bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyamines XV. Thermodynamics of Metal Complex Formation of Linear Tetraamines Containing Two Ethylenediamine Residues
Authors: Anderegg Giorgio , Bläuenstein Peter 
Published: December 2004

AbstractThe complex formation of Co2+, Ni2+, Cu2+, Zn2+, Pb2+ and Hg2+ with three tetraamines of type H2N(CH2)2NH(CH2)nNH(CH2)2NH2 (= 2, n, 2‐tet) for n = 2. 3 and 4, and with N‐methylethylenediamine (= nmen) have been investigated at 25° and I = 1(KNQ3). The stability constants and the heat evolved by formation of the (1:1)‐complexes ML have been determined. It is shown that the more stable complexes are normally formed by 2,3,2‐tet‐ligands. These results are discussed relating the thermodynamic data obtained to the stereochemistry of the complexes and using the visible spectra of the complexes in solution. The change in enthalpy is found to be the dominant factor and the measure of the steric strain whereas the entropy of complex formation decreases slowly.
Eine neue, einfache Synthese von 2,3,5‐Trichlorpyridin
Authors: Steiner Eginhard , Martin Pierre , Belluš Daniel 
Published: December 2004

A New Simple Synthesis of 2,3,5‐TrichlorpyridineA simple synthesis of 2,3,5‐trichloropyridine by the copper‐catalyzed free radical addition of chloral to acrylonitrile with or without isolation of the primary 1:1 adduct,4‐formyl‐2,4,4‐trichlorobutyronitrile (1), is described.
Dimetallic Complexes with Bridging Seven‐membered Cycloolefins. Synthesis, Multinuclear NMR.‐Spectroscopic Properties and Structure
Authors: Salzer Albrecht , Egolf Thomas , Von Philipsborn Wolfgang 
Published: December 2004

AbstractThe synthesis of dimetallic olefin complexes of the type L1M1C7H7M2L2 (M1 = Fe, Co, Rh; M2 = Rh, Ir, Pd; L1 = CO, C5H5; L2 = diene, allyl, P(OR)3) is described. The fluxional structures were investigated by 13C‐, 57Fe‐ and 103Rh‐NMR.‐spectroscopy, and a cisoid dimetallic coordination, including a (metal, metal)‐bond, can be deduced for the C7H7‐ring. 57Fe‐ and 103Rh‐chemical shifts give indications for the charge distribution in the 34e‐complexes. The homodimetallic complex (Cp)Rh(tropone)Rh(Cp) (13, Cp = cyclopentadienyl) and the corresponding 2‐methoxytropone complex 14 were synthesized in addition to the above mentioned complexes. A fluxional bis(1‐3‐η‐allyl)‐coordination of the two Rh‐atoms was derived from the temperature‐dependent 13C‐NMR.‐spectra. A spin simulation of the (Cp)‐multiplets of 12 and 13 yields information about (Rh, Rh)‐spin‐coupling which amounts to ≈5 Hz at 30°.
Substituted 2‐Phenyl‐ and 2‐Cyclohexyl‐trans‐decalins, New Classes of Nematic Liquid Crystals
Authors: Petrzilka Martin , Schleich Kuno 
Published: December 2004

AbstractVersatile procedures for the preparation of the title compounds are described. Representatives of ketones (12and27), hydrocarbons (19and28), acids (13), esters (15. and20), ethers (22) and nitriles (18) possess wide‐range nematic phases, provided their terminal chains R2and R3contain at least three methylene units.
A convenient and diastereoselective route to homoallyl alcohols: Addition of (z)‐ or (e)‐alkenyl‐dimethoxyboranes to aldehydes
Authors: Fujitta Katsuramaru , Schloser Manfred 
Published: December 2004

Abstract(Z)‐2‐Butenyl‐dimethoxyborane adds smoothly to propanal and benzaldehyde to afford the homoallyl alcohols (R*,R*)‐1 and (R*,R*)‐2, In contrast (E)‐2‐butenyl‐dimethoxyborane leads to adducts having the (R*,S*)‐configuration. Dimethoxy‐(Z)‐2‐pentenylborane, dimethoxy‐(Z)‐(2‐methyl‐2‐butenyl)borane and (2Z,4E)‐or (2E,4Z)hexadienyl‐dimethoxyborane, treated with propanal, give (R*,R*)‐3, (R*,R*)‐4, (E),(R*,S*)‐5 and (Z),(R*, R*)‐5, respectively. A transition state model implying a pericyclic electron motion is in perfect agreement with the regio‐ and stereoselective outcome of these borane reactions.
The Synthesis of 5,11,17‐Trihalotetracyclo [13.3.1.13,7.19,13]henicosa‐1 (19),3,5,7 (20),9,11,13 (21), 15,17‐nonaene‐19,20,21‐triols and 5,11,17‐trihalo‐19,20,21‐trihydroxytetracyclo [13.3.1.13,7. 19,13]henicosa‐1 (19),3,5,7 (20),9,11,13(21), 15,17‐nonaene‐8,14‐dione [1]. Cyclo‐derivatives of Phloroglucide Analogues
Authors: Moshfegh Ali A. , Beladi Effat , Radnia Lida , Hosseini Afsaneh S. , Tofigh Soosan , Hakimelahi Gholam H. 
Published: December 2004

AbstractThe synthesis of the title compounds (1 and 3) is described. Some of the compounds prepared were found to be active against a number of pathogenic microorganisms in vitro. Structure‐activity relationship is briefly discussed.
Structural Analogues Of Aporphines Part 1: Synthesis of Apomorphines with the Catechol Moiety Replaced by 5‐membered Heterocycles
Authors: Berney Daniel , Schuh Karlheinz 
Published: December 2004

AbstractAnalogues of apomorphine (1) having the catechol moiety replaced by pyrrole (→10, 18), pyrazole (→12), isoxazole (→13, 14), thiazole (→16) and thiadiazole (→20) ring systems have been synthesized from the key intermediate ketone 6.
Thermal Isomerization of 7,8‐Diazabicyclo[4.2.2]deca‐2,4,7,9‐tetraene N‐oxide to Benzaldehyde Oxime
Authors: Olsen Henrik 
Published: December 2004

AbstractThermal transformation of 7,8‐diazabicyclo[4.2.2]deca‐2,4,7,9‐tetraene N‐oxide (3) was observed, (Z)‐benzaldehyde oxime being the major product, with (E)‐benzaldehyde oxime as a minor product. N‐Oxide 3 was labeled with deuterium α to the oxidized N‐atom. The location of the deuterium label in the thermolysis products fitted one of two reasonable mechanisms.
Photon‐Triggered Complex Formation: Radical Complexes of o‐Benzosemiquinone, Dopa, Dopamine and Adrenaline Formed by Electron‐Transfer Reaction from Excited Tris (2,2′‐bipyridyl)ruthenium (II)
Authors: Plancherel Dominique , von Zelewsky Alex 
Published: December 2004

AbstractThe pyrocatechol derivatives, dopamine (2), adrenaline (3) and L‐dopa (4) form in their semiquinoid oxidation states complexes with several closed‐shell metal ions like Zn2+, Cd2+ and Y3+. This complex formation can be triggered by visible light via a one‐electron transfer reaction from the pyrocatechol derivative to (3CT)Ru(bpy), which is thereby reduced (Schemes 1 and 2), The quenching of the triplet charge‐transfer state, (3CT)Ru(bpy) cannot be measured by conventional methods (Stern‐Volmer plot), because the bimolecular electron‐transfer rate is too slow (kq < 10−7 M−1 s−1). ESR. spectroscopy shows, however, clearly the paramagnetic reaction products. The concentration of these paramagnetic species is strongly enhanced by complex formation.The hindered rotation of the side chain in L‐dopa and in its Y3+‐complex is described within a two‐jump model, which gives best agreement between calculated and measured spectra assuming an energy of 37 kJmol−1 for the rotational barrier.
Forward Electron Scattering in Benzene; Forbidden Transitions and Excitation Functions
Authors: Allan Michael 
Published: December 2004

AbstractA systematic study of vibronic excitation in benzene via forward electron scattering was carried out using a novel type of a trochoidal electron spectrometer. Energy‐loss spectra in the energy range 1.0–9.5 eV, with residual energies 0.03–20 eV as well as excitation functions for individual vibrational levels of some of the triplet and singlet states are presented and discussed. Following observations were made. (1) A new s‐type Rydberg series with quantum defect δ = 0.86. (2) Additional information on the complex 6–6.5 eV band. (3) A new core excited shape resonance at 6.5 eV. (4) A narrow Feshbach resonance at 5.87 eV, The new spectrometer is suggested as a tool for routine study of forbidden transitions and negative ion states in organic molecules.
Preparation of 1,2exo‐ and 1,2endo‐Diiodo‐bicyclo[2.2.1]heptane
Authors: Camenzind Hugo , Krebs Ernst‐Peter , Keese Reinhart 
Published: December 2004

Abstract1,2 exo‐Diiodo‐norbornane (4) was prepared from norcamphor hydrazone by oxidative iodination and subsequent rearrangement of the 2,2‐diiodo‐bicyclo [2.2.1]heptane (2). The stable α‐iodohydrazone 11 was obtained from 1‐iodo‐bicyclo[2.2.1]heptan‐2‐one (10), which itself was prepared from 1‐iodo‐norbornene (5). Subsequent treatment of 11 with iodine lead to 1,2,2‐triiodo‐norbornane (12) and l,2‐diiodo‐norborn‐2‐ene (13). 1,2 endo‐Diiodo‐norbornane (14) was obtained by stereoselective reduction of 12 with tribtityltinhydride or by reaction of 13 with diimide.
Solvent‐Induced Deuterium Isotope Effects in 13C‐ and 15N‐NMR. Spectra of Enaminones
Authors: Kozerski Lech , von Philipsborn Wolfgang 
Published: December 2004

AbstractThe effect of deuterium on the 13C and 15N chemical shifts of enaminones has been investigated. D/H isotope shifts are reported for neutral and protonated species, i.e., when the isotope is exchanged on the C(2)‐, N‐, or O‐atoms. In cases of slow exchange the isotope shifts were obtained from solutions containing both isotopomers, whereas for fast exchange (acidic solutions) either separate NMR. sample tubes (15N‐NMR.) or coaxial tubes (13C‐NMR.) were used.In neutral molecules the isotope effects δC(D, H) are intrinsic in nature. In acidic solutions, the enaminocarbonyl cations formed exhibit δC(D, H)‐ and δN(D, H)‐values which are discussed in terms of the proton transfer. The mesomeric character of the cations is reflected by characteristic features in the δC(D, H)‐ and δN(D, H)‐values, which can be ascribed to isotopic perturbation of resonance.O‐Protonation shifts in the 15N‐resonance, observed for the first time, are large and positive (+60 to +76 ppm), in contrast to amides, where the effects are of the same sign but an order of magnitude smaller. Both protonation shifts and solvent‐induced isotope effects are discussed in connection with the nucleophilic character of the reactive centers in the enaminone synthon.
Synthese von 1, 2‐annelierten 1, 4‐Benzodiazepinen und 4, 1‐Benzoxazepinen
Authors: Müller Werner , Stauss Urs 
Published: December 2004

AbstractThe syntheses of 1, 2‐annelated 1, 4‐benzodiazepines (IV, Y = N) and 4, 1‐benzoxazepines (IV, Y = 0) are described (Scheme 1). The key step is a nucleophilic aromatic substitution of 2‐substituted piperazines (II, Z = NCH3), piperidines (II, Z = CH2) or pyrrolidines (II, Z= (CH2)0) with activated aryl halides (I).
Nachweis von C (15)‐epimeren Coleonen C und D in der Natur und ihre Bedeutung für den sterischen Verlauf der Bildung des Spirocyclopropanrings
Authors: Rüedi Peter , Schmid Jean Martin , Eugster Conrad Hans 
Published: December 2004

Natural Occurrence of C(15)‐Epimeric Coleons C and D and its Significance to the Stereochemistry of the Formation of a SpirocyclopropanringIn a previous paper some evidence was presented for a predominant occurrence of epimeric coleons ((15S)‐coleon C ((15 S)‐1a), and (15S)‐coleon D ((15S)‐2a)) in Plectranthus lanuginosus [1], The proposed structures have now been proven by careful comparison of their physical data with those of the already described C(15)‐epimers whose structures were deduced by X‐ray analysis of a derived cis‐diketone 3 [5], Examination of the epimeric purity of coleons possessing a 2‐hydroxy‐1‐methylethyl side‐chain (coleons C, D, H, I, I′ and derivatives) isolated from seven different species (Coleus, Plectranthus and Solenostemon) has shown that these coleons always occur as a mixture of C(15)‐epimers, although in most cases with one predominant epimer. The consequences for the stereochemistry of the postulated in vivo formation of the methyl‐substituted spirocyclopropane substructure is discussed.
Simplified Liquid‐Phase Preparation of Four Decadeoxyribonucleotides and their Preliminary Spectroscopic Characterization
Authors: Denny William A. , Leupin Werner , Kearns David R. 
Published: December 2004

AbstractFour self‐complementary decadeoxyribonucleotides, dApTpApTpApTpApTpApT, dApTpApTpCpGpApTpApT, dApTpApTpGpCpApTpApT and dApApApApApTpTpTpTpT, were chemically synthesized by the phosphotriester procedure. Efforts were concentrated on keeping the procedure as simple as possible, concomitant with obtaining high‐purity products at each step of the process. The decamers were elaborated from the 3'‐end, starting with a 3'−O‐benzoylated monomer according to the scheme: monomer + monomer → dimer + dimer → tetramer + dimmer → hexamer + tetramer → decamer. Purity of intermediates and of the fully blocked decamers were monitored by chromatography and by 300‐MHz 1HN M R. spectroscopy. The deblocked decadeoxyribonucleotides were characterized by their UV., CD., and 1HNMR. spectra.
Structure‐Activity Relationship of Oxygenated Morphinans. VII. 5‐Methylated and 14‐Hydroxy‐substituted Agonists and Antagonists of the 4‐Hydroxy‐ and 3, 4‐Dioxygenated 6‐Morphinanone Series
Authors: Brossi Arnold , Atwell Louise , Jacobson Arthur E. , Rozwadowska Maria D. , Schmidhammer Helmut , Flippen‐Anderson Judith L. , Gilardi Richard 
Published: December 2004

AbstractSeveral morphinanone agonists differently substituted at C(3), C(4), C(5) and C (14) and antagonists of the 4‐hydroxy and 3, 4‐dimethoxy series were prepared by conventional chemistry. It was demonstrated that the oxygenation pattern in the bay‐area, encompassing C(3) and C(4), is important. Alkylation at C(5) or hydroxylation at C(14) lowered the potency of the compounds. The most potent agonist was found to be the N‐phenethyl‐substituted ketone 27, which was six times more potent than morphine in the hot‐plate assay. The 3, 4‐methylenedioxy‐substituted ketone 9 was about 20 times less potent than its 3, 4‐dimethoxy congener. An X‐ray analysis of 9 and a representative agonist showed that the stereochemical features in the bay‐area were similar and could not be used to explain this difference.
Intramolecular Transfer of Excitation Energy, Complexation with Metal Ions, and Interactions with Liposomes of Cyclo [tryptophyl‐sarcosyl‐sarcosyl‐Nϵ‐dansyllysyl‐prolyl]
Authors: Kimura Shunsaku , Imanishi Yukio 
Published: December 2004

AbstractA cyclic pentapeptide containing an energy donor group and an energy acceptor group within the molecule, cyclo [Trp‐Sar‐Sar‐Lys (DNS)‐Pro], was synthesized. Its conformation, complexation with metal ions, intramolecular energy transfer, and interaction with liposomes were investigated. The precursor, cyclo [Trp‐Sar‐Sar Lys (Z)‐Pro], contained one cis‐sarcosyl peptide bond and a β‐turn in which the Pro‐residue occupied the 3rd position. This cyclic pentapeptide formed a complex selectively with Ba2+ and its binding constant in 95% aqueous methanol solution was 2.0 × 103 1 · mol−1. The intramolecular energy‐transfer efficiency of cyclo [Trp‐Sar‐Sar‐Lys (DNS)‐Pro] was almost constant between − 60° and 40° in ethanol, while it increased at temperatures lower than 34° in liposomes as a result of the pre‐transition of the lipid assembly. On the other hand, the intramolecular energy transfer efficiency of cyclo [Trp‐Sar‐Sar‐Lys (DNS)‐Pro] decreased upon complexation with Ba2+.
Stoffwechselprodukte von Mikroorganismen. 219. Mitteilung. Versuche zur Strukturaufklärung von Niphimycin, 2. Teil. Die Konstitution von Desmalonyl‐niphimycin I
Authors: Keller‐Schierlein Walter , Joos Beda , Kaiser Hans‐Peter , Gassmann Peter 
Published: December 2004

On the Structural Elucidation of Niphimycin, Part II. The Constitution of Demalonylniphimycin IA stepwise degradation of copiamycin and niphimycin I with ozone and sodium periodate, partly combined with D‐labelling, and intense spectroscopic investigations of the degradation products led to the structural formulae 34 for demalonylcopiamycin (in agreement with the structure proposed by Iwasaki et al. for the same antibiotic) and 38 for demalonylniphimycin. The antibiotics copiamycin and niphimycin are half esters of malonic acid and the macrolide polyols 34 and 38, resp., with uncertain positions of the malonyl residues.
Saponins with Molluscicidal Properties from Lonicera nigraL
Authors: Domon Bruno , Hostettmann Kurt 
Published: December 2004

AbstractEight triterpenoid saponins (1–8) have been isolated from the berries of Lonicera nigra L. (Caprifoliaceae) by combination of droplet counter‐current chromatography and column chromatography on silica. The structures have been established by 1H‐NMR., 13C‐NMR. spectroscopy, FD.‐MS., FAB.‐MS. and D./CI.‐MS., and on the basis of acidic and basic hydrolyses. The monodesmosidic saponins 1–5 possess strong molluscicidal activity against the schistosomiasis‐transmitting snail Biomphalaria glabrata, whereas the bidesmosidic saponins 6–8 are inactive.
Spirocoleone: Synthese und Charakterisierung von vier diastereomeren Spiro (methylcyclopropan)‐Substrukturen; Revision der Konfiguration an C(12) und C(15) von Coleon P und Derivaten sowie von Coleon‐Z‐Derivaten; Röntgenstrukturanalysen von Lanugon J und weiteren Spirocoleonen
Authors: Rüedi Peter , Schmid Jean Martin , Prewo Roland , Bieri Jost Hans , Eugster Conrad Hans 
Published: December 2004

Spirocoleons: Synthesis and Characterization of Four Diastereomeric Spiro (methylcyclopropane) Substructures; Revision of the Configuration at C(12) and C(15) of Coleon P and Derivatives and Coleon‐Z Derivatives; X‐Ray Analysis of Lanugon J and of Further SpirocoleonsX‐ray analyses show the correctness of the previously published structure of coleon Q (1), establish the structure of lanugon J (4a), and necessitate a revision of the configuration at C(12) and C(15) in coleon P (3a) and its derivatives 3b and 3c, and furthermore of the coleon Z derivatives 11a–11d. Two further diastereomeric spiro (methylcyclopropane) substructures have been generated by photoisomerization of lanugon J (4a) and 12‐O‐desacetylcoleon N (8); they represent the novel cis‐type B with (12R, 13R, 15S)‐ and the novel trans‐type D with (12R, 13R, 15R)‐configuration (Scheme 1). The structures of the photoproducts 5a ((12R, 13R, 15R)‐lanugon J) and 7a ((12R, 13R, 15S)‐lanugon J) were established by X‐ray analysis. So far, only two of the eight possible diastereomers of the spiro‐(methylcyclopropane) substructure I have been detected in nature, i.e. the trans‐type A with (12R, 13S, 15S)‐ and the cis‐type C with (12R, 13S, 15R)‐configuration. The four diastereomers A‐D, all possessing (12R)‐configuration, show very similar properties. However, careful comparison of spectral and chiroptical data allow a differentiation, even in the case of functionalization of H3C(17). The (12S)‐counter‐parts could not yet be prepared.
Biosynthesis of Benzo[c]phenanthridine Alkaloids Sanguinarine, Chelirubine and Macarpine
Authors: Takao Narao , Kamigauchi Miyoko , Okada Momoyo 
Published: December 2004

AbstractThe biosynthesis of the benzo[c]phenanthridine alkaloids was investigated in a cell suspension culture of Macleaya cordata (papaveraceae). Feeding experiments define the biosynthetic pathway (–)‐7,8,13,13a‐tetrahydrocoptisine →(–)‐cis‐N‐methyl‐7,8,13,13a‐tetrahydrocoptisinium salt 15→ protopine (5)→ sanguinarine (1)→ chelirubine (3)→ macarpine (4).
Deblocking ofo‐Nitrophenylsulfenyl‐Protected Peptides by Ammonium Thiocyanate and (2‐Methyl‐1‐indolyl)acetic acid
Authors: Lüscher Immanuel F. , Schneider Conrad H. 
Published: December 2004

AbstractThe thiocyanate cleavage of theNa‐o‐nitrophenylsulfenyl group from peptides in solution or on a solid support proceeds effectively in the presence of (2‐methyl‐1‐indolyl)acetic acid. This scavenger was prepared from 2‐methylindole and sodium bromoacetate; it can readily be removed by extraction with base after the cleavage reaction, together with (2‐methyl‐3‐(2‐nitrophenylthio)‐1‐indolyl)acetic acid.
Propellanes. LXVI. Exo‐ and Endo‐Diels‐Alder adducts of 4‐substituted 1,2,4‐triazoline‐3, 5‐diones with various 1, 6‐methano [10]annulenes
Authors: Ashkenazi Pnina , Kaftory Menachem , Ginsburg David 
Published: December 2004

AbstractRelatively few exo‐adducts have been obtained from the title compounds. Only one such mono‐adduct, 3, is known. Several exo‐endo‐bis‐adducts have been obtained but the structure of one of these, 5, has been proved unequivocally by X‐ray structural determination.
Electronic States of Phenylene and Naphthylene Bicyclobutanes. Linear Dichroism in Stretched Polyethylene
Authors: Spanget‐Larsen Jens , Gubernator Klaus , Gleiter Rolf , Thulstrup Erik W. , Bianco Bernard , Gandillon Gérard , Burger Ulrich 
Published: December 2004

AbstractExcited singlet states of bicyclobutylene‐benzene (2), 1,2:4,5‐bis (bicyclo‐butylene)benzene (3), 2,3‐bicyclobutylene‐naphthalene (4), and 1,8‐bicyclobutylene‐naphthalene (5) are investigated by means of linear dichroic absorption spectroscopy of molecules oriented in stretched polyethylene films and by semiempirical model calculations. The results indicate a strong hyperconjugative impact of the bicyclobutylene group on the aromatic chromophores in these compounds. Valence isomerization to aromatic products is predicted as the preferred photochemical pathway.
Syntheses of Optically Active Verrucarinic Acid. 40th Communication on Verrucarins and Roridins
Authors: Herold Peter , Mohr Peter , Tamm Christoph 
Published: December 2004

AbstractThree syntheses of (2S, 3R)‐2,5‐dihydroxy‐3‐methylpentanoic acid (verrucarinic acid) and its derivatives suitably protected for the further transformation to macrocyclic trichothecenes are described. These involve an enantioselective ester hydrolysis by pig liver esterase, a Sharpless epoxidation and an asymmetric hydroboration.
Tricyclo[3.3.0.02,8]Octanones as Building Blocks in Natural Products Synthesis. II. A new synthesis of loganin
Authors: Kon Kenji , Isoe Sachihiko 
Published: December 2004

AbstractThe stereocontrolled synthesis of loganin from 4‐methyltricyclo[3.3.0.02,8]octan‐3‐one is described.
The Synthesis of n,n‐Dimethyl‐2‐(1‐phenyl‐2,5‐cyclohexadien‐1‐yl)‐ethylamine and of Mesembrine‐Like Metabolites of this Potential Analgesic
Authors: Müller Peter M. , Pfister Rudolf 
Published: December 2004

AbstractThe synthesis of the analgesic compound N,N‐dimethyl‐2‐(1‐phenyl‐2,5‐cyclohexadien‐1‐yl)ethylamine (1) is described. Its structural relation to morphine and its pharmacological activity is shortly discussed. The isolation of three mesembrinelike metabolites of 1 from the plasma of rats is reported along with synthetic work permitting the determination of the relative configuration of these metabolites.
Photosensitized Oxygenation of Abieta‐7,9(11)‐dien‐13β‐ol
Authors: Zelnik Raymond , Rabenhorst Ema , Haider Akhtar , Lauterwein Jürgen , Wyler Hugo 
Published: December 2004

AbstractDehydration of abiet‐8‐ene‐7β, 13β‐diol (ibozol, 1) leads to abieta‐7,9(11)‐dien‐13β‐ol (2) which aromatizes slowly to the known abieta‐8,11,13‐triene (3). Photosensitized oxygenation of the heteroannular diene 2 yields a mixture from which three compounds were identified; abiet‐7‐ene‐9α, 11α, 13β‐triol (4), abieta‐8,11,13‐trien‐7‐one (5), and abieta‐8,11,13‐trien‐7α‐ol (6).