B.L. Sondengam

Isolation of α-corymbolol, an eudesmane sesquiterpene diol from Cyperus articulatus

Abstract A new sesquiterpenic alcohol, α-corymbolol has been isolated from the rhizomes of Cyperus articulatus along with the known corymbolone. The structure and stereochemistry was assigned on the basis of spectroscopic data and the reduction of corymbolone into α-corymbolol and β-corymbolol.

Structure of the chalcone dimers lophirone F, G and H from Lophira lanceolata stem bark.

Abstract Structural elucidation of three chalcone dimers, (lophirones F, G and H) isolated from Lophira lanceolata stem bark, and their permethylethers, is discussed using spectral chemical evidence.

New isoflavones from Ceiba pentandra

Two new isoflavones, pentandrin (1) and pentandrin glucoside (2), were isolated from the stem barks of Ceiba pentandra along with beta-sitosterol and its 3-O-beta-D-glucopyranoside, which was isolated for the first time from this plant. The structures of these compounds were elucidated with the help of spectroscopic techniques, while the structure of 1 was unambiguously confirmed by single-crystal X-ray diffraction studies.

Structure of lophirones B and C, biflavonoids from the bark of Lophira lanceolata.

Abstract Two new isomeric biflavonoids, lophirone B and lophirone C have been isolated from the stem bark of Lophira lanceolata . Their structures were determined by the use of chemical and spectroscopic methods including 2D NMR techniques.

Crotonadiol, a labdane diterpenoid from the stem barkof Croton zambesicus

Abstract A new labdane diterpenoid, crotonadiol, was isolated from an extract of the stembark of Croton zambesicus together with the known clerodane crotocorylifuran and twotrachylobanes: 7 β -acetoxytrachyloban-18-oic acid and trachyloban-7 β ,18-diol. Lupeol, β -sitosterol and its 3- β -glucopyranosyl derivative were also isolated. The structure of crotonadiolwas determined as 8 (17),13-labdadiene-6a,15-diol, by spectral analysis.

A new benzoylglucoside and a new prenylated isoflavone from lophira lanceolata

A new benzoylglucoside, lanceoloside A (1), and a new prenylated isoflavone, lanceolone (2), have been isolated from the air-dried leaves of Lophira lanceolata. Both structures were established from spectroscopic and chemical evidence.

Geranyl coumarins from Clausena anisata

Abstract Two new geranyl coumarins have been isolated from the leaves of Clausena anisata and identified as anisocoumarins I and J on the basis of spectral data and chemical correlation. The isolation of 21 coumarins from the leaves, stem-bark and roots of this plant and their biogenesis is also discussed.

Structures of isombamichalcone and lophirochalcone, bi- and tetra-flavonoids from Lophira lanceolata

Abstract From the stem bark of Lophira lanceolata two new flavonoids, a chalcone dimer, isombamichalcone 1 , and a tetraflavonoid, lophirochalcone 4 have been isolated.

Two saponins from Pteleopsis hylodendron

Abstract Two new saponins, 2α,3α,19α,23-tetrahydroxyolean-12-en-28-O-β- d -galactoside, and sitosterol α(1→3) diglucoside, were isolated from the stem barks of Pteleopsis hylodendron along with a known triterpenoid, 2α,3β,21β,23-tetrahydroxyolean-12-en-28-oic acid, which was isolated for the first time from this plant. The structures of these compounds were elucidated with the help of spectroscopic studies.

Seco-ring-A-triterpenoids from the rootwood of Musanga cecropioides

Abstract From the rootwood of the African tree Musanga cecropioides, three seco-triacidic triterpenes, cecropiacic acid, musangic acids A and B were isolated as their trimethyl esters. Their structures were determined on the basis of a spectral analysis.