Ludwig Kraut

Phenanthrenes and bibenzyls from a Plagiochila species

Abstract Nineteen phenolic compounds consisting of 9,10-dihydrophenanthrenes, a phenanthrene, bibenzyls and bis bibenzyls were isolated from a neotropical Plagiochila species. The structures of seven new 9,10-dihydrophenanthrenes, a new phenanthrene, a new bibenzyl and three novel bisbibenzyls of the isoplagiochin-type, including a monochlorinated derivative, together with seven known products, were established by spectroscopic techniques.

Sesquiterpene lactones and 3-benzylphthalides from Frullania muscicola☆

Abstract Among the sesquiterpenes from Frullania muscicola two new cis -annelated 12,6-eudesmanolides, a new 12,6-eremophilanolide and two new dimeric eudesmane sesquiterpene lactones were identified in addition to three known eudesmanolides and the sesquiterpene alcohol drimenol. Two of the three 3-benzylphthalides isolated from F. muscicola are also new natural products.

Carboxylated α-pyrone derivatives and flavonoids from the liverwort Dumortiera hirsuta

Abstract Three new carboxylated α-pyrone derivatives, dumortins A-C, and a new flavone glycoside have been isolated from the liverwort, Dumortiera hirsuta , together with the known flavonoids, luteolin, luteolin -5-O-β- d -glucuronide and luteolin -7-O-β- d -glucuronide . The structures of the new α-pyrones were confirmed spectroscopically as 4-(3′,4′-dihydroxy- E -styryl)-6-carboxy-α-pyrone,4-[2-(3′,4′-dihydroxyphenyl)-ethyl]-6-carboxy-α-pyrone and 3-[1-hydroxy-2-(3′,4′-dihydroxyphenyl)-ethyl]-6-carboxy-α-pyrone. The new flavonoid was elucidated as luteolin -5-O-β- d -glucuronide-6″-methyl ester. The structures of dumortins A and B were confirmed by independent chemical synthesis.

Prenylated bibenzyl derivatives from Lethocolea glossophylla and Radula voluta

Abstract Phytochemical investigation of the liverwort, Lethocolea glossophylla , yielded five new prenylated bibenzyl derivatives. Their structures were elucidated by spectral analysis as 2-carboxy-3-methoxy-4,6-di-(3-methyl-2-butenyl)-5,4′-dihydroxy- bibenzyl, 2,4-di-(3-methyl-2-butenyl)-3,5,4′-trihydroxy-bibenzyl, 2,2-dimethyl-5-hydroxy-6-(3-methyl-2-butenyl)-7-[2-(4′- hydroxyphenyl)-ethyl]-chromene, 2,2-dimethyl-5-hydroxy-7-[2-(4′-hydroxyphenyl)-ethyl]-8-(3-methyl-2-butenyl)-chromene and as a bisprenylated bisbibenzyl (glossophyllin) with a chromene and a chromane moiety. From Radula voluta , the previously known bibenzyls, 2-(3-methyl-2-butenyl)-3,5-dihydroxy-bibenzyl and 2-geranyl-3,5-dihydroxy-bibenzyl, were isolated and identified.

Acylated flavone and glycerol glucosides from two Frullania species

Abstract Eight new compounds were identified from Frullania muscicola; five flavone O-glycosides with 3-hydroxy-3-methyl glutaric acid and three glycerol glucosides acylated with caffeic acid, together with three known flavone O-glucosides. From F. polysticta, two known flavone C-glycosides and three new acylated flavone O-glycosides with 3-hydroxy-3-methyl glutaric acid as acyl moiety were characterized.

External accumulation of biflavonoids on gymnosperm leaves

Abstract Biflavonoids are well known to occur in many Gymnospermae. Here we report on their occurrence in epicuticular material of a number of species. Several compounds are characterized by detailed NMR studies and FAB-MS. They are identified as amentoflavone, bilobe-tin, podocarpus-flavone A, sciadopitysin, dihydrosciadopitysin and cupressuflavone.

Isolation and synthesis of rufulamide, an oligopeptide analogue from Metzgeria rufula☆

Abstract An oligopeptide analogue consisting of l -glutamic, malonic and 2 molecules of anthranilic acid combined via amide bonds was isolated from the liverwort Metzgeria rufula . Its structure was elucidated by spectroscopic methods and by chemical synthesis.

Flavonoid aglycones and flavonol glycosides in the lipophilic leaf exudate of Nothofagus antarctica

The thin resinous layer on young leaflets of Nothofagus antarctica has been found to contain not only some flavonoid aglycones, but also several glycosides of quercetin and myricetin.

The First Biflavone Found in Liverworts and Other Phenolics and Terpenoids from Chandonanthus hirtellus ssp. giganteus and Plagiochila asplenioides

A biflavone was isolated from a liverwort (Chandonanthus hirtellus ssp. giganteus) for the first time. Its structure was determined as dicranolomin. Moreover luteolin and the new compound vanillic acid-4-O-neohesperidoside were identified from this Chandonanthus species. From Plagiochila asplenioides we isolated the new sesquiterpenoid (-)-gymnomitr-8(12)-en-9β-ol with chair conformation of the cyclohexane ring together with plagiochiline P and the diterpenoid anadensin, both new to this liverwort

Flavonoids from Some Frullania Species (Hepaticae)

Abstract From Frullania teneriffae 5 known flavone aglycones and 6 flavone glycosides were isolated, among them the new 6-OH-luteolin-6-O-β-ᴅ-glucoside-7-O-β-ᴅ-glucoside-6′′′-(3-hydroxy-3-methylglutaroylester). F. cesatiana contains 2 flavone-di-C-glucosides and the new 6-OH-luteolin-7-O-β-ᴅ-glucoside-6′′-(3-hydroxy-3-methylglutaroylester)-3′-O-glucuronide. The phenolic pattern of F. eboracensis was compared to that of F. muscicola. The known 6-OH-luteolin-7-O-β-ᴅ-glucoside-6′′-(3-hydroxy-3-methylglutaroylester) was identified from F. gibbosa and F. arecae.