In the course of our research program aimed at the discovery of biologically active compounds from fungi, we have reported previously the isolation and structure elucidation of lanostane triterpenoids from the fruit bodies of Laetiporus versisporus (LLOYD) IMAZ. (Polyporaceae), 1,2) and benzofuran glycosides and a C 10 acetylenic acid from L. sulphureus (FR.) MURR. var. miniatus (JUNGH.) IMAZ., 3) and a eudesmane sesquiterpene from Lactarius laeticolorus (IMAI) IMAZ. (Russulaceae). 4) We have initiated the chemical study for Chlorophyllum molybdites (MEYER : FR.) Massee belonging to the family Agaricaceae. It is a poisonous mushroom growing on the lawn and grass ground and is distributed in tropical and subtropical regions and a restricted area in Japan.5,6) Chemical study on this fungus had led to the isolation of the pyrrolidine derivative alkaloids lepiotins A and B by Ohta et al. 7)The 70% EtOH extract of the fresh fruit bodies of the fungi was separated by successive chromatographic steps on a silica gel column followed by reversed-phase HPLC with 70-87% MeOH to afford two new steroidal compounds, 1 and 2, together with six known ones. The known compounds, (22E, 24R)-5a ,8a -epidioxyergosta-6,9,22-triene-3b -ol (3), (22E, 24R)-ergosta-8(14),22-diene-3b ,7a -diol (4), (22E,24R)-5a , 6a-epoxyergosta-8(14),22-diene-3b,7a-diol (5), (22E,24R)-ergosta-7,22-diene-3b ,5a ,6b -triol (6),9) have previously been isolated from fungi and marine sponges.Compound 1 was obtained as an amorphous powder, which showed an [MϩH] ϩ ion at m/z 437.3532 in the highresolution (HR)-FAB-MS. This corresponds to a molecular formula C 29 H 44 N 2 O, requiring nine unsaturation equivalents. The IR spectrum of 1 showed absorptions at 3450, 1655, and 1545 cm Ϫ1. The UV spectrum of 1 exhibited absorption maximum at 285.5 (log e 4.21) nm, implying the presence of a heteroannular triene system in the compound. H-detected heteronuclear multiple bond correlation spectrum (HMBC), and rotating frame nuclear Overhauser and exchange spectroscopy (ROESY) experiments enabled us to identify the (22E)-ergosta-4,6,8(14),22-tetraene nucleus.11) The stereochemistry at the C-24 position for 1 was determined as R by comparison with the chemical shift values of 3-8. 8,9,11) The remaining unassigned carbon at d 159.2 (s) was given the long-range correlation from the doublet proton at d 6.90, which was showing geminal coupling with H-3 at d 4.87 (m). These observations recognized the presence of the urea junction at C-3 position, in addition to taking its molecular formula into consideration. Next, the nuclear Overhauser effect (NOE) interactions were observed between H-3/H-2a, H-3/H-2b, H-3/NH, and H-3/H-4, in turn, NH/H-1a, suggesting a-orientation of the ureido group at C-3. Accordingly, these studies led to structure 1 as (22E,24R)-3a-ureido-ergosta-4,6,8(14),22-tetraene.Compound 2 was obtained as an amorphous powder, and the molecular formula was established as C 34 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan. Received February 19, 2001 accept...
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