The structure of two new coumarins from the roots of Lomatium columbianum

Two new coumarins, obtained from the roots of Lomatium columbianum are shown to be trans-p-coumaroyllomatin and cis-p-coumaroyllomatin. Furthermore, the roots afforded columbianadin, selinidin, lomatin, (+)-dihydrooroselol, and a mixture of monoesters of khellactone.     

Peucelinendiol,a new acyclic diterpenoid from Peucedanum oreoselinum

A new diterpenoid has been isolated from roots of Peucedanum oreoselinum. Mainly by spectroscopic methods, its structure is shown to be (+)-(E)-7-hydroxymethyl-2,6,10,14-tetramethyl-2,9,13-pentadecatrien-6-ol, yet without specification of stereochemistry at C-6 and C-7. Furthermore the roots afforded a high yield of falcarindiol, (+)-(Z)-heptadeca-1,9-dien-4,6-diyn-3,8-diol.     

New coumarins from Coleonema album

Six coumarins have been isolated from the aerial parts of Coleonema album and identified as ulopterol, 7-(3′, 3′-dimethylallyloxy)-coumarin, (R)-(+)-2′,3′-epoxy-suberosin, and the novel coumarins (R)-(+)-7-(2′, 3′-epoxy-3′-methylbutoxy)-coumarin, (R)-(+)-7-(2′,3′-dihydroxy-3′-dihydroxy-3′-methylbutoxy)-coumarin and (R)-(+)-7-methoxy-8-(2′,3′-epoxy-3′-methylbutoxy)-coumarin.     

A new coumarin from Ferula loscosii and the correct structure of coladonin

From the roots of Ferula loscosii the coumarins umbelliprenin, coladin and coladonin and the new natural isovaleryl derivative of the latter have been isolated. A study which confirms the structure of coladonin and its difference from farnesiferol A is also given.     

New coumarins from Seseli sibiricum

Three new coumarins, sesebrin(7-methoxy-5-[3-methylbut-2-enyloxy]-8-[3-methyl-2,3-epoxybutyl] coumarin), sesebrinol(7-methoxy-5-[3-methylbut-2-enyloxy]-8-[3-methyl-2,3-dihydroxybutyl] coumarin) and sibiricol (7-methoxy-5-hydroxy-8-[3-methylbut-2-enyl] coumarin) have been isolated from the roots of Seseli sibiricum, in addition to sitosterol and 7 known coumarins, isobergapten, bergapten, phellopterin, sibiricin, coumurrayin, osthenol and meranzin hydrate.     

Oxepine derivatives from the roots of Smyrnium rotundifolium

Besides the known eudesmanolides and oxepine derivatives we have isolated two new oxepine type sesquiterpene lactones from the roots of Smyrnium rotundifolium. The new compounds were smyrnicordi-8-enolide and isosmyrnicordiolide, its stereochemistry at C-8 and C-10 could not be established.     

Coumarins from Musineon divaricatum

A chemical investigation of Musineon divaricatum has resulted in the isolation of 19 coumarins, five of which are novel compounds; 18 are khellactone derivatives. The coumarins were isolated from the crude extracts by a combination of adsorption chromatography, gel permeation and HPLC; the more successful HPLC separations utilized a nitrile bonded phase column. The structures were determined by ¹H NMR and mass spectral studies and by comparisons with literature data. The relative configuration for the entire series was secured from ¹H NMR data, while the absolute configuration could be assigned with any certainty only in the cases of two of the compounds.     

Isolation and synthesis of two coumarins from melampodium divaricatum

Two new coumarin isomers have been isolated from Melampodium divaricatum and identified by spectral procedures as 8-hydroxy-7-(3′-methyl-2′-butenyloxy)coumarin (1) and 7-hydroxy-8-(3′-methyl-2′-butenyloxy)coumarin (2). The regioselective synthesis of each isomer was made by two different alkylation pathways confirming their structures.     

Pyranocoumarin derivatives from Seseli tortuosum

Trans-khellactone, cis-khellactone, 3′-senecioyl-cis-khellactone, 3′-senecioyl-4′-acetyl-cis-khellactone, 4′-senecioyl-cis-khellactone, 3′-acetyl-4′-senecioyl-cis-khellactone, 3′,4′-di-isovaleryl-cis-khellactone, 3′,4′-disenecioyl-cis-khellactone, 3′-angeloyl-4′-isovaleryl-cis-khellactone and 3′-isovaleryl-4′-angeloyl-cis-khellactone were obtained from the aerial part of Seseli tortuosum.     

New antileishmanial sesquiterpene coumarins from Ferula narthex Boiss

Two new sesquiterpene coumarins, fnarthexone (1) and fnarthexol (2), along with three known coumarin derivatives, conferol (3), conferone (4) and umbelliferone (5), were isolated from the plant Ferula narthex Boiss. The structures of the compounds 1–5 were elucidated using modern spectroscopic techniques. The structure of compound 3 was unambiguously deduced by the single-crystal X-ray diffraction technique. Compounds 1–4 were tested for in vitro leishmanicidal activity and promising results were obtained. Conferol (3) was found to be the most potent with IC₅₀ value of 11.51 ± 0.09 μg/mL.     

Mammea-type coumarins from Mammea usambarensis Verdc.

Phytochemical investigations of Mammea usambarensis resulted into the isolation a δ-tocotrienol (1) and five known mammea-type coumarins (2–6). Their structures were determined by NMR, IR, and LC-MS spectroscopic methods and by comparison of their spectral and physical data with those reported previously in the literature. The presence of these compounds is consistent with the compound classes reported from other members of the genus Mammea. Compound 6 is isolated from the Mammea genus for the first time. This is the new source of mammea-type coumarin compounds while the chemotaxonomic significance of this investigation is summarized.     

New coumarins from the umbels of Seseli sibiricum

Three new coumarins, seselinal, sesibiricol and sibirinol, and 12 known coumarins have been isolated from the umbels of Seseli sibiricum. The new coumarins have been characterized as 5, 7-dimethoxy-8-(2-methyl-2-formylpropyl)-2H-1-benzopyran-2-one, 5-(3-methylbut-2-enyloxy)-7-methoxy-8-(2-hydroxy-3-methylbut-3-enyl)-2H-1-benzopyran-2-one and 5,7-dimethoxy-8-(2-hydroxy-3-methylbut-3-enyl)-2H-1-benzopyran-2-one,respectively. The known ones were identified as sesibiricin, isosibiricin, osthol, coumurrayin, sesebrin, sesebrinol, sibiricin, imperatorin, bergapten, xanthotoxin, isopimpinellin and mexoticin.