The structure of siccanin

Meroterpenoids produced by fungi

“…131 Its structure was determined by X-ray diffraction. 132 Subsequent work on the culture broth of this microorganism allowed the isolation of siccanochromenes A-H 263-270, siccanochromenic acid 271 and presiccanochromenic acid 272, which were presumed to be possible biosynthetic intermediates of 262. [133][134][135] The biosynthetic pathway (Scheme 15) to 262 is based on experiments using cell-free systems and intact The lipophilic fraction of the acetone extract of fresh specimens of the mushroom Albatrellus ovinus collected in the neighbourhood of Zbiroh in Bohemia (Czechoslovakia) contained as the main components two closely related antibiotically active phenolic compounds, grifolin 274 and neogrifolin 275.…”

Biosynthesis of sesquiterpenes

“…As well as trans-7-monocyclofarnesol (48) mentioned previously, Helminthosporium siccans also produces a novel group of chromene derivatives, the siccanochromenes322 and the chroman derivative siccanin (154). 323 Two intermediates were isolated (as their methyl esters) after [2-14C] mevalonate (6) indicated that 4% of the total activity was in the carboxylic acid fraction 324 These intermediates were shown to be presiccanochromenic acid (155) and siccanochromenic acid (156).…”

Biomimetic Total Synthesis of Rhodonoids C and D, and Murrayakonine D

“…Alternatively, initial 5- exo-tet ring opening of epoxide 8 (via an S N 2 mechanism, with inversion at C-12) could give o -quinone methide 10 , and then 2 via a final cyclization (path b). The structure of 2 is similar to that of siccanin ( 6 ), a meroterpenoid that has been proposed to be biosynthesized via an analogous rearrangement of an epoxy-chromene . However, attempts to achieve a biomimetic synthesis of siccanin by Trost and co-workers failed under acidic conditions, and a radical cyclization strategy was used instead …”