Synthesis of cyathiformines A-C: Unusual fungal metabolites derived from chorismic acid

Tanzawaic acids isolated from a marine-derived fungus of the genus Penicillium with cytotoxic activities

“…The most significant difference was the absence of methine H-10. A signal observed at δ C 72.1 in the 13 C NMR, and its HMBC correlation with methylene H 2 -18 indicated the substitution of C-10 with a hydroxyl group and confirmed the structure of compound 3.…”

“…13 C NMR, and its HMBC correlation with methylene H 2 -18 indicated the substitution of C-10 with a hydroxyl group and confirmed the structure of compound 3. The spectroscopic data of 2 were very similar to those of 1, the most significant differences being the presence of signals indicative of an acetate group (δ H 2.04 (s); δ C 20.9 and δ C 171.2) and the chemical shift of C-18 (δ H 3.87 (d, J = 6.6); δ C 69.2).…”

“…The structure of 1 was established from NMR analysis using one-and two-dimensional NMR techniques including proton, carbon, COSY, HMQC, HMBC, DEPT, and NOESY. The 13 C NMR and DEPT spectra (Table 1) showed 18 signals assigned to 2 × CH 3 , 3 × CH 2 (one geminal to hydroxyl group), 12 × CH (six olefinic), and one carbonyl quaternary carbon. The 1 H NMR spectrum displayed signals for six olefinic protons at δ 5.77 (d, 15.4), 7.36 (dd, J = 10.9, 15.4), 6.26 (dd, J = 10.1, 15.1), 6.12 (dd, J = 10.9, 15.1), 5.58 (ddd, J = 2.7, 4.5, 9.5) and 5.45 (ddd, J = 1.9, 1.9, 9.5); a methylene geminal to the hydroxyl group at δ 3.45 (d, J = 6.4); ten aliphatic protons at δ 2.44-0.75 ppm; and two methyl groups at δ 0.93 (d, J = 7.2) and 0.92 (d, J = 6.4).…”

Synthesis of Marine-Derived Carbasugar Pericosines

“…5 [79][80][81][82]95]. Interestingly 6 corresponds to the core section of the chlorine-containing natural product (75), which had previously been isolated from two kinds of fungi, and cyathiformine C (76), which are metabolites of basidiomycetous fungi [82,83,96,97].…”

“…During 1993 and 1994, two research SCHEME 6 Syntheses of pericosines D and D o . groups independently reported the synthesis of chlorohydrin 76 from epoxide 77, which is a natural product isolated along with 76, based on the biosynthetic hypothesis [96,97]. The results implied that this was a plausible precursor for pericosines via a biosynthetic pathway.…”