Piotr Skibicki

Salograviolide A, a sesquiterpene from Centaurea salonitana

Abstract A methanol extract of Centaurea salonitana gave 3β-acetoxy-8α,9β-dihydroxy-1αH,5αH,6βH,7αH-guai-4(15),10(14),11(13)-triene-6,12-olide. The structure of the new polyunsaturated dihydroxyguaianolide was established by spectroscopy and confirmed by single crystal X-ray diffraction.

Marasmane lactones from Lactarius vellereus

Abstract An ethanol extract of Lactarius vellereus gave 7α,8α,13-trihydroxy-marasm-5-oic acid γ-lactone and 13-hydroxy-marasm-7(8)-en-5-oic acid γ-lactone in addition to known compounds. The structure of the dihydroxylactone was established by spectroscopy and confirmed by single crystal X-ray diffraction. The structure of the unsaturated lactone was substantiated by spectroscopy and transformation to the former dihydroxylactone.

2(3)-8(9)-bisanhydrolactarorufin A and a highly oxygenated furanol from Lactarius vellereus

Abstract An ethanol extract of Lactarius vellereus gave 5,13-epoxy-3β-hydroxy-lactara-2(9),5,7(13)-trien-4,8-dione and 13-hydroxy-lactara-2,6,8-trien-5-oic acid γ-lactone, in addition to the known sesquiterpenes. The structure of the new monohydroxy-di-oxo-furan was established by spectroscopy and confirmed by single crystal X-ray diffraction. The structure of the new lactone was established by spectroscopy.

Furantriol, a lactarane sesquiterpene from Lactarius mitissimus

Abstract An ethanolic extract of Lactarius mitissimus gave the furantriol (2S*,3S*,8S*,9R*,11S*)-3,8,14-trihydroxy-5,13-oxa-lactaran-5,6-7,13-diene in addition to known sesquiterpenes. The structure of this new trihydroxylactarane was established by1H and13C NMR spectroscopy and confirmed by chemical correlation with lactarorufin B.

Normarasmane sesquiterpenes from Lactarius vellereus

Abstract Ethanolic extracts of Lactarius vellereus gave, in addition to known sesquiterpenes, one new highly oxygenated marasmane lactone and two new 13-normarasmane sesquiterpenes, which are the first representatives of such a class of compounds. Molecular configurations and conformations have been established by spectroscopic methods.

3-Deoxy-3-epi-lactaroscrobiculide b, a sesquiterpene from Lactarius vellereus

Abstract An ethanol extract of Lactarius vellereus contained a new 5-hydroxy-lactara-6,8-dien-13-oic acid γ-lactone in addition to known sesquiterpenes. The structure of the new compound was established by 1 H and 13 CNMR spectroscopy. An unambiguous assignment of stereochemistry at C-3 of this compound was accomplished by independent synthesis of both C-3 epimers.

A highly oxygenated phenanthrofuran skeleton diterpene from Euphorbia acaulis

Abstract A highly oxygenated ent-abietane skeleton diterpene isolated from Euphorbia acaulis has been identified as (4R,4aR)4,4a-dihydroxy-3-hydroxymethyl-7,7,10a-trimethyl-2,4,4a,5,6,6a,7,8,9,10,10a,10b-dodecahydrophenanthro [3,2-b]furan-2-one by spectroscopic methods and its formation from caudicifolin by aqueous HCIO 4 hydrolysis.

New Constituents of Lactarius vellereus

Abstract Two new sesquiterpenes 7α, 8α, 13, 14-tetrahydroxy-marasm-5-oic acid γ-lactone, and 10β-hydroxy-lactarorufin A as well as the known dipeptide cyclo-L-prolyl-L-leucyl were isolated by multiple chromatography of the ethanolic extract of Lactarius vellereus.

X-ray structural investigation of 5,13-epoxy-3β-hydroxy-lactara-2(9),5,7(13)-trien-4,8-dion

Abstract5,13-Epoxy-3β-hydroxy-lactara-2(9),5,7(13)-trien-4,8-dion was investigated by X-ray diffractometric methods. The compound is orthorhombic:P212121,a=7.677(1),b=11.244(2),c=15.277(2) Å andZ=4. The structure was solved by direct methods and refined by full-matrix least-squares, givingR=0.0387 for 1522 observed reflections. An internal hydrogen bond of medium strength was registered in the molecular structure.

Crystal and molecular structure of 7α, 8α, 13-trihydroxy-marasman-5-oic acid γ-lactone, C15H22O4

The structure of the title compound has been investigated by X-ray diffraction methods. The crystals are monoclinic, space groupP21, with cell dimensions:a=9.802(3),b=6.192(1),c=12.392(2) Å, andβ=112.40(2)°. The structure was solved by direct methods, and refined with 1492 unique reflections by a full-matrix, least-squares procedure givingR=0.0450. Thetrans arrangement of H-8α and H-9α hydrogens as deduced from earlier1H NMR experiments was fully confirmed by the X-ray investigations.