E.I. Mass Spectrometry of 2,3-Tetralene Epoxide and Episulfide

Chemical Constituents of Papulaspora immersa, an Endophyte from Smallanthus sonchifolius (Asteraceae), and Their Cytotoxic Activity

“…On the basis of the above mentioned data, the structure of 10 was established as 2,3-epoxy-1,2,3,4-tetrahydronaphthalene-c-1,c-4,8-triol. A similar ring system was found in the structures of mycochrysone and cervicarcin, compounds produced by fungi [32]; however, compound 10 had been previously obtained only as a synthetic reduction product of juglone epoxide [33]. 7)), together with fragment-ion peaks at m/z 91 ([M À Me À 2 CO À HCCMe À H 2 O] þ ) and 67 ([M À Me À 2 CO À HCCMe À HCCOH] þ ), ascertained the OH linkage site at C(7).…”

“…The molecularion peak was not observed in the EI mass spectrum, but a peak corresponding to ([M À H 2 O] þ ) at m/z 176 and an intense peak at m/z 147 ([M À CHO] þ ) instead, due to radical-cation rearrangement characteristic of 2,3-tetralin epoxide compounds [32]. The 1 H-NMR spectrum (600 MHz; Table 2) revealed a group of signals characteristic of a trisubstituted aromatic ring at d(H) 7.08 (dd, J ¼ 7.8, 7.2, HÀC(6)), 6.82 (dd, J ¼ 7.8, 1.2, HÀC(7)), and 6.74 (br.…”