Marden A. De Alvarenga

Dihydroisocoumarins and phthalide from wood samples infested by fungi

Abstract Wood samples, infested by fungi during storage, were shown to contain, besides the known 5-methyl-mellein, additional (3 R )-8-hydroxy-3-methyl-3,4-dihydroisocoumarins substituted by 7-methyl, 5-formyl, 5-carboxy, 5-hydroxy, 5-methoxy, 6-methoxy-5-methyl and 6,7-dimethoxy-5-methyl groups, as well as 6-formyl-7-hydroxy-5-methoxy-4-methylphthalide. Several 2-methylchromanones were synthesized in order to show that this class of compounds can be distinguished from 3-methyl-3,4-dihydroisocoumarins by MS.

New neolignans from Talauma ovata.

The hexane extract of the bark of Talauma ovata yielded three new natural neolignans, identified as acetyl oleiferin-C (4), acetyl oleiferin-F (7) and acetyl oleiferin-G (8), together with the known compounds dihydroguaiaretic acid (1), austrobailignan-5 (2), oleiferin-C (3), austrobailignan-6 (5) and oleiferin-F (6).

Methyl- and methylthio-phenanthrenes from Micrandropsis scleroxylon

Abstract The trunk wood of Micrandropsis scleroxylon W. Rodr. (Euphorbiaceae) contains besides sitosterol, stigmasterol and ferulic acid, three novel compou

Bicyclo[3,2,1]octanoid, neolignans from Aniba simulans

Abstract Six bicyclo[3,2,1]octanoid neolignans, isolated from the benzene extract of Aniba simulans Allen (Lauraceae) trunk wood, are shown to derive from two basic structures: 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-3-oxobicyclo[3,2,1]octane, substituted by 4-hydroxy, 4-hydroxy-5-methoxy, 4-methoxy or 4,5-dimethoxy groups; and 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-4-oxobicyclo[3,2,1]oct-2-ene, substituted by 3-hydroxy or 3-hydroxy-5-methoxy groups. The structural proposals are based on spectral data, interconversions synthesis of a derivative from the known (2 R ,3 S ,3a S )-3a-allyl-5-methoxy-2-(3′-methoxy,4′,5′-methylenedioxyphenyl)-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran.

Neolignans from Aniba burchellii

Abstract Seven neolignans, isolated from the benzene extract of Aniba burchellii Kosterm. (Lauraceae), included the hitherto unknown (2S,3S,5S)-5-allyl-5-methoxy-3-methyl-2-(3′,4′-methylenedioxyphenyl)-2,3,5,6-tetrahydro-6-oxobenzofuran and (1R,5R,6R,7R)-1-allyl-6-(4′-hydroxy-3′-methoxyphenyl)-3-methoxy-7-methyl-4,8-dioxobicyclo-[3,2,1]oct-2-ene. The former structure was previously assigned to a constituent of A. terminalis Ducke which is in fact the 5R-epimer. In addition to the latter constituent, all other previously described 4-oxobicyclo[3,2,1]oct-2-ene neolignans had their absolute configuration established.

Benzofuranoid neolignans from Aniba simulans

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

Methylphenanthrenes from Sagotia racemosa

Abstract The trunk wood of Sagotia racemosa Baill. (Euphorbiaceae) contains two previously unknown micrandrols E (6-hydroxy-7-methoxy-1,2-dimethylphenanthrene) and F (6-hydroxy-7-methoxy-1,2-dimethyl-9,10-dihydrophenanthrene).

Naringenin coumaroylglucosides from Mabea caudata

Abstract 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).

Diterpenoids from Micrandropsis scleroxylon

Abstract The structure of micrandrol-C from Micrandropsis scleroxylon (Euphorbiaceae) is revised to 2,6-dihydroxy-7-methyl-1-methylthiophenanthrene. This and other micrandrols are probably diterpenes in view of their co-occurrence with micrandrol-D, the hemiketal of 1,2,3,4,9,10-hexahydro-6-hydroxy-4a-hydroxymethyl-1,1,7-trimethy-2-oxophenanthrene.

Diasin, A diterpene from Croton diasii

Abstract The trunkwood of Croton diasii Pires (Euphorbiaceae) contains diasin, a novel rearranged labdanic diterpene which includes furan, carbomethoxy, γ