New Triquinane-Type Sesquiterpenoids fromMacrocystidia cucumis (Basidiomycetes)

New Chlorinated 2,5-Diketopiperazines from Marine-Derived Bacteria Isolated from Sediments of the Eastern Mediterranean Sea

“…The organic extracts of five marine-derived bacterial strains, specifically Bacillus endophyticus BI0327, Streptomyces albidoflavus BI0383, Nocardiopsis aegyptia BI0618, Streptomyces smyrnaeus BI0918, and Bacillus subtilis BI0980, isolated from marine sediments collected in the Aegean and Ionian seas, were subjected to repetitive chromatographic fractionations to yield three new natural products, namely cis-cyclo(Pro-3-chloro-Tyr) (15), trans-cyclo(Pro-3-chloro-Tyr) (16), and cis-cyclo(3-chloro-Tyr-Ile) (31), and 29 previously reported metabolites, which were identified as cyclo(Pro-Gly) (1) [24,25], cis-cyclo(Pro-Ala) (2) [26,27], cis-cyclo(Pro-Val) (3) [28][29][30], cis-cyclo(Pro-Leu) (4) [25,29,31,32], trans-cyclo(Pro-Leu) (5) [31,33], cis-cyclo(trans-4-Hyp-Leu) (6) [34], trans-cyclo(cis-4-Hyp-Leu) (7) [35], cis-cyclo(Pro-Ile) (8) [28,31,36], trans-cyclo(Pro-Ile) (9) [36,37], cis-cyclo(Pro-OMet) (10) [38], cis-cyclo(Pro-Phe) (11) [28,30,31,39,40], trans-cyclo(Pro-Phe) (12) [33,36,40], cis-cyclo(trans-4-Hyp-Phe) (13) [36,41], cis-cyclo(Pro-Tyr) (14) [42,43], cis-cyclo(Pro-Trp) (17) [44,45], cyclo(Leu-Gly) (18) [46]…”

Synthesis and rearrangement of [1,1′-bicyclobutyl]-1-ols and spiro[3.4]octan-5-ols: a general access to bicyclo[3.3.0]octenes (hexahydropentalenes)

“…For the mechanism of the rearrangement of 37, we refer to a closely related example. 24 From a synthetic point of view it is interesting to note that 42, 45 and 46 represent partial structures of the linear triquinanes endo-hirsutene (47), 29 endo-capnellene (48) 30 and both ceratopicanol (49) 31 and cucumin-H (50), 27,32 respectively (Scheme 8). While examples for successful syntheses of angular triquinanes via cyclobutylmethyl to cyclopentyl rearrangements are known, 33 their potential for a synthesis of linear triquinanes remains to be explored.…”

Two new sesquiterpenoids from cultures of the basidiomycete Tremella foliacea

“…The data suggested that 2 was a cucumane-type sesquiterpenoid similar to cucumin G [8], except for a hydroxyl group at C-15 in 2 instead of the hydroxyl group at C-5 in cucumin G, which was supported by the HMBC correlations from H-15 to C-3 (d C 147.2, s), C-4 (d C 135.9, s), and C-5 (d C 33.8, t) ( Figure 2). The relative configuration of 2 was determined by ROESY correlations of H-12 with H-2 and H-9, 14-Me with H-5b and H-6b, which indicated that 14-Me was b-oriented, while H-2 and H-9 were a-oriented.…”