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Synthèse de l'évernine
Author(s) -
Nicollier Gilles,
Rebetez Michel,
Tabacchi Raffaele,
Gerlach Hans,
Thalmann Adolf
Publication year - 1978
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19780610816
Subject(s) - chemistry , saponification , hydrogenolysis , trifluoroacetic anhydride , organic chemistry , aromatization , medicinal chemistry , ether , yield (engineering) , derivative (finance) , condensation , catalysis , materials science , physics , economics , financial economics , metallurgy , thermodynamics
Synthesis of Evernin Two syntheses of the depside evernin 6 are described. Condensation of methyl acetoacetate and methyl crotonate followed by aromatization and reduction with Raney ‐Ni led to methyl orsellinate (3) . The condensation of everninic acid (4) , obtained by partial methylation of 3 and saponification of the methyl ester, with methyl 2, 4‐dihydroxy‐3, 6‐dimethylbenzoate (methyl β‐orcin carboxylate) (5) in presence of cyclohexylcarbodiimide gave evernin ( 6 ). In a second syntheis methyl dihydroorsellinate (1) was regiospecifically converted into its 4‐methyl enol ether and aromatized via the benzene selenenyl derivative to yield methyl evernate (7) . Benzylation followed by saponification gave the free acid 8 . Methyl β‐orcin carboxylate (5) was synthesized in an analogous way from methyl 3,6‐dimethyl‐2,4‐dioxocyclohexanecarboxylate. Condensation of 8 with the methyl ester 5 by treatment with trifluoroacetic anhydride in toluene yielded 9 , which could be converted into evernin ( 6 ) by hydrogenolysis of the benzyl ether.