Violastyrene and isoviolastyrene,cinnamylphenols from Dalbergia miscolobium

The heartwood of Dalbergia miscolobium contains, in addition to the neoflavonoids (S)-4-methoxydal-bergione, (S)-4′-hydroxy-4-methoxydalbergione and dalbergin, the isoflavone di-O-methyldaidzein, the benzophenone cearoin and two cinnamylphenols, violastyrene [E-1-(3-hydroxy-2,4-dimethoxybenzyl)-2-phenylethylene] and isoviolastyrene [E-1-(4-hydroxy-2,3-dimethyoxybenzyl)-2-phenylethylene]. The structural determination of the cinnamylphenols relied on spectra, degradations and synthesis.     

Mucronustyrene,mucronulastyrene and villostyrene,cinnamylphenols from Machaerium mucronulatum and M. villosum

The wood of Machaerium mucronulatum contains, in addition to chalcones and isoflavonoids, the cinnamylphenols mucronustyrene[E-1-(4-hydroxy-2,3-dimethoxybenzyl)-2-phenylethylene], mucronulastyrene[Z-1-(4-hydroxy-2,3-dimethoxybenzyl)-2-phenylethylene] and villostyrene [Z-I-(4-hydroxy-2,3-dimethoxybenzyl)-2-(2-methoxyphenyl)-ethylene. Isoflavonoids and villostyrene were also found in the heartwood of M. villosum. The structural determination of the cinnamylphenols relied on spectra, degradations and syntheses.     

Pterocarpans from Dalbergia spruceana

The wood of Dalbergia spruceana contains, besides O-acetyloleanolic acid, elemicin and 3,4,5-trimethoxy-cinnamaldehyde; the neoflavonoids (S)-4-methoxydalbergione and dalbergin; the isoflavones biochanin-A, formononetin, pseudobaptigenin and caviunin; and the pterocarpans (±)-medicarpin, (±)-maackiain, as well as the 3,4-dihydroxy-, 3-hydroxy-4-methoxy- and 4-hydroxy-3-methoxy-derivatives of (6aR,11aR)-8,9-methylenedioxypterocarpan. The constitutions of the three last named compounds were deduced by spectra and confirmed by synthesis of (±)-4-hydroxy-3-methoxy-8,9-methylenedioxypterocarpan.     

Neoflavonoids and the cinnamylphenol kuhlmannistyrene from Machaerium kuhlmannii and M. Nictitans

The trunkwood of Machaerium kuhlmannii contains methyl palmitate, 3-O-acetyloleanolic acid and sitosterol; the benzene derivatives 2,3-dimethoxyphenol, 2,6-dimethoxyphenol, 2-hydroxy-3-methoxyphenol, 2,3-dimethoxybenzaldehyde and methyl 3-(2-hydroxy-4-methoxyphenyl)-propionate; the isoflavonoids formononetin and (6aS,11aS)-medicarpin; the neoflavonoids (R)-3,4-dimethoxydalbergione, (R)-3,4-dimethoxydalbergiquinol, kuhlmanniquinol [(R)-3-(4-hydroxyphenyl)-3-(5-hydroxy-2,3,4-trimethoxyphenyl)-propene], dalbergin, kuhlmannin (6-hydroxy-7,8-dimethoxy-4-phenylcoumarin) and kuhlmannene (6-hydroxy-7,8-dimethoxy-4-phenylchrom-3-ene), as well as the cinnamylphenol kuhlmannistyrene [Z-1-(5-hydroxy-2,3,4-trimethoxybenzyl)-2-(2-hydroxyphenyl)-ethylene]. Five of these compounds, in addition to (R)-4′-hydroxy-3,4-dimethoxydalbergione, were also isolated from a trunkwood extract of M. nictitans. Structural assignments were confirmed by chemical interconversion and by the synthesis of (±)-kuhlmanniquinol.     

Isoflavonoids from Myroxylon peruiferum

Considerable differences in flavonoid composition of the trunkwood characterize different specimens of Myroxylon balsamum (L.) Harms. Only calycosin among the 11 flavonoids found in M. peruiferum L.f., presently considered synonymous with M. balsamum, had previously been located in the latter species. Two of these flavonoids, 2′-hydroxy-7,3′,4′-trimethoxyisoflavanone and 2′-hydroxy-7,3′,4′-trimethoxyisoflavone are new natural products.     

Benzofuranoid neolignans from Aniba simulans

Forteen neolignans, isolated from the benzene extract of Aniba simulans (Lauraceae) trunk wood, included the hitherto undescribed (2S, 3S, 5R)-5-allyl-5,7-dimethoxy-2-(3′,4′,5′-trimethoxyphenyl)-3-methyl-2,3,5,6-tetra-hydro-6-oxobenzofuran, (2R,3S,5R) -5-allyl-5-methoxy-2-(3′-methoxy-4′,5′-methylenedioxyphenyl)-3-methy1-2,3,5, 6-tetrahydro-6-oxobenzofuran, (2S,3S)-6-O-allyl -5-methoxy-2-(3′-methoxy-4′-5′-methylenedioxyphenyl)-3-methyl-2,3-dihydrobenzofuran, (2R,3S)-6-O-allyl-5-methoxy-2- (3′-methoxy-4′,5′-methylenedioxyphenyl)-3-methyl-2,3-dihydrobenzofuran and 7-allyl-6-hydroxy-5-methoxy-2-(3′-methoxy-4,5′ -methylenedioxyphenyl)-3-methylbenzofuran.     

Variabilin,a 6a-hydroxypterocarpan from Dalbergia variabilis

Bark and wood of the creeper Dalbergia variabilis contain the previously described friedelin, O-acetyl-oleanolic acid, formononetin, 8-O-methylretusin, (+)-vestitol, (±)-mucronulatol, (+)- and (±)-medicarpin, besides (+)-variabilin [(6aR,11aR)-6a-hydroxy-3,9-dimethoxypterocarpan]. This structure was confirmed by the conversion of (+)-variabilin into di-O-methylcoumestrol.     

Pisum sativum stress metabolites: Two cinnamylphenols and a 2′-methoxychalcone

An HPLC study of copper(II) chloride treated Pisum sativum has shown that the cinnamylphenols obtustyrene [E-1-(4-hydroxy-2-methoxybenzyl)-2-phenylethylene] and xenognosin [E-1-(4-hydroxy-2-metboxy-benzyl)-2- (4-hydroxyphenyl)ethylene] as well as the chalcone 4,4′-dihydroxy-2′-methoxychalcone accumulate as de novo metabolites in the stressed plant. This chalcone has not previously been identified from a plant source. The biosynthetic and stress response relationships of these compounds are discussed.     

Neolignans from an Aniba species

A benzene extract of the trunk wood of an Aniba species contained 3a-allyl-2-aryl-5-methoxy-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofurans which may be responsible, through sequential Cope, retro-Claisen and Claisen rearrangements respectively for the formation of the co-occurring 5-allyl-2-aryl-5-methoxy-3-methyl-2,3,5,6-tetrahydro-6-oxobenzofurans; the 6-O-allyl-2-aryl-5-methoxy-3-methyl-2,3-dihydrobenzofurans and the 7-allyl-2-aryl-6-hydroxy-5-methoxy-3-methyl-2,3-dihydrobenzofurans. The examination of the stereochemistry of these products led to the formulation of burchellin, previously isolated from Aniba burchellii Kostermans, as (2S,3S,3aR)-3a-allyl-5-methoxy-2-piperonyl-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran. The structure 1-allyl-4,8-dihydroxy-7-(3-methoxy-4,5-methylenedioxyphenyl)-6-methyl-3-oxobicyclo[3,2,1]octane is tentatively proposed for an additional neolignan.     

Petrostyrene,a cinnamylphenol from Machaerium acutifolium

The trunkwood of Machaeriun acutifolium contains, in addition to pinosylvin monomethyl ether and (+)-medicarpin, a cinnamylphenol, petrostyrene [E-1-(5-hydroxy-2,3,4-trimethoxybenzyl)-2-(2-hydroxyphenyl)-ethylene], whose characterisation relied on spectra and synthesis of the dimethyl and diethyl ethers.     

Vestitol and vesticarpan,isoflavonoids from Machaerium vestitum

The wood of Machaerium vestitum contains the previously described O-acetyloleanolic aldehyde, formononetin, (+)-medicarpin, and (?)-mucronulatol, besides (+)-vestitol [(3S)-7,2′-dihydroxy-4-methoxyisoflavan] and (+)-vesticarpan [(6aS,11aS)-3,10-dihydroxy-9-methoxypterocarpan]. The constitutions of vestitol and vesticarpan were deduced by spectra and confirmed by syntheses.     

Duartin,an isoflavan from Machaerium opacum

The heartwood of Machaerium opacum contains 2,3-dimethoxyphenol, the stilbenes pinosylvin monomethyl ether and dimethyl ether, and the isoflavans (?)-duartin and (?)-mucronulatol. The structure of (3S)-7,3′-dihydroxy-8,2′,4′-trimethoxyisoflavan was deduced for duartin and the constitution confirmed by synthesis of the racemate.     

Mucronulatol,mucroquinone and mucronucarpan,isoflavonoids from Machaerium mucronulatum and M. villosum

Additionally to the cinnamylphenols described in a previous paper, wood samples of Machaerium mucronulatum and M. villosum contain isoflavones, besides (?)-duartin, (?)- and (±)-mucronulatol [(3S)- and rac-7,3′-dihydroxy-2′,4′-dimethoxyisoflavan], (?)-mucroquinone [(3S)-2-methoxy-5-(7-hydroxy-8-methoxychroman-3-yl)-1,4-benzoquinone] and (+)-mucronucarpan [(6aS,11aS)-2,10-dihydroxy-3,9-dimethoxypterocarpan]. The constitutions of mucronulatol, mucroquinone and mucronucarpan were deduced by spectra and degradations, and confirmed by syntheses.     

A new dihydrobenzofuran from Liatris provincialis

A chloroform extract of Liatris provincialis Godfrey gave as a minor component a new dihydrobenzofuran, whose structure was established as I.     

Two new aryl naphthalide lignans from Polygala chinensis

Chinensinaphthol and chinensinaphihol methyl ether, two new 1-ary]-2,3-naphthalide lignans, have been isolated from the title plant. Structures (2) and (3) have been established for them by chemical transformations and spectral evidence. Significant quantitative variations in the content of the cyclic and the acyclic lactonic lignans (1–3, 5–7) of P. chinensis have been observed in plant material, collected from the same locality and examined in 3 consecutive years.     

Arylbenzofurans from Dalbergia parviflora

The isolation of two polysubstituted arylbenzofurans from the heartwood of Dalbergia parviflora is described. Their structures were elucidated mainly by spectroscopic techniques (UV, IR, ¹H and ¹³C NMR). They were named parvifuran (5-hydroxy-6-methoxy-3-methyl-2-phenylbenzofuran) and isoparvifuran (5-hydroxy-6-methoxy-2-methyl-3-phenylbenzofuran) and are the first compounds of this class isolated from a Dalbergia species.     

Neoflavanoids of Dalbergia melanoxylon

The heartwood of Dalbergia melanoxylon has yielded new examples of known neoflavanoid types. The isolates included 4-phenylcoumarins, (S)-4-methoxydalbergiones and benzophenones which have the corresponding oxygenation pattern. The structures of the extractives have been examined by physical methods, and confirmed by conversion to known compounds or by independent synthesis. A 2-cinnamylphenol (6) and 3-cinnamylflavan (7) were the only products in a condensation reaction in the attempted synthesis of the 4-methoxydalbergione (1b).