Four analogues of spiroleptosphol isolated from Leptosphaeria doliolum.
Spiroleptosphol B (2), spiroleptosphol C (3), norleptosphol C (4) and hydroleptosphol (5) were isolated from ascomycete Leptosphaeria doliolum. Detailed (1)H and (13)C NMR spectral analyses revealed these were structural analogues of spiroleptosphol (1) which we have recently isolated from the same fungi. Spiroleptosphol B (2) carried an unprecedent 5,3-dioxatricyclo[4.4.0.1(1.4)]undecane framework in place of the spirobicyclo ring system of 1. Spiroleptosphol C (3) was a 17-(R)-hydroxy derivative of 1. Norleptosphol C (4) was deduced to be the monocyclic structure biosynthetically resulted by decarboxylation from 3. Although 5 gave broaden (1)H NMR spectrum, it was gradually transformed to 2 which suggested being a hydrolysate of 1.
Murakami
Takanori
T
Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-Cho, Hirosaki, Aomori 036-8561, Japan.
Tsushima
Taro
T
Takada
Noboru
N
Tanaka
Kazuaki
K
Nihei
Ken-ichi
K
Miura
Tomisato
T
Hashimoto
Masaru
M
D001203:Ascomycota / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013141:Spiro Compounds / Q000737:chemistry / Q000302:isolation & purification*
D013141:Spiro Compounds; C532933:spirolephtoshol