N.) in suspension culture was simultaneously decreased by the addition of kinetin at concentrations above 2.5 × 10⁻⁵m. Ribosomal RNA was the first RNA species affected by kinetin. The purine derivatives, adenine and N⁶-methyl-aminopurine, which exhibit low cytokinin activity overcame the inhibitory effects of kinetin. However, purine derivatives without cytokinin activity, guanine, N^6,6-dimethyl-aminopurine, and 2-aminopurine, did not relieve kinetin inhibition.     

Eudesmane derivatives from Verbesina species

The investigation of seven Verbesina species afforded, in addition to known compounds, several new eudesmane and germacrane derivatives, all bearing a cinnamate or derivatives as residue. Furthermore, a new bisabolene aldehyde and two acetophenone derivatives were isolated. The structures were elucidated mainly by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.     

Sesquiterpene lactones and other constituents from Schistostephium species

From four Schistostephium species, in addition to known compounds, 43 new ones were isolated, three isocomene, two bisabolene, two eudesmane, two allo-himachalene and two nerolidol derivatives, two sesquiterpenes with a new carbon skeleton derived from isocomene, nine eudesmanolides, 20 6,12- and 8,12-germacranolides respectively, and a prostaglandin-like acid. The structures were elucidated by spectroscopic methods, especially high field ¹H NMR and some chemical transformations. The stereochemistry of some 8,12-germacranolides was established by partial synthesis which required revision of the previous assignments of the configuration of inunolide, its 4,5- and 1,10-epoxide, vernudifloride, simsiolide, 6-hydroxy-1,10-epoxyinunolide and perhaps also of tanachin. The chemotaxonomic situation is discussed briefly.     

8-Oxo-α-selinen und neue scopoletin-derivate aus Conyza-arten

The investigation of three South African and a North American Conyza species afforded, in addition to known compounds, a new eudesmane ketone and five new scopoletin derivatives. The structures are elucidated by spectroscopic methods and by some chemical transformations. Two of the scopoletin enol ethers have very unusual structures. While most of the Conyza species investigated so far contain typical C₁₀-acetylenes, also present in related genera, there are some with different chemistry. The relationship of the genus to Aster and Erigeron, however, is clearly indicated.     

Neue sesquiterpene,triterpene, flavanone und andere aromatische verbindungen aus Flourensia heterolepis

The investigation of a further Flourensia species afforded in addition to already known compounds 12 new sesquiterpene acids isolated as their methyl esters, a new eudesmane diol, four lupane derivatives and two flavanones, two cinnamic acid derivatives, also isolated as methyl esters and a ketone. The structures are elucidated mainly by spectroscopic methods and by some chemical transformations. Several of the compounds isolated are more or less similar to those isolated from other Flourensia species; the considerable amounts of eudesmanes, however, are unusual. The overall picture of the genus is still relatively uniform. Close relationships to Helianthella are obvious, while to Helianthus, placed in the same subtribe, no clear relations are visible.     

Neue ent-atisiren- und ent-kaurensäure-derivate aus Helianthus-arten

The investigation of four Helianthus species afforded, in addition to known compounds, four new atisirenic acid derivatives, a new ent-kaurenic acid derivative, three new labdane derivatives and an unknown C₁₅-acetylenic compound. The structures of the diterpenes were elucidated by intensive NMR studies and some chemical transformations. An unusual fragmentation in the mass spectra of the atisirenes is discussed briefly.     

β-Isocomen,ein neues sesquiterpen aus Berkheya-arten

The investigation of several Berkheya species afforded in addition to already known compounds three unusual sesquiterpene hydrocarbons. Together with modhephene and isocomene, a new one is present, its structure being elucidated by spectroscopic methods and by some chemical transformations. All 18 species investigated contain the typical thiophene derivatives, isolated earlier; the patterns of compounds present divide the species into two groups.     

Neue phloroglucin-derivate aus Leontonyx-arten sowie weitere verbindungen aus vertretern der tribus inuleae

The investigation of several South African species of the tribe Inuleae afforded in addition to known compounds 16 new constituents. From Leontonyx a group of 9 new phloroglucinol derivatives, from Stoebe species two new p-hydroxyacetophenone, two thymol and two coumaric acid derivatives and from Relhania a new euparine-derivative were isolated. The structures are elucidated mainly by spectroscopic methods. The chemotaxonomic aspects are discussed briefly. The phloroglucinol derivatives, which in part are derived from geraniol, seem to be especially characteristic.     

Sesquiterpene and diterpene derivatives from Solidago species

The investigation of four Solidago species afforded, in addition to known compounds, four new caryophyllene derivatives, two eudesmanes, two abietanes, a clerodane, two labdanes, three kauranes and an anol angelate. The structures were elucidated by spectroscopic methods and by some chemical transformations. While the diterpenes isolated are widespread in the genus Solidago, the sesquiterpenes have not been obtained before from any species. The overall picture of the large genus, however, is relatively uniform.     

Neue sesquiterpene und acetylenverbindungen aus Cineraria-arten

The investigation of several members of the South African genus Cineraria affords, in addition to known compounds, several new eremophilene derivatives together with modified types all derived from a carbon skeleton where the 5-methyl has migrated to C-6. Some of these compounds are transformed to unusual enol lactones. Furthermore some derivatives of himachalene are present. All species also contain C₁₁-acetylenes, most of which are new. Senecio deltoideus also contains some of these compounds. The chemotaxonomic situation is discussed.     

Studies on erythrocruorin. VI. Ferric derivatives of earthworm erythrocruorin.

Oxidation of the ferrous derivatives of earthworm erythrocruorin with potassium ferricyanide at pH 7 gives rise to met-erythrocruorin with the characteristic spectral properties of aquo-met-haem proteins. Met-erythrocruorin maintains the same overall conformation (s_20,w, α-helicalcontent) as the native protein. However, its stability is limited to a very narrow pH range around neutrality; outside this range it is converted rapidly and irreversibly to another spectral species (hemichrome). The erythrocruorin-hemichrome undergoes a reversible pH-dependent transition (pK = 9.2) which is accompanied by a decrease in α-helical structure.On reduction the met-form and the hemichrome yield the deoxy and oxy derivatives. Hemichrome formation is accompanied by a drastic change of the quaternary structure; thus the sedimentation coefficient drops from 60 S to ~4 S and the α-helical content decreases. By addition of ligands (CN^?, N₃^?) or by reduction to the ferrous form, the hemichrome reassociates into 10 S subunits.     

Labdane derivatives from hemizonia species

The investigation of three Hemizonia species afforded in addition to known compounds seven new labdane derivatives, all derived from labd-13-en-15-ol. The absolute configuration of these diterpenes was determined by degradation of the triol by periodate cleavage, which afforded a known norditerpene ketone. From H. fitchii two new chromene esters and the cis-isomer of a known coumarate were isolated. H. congesta afforded in addition to labdane derivatives a hydroxycubebol.