bluuebunny/crossref_metadata_2025_split huggingface dataset:
Setting the Bridgehead Oxidation Level in trans‐Tricyclo[9.3.1.03,8]pentadecanes as a Prelude to the Dual Synthesis of Taxol and Taxusin
Authors: Paquette Leo A. , Combrink Keith D. , Elmore Steven W. , Zhao Mangzhu 
Published: December 2004

AbstractThe key elements associated with the synthetic elaboration of functionalized trans‐tricyclo‐[9.3.1.03,8]pentadecanes carrying either a bridgehead H or OH substituent are detailed. Starting with 12, a ketone available in two steps from (R)‐2‐oxo‐7,7‐dimethyl‐l‐vinylbicyclo[2.2.1]heptane, it proved possible to introduce trans‐B/C ring juncture configuration as in 16 in five steps. This advanced intermediate constitutes the point of bifurcation. The pathway to taxusin precursor 23 was attained by stereospecific osmylation, reduction, and pinacol‐like 1,2‐Wagner‐Meerwein rearrangement within acetoxy mesylate 22c. Still more abbreviated is the route to 32, which again takes advantage of the osmylation step but proceeds, forward without reduction of the rear carbonyl group. Once hydroxy diketone 31 is produced, equilibration in the presence of (t‐BuO)3Al results in complete conversion to 32. The many stereoselective transformations developed in the course of this study, in combination with the several thermodynamic questions that have been clarified, are expected to be highly serviceable as more advanced thrusts toward taxusin and taxol are mounted.
Reaction of Diphenyl Phosphorochloridate with Amide Enolates: A new and convenient synthesis of 2‐monosubstituted 3‐(n‐methyl‐n ‐phenylamino)‐2H‐azirines
Authors: Villalgordo José M. , Heimgartner Heinz 
Published: December 2004

AbstractReaction of diphenyl phosphorochloridate with amide enolates and subsequent treatment with NaN3 leads to 2‐monosubstituted 3‐amino‐2H ‐azirines 5 in moderate yields. The reactivity of these azirines is briefly explored.
Carbonyliron Complexation and Carbonyl Insertion of Allenic Ketones
Authors: Trifonov Latchezar S. , Orahovats Alexander S. , Linden Anthony , Heimgartner Heinz 
Published: December 2004

AbstractThe allenic α‐ketones 5a–f give, on irradiation in the presence of [Fe(CO)5], the bis(tricarbonyliron) complexes 6a–f. In the case of ketone 5e, a minor bis(tricarbonyliron) complex with the proposed unique structure 8 is also obtained. Ketones 5a–d, which are disubstituted at C(4), under the same conditions, afford also the lactones 7a–d in moderate yields. The latter reaction is a new carbonyliron‐mediated carbonyl insertion. The structure of the binuclear complexes 1a and 6e were established by X‐ray crystallography.
Säurekatalysierte Umsetzungen von 2‐ Vinylanilin‐Derivaten mit 1‐Benzyl‐ und 1‐Methylpiperidin‐4‐on: Eine Elegante Synthese Neuer Polycyclischer Indol‐Derivate
Authors: Walter Harald , Sauter Hanspeter , Schneider Josef 
Published: December 2004

Acid‐Catalyzed Reactions of 2‐Vinylaniline Derivatives with 1‐Benzyl‐ and 1‐Methylpiperidin‐4‐one: An Elegant Synthesis of New Polycyclic Indole DerivativesThe reaction of 2‐vinylaniline derivatives with 1‐benzylpiperidin‐4‐one or 1‐methylpiperidin‐4‐one in toluene at temperatures between 115 and 120° with toluene‐4‐sulfonic acid as catalyst leads in good yields to a new class of polycyclic indole derivatives (Scheme 1, Table 1). The structure of the new diastereoisomerically pure racemic compounds 1–5 is determined by NMR‐spectroscopic methods. A reaction mechanism proceeding via cyclization of enamine 9, leading to a racemic, tricyclic reactive intermediate 10, and subsequent intramolecular 1,5‐dipolar cyclization as key steps in proposed for the formation of octahydropyrido[4′,3′:4]cyclobut[1,2‐b]indoles 1–5. The scope and limitations of the new method are discussed (see Table 2).
Radical Rearrangements of 2‐O‐(Diphenoxyphosphoryl)glycosyl Bromides
Authors: Koch Andreass , Giese Bernd 
Published: December 2004

AbstractA variety of 2‐deoxy‐1‐O‐diphenoxylphosphoryl‐hexopyranoses were generated in situ by a radical 2→1 migration of the phosphate group. The structures of the reactive rearrangement products were fully elucidated by NMR spectroscopy. Rate constants for this new rearrangement were determined fro a variety of substrates.
Synthesis and Antiviral Activity of Novel Adamantylpeptides
Authors: Vranešić Branka , Tomašić Jelka , Smerdel Stainslav , Kantoci Darko , Benedetti Fabio 
Published: December 2004

AbstractA novel type of compound that contains a peptide specific for bacterial peptidoglycans (immunomodulatory activity) and an adamantyl residue (antiviral activity) was synthesized. Thus, L‐Ala‐D‐γGln was linked to DL‐Gly(Ada) yielding two diasteroisomers 3a and 3b, i.e. ambo‐Gly(Ada)‐L‐Ala‐D‐γGln (γGln = isoglutamine‐4‐amino‐4‐carbamoylbutanoic acid; Ada = adamantyl). The diastereoisomers were easily separated by column chromatography (silica gel) and characterized, but only the use of a stereospecific enzyme led to the assignment of the configuration of the Gly(Ada) moiety in the two diastereoisomers. The cytotoxic effect and antiviral activity of the novel adamantyltripeptides 3a and 3b, observed as the cell survival and the infectivity reduction of the influenza A virus H1N1 and H3N2 strains, respectively, were studied on MDCK cells in vitro. Both 3a and 3b exhibited low cytotoxicity for MDCK cells and reduced the infectivity of the influenza A virus strains, but to a different extent on different Strain.
Synthesis of Aristotelia‐Type Alkaloids. Part XII. Total synthesis of (−)‐tasmanine. Stereoelectronic factors that control the rearrangement of 3H‐indol‐3‐ol derivatives to oxindoles ( = 1,3‐dihydro‐2H‐indol‐2‐ones) or to pseudoindoxyls ( =1,2‐dihydro‐3H‐indol‐3‐ones)
Authors: Güller Rolf , Borschberg Hans‐Jürg 
Published: December 2004

AbstractThe oxidative transformation of (+)‐aristoteline ((+)‐5) into its metabolites, the recently synthesized indole alkaloids (−)‐serratoline ((−)‐6), (+)‐aristotelone ((+)‐2), and (−)‐alloaristoteline ((−)‐22), was investigated in more detail. It was demonstrated that the diastereoface selectivity of the reaction of (+)‐5 with 3‐chloroperbenzoic acid can be altered by variation of the solvent as well as by addition of CF3COOH. The chemoselectivity of the 1,2‐rearrangement of the intermediate 3H‐indol‐3‐ol derivatives could be controlled as follows: treatment of 3H‐indol‐3‐ols with aqueous polyphosphoric acid led to the pseudoindoxyl ( = 1,2‐dihydro‐3H‐indol‐3‐one) derivatives, whereas an analogous treatment of the corresponding O‐benzoates furnished exclusively the corresponding, constitutionally isomeric 2‐oxindole ( = 1,3‐dihydro‐2H‐indol‐2‐one) products. Exploitation of these and related findings led to efficient total syntheses of the Aristotelia alkaloid (−)‐tasmanine ((−)‐1) and of the corresponding unnatural epimer (+)‐12, as well as of the two pseudoindoxyls (+)‐aristotelone ((+)‐2) and (−)‐2‐epiaristotelone ((−)‐11). All these transformations were carried out with synthetic (+)‐aristoteline ((+)‐5) as the single indole alkaloid precursor.
The Donor‐Acceptor‐Acceptor Purine Analog: Transformation of 5‐aza‐7‐deaza‐1H‐isoguanine (=4‐aminoimidazo‐[1,2‐a]‐1,3,5‐triazin‐2(1H)‐one) to 2′‐deoxy‐5‐aza‐7‐deaza‐isoguanosine using purine nucleoside phosphorylase
Authors: Voegel Johannes J. , Altorfer Michael M. , Benner Steven A. 
Published: December 2004

AbstractA new synthesis is reported for 4‐aminoimidazo[1,2‐a]‐1,3,5‐triazin‐2(1H)‐one ( =5‐aza‐7‐deaza‐isoguanosine; 8), a purine analog that, when incorporated into an oligonucleotide chain, presents a H‐bond donor‐acceptor‐acceptor pattern to a complementary pyrimidine analog. A protected ribose derivative was coupled to 8 to yield 4‐amino‐8‐(β‐D‐ribofuranosyl)imidazo[1,2‐a]‐1,3,5‐triazin‐2(8H)‐one ( =5‐aza‐7‐deaza‐isoguanosine; 11) after deprotection, Alternatively, direct synthesis of both the ribo derivative 11 and the corresponding deoxyribo derivative 17 as the β‐D‐anomers was achieved using the enzyme purine nucleoside phosphorylase in a one‐pot reaction. This adapts a known synthetic approach to yield a new strategy for obtaining diastereoisomerically pure deoxyribonucleoside analogs on 1‐gram scales.
Muricatetrocins A and B and Gigantetrocin B: Three New Cytotoxic Monotetrahydrofuran‐Ring Acetogenins from Annona muricata
Authors: Rieser Matthew J. , Fang Xing‐Ping , Anderson Jon E. , Miesbauer Laura R. , Smith David L. , McLaughlin Jerry L. 
Published: December 2004

AbstractExtracts from the seeds of Annona muricata yielded three new Annonaceous acetogenins: muricatetrocin A (= (5S)‐3‐{(2R)‐2‐hydroxy‐9‐{(2R,5S)‐tetrahydro‐5‐[(1S,4S,5S)‐1,4,5‐trihydroxyheptadecyl]furan‐2‐yl}nonyl}‐5‐methylfuran‐2(5H)‐one; 1), muricatetrocin B (= (5S)‐{(2R)‐2‐hydroxy‐9‐{(2S,5S)‐tetrahydro‐5‐[(1S,4S,5S)‐1,4,5‐trihydroxyheptadecyl]furan‐2‐yl}nonyl}‐5‐methylfuran‐2(5H)‐one; 2), and gigantetrocin B (= (5S)‐3‐{(2R)‐2‐hydroxy‐7‐{(2S,5S)‐tetrahydro‐5‐[(1S,4R,5R)‐1,4,5‐trihydroxynonadecyl]furan‐2‐yl}heptyl}‐5‐methyl‐furan‐2(5H)‐one; 3). Their C‐skeletons were deduced by mass spectrometry. Configurations were determined by 1H‐NMR of ketal derivatives and 2D‐NMR experiments utilizing Mosher esters. A previously described compound, gigantetrocin A (= (5S)‐3‐{(2R)‐2‐hydroxy‐7‐{(2S,5S)‐tetrahydro‐5‐[(1S,4S,5S)‐1,4,5‐trihydroxynonadecyl]furan‐2‐yl}heptyl}‐5‐methylfuran‐2‐(5H)one; 4), was also isolated and is new to this species. Compounds 1–4 were all selectively cytotoxic for the HT‐29 human colon‐tumor cell line with potencies at least 10 times that of adriamycin.
Cation Transport across Bulk Liquid Organic Membranes with Oligomers of (R)‐3‐Hydroxybutanoic Acid
Authors: Bürger H. Michael , Seebach Dieter 
Published: December 2004

AbstractSeveral oligomeric derivatives 1–5 of (R)‐3‐hydroxybutanoic acid and a cyclic trimer of (R)‐3‐hydroxypentanoic acid (6) were used as ionophores to transport potassium picrate across a bulk liquid CH2Cl2 membrane. Using the cyclic trimer 1 and an oligomer mixture of (R)‐3‐hydroxybutanoic acid, 5 (ca. 28‐mer), for the transport experiments, the alkali‐metal ions from Li+ to Cs+ and the alkaline‐earth‐metal ions from Mg2+ to Ba2+ were also shown to be transported through the organic phase. Although a pronounced enhancement of the transport rates was observed in the presence of 3‐hydroxyalkanoate oligomers, no special selectivity for one ion was detected. The ionophore properties of the investigated oligomers and oligolides derived from 3‐hydroxybutanoic acid are compatible with the alleged role of oligo(3‐hydroxybutanoate) (c‐PHB; ca. 120‐mer) as component of ion channels through cell membranes.
Asymmetric Catalysis by Vitamin B12: The Isomerization of Achiral Aziridines to Optically Active Allylic Amines
Authors: Zhang Zhong Da , Scheffold Rolf 
Published: December 2004

AbstractAchiral N‐acylaziridines are isomerized to optically active N‐acyl‐allylamines in ee's of up to 95% by catalytic amounts of cob(I)alamin in MeOH.
An Unusual Rearrangement of a Lithiated N‐Acyl‐tetrahydroisoquinoline to an Amino‐indan Skeleton and Structural Comparison of 3‐Amino‐2‐methylindan‐ and ‐tetrahydronaphthalene‐2‐carboxylic Acids as Possible Building Blocks for Peptide‐Turn Mimics
Authors: Gees Thomas , Schweizer W. Bernd , Seebach Dieter 
Published: December 2004

AbstractLithium 1‐lithio‐6,7‐dimethoxy‐3‐methyl‐2‐pivaloyl‐1,2,3,4‐tetrahydroisoquinoline‐3‐carboxylate rearranges to the dilithio derivative of 5,6‐dimethoxy‐2‐methyl‐1‐(pivaloylamino)indan‐2‐carboxylic acid (2, [1,2]‐sigmatropic shift with retention of configuration) by 1,2‐migration resembling the Wittig rearrangement of deprotonated ethers (Scheme 2). The structure, including absolute configuration of the rearrangement product, was determined by X‐ray diffraction. Structural conditions for the rearrangement to occur are tested by subjecting various other tetrahydroisoquinoline derivatives (6, 7, 10, 15) to the metalating conditions. Only one other compound was found to undergo the same rearrangement (15 → 16). Possible mechanisms of the rearrangement are discussed (B–G). Due to the presence of a tetrasubstituted C‐atom, the indan‐type β‐amino‐acid derivative 2 has a conformationally locked structure (NCCCO2R dihedral angle 44°). For comparison, the corresponding tetralin‐type β‐aminoacid derivatives 19–22 were prepared, and it was shown by X‐ray analysis (of the ester 21) that these have larger dihedral angles (ca. 60°). It is proposed that β‐amino acids of the type described here could be incorporated into peptides, providing bents of known angles along the peptide backbone.
HPLC and 1H‐NMR Studies of Alkaline Hydrolysis of Some 7‐(Oxyiminoacyl)cephalosporins
Authors: Vilanova Bartolomé , Muñoz Francisco , Donoso Josefa , Blanco Francisco García 
Published: December 2004

AbstractAlkaline hydrolysis (pH 10.5) of the three 7‐(oxyiminoacyl)cephalosporins 1a–c (cefuroxime, ceftazidime, and ceftriaxone) was studied at 37° using HPLC and 1H‐NMR techniques. The 7‐epicephalosporin 2, the 3‐methylidene compound 3, and the 6‐epimer 4 of the 3‐methylidene compound 3 were identified for each cephalosporin as the major degradation products under the conditions used; ceftazidime (1b) yielded also the Δ2‐isomer 5b (Scheme 1). A kinetic scheme was developed to account for the production of these compounds, and the different kinetic constants involved in the process were calculated. The experimental results show that the presence of a pyridinio group at position C–C(3) favours the appearance of the Δ2‐isomer, which was detected mainly in cephalosporins bearing an ester function at C(4). The presence of an oxyimino group at CCONHC(7) facilitates epimerization at C(7) (→ 2), whereas that of an electron‐withdrawing group at CC(3) results in a increased formation constant for the 3‐methylidene compound 3. The 3‐methylidene compounds 3a–c produced by the three cephalosporins on cleavage of the β‐lactam ring all underwent epimerization at C(6) to yield the corresponding 6‐epimer 4.
Lanthanide‐Ion Complexation by D‐Glucuronic and D‐Galacturonic Acids
Authors: Fuks Leon , Bünzli Jean‐Claude G. 
Published: December 2004

AbstractTo assess the potential of naturally occurring substances in the treatment of heavy‐metal intoxication, the interaction between D‐galacturonic and D‐glucuronic acids with several trivalent lanthanide ions has been studied in aqueous solutions by means of a spectrophotometric method (27°; 0.1M NaClO4; pH 4.0). Values for the overall stability constants for [LnL] and [LnL2] (Ln = La, Ce, Pr, Nd, Gd, or Lu) complexes are presented and discussed. The interpretation of the data shows that, similarly to acetates, the COOH group coordinates metal ions in both [LnL] and [LnL2] complexes. The 1:1 complexation is supplemented by the ring C(5)O‐atom. Moreover, the C(4)O‐atom seems to play an important role in the steric hindrance of the chelating ligand molecules.
Enantioselective synthesis of (−)‐conduramine C1 and aminobromocyclitol derivatives
Authors: Allemann Susy , Vogel Pierre 
Published: December 2004

Abstract(1S,2R,6R,7R)‐4‐Phenyl‐3,10‐dioxa‐5‐azatricyclo[5.2.1.02,6]dec‐4‐en‐9‐one ((+)‐5) obtained in 6 steps from the Diels‐Alder adduct of furan to 1‐cyanovinyl (1S)‐camphanate ((+)‐3) was reduced to the corresponding endo‐alcohol (−)‐6 the treatment of which with HBr/AcOH provided (−)‐(3aS,4S,6R,7S,7aR)‐4β‐bromo‐3aβ,4,5,6,7,7aβ‐hexahydro‐2‐phenyl‐1,3‐benzoxazole‐6β,7α‐diyl diacetate ((−)‐17). Elimination of HBr with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) and acidic hydrolysis furnished (−)‐(1R,2S,3R,4R)‐4‐aminocyclohex‐5‐ene‐1,2,3‐triol (  (−)‐conduramine C1;(−)‐1).
Electrochemical Study of Phase‐Transfer Catalysis Reactions: The Williamson ether synthesis
Authors: Tan S. N. , Dryfe R. A. , Girault Hubert H. 
Published: December 2004

AbstractThe transfer properties of the ionic species involved in the Williamson ether synthesis by phase‐transfer catalysis were investigated using electrochemical techniques developed for the study of polarised liquid/liquid interfaces. This approach allows the measurement of the apparent partition coefficients of the transferring species. From these data, it is proposed that the role of the phase‐transfer catalyst salt in the reaction mechanism is to establish a Galvani distribution potential difference between the two phases which in turn acts as the driving force for transferring the reactive aqueous ions to the organic phase.
Bovine α‐Lactalbumin: Identification of two metal‐ion‐binding sites using the europium (III) luminescent probe
Authors: Bünzli Jean‐Claude G. , Pfefferlé Jean‐Marc 
Published: December 2004

AbstractThe luminescent EuIII ion has been used to probe the metal‐binding sites of bovine α‐lactalbumin (BLA) in D2O. Upon addition of apo‐BLA to an EuIII‐containing solution, the intrinsic luminescence of the protein is quenched, and the EuIII luminescence is enhanced. Luminescent titrations point to there being at least two different metal‐binding sites in the apo‐protein. Curve analysis of the high resolution 5D0←7F0 excitation spectra reveals the existence of three different environments for the bonded EuIII ions. Two environments, labelled Ia and Ib, give 5D0←7F0 bands very close in energy; they contain four negatively charged groups and are assigned to one site we identify as the calcium‐binding site. Site I is protected from solvent influences and is somewhat rigid, since it displays selectivity towards lanthanide ions. The origin of the two similar environments Ia and Ib could not be determined unambiguously. The third environment is ascribed to a nonspecific metal‐binding site in which the EuIII ion is more exposed to the solvent (site II). It is sequentially populated after saturation of site I, and its population is pH‐dependent. The affinity constant of EuIII for this site was estimated from the excitation spectra: log K2app  3.5(1). Assignment of the metal binding sites has been facilitated by comparison with model compounds, [Eu(dota)]− (dota  1,4,7,10‐tetraazacyclododecane N,N′,N″, N‴‐tetraacetate), [Eu(dtpa)]2− (dtpa  diethylenetriamine tetraacetate), and [Eu(bsa)] (bsa  bovine serum albumin). The usefulness and limits of the use of curve‐analysis procedures to unravel the various components of 5D0←7F0 excitation spectra in biological materials are also discussed.
N7‐DNA: Synthesis and Base Pairing of Oligonucleotides containing 7‐(2‐Deoxy‐β ‐D‐erythro‐pentofuranosyl)adenine (N7Ad)
Authors: Seela Frank , Winter Holger 
Published: December 2004

AbstractThe synthesis of oligonucleotides containing 7‐(2‐deoxy‐β ‐D‐erythro‐pentofuranosyl)adenine (N7Ad; 1) is described. Compound 1 was obtained from the precursor 4‐amino‐1H ‐imidazole‐5‐carbonitrile 2‐deoxyribonucleoside 6 and was found to be much more labile than Ad. The N6‐benzoyl protecting group (see 8) destabilized the N‐glycosylic bond further and was difficult to remove by NH3‐catalyzed hydrolysis. Therefore, a (dimethyl‐amino)methylidene residue was introduced (→9). Amidine 9 was blocked at OHC(5′) with the dimethoxytrityl residue ((MeO)2Tr), and phosphonate 4 as well as phosphoramidite 5 were prepared under standard conditions. Phosphonate 4 was employed in solid‐phase oligonucleotide synthesis. Homooligonucleotides as well as self‐complementary oligonucleotides were prepared. The oligomer d[(N7A)11‐A] (11) formed a duplex with d(T12) (13). Antiparallel chain polarity and reverse Watson‐Crick base pairing was deduced from duplex formation of the self‐complementary d[(N7A)8‐T8] (14).
[M(bpy)3] (M = Fe, Ru, Os): New Crystalline Materials from the reductive electrocrystallization of [M(bpy)3](PF6)2
Authors: Pérez‐Cordero Eduardo , Buigas Rosanna , Brady Nancy , Echegoyen Luis , Arana Claudia , Lehn Jean‐Marie 
Published: December 2004

AbstractReductive electrocrystallization at a constant current density (11.0–11.5 μA/cm2) of millimolar solutions of [M(bpy)3](PF6)2, where M = Fe, Ru, or Os, and bpy = 2,2′‐bipyridine in acetonitrile containing 0.1M Bu4NPF6 results in the formation of dark crystals on the Pt cathode. The crystals grow as long, thin, and shiny needles having a hexagonal cross section of 0.1–0.5 mm in diameter. Combustion microanalyses results are consistent with the composition for [Fe(bpy)3], [Ru(bpy)3], and [Os(bpy)3]. In addition, the chromophores are conserved, as confirmed by recording both the electronic and the 1H‐NMR spectra after reoxidation of the electrocrystals in humid air. The spectra are identical to those for authentic samples of [Fe(bpy)3]2+, [Ru(bpy)3]2+, and [Os(bpy)3]2+. A ratio of 2.0 ± 0.1 e−/molecule is observed upon completion of the controlled potential electrolysis of a solution of [M(bpy)3]2+, which results in the precipitation of a dark solid and the almost complete fading of the color of the original solution. Unexpectedly, the crystals do not exhibit an ESR signal. These data indicate the formation of novel materials, crystalline [Fe(bpy)3], [Ru(bpy)3], and [Os(bpy)3].
Asymmetric Total Synthesis of (11R, 12S, 13S, 9Z, 15Z)‐9, 12, 13‐Trihydroxyoctadeca‐9, 15‐dienoic Acid, a self‐defensive agent against rice‐blast disease
Authors: Baudat Alain , Vogel Pierre 
Published: December 2004

AbstractThe Diels‐Alder adduct of furan and 1‐cyanovinyl (1′R)‐camphanate was converted into methyl [(tert‐butyl)‐dimethylsilyl 5‐deoxy‐2, 3‐O‐isopropylidene‐β‐L‐ribo‐hexofuranosid] uronate ((+)‐4). Reduction with diisobutyl‐aluminium hydride gave the corresponding aldehyde which was condensed with the ylide derived from triphenyl‐(propyl)phosphonium bromide to give (1R, 2S, 3S, 4S)‐1‐[(tert‐butyl)dimethylsilyloxy]tetrahedro‐2, 3‐(isopropyl‐idenedioxy)‐4‐[(Z)‐pent‐2′ ‐enyl]furan ((+)‐7). Removal of the silyl protective group gave a mixture of the corresponding furanose that underwent Wittig reaction with the ylide derived from [8‐(methoxycarbonyl)‐octyl]triphenylphosphonium bromide to yield methyl (11R, 12S, 13S, 9Z, 15Z)‐13‐hydroxy‐11, 12‐(isopropylidene‐dioxy)octadeca‐9, 15‐dienoate ((−)‐9). Acidic hydrolysis, then saponification afforded (11R, 12S, 13S, 9Z, 15Z)‐11, 12, 13‐trihydroxyoctadeca‐9, 15‐dienoic acid (1).