2539-02-8Relevant articles and documents
Laccase-mediated oxidation of totarol
Ncanana, Sandile,Baratto, Lara,Roncaglia, Lucia,Riva, Sergio,Burton, Stephanie G.
, p. 1507 - 1513 (2007)
In this study, novel dimers of the biologically active phenolic compound totarol were synthesized using the phenol oxidase enzyme lacease, obtained from Trametes pusbescens, in organic solvent medium. Two dimeric products, linked either by carbon-carbon or by carbon-oxygen bonds, were isolated and characterized. The effect of changes in various parameters such as solvent, temperature, pH and buffer concentration on the conversion of totarol by lacease was investigated. The nature of the organic solvent, in particular, was found to affect the nature and the ratio of the products obtained.
Chemoenzymatic synthesis of (+)-totarol, (+)-podototarin, (+)-sempervirol, and (+)-jolkinolides E and D
Miyake, Takahiro,Kigoshi, Hideo,Akita, Hiroyuki
, p. 2915 - 2922 (2008/09/17)
The enzymatic resolution products [(1R,4aR,8aR)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal (8aR)-7 (98% ee) and {acetate of (1S,4aS,8aS)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal} (8aS)-9 (>99% ee)] obtained by the lipase-catalyzed enantioselective acetylation of (±)-7 in the presence of vinyl acetate as an acyl donor were converted to the α,β-unsaturated ketones (8aR)-6 and (8aS)-6, respectively. Concise syntheses of (+)-totarol 1, (+)-podototarin 2 and (+)-sempervirol 3 were achieved based on Michael reactions between (8aS)-6 and the appropriate β-keto ester followed by aldol condensation. The first chiral syntheses of (+)-jolkinolides E 4 and D 5 were achieved from (5R,10R,12R)-12-hydroxypodocarpa-8(14)-en-13-one 15 derived from (8aR)-6.
Phenolic Oxidations of Totarol
Cambie, Richard C.,Higgs, Paul I.,Read, Christine M.,Rutledge, Peter S.,Ryan, Glen R.,Woodgate, Paul D.
, p. 681 - 697 (2007/10/02)
Methods for the direct oxidation of the C 12 position of totarol (1) or its methyl ether (4) have been examined.Treatment of (1) with benzeneseleninic anhydride gave the 9-hydroxy dienone (16) which on ozonolysis afforded the spiro butenolide (21), formed via the ozonide (22).The rearranged ether (18) was obtained from one oxidation with benzeneseleninic anhydride.Mercuriation of totarol and totaryl methyl ether gave the mercuriochlorides (5) and (7) but attempts to form the methoxy acetate (6) from (7) by boronation/oxidation and acetylation were unsuccessful.Treatment of totaryl methyl ether (4) with thallium(III) trifluoroacetate gave dienone 14- and 9-trifluoroacetates (25) and (17).Reaction of the (η6-arene)tricarbonylchromium(0) complexes (28) and (29) of (4) with lithioacetonitrile gave the 7α-alcohol (30) but reaction with t-butyllithium and then with copper(I) bromide/dimethyl sulfide and MoOPH gave the methoxyphenol (12) in 66percent yield.