bluuebunny/crossref_metadata_2025_split huggingface dataset:
Push‐pull‐Cyclobutadiene
Authors: Neuenschwander M. , Niederhauser A. 
Published: December 2004

AbstractTwo push‐pull‐cyclobutadienes 10b and 10c are prepared by reaction of two eq. of the corresponding acetylenes having electrondonating and electronaccepting groups (4) with one eq. of HBF4 to cyclic cyanine salts, followed by elimination of HBF4 with KOC(CH3)3. These cyclobutadienes, stable in cristalline form at room temperature respectively for a short time (10b RCH3) or for several days (10c ROCH3), are extremely reactive in solution towards various nucleophiles and electrophiles. Cleavage of the nascent cyclobutenes leads to butadienes. The cyclobutadienes 10 dimerise thermally to cyclooctatetraenes 18.
Komplexone XLIII. Die Komplexe des dreiwertigen Antimons mit Polyaminocarboxylaten
Authors: Anderegg G. , Malik S. 
Published: December 2004

AbstractIf a strong base is added to solutions containing complexes of trivalent antimony with aminopolycarboxylates, these ligands are displaced, and oversaturated solutions of antimony (III) hydroxide are formed. This reaction has been used to investigate the formation of complexes of SbIII with the following ligands: N′‐hydroxyethyl‐ethylenediamine‐N,N,N′‐triacetate ion, ethylenediamine‐N,N,N′,N′‐tetraacetate ion, 1,2‐diaminocyclohexane‐N,N,N′,N′‐tetraacetate ion, and diethylenetriamine‐N,N,N′,N″,N″‐pentaacetate ion.
Komplexone XLIV. Die Komplexe der Anionen der Triäthylentetraminhexa‐Essigsäure mit Calcium(II), Kupfer(II) und Zink(II)
Authors: Linden W. v. D. , Anderegg G. 
Published: December 2004

AbstractUsing pH‐methods ‐ direct titration according to Schwarzenbach, and ligand‐ligand exchange ‐ the stability constants of the complexes of divalent calcium, copper and zinc ions with the anions of triethylenetetramine hexaacetic acid have been determined. The complications arising by the interpretation of the experimental measurements of pH‐values below 3.5 are discussed. These factors are normally not taken into account, and often wrong values of the equilibrium constants have been communicated.
Die Komplexbildungstendenz des dreiwertigen Antimons in wässeriger Lösung
Authors: Anderegg G. , Malik S. 
Published: December 2004

AbstractThe formation of the complexes of trivalent antimony ion with the following ligands has been investigated with pH measurements: D‐tartaric acid, L‐tartaric acid, catechol, catechol‐3,5‐disulfonic acid, 2,3‐dihydroxybenzoic acid, mercaptoacetic acid, rac‐thiomalic acid, meso‐, rac‐dithiotartaric acid, and mercapto‐ethanol. Using the determined equilibrium constants, a classification of the ligands with respect to their ability to sequester the cation studied is given. In a discussion in which data of the literature are also included the structure of the tartar emetic, the possibility of a volumetric determination of the antimony, some problems concerning the coordination number, and the structure of the complexes are examined.
Über En‐synthesen mit Singulett‐Sauerstoff [1] II. Die Farbstoff‐sensibilisierte Photooxygenierung von (—)‐Thujopsen und die Stereochemie der dargestellten Thujopsanole
Authors: Ohloff G. , Strickler H. , Willhalm B. , Borer C. , Hinder M. 
Published: December 2004

AbstractThe dye‐sensitized photooxygenation of (–)‐thujopsene (1) leads to two allyl hydroperoxides 16 and 17 (ratio 2:1). From the structure of the corresponding alcohols 2 and 3 it is possible to demostrate the complete stereospecificity of the addition of 1Δg‐oxygen to the acceptor system. In this way it is shown that 1 exists in only one conformation in solution. The production of the rearranged product 23 can be explained by Hock fission from the allyl hydroperoxides 16 or 17 following the Criegee mechanism. Under the epoxidation conditions 1 is converted mainly to the two new odorous substances (–)‐3‐thujopsanone (4) and (–)‐3‐isothujopsanone (5). A series of sesquiterpenes with the thujopsane skeleton is also described, all of which have been intercorrelated.
Photochemical Reactions. Part 58 [1]. On the mechanism of the rearrangement of the triplet‐excited α, β‐unsaturated δ‐diketone 3, 7‐dioxo‐4, 4‐dimethyl‐17 β‐acetoxy‐Δ5‐androstene
Authors: Domb S. , Schaffner K. 
Published: December 2004

AbstractIn einer vorangehenden Arbeit [2] wurde gezeigt, dass sich das triplettangeregte α, β‐ungesättigte δ‐Diketon 1 in die beiden stereoisomeren Cyclopropyl‐diketone 2 und 3 umlagert. Neue Resultate vermitteln nun einen näheren Einblick in die mechanistischen Aspekte dieser Photoreaktion. Die Bestrahlung der 4α‐Trideuteromethyl‐Verbindung 7 in Dioxan mit 2537 Å lieferte nach einem Umsatz von ≧ 30% die an C‐4 sterisch äquilibrierten Photoisomerenpaare 8a, b und 9a, b während im regenerierten Ausgangsmaterial (7) die C(4)‐Chiralität erhalten blieb. Dieser Befund spricht gegen eine konzertierte Umlagerung und ist indikativ für einen schrittweisen Reaktionsablauf.
Darstellung und Eigenschaften verschiedener 3‐Benzazocine, eine Klasse potentieller Analgetika
Authors: Pecherer B. , Stumpf J. , Brossi A. 
Published: December 2004

AbstractIn continuation of our study on new types of analgesics, we synthesized various hexahydro‐3‐benzazocines. The synthesis of these compounds, starting from well‐known intermediates, is described in this paper. The compounds do not exhibit biological activities worthy of further exploration.
Stoffwechselprodukte von Mikroorganismen 80. Mitteilung [1] Aranciamycin
Authors: Keller‐Schierlein W. , Sauerbier J. , Vogler U. , Zähner H. 
Published: December 2004

AbstractAranciamycin is a new antibiotic isolated from cultures of a strain of Streptomyces echinatus. The orange‐yellow acidic compound, C27H28O12, is a glycoside of an aglycone, aranciamycinone, and a 6‐deoxyhexose monomethyl ether.The aglycone, C20H16O8, is composed of a 1, 8‐dihydroxyanthraquinone nucleus, to which a fourth carbocyclic six‐membered ring is condensed, bearing a tertiary C‐methyl group, a tertiary and a secondary hydroxyl group, a secondary methoxyl group, and a carbonyl group. A partial formula of the aglycone is given.Aranciamycin as well as its aglycone are strongly inhibitory against gram‐positive bacteria on synthetic media. The antibiotic activity is considerably decreased by the addition of amino‐acid combinations and pyruvate to the test medium.
Untersuchung des UV. Spektrums von Acenaphtylen durch Beobachtung des durch ein elektrisches Feld induzierten Dichroismus
Authors: Seibold K. , Zahradnik R. , Labhart H. 
Published: December 2004

AbstractThe absolute direction of transition moments and the change of the dipole moment upon transition to excited states of acenaphthylene are determined from the influence of an electric field on the optical density of a solution. The results agree well with predictions from PPP‐calculations. In the lowest excited state the dipole moment is antiparallel to the ground state dipole moment.
The electron spin resonance spectrum of the triphenylsilyl radical formed by the X‐irradiation of monocrystalline triphenylsilane
Authors: Geoffroy M. , Lucken E. A. C. 
Published: December 2004

AbstractThe electron spin resonance spectrum of X‐irradiated monocrystalline triphenylsilane has been studied at room temperature. The main radical species present is the triphenylsilyl radical, formed both as isolated radicals and pair‐wise trapped radicals. For the radical pairs the analysis of the dipole coupling tensor indicates an inter‐radical distance of 7.36 Å. The 29Si hyperfine tensor has been determined, and the values discussed in terms of the electronic structure of the triphenylsilyl radical.
Schmelzreaktionen mit Aluminiumchlorid 5. Mitteilung [1] Nebenreaktionen bei der Carbazolierung von Di‐(1‐anthrachinonyl)‐amin in Pyridin‐Aluminiumchlorid‐Schmelzen
Authors: Wick A. K. 
Published: December 2004

AbstractSome by‐products of the carbazolation of di‐(1‐anthraquinonyl)‐amine in aluminium chloride‐pyridine fusions rich in aluminium chloride are shown to result from pyridiniosubstitution and higher condensation of the 1, 2; 7, 8‐diphthaloyl‐carbazole primarily formed.
Fluorénacènes et fluorénaphènes Synthèses dans la série des indéno‐fluorènes, XV [1] Méthyl‐5‐dihydro‐10, 12‐indéno [2, 1‐b]fluorène
Authors: Chardonnens Louis , Häger Josef 
Published: December 2004

AbstractStarting from α‐methylchalcone and diethyl ketone the title compound, II, has been synthesized in 6 steps (overall yield 26%). As an intermediate compound the gold yellow 10, 12‐dioxoderivative of II was also obtained.
Muscarine and Muscarine Isomers in Selected Inocybe Species
Authors: Catalfomo Philip , Eugster Conrad Hans 
Published: December 2004

AbstractThe distribution and relative concentrations of muscarine and its isomers in Inocybe species were determined. Notable was the finding that I. cinnamomea A. H. Smith, I. geophylla Karst, and I. lacera (Fr.) Quél. contained concentrations of epi‐muscarine equal to or‐higher than muscarine itself.
Synthesen in der Polymyxinreihe. 12. Mitteilung. Die Synthese von Polymyxin D1
Authors: Studer R. O. , Lergier W. 
Published: December 2004

AbstractThe synthesis of the cycloheptapeptide XI (Figure 1), corresponding to the structure proposed by T. Suzuki et al, for the antibiotic Polymyxin D1 is reported. This synthetic compound proved to be identical in all respects with natural Polymyxin D1.
New Methods for the Synthesis of Oxygenated Carotenoids
Authors: Surmatis J. D. , Walser A. , Gibas J. , Schwieter U. , Thommen R. 
Published: December 2004

AbstractSix keto carotenoids (4, 5, 6, 11, 12, and 22) were synthesized from intermediates which were prepared from the condensation products of mesityl oxide and acetoacetic ester. Compounds 4 and 22 can serve as precursors for zeaxanthin, while 5 can be used as an intermediate for xanthophyll. Echinenone and canthaxanthin were prepared by a new approach from vitamin A. Two new types of keto carotenoids with the keto functions incorporated into the unsaturated chain were prepared.
Lattice Energy, Lattice Constant, and Thermodynamic Properties of γ–Al2O3
Authors: Borer W. J. , Günthard Hs. H. 
Published: December 2004

AbstractBasierend auf bekannten thermodynamischen Daten von α‐Al2O3 (Korund) und der Phasenumwandlung α‐Al2O3→ γ‐Al2O3 werden eine Reihe von Konsequenzen für die Natur der γ‐Phase diskutiert. Es wird gezeigt, dass die Annahme einer unterkühlten Flüssigkeit für die γ‐Phase mit zuverlässigen Daten schwer verträglich ist. Andererseits sind diese Daten konsistent mit einer ungeordneten kubischen Struktur der γ‐Phase, die für alle Temperaturen bis zum Schmelzpunkt des α‐Al2O3 in Bezug auf dieses als thermodynamisch unstabil betrachtet werden kann. Die bisher bekannten Daten der Phasenumwandlung γ→α weisen insgesamt auf einen kinetisch kontrollierten Prozess hin, obwohl sie wechselseitig nicht konsistent sind. Es wird der Coulomb‐Anteil der Gitterenergie von‐γ‐al2O3 numerisch berechnet und eine Gitterkonstante von 7,883 Å (25°25) für die ungeordnete spinellartige γ‐Al2O3 Struktur aus thermodynamischen Daten abgeleitet.
Synthese von Diazoketonen aus Acylaminosäuren unter Verwendung von gemischten Anhydriden bzw. N, N′–Dicyclohexyl‐carbodiimid
Authors: Penke Botond , Czombos József , Baláspiri Lajos , Petres Jolán , Kovács Kálmán 
Published: December 2004

AbstractAus Benzyloxycarbonyl‐ und t‐Butyloxycarbonyl‐aminosäuren werden über gemischte Anhydride oder mittels N, N′‐Dicyclohexyl‐carbodiimid durch Reaktion mit Diazomethan Diazoketone hergestellt, wobei die in der Literatur [6] [7] erwähnte Oxazolonbildung nicht beobachtet wird. Durch Wolff'sche Umlagerung der Diazoketone lassen sich optisch aktive Peptide mit β‐Aminosäureresten leicht herstellen.
Die Photoelektron‐Spektren der Monohalogenacetylene
Authors: Haink H. J. , Heilbronner E. , Hornung V. , Kloster‐Jensen Else 
Published: December 2004

AbstractThe photoelectron spectra of the four monohaloacetylenes XCCH with X  F, Cl, Br, I have been recorded. The first four bands of these spectra are assigned (in order of increasing ionization potentials) to the following states: band 1: 2Π3/2(1), 2Π1/2(1); band 2: 2Π3/2(2), 2Π1/2(2); band 3: 2Σ+(3); band 4: 2Σ+(4). A correlation diagram based on a simple ZDO‐MO model shows that the observed band positions and the size of the splits due to spin‐orbit coupling can be satisfactorily explained in terms of such a model. It is found that the orbital energies AX of the postulated halogen npλ(X)‐basis orbitals are a linear function of the ionization potentials I(X) of the free atoms X. The validity of the ZDO‐MO‐model is confirmed by the excellent qualitative agreement between the observed and predicted spacings of the vibrational fine structure of the π‐bands.
Le diméthyl‐ et le diéthyl‐tétracarbonylosmium Synthèse et réactivité
Authors: L'Eplattenier F. , Pélichet Mlle C. 
Published: December 2004

AbstractThe sodium salt Na2[Os(CO)4] has been obtained in high yields by the reduction of either OsH2(CO)4 or Os3(CO)12 with sodium sand in the presence of catalytic amounts of 2, 2′‐bipyridyle. The reaction of Na2[Os(CO)4] with alkylating agents such as methyl and ethyl iodide produces OsR2(CO)4 (R = CH3, C2H5). NMR. and IR. spectra indicate a cis‐octahedral structure of symmetry C2v for these new alkyl compounds. Bromine breaks one osmium‐carbon bond in cis‐Os(CH3)2(CO)4 to give cis‐OsCH3Br(CO)4, whereas in cis‐Os(C2H5)2(CO)4 both ethyl groups are easily displaced by bromine to give cis‐OsBr2(CO)4. Under CO pressure and at elevated temperature cis‐Os(CH3)2(CO)4 is converted to Os(CO)5 and ethane. With cis‐Os(C2H5)2(CO)4 two CO are inserted in osmium‐carbon bonds to give . NMR. and IR. data suggest a cis‐configuration for this derivative and the possibility of the presence of rotational isomers.
Synthesen von cis‐ und trans‐1,2,3,4,4a, 10a‐Hexahydro‐1,4‐benzodioxino[2,3‐c]‐pyridinen
Authors: Berthold R. , Niklaus P. , Stoll André P. , Troxler F. 
Published: December 2004

AbstractCis‐ and trans‐1,2,3,4,4a,10a‐hexahydro‐1,4‐benzodioxino[2,3‐c]pyridines have been synthetised and their structures established by NMR.‐spectroscopy.
Reaction of 2‐Methylnorborn‐2‐ene with N‐Bromosuccinimide [1]
Authors: Jefford C. W. , Wojnarowski W. 
Published: December 2004

AbstractThe reaction of 2‐methylnorborn‐2‐ene with N‐bromosuccinimide produced exo‐3‐bromo‐2‐methylenenorbornane and 2‐methyl‐3‐bromonortricyclene in a 3:1 ratio. No 2‐bromomethyl‐norborn‐2‐ene was found. Most of the unreacted olefin was found to be isomerized to 2‐methylenenorbornane.The hydrolysis of 2‐methyl‐3‐bromo‐nortricyclene with silver acetate in a 50% mixture of acetone and water afforded the corresponding alcohol and acetate. Exo‐3‐bromo‐2‐methylenenorbornane on similar treatment gave the exo‐3‐hydroxy‐2‐methylene‐norbornane and 2‐hydroxymethyl‐norbornane and 2‐hydroxymethyl‐norborn‐2‐ene and their corresponding acetates in a 3:2 ratio.An ionic rather than a radical mechanism is proposed for the bromination reaction. In the solvolysis reactions of the resulting bromides the nature of the ionic intermediates is discussed.
Inter‐ und intramolekulare Umlagerung der Sulfogruppe in 2‐Naphtol‐1‐sulfonsäure
Authors: Fisher P. B. , Zollinger H. 
Published: December 2004

AbstractThe isomerisation of 2‐naphthol‐1‐sulfonic acid (potassium salt) into 2‐naphthol‐6‐sulfonic acid has been studied using labelled sulfuric acid (H235SO4). In 40 to 50% aqueous sulfric acid the reaction takes place exclusively by an intermolecular mechanism (protio‐desulfonation and resulfonation). In glacial acetic acid, in the presence of an excess of sulfuric acid, the rearrangement is partly intramolecular. With an equimolar amount of sulfuric acid the rearrangement is completely intramolecular. This reaction is first order with respect to 2‐naphthol‐1‐sulfonic acid and zeroth order with respect to excess of sulfuric acid. A mechanism for the reaction is proposed.
Contribution à la connaissance des o‐menthols et des o‐menthones (carquéjanols et carquéjanones). 3e communication
Authors: Ferretti‐Alloise Maria Giulia , Jacot‐Guillarmod André , Naves Yves‐René 
Published: December 2004

AbstractThe alcohols (+)‐carquejanol, (−)‐neocarquejanol, (−)‐isocarquejanol, and (−)‐neoisocarquejanol are described, and their conformations and configurations are studied by IR., NMR. and mass spectroscopies. Isocarquejanol is a mixture of conformers approximatively 50:50 with, respectively, axial and equatorial OH.
Chaleurs d'adsorption de quelques cycloalcanes sur du silicagel par chromatographie gaz‐solide
Authors: Jeanneret C. , Stauffer H. P. , Fernandez‐Garcia J. G. , Boissonnas C. G. 
Published: December 2004

AbstractHeats of adsorption on silicagel, for different cycloalcanes, have been measured by gas‐solid chromatography. The experiments were carried out between 180 and 210°C. Values based on the corresponding retention times and temperature parameters for cyclopentane, cyclohexane, cycloheptane, and cyclooctane were found to be 7.5, 8.3, 10.0 and 11.5 kcal/mole, respectively.
Über das makrocyclische Spermidinalkaloid Inandenin. 138. Mitteilung über Alkaloide.
Authors: Veith H. J. , Hesse M. , Schmid H. 
Published: December 2004

AbstractThe novel spermidine alkaloid inandenine was isolated from Oncinotis inandensis Wood et Evans. It was found to be a mixture of two isomers A and B, which could not be separated hitherto. Chemical and mass‐spectrometric investigations revealed that both alkaloids possess the macrocyclic 21‐ring structure 3a and 3b. These two formulae differ only with respect to the position of the ketogroup. Structural elements of the two bases are 9‐oxo‐ and 10‐oxo‐palmitic acid, respectively, and spermidine.
Über die Reaktion von Schwefel mit N,N'‐Dimethyl‐äthylendiamin und Formaldehyd. Eine neue Methode zur Herstellung von 1, 3‐Dimethylimidazolidin‐2‐thion und N‐Formyl‐N'‐thioformyl‐N, N'‐dimethyl‐äthylen‐1,2‐diamin
Authors: Maier Ludwig 
Published: December 2004

AbstractThe reaction of sulfur with N, N'‐dimethylethylenediamine and formaldehyde has been studied. A simple, one step process for the preparation of N‐formyl‐N'‐thioformyl‐N, N'‐dimethylethylene‐1, 2‐diamine (I) and 1, 3‐dimethylimidazolidine‐2‐thione (II) is reported. The physical properties and 1H‐NMR. spectra of I and II are given.
Photoelectron‐spectroscopic Evidence Concerning “Homo‐aromaticity”
Authors: Bischof P. , Gleiter R. , Heilbronner E. 
Published: December 2004

AbstractThe first of the two π‐bands in the photoelectron spectrum of cis‐cis‐cis‐1, 4, 7‐cyclononatriene (I, symmetry C3v) shows a Jahn‐Teller split. This is consistent with the prediction of molecular orbital theory that the top occupied orbitals of I are e(π) and a1(π) respectively. From the difference ϵ(e(π)) ‐ ϵ(a1(π)) = 0.90 to 0.97 eV a value of β1,3 = −0.68 eV = 0.27 β (β = ‐2.5 eV) is obtained for the homoconjugative interaction of two π‐orbitals in I. This value represents almost exclusively through‐space interaction between the π‐orbitals. Through‐bond interaction (hyperconjugation) is a minor effect in I. A comparison of the photoelectron data of bicyclo [4.2.1] nonatriene with those of norbornene and cycloheptadiene shows that homoconjugation (homo‐aromaticity) can only be detected by photoelectron spectroscopy if the interacting π‐bonds (basis orbitals) are symmetry equivalent or have accidentally (almost) degenerate energies.
Über Pterinchemie. 33., vorläufige Mitteilung. Luftoxydation von 6,6‐disubstituierten Tetrahydropterinen, ein Beitrag zur Frage der Existenz von Parachinoid‐dihydropterinen
Authors: Viscontini M. , Frater‐Schroeder M. , Cogoli‐Greuter M. , Argentini M. 
Published: December 2004

AbstractDie Luftoxydation von 6,6‐disubstituierten Tetrahydropterinen führt nicht, wie vermutet, zu Parachinoid‐dihydropterinen, sondern unter Verlust einer der beiden Seitenketten zu 7, 8‐Dihydropterinen. Dieses Ergebnis wird im Zusammenhang mit der existierenden Theorie der Tetrahydropterin‐Oxydation kurz diskutiert.
Oxydation allylique sélective en chimie des sucres au moyen du réactif de Fétizon. Note de laboratoire
Authors: Tronchet J. M. J. , Tronchet Mme J. , Birkhäuser Mme A. 
Published: December 2004

AbstractD‐glucal is selectively oxidised to the corresponding enone with a 60–80% yield by Fétizon's reagent (Ag2CO3‐celite).
Die photosensibilisierte Oxydation einwertiger Phenole zu Chinonen
Authors: Pfoertner K. , Böse D. 
Published: December 2004

AbstractThe photosensitized oxidation of methyl substituted phenols with free para‐positions starts with an electrophilic attack of position 4 by singlet oxygen. This follows from the course of the reaction using phenols with methyl groups in different positions. The influence of the solvent shows that the hydroperoxide formation from the primary oxygen adduct proceeds via an inter‐molecular hydrogen shift. The solvent is the hydrogen donator, whereas the phenoxy radicals resulting from the oxidation of the phenol by the excited sensitizer are the hydrogen acceptors. Finally, the quinones are formed from the hydroperoxides by elimination of water.
Mechanismus und Selektivität des Alkali‐Ionentransportes in Modell‐Membranen in Gegenwart des Antibioticums Valinomycin
Authors: Wipf H.‐K. , Olivier A. , Simon W. 
Published: December 2004

AbstractSelective transport of potassium ions through synthetic membranes impregnated with valinomycin in octane‐2‐ol in the presence of equal amounts of K+ and Na+ or Li+ ions is induced on application of a potential difference across these membranes. By using 14C‐labelled valinomycin it is shown that transport of potassium ions is accompanied by an equivalent transport of valinomycin within the membrane, consistent with the formation of a 1 : 1 complex of K+ with valinomycin. The exchange of ligands is shown to occur during the transport process so that a carrier‐relay mechanism, as proposed earlier for macrotetrolide‐mediated potassium transport, accounts for all experimental results on the bulk membranes studied.
ESR. Spectra of the Radical Anion of Dimethyl‐phenyl‐phosphine
Authors: Gerson F. , Plattner G. , Bock H. 
Published: December 2004

AbstractESR. spectra of the radical anion (I⊖) produced from dimethyl‐phenyl‐phosphine (I) both by electrolysis and reaction with alkali metals have been studied upon variation of temperature. The coupling constant assigned to the 31P nucleus depends strongly on temperature, whereas the coupling constants attributed to protons do not exhibit such a dependence. The π‐spin populations at the benzene ring of I⊖ give evidence ‐ in accordance with other experimental data [1] [2] – that the dimethylphosphino substituent is electron‐attracting. This effect is thought to be due mainly to P ← Cπ delocalization, which is analogous to the SiCπ interaction in trimethylsilyl‐substituted π‐systems [3].The ESR. spectrum previously [4] ascribed to I⊖ is shown to arise from a secondary radical. The formation and structure of this radical are briefly discussed.
The Partial O‐Demethylation of Aromatic‐Substituted 3,4‐Dihydroisoquinolines
Authors: Brossi A. , Teitel S. 
Published: December 2004

AbstractA detailed study has shown that all possible aromatic dimethoxy‐substituted 3,4‐dihydroisoquinolines can be partially O‐demethylated by controlled acid hydrolysis. Based on the structure elucidation of the monophenols thus obtained, it was established that preferential cleavage occurs at the 5‐methoxyl with the 5,6‐ and 5,8‐isomers 1 and 3, respectively, at the 6‐methoxyl with the 6,8‐isomer 4, at the 7‐methoxyl with the 5,7‐isomer 5, and at the 8‐methoxyl with the 7,8‐isomer 2.