New Kaurance Diterpenoids from the Aerial Parts of Distichoselinum tenuifolium

The Biotransformation of Two 3,15-Oxygenate ent-Kaurane Derivatives by Gibberella fujikuroi

“…The chemical shifts and splitting patterns of these hydrogens in 10 and 12 are typical of protons geminal to these oxygenated functions at C-11- (β). 1,2 Thus, the structure assigned to this metabolite was 3R,7R,11β-trihydroxy-15-oxo-ent-(16S)-kaurane (10).…”

“…The initial substrate, 3α,15β-dihydroxy- ent -kaur-16-ene ( 1 ), was isolated for the first time from the Japanese liverwort Jungermannia vulcanicola , and now we have obtained it by hydrolysis of the 15-angelate 2 , which occurs in Elaseolinum tenuifolium . , …”

“…The initial substrate, 3R,15β-dihydroxy-ent-kaur-16ene (1), was isolated for the first time from the Japanese liverwort Jungermannia vulcanicola, 8 and now we have obtained it by hydrolysis of the 15-angelate 2, which occurs in Elaseolinum tenuifolium. 9,10 The incubation with the fungus was carried out in the presence of AMO 1618, a compound that inhibits the formation of ent-kaur-16-ene without disturbing the post-kaurene metabolism. 11,12 This facilitates the isolation of the metabolites formed.…”

“…The neutral fraction was chromatographed on Si gel eluting with petroleum ether-EtOAc mixtures, giving starting material (1) (110 mg), 3R,7R-dihydroxy-15-oxoent-(16S)-kaurane (8) (2 mg), 3R,7R,15β-trihydroxy-entkaur-16-ene (5) (7 mg), a mixture of 3R,15β-dihydroxy-11β,16β-epoxy-ent-kaurane ( 15) and 3R,11β,15β-trihydroxy-ent-16-ene (13) (4 mg), 3R,7R,11β-trihydroxy-15-oxo-ent-(16S)-kaurane (10) (12 mg), and 3R,7R,11β,-15β-tetrahydroxy-ent-kaur-16-ene (17) 6 Hz,3.93 (1H,dd,J ) 11.6,4.5 Hz,; 13 C-NMR data, see Table 2; EIMS m/z [M] + 320 (89), 302 (21), 287 (9), 284 (6), 269 (8), 262 (100), 256 (2), 244 (7), 241 (7), 211 (4); HREIMS m/z 320.2350 [M] + , C 20 H 32 O 3 requires 320.2351.…”

“…The incubation of 3R,15β-dihydroxy-ent-kaur-16-ene (1) with the fungus Gibberella fujikuroi gave 3R,7R,15β-trihydroxy-ent-kaur-16-ene (5), 3R,11β,15β-trihydroxy-ent-kaur-16-ene (13), and 3R,7R,11β,15β-tetrahydroxy-ent-kaur-16-ene (17). The ether 3R, and the isomerized compounds 3R,7R-dihydroxy-15-oxo-ent-(16S)-kaurane (8) and 3R,7R,11β-trihydroxy-15-oxo-ent-(16S)-kaurane (10) were also obtained. The incubation of 3R-hydroxy-15-oxo-ent-(16S)-kaurane (7) with the fungus also afforded compounds 8 and 10, as well as 3R,11β-dihydroxy-15-oxo-ent-(16S)-kaurane (20), 3R,6R,11β-trihydroxy-15-oxoent-(16S)-kaurane, (22) 3R,6β,7R-trihydroxy-15-oxo-ent-(16S)-kaurane (25), and 3R,11β,16Rtrihydroxy-15-oxo-ent-(16S)-kaurane (27).…”