Biogenetic type synthesis of grasshopper ketone and loliolide and a possible biogenesis of allenic carotenoids

Evaluation of the Allelopathic Potential of Leaf, Stem, and Root Extracts of Ocotea pulchella Nees et Mart

“…This extract was purified by chromatography and the following allelochemicals were characterized: five sesquiterpenes ( 1 – 5 ), one fatty acid ( 6 ), two flavonoids ( 7 and 8 ), one phenylethanoid glucoside ( 9 ), two aromatic esters ( 10 and 11 ), and two sugars ( 12 and 13 ). The isolated compounds were identified by comparison of their spectroscopic data ( 1 H‐NMR, 13 C‐NMR, IR, and MS) with those reported in the literature for 1 β ,6 α ‐dihydroxy‐eudesm‐4(5)‐ene ( 1 ) ; 1 β ‐hydroxyeudesma‐5,11‐diene ( 2 ) ; T‐cadinol ( 3 ) ; loliolide ( 4 ) ; spathulenol ( 5 ) ; dimorphecolic acid ( 6 ) ; afzelin ( 7 ) ; kaempferol‐4′‐ O ‐rhamnopyranoside ( 8 ) ; benzyl salicylate ( 10 ); benzyl benzoate ( 11 ) ; both anomers of d ‐xylopyranose ( Fig. ).…”

Synthese von enantiomerenreinen ‘Grasshopper’‐Ketonen und verwandten Verbindungen

“…Oxidation eines /3-Ionols mit 'O,/hv [23] [20]. In allen diesen Synthesen sind Racemate oder ein partielles Racemat [22] 3592,3440, 1938, 1732, 1673 1,148, 1,375, 1,419, 2,175, 4,36, 5,844 1,149, 1,421, 1,424, 2,036,2,179, 5,37, 5 Bei den 'H-NMR-Spektren interessiert vor allem die Lage des jeweiligen Allen-Protons im Zusammenhang rnit der Diskussion um die Biogenese der Allen-Endgruppe.…”

Flavours and Fragrances

“…[32][33][34] The oxidative degradation of carotenoids [37] Rose furan β-Damascenone β-Damascone β-Carotene Violaxanthin example, from β-carotene by way of neoxanthin to the so-called "grasshopper ketone" [35], which after reduction, addition of water and dehydration gives damascenone. β-Damascone correspondingly derives from deoxyneoxanthin.…”

“…Since damascone is practically always detected together with ionones, the following genesis is also conceivable; both, in vitro and, by analogy, in vivo. [36,37] Laboratory experiments suggest the following pathway:…”