bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Exchange on Hexaaquavanadium(III): a Variable‐Temperature and Variable‐Pressure17O‐NMR Study at 1.4 and 4.7 Tesla
Authors: Hugi Alain D. , Helm Lothar , Merbach André E. 
Published: December 2004

AbstractWater exchange on hexaaquavanadium (III) has been studied as a function of temperature (255 to 413 K) and pressure (up to 250 MPa, at several temperatures) by17O‐NMR spectroscopy at 8.13 and 27.11 MHz. The samples contained V3+(0.30–1.53 m), H+(0.19–2.25 m) and17O‐enriched (10–20%) H2O. The trifluoromethanesulfonate was used as counter‐ion, and, contrary to the previously used chloride or bromide, CF3SOis shown to be non‐coordinating. The following exchange parameters were obtained:k= (5.0 ± 0.3) · 102s−1, ΔH* = (49.4 ± 0.8) kJ mol−1, ΔS* = −(28 ± 2) JK−1mol−1, ΔV* = −(8.9 ± 0.4) cm3mol−1and Δβ* = −(1.1 ± 0.3) · 10−2cm3mol−1MPa−1. They are in accord with an associative interchange mechanism,Ia. These results for H2O exchange are discussed together with the available data for complex formation reactions on hexaaquavanadium(III). A semi‐quantitative analysis of the bound H2O linewidth led to an estimation of the proportions of the different contributions to the relaxation mechanism in the coordinated site: the dipole‐dipole interaction hardly contributes to the relaxation (less than 7%); the quadrupolar relaxation, and the scalar coupling mechanism are nearly equally efficient at low temperature (∼ 273 K), but the latter becomes more important at higher temperature (75–85% contribution at 360 K).
Synthese und Reaktionen des 5‐[p‐(Dimethylamino)phenyl]‐2,2‐dimethyl‐4‐phenyl‐3‐oxazolins
Authors: Foricher Joseph , Montavon François , Pfoertner Karl‐Heinz , Schönholzer Peter 
Published: December 2004

Synthesis and Reactions of 5‐[p‐(Dimethylamino)phenyl]‐2,2‐dimethyl‐4‐phenyl‐3‐oxazolineThe title compound 8 has been synthesized in a one‐pot reaction of 4′‐(dimethylamino)benzoin (4) with 2‐propanone and NH3. The preparation of the intermediate 4 from 3 is the first example of an acid‐catalyzed transformation of the stable benzoin 3 into the corresponding less stable benzoin 4. Structures and yields of various by‐products occurring under different reaction conditions during the synthesis of 8 from 4 are given. The O‐atom of the 3‐oxazoline ring in 8 could be replaced by S from P2S5 yielding the 3‐thiazoline 14. Separation of the enantiomers of the racemate 8 could only be performed by transforming them into the trimethylanilinium salts 8b and 8c of (−)‐ and (+)‐10‐camphorsulfonic acid, respectively. Solid NaOAc in boiling toluene caused the precipitation of the 10‐camphorsulfonic acids from the quaternary ammonium salts as sodium salts and the removing of the third methyl group from the quaternary ammonium salts as AcOMe to give the enantiomers (−)‐(5S)‐8 and (+)‐(5R)‐8. Their absolute configurations are deduced from an X‐ray analysis of 8b.
Propellanes. Part LXXVIII. Preparation of Several Triaza[3.3.3]propellanes and an Oxadiaza[3.3.3]propellane
Authors: Weinberg Olga , Knowles Philip , Ginsburg David 
Published: December 2004

Abstract3,7,10‐Tribenzyl‐3,7,10‐triaza[3.3.3]propellane (4a), 3,7‐dibenzyl‐10‐phenyl‐3,7,10‐triaza[3.3.3]propellane (4c), 3,7‐dibenzyl‐10‐(p‐tolyl)‐3,7,10‐triaza[3.3.3]propellane (4b), and 3‐oxa‐7,10‐diaza[3.3.3]propellane (6) have been prepared.
Synthesis of the Glycopeptide Partial Sequence A80–A84 of Human Fibroblast Interferon
Authors: Kunz Horst , Waldmann Herbert 
Published: December 2004

AbstractThe glycopentapeptide H‐(GlcNAcβ1‐)Asn‐Glu‐Thr‐Ile‐Val‐OH (10) representing the partial sequence A80–A84 of human fibroblast interferon was synthesized using the newly developed allyl‐ester protection of carboxy functions. The allyl esters, which are stable to acids and to bases, can be cleaved under very mild, neutral conditions using tris(triphenylphosphine)rhodium(I) chloride or tetrakis(triphenylphosphine)palladium(0) as a catalyst. This synthetic method opens up a preparative route to glycopeptide model structures of glycoproteins of high biological interest.
The Structure of Pyroergotamine
Authors: Day Roberata O. , Day Victor W. , Wheeler Desmond M. S. , Stadler Paul A. , Loosli Hans‐Rudolf 
Published: December 2004

AbstractThe molecular structure of pyroergotamine has been determined by single‐crystal X‐ray diffraction analysis to be the pyruvoyldiketopiperazine 1. The diketopiperazine ring exists in a folded or boat conformation, with a dihedral angle of 40° between the two almost planar peptide units. The R‐group of the phenylalanine residue occupies a quasi‐axial position of the diketopiperazine ring, while that of the proline residue is in a quasi‐equatorial position. Puzzling spectroscopic and chemical properties of the compound can be rationalised in terms of crowding within the molecule.
Transamidation reactions. Part 11. N‐substituted 3‐aminopropanenitriles and 2‐aminoacetonitriles as Schiff‐base equivalents
Authors: Askitoǧlu Elefteria , Guggisberg Armin , Hesse Manfred 
Published: December 2004

AbstractIn presence of a strong base, the 13‐membered cyclic compound 3 yielded, by loss of acetonitrile or its equivalent, the bicyclic product 5 instead of the 17‐membered compound 4 as expected (Scheme 2). Investigation of model compounds (Scheme 4) and of model reactions (Schemes 5 and 6) led to the conclusion that the reaction proceeds via an intermediate formaldehyde imine; a Schiff base, e.g. 3b (Scheme 5), which reacts intra‐ and intermolecularly with a nucleophile to form a Mannich‐type product. It seems to be a general principle that N‐substituted 3‐aminopropanenitrile and 2‐aminoacetonitrile derivatives behave in the presence of a strong base as Schiff ‐base equivalents (Schemes 5 and 6).
Deoxy‐nitrosugars. 10th Communication. Synthesis of Isosteric Phosphonate Analogues of Ulose‐1‐Phosphates
Authors: Julina Radomir , Vasella Andrea 
Published: December 2004

AbstractA general approach to isosteric phosphonate analogues of ulose‐l‐phosphates is described. A base‐catalysed chain elongation via a Michael addition of 1‐deoxy‐1‐nitro‐sugars 4, 8, and 16 to the vinylphosphonate 18 followed by hydrolysis of the nitro adducts gave the analogues of D‐ribulose‐1‐phosphate, D‐fructose‐1‐phosphate, and D‐sedoheptulose‐1,7‐diphosphate 21, 23, and 27, respectively, in high yields.
Laser Flash Photolysis of Chloranil in Solution
Authors: Guerry‐Butty Elisabeth , Haselbach Edwin , Pasquier Cécile , Suppan Paul , Phillips David 
Published: December 2004

AbstractChloranil (2,3,5,6‐tetrachloro‐2,5‐cyclohexadiene‐1,4‐dione; C) in deoxygenated acetonitrile shows transient absorptions which are assigned to the radical anion \documentclass{article}\pagestyle{empty}\begin{document}$ \rm {C}^{- \kern-4pt {.}} $\end{document} and to the triplet 3C*. The absorption due to \documentclass{article}\pagestyle{empty}\begin{document}$ \rm {C}^{- \kern-4pt {.}} $\end{document} rises ‘instantly’ during the 12 ns laser flash and then more gradually in a time of μs. This observation is explained as electron capture from neat acetonitrile by photoexcited C taking place from both its singlet and triplet states with rate constants estimated as 109 and 104 s−1 M−1, respectively.
The Chiral Glycine Enolate Derivative from 1‐Benzoyl‐2‐(tert‐butyl)‐3‐methyl‐1,3‐imidazolidin‐4‐one is Alkylated in the 5‐Position with Relative Topicitylk. Preliminary Communication
Authors: Seebach Dieter , Miller David D. , Müller Stefan , Weber Theodor 
Published: December 2004

AbstractAn overall enantioselective substitution of the R‐group of an α‐hydroxy‐ or α‐amino acid1[RCH(XH)COOH] by another R‐group is possible through heterocycles2obtained from1with pivaladehyde (1 → 7). Therac‐ and the (S)‐(+)‐heterocycles8(title compounds of type5) are prepared from glycine andO‐benzyl‐(S)‐serine, respectively. Their enolates (cf.9, type6) are alkylated with iodomethane, iodobutane, 2‐iodopropane, benzyl bromide, and acetone to give thetrans‐disubstituted imidazolidinones10with ≥ 95% diastereoselectivity. The configuration of the products is established by chemical correlation with alanine, phenylalanine, and valine.
Deoxy‐nitrosugars. 11th Communication. Reactions of 1‐C‐nitroglycosyl halides and 1‐C‐nitroglycosyl sulfones with dialkyl‐phosphite anions: Nucleophilic attack vs. single‐electron transfer
Authors: Meuwly Roger , Vasella Andrea 
Published: December 2004

AbstractTreatment of the chloro‐nitro‐ribofuranose 7 with KPO(OMe)2 gave the O‐amino phosphate 8 (5 %) and the nitrile 9 (62 %). Compound 9 was also obtained by the reaction of 8 with KPO(OMe)2, and its structure was established by X‐ray analysis. Treatment of the chloro‐nitro‐mannofuranose 10, the bromo‐nitro‐ribofuranose 14, or the bromo‐nitro‐mannofuranose 16, respectively, with the K or Na salt of HPO(OMe)2 lead also to O‐amino phosphates and nitriles. The (1‐C‐nitroglycosyl)phosphonate 22 was obtained (21 %) together with the nitrile 21 (51 %) from the chloro‐nitro‐mannofuranose 10 and KPO(OEt)2. The reaction of the 1‐C‐nitroglycosyl sulfone 25 (NO2‐group endo) with KPO(OEt)2 gave the (1‐C‐nitroglycosyl)phosphonate 22 (61%) and the nitrile 21 (11 %), whilst the anomeric sulfone 26 (NO2‐group exo) gave 22 (15 %) and 21 (58 %). In the presence of [18] crown‐6, a mixture of the anomers 25 and 26 gave the (1‐C‐nitroglycosyl)phosphonate 22 in 67 % yield together with 21 (13 %). These findings are rationalized as the result of a competition between a nucleophilic attack of the dialkyl‐phosphite anions on the NO2‐group leading ultimately to the nitrile 21 and a single‐electron transfer reaction leading to the (1‐C‐nitroglycosyl)phosphonate 22.
Diels‐Alder‐Reaktionen mit aktivierten 4‐Methyl‐1,3‐pentadienen
Authors: Kienzle Frank , Mergelsberg Ingrid , Stadlwieser Josef , Arnold Wolf 
Published: December 2004

Diels‐Alder Reactions with Activated 4‐Methyl‐1,3‐pentadienesEthyl 4‐methyl‐1,3‐pentadienyl ether, trimethyl[(4‐methyl‐1,3‐pentadienyl)oxy]silane, and 1‐(4‐methyl‐1,3‐pentadienyl)pyrrolidine and the corresponding piperidine analogue have been used in Diels‐Alder reactions with acrylonitrile, ethyl acetylenedicarboxylate, maleic anhydride, and 2,6‐dimethyl‐p‐benzoquinone.
ESR‐Spectroscopic Investigation of Radical Cations, Radical Anions, and Radical Trianions of Didehydro[n]annulenes
Authors: Huber Walter 
Published: December 2004

AbstractThe didehydro[n]annulenes 1 (n = 14), 2 (n = 18), and 3 (n = 22) are oxidized to radical cations. Reduction of the title compounds leads to radical anions and, in the case of 2 and 3, to radical trianions. The hyperfine data of the paramagnetic derivatives are rationalized in terms of the occupation of n‐membered (n = 14, 18, 22) π‐perimeter MO's (HOMO, LUMO, NLUMO). The contact‐ion pairs of the radical anions show unexpectedly large alkali‐metal coupling constants.
Synthesis of Enantiomerically Pure Pheromones of South‐Pacific Brown Algae: Hormosirene and Dictyopterene A
Authors: Schotten Theo , Boland Wilhelm , Jaenicke Lothar 
Published: December 2004

AbstractHormosirene ((−)‐1; (1R,2R)‐1‐((1E,3Z)‐1,3‐hexadienyl)‐2‐vinylcyclopropane) is the specific sex attractant of several brown algae of the Australian shelf, while dictyopterene A ((+)‐2; (1R, 2R)‐1‐((1E)‐1‐hexenyl)‐2‐vinylcyclopropane) is found as a minor constituent of the pheromone bouquets. The asymmetric synthesis of the two hydrocarbons is performed by resolution of the amides (−)‐5 and (+)‐5a obtained from (−)‐(R)‐2‐phenylglycinol and racemic trans‐vinylcyclopropanecarboxylic acid (rac‐4) on silica gel. Both diastereoisomers are obtained optically pure. They are converted by stereoselective Wittig olefination into the title compounds. Compound (−)‐1 is the active mating pheromone of the reproductive system of the seaweed Xiphophora chondrophylla as established by biological‐activity assays.
Zur Kenntnis des Faktors F430 aus methanogenen Bakterien: Über die Natur der Isolierungsartefakte von F430, ein Beitrag zur Chemie von F430 und zur konformationellen Stereochemie der Ligandperipherie von hydroporphinoiden Nickel(II)‐Komplexen
Authors: Pfaltz Andreas , Livingston Douglas A. , Jaun Bernhard , Diekert Gabriele , Thauer Rudolf K. , Eschenmoser Albert 
Published: December 2004

Factor F430 from Methanogenic Bacteria: On the Nature of the Isolation Artefacts of F430, a Contribution to the Chemistry of F430 and the Conformational Stereochemistry of the Ligand Periphery of Hydroporphinoid Nickel(II) ComplexesFactor F430 (1), a coenzyme from methanogenic bacteria, when heated in aqueous solution isomerizes to 12,13‐di‐epi‐F430 (5) via 13‐epi‐F430 (3). The equilibrium mixture of the three F430 isomers in aqueous phosphate buffer solution (pH 7, 100°) contains 88 % of 5, 8 % of 3, and 4 % of 1 (Scheme 1). The structural assignment for the F430 isomers rests on FAB‐MS‐, UV/VIS‐, 1H‐ and 13C‐NMR spectra of their pentamethyl esters. Chemical proof for the double epimerization at the two chiral centers of F430's ring C was provided by ozonolytic degradation of the di‐epimer to give a ring‐C‐derived succinimide derivative that was shown to be the enantiomer of the one previously obtained by ozonolysis of F430M (see Scheme 2). The two F430 ring‐C epimers 3 and 5 are the isolation artefacts described in the earlier F430 literature. F430 is susceptible to autoxidation in air and the product, that absorbs at 560 nm, was shown to be the 12,13‐didehydro derivative 8 of F430 by spectroscopic characterization of its pentamethyl ester 9. The dehydrogenation product 8 can be diastereoselectively reduced with Zn in AcOH to give natural F430 as the main product rather than the thermodynamically more stable F430‐di‐epimer (Scheme 3). In the double epimerization of F430, the two ring‐C side chains change from a trans‐quasi‐diaxial arrangement to the (locally) enantiomorphic position in which the same side chains are again in a trans‐quasi‐diaxial arrangement. This equilibrium paradox as well as the kinetic diastereoselectivity of the reduction of 12,13‐didehydro‐F430 (8) are rationalized to be consequences of the general phenomenon documented earlier (see the preceding paper) according to which hydroporphinoid Ni(II) complexes all show a characteristic conformational ruffling of their ligand system due to the tendency of the (small) Ni(II) ion to contract the size of the ligand's central coordination hole (see Fig. 5 and 6).
Photoisomerisierung und Relaxation symmetrischer Triazacarbocyanine in einem Alkoholgemisch
Authors: Balli Heinz , Eichenberger Thomas , Hellrung Bruno , Scheibli Peter 
Published: December 2004

Photoisomerization and Relaxation of Symmetrical Triazacarbocyanine Dyes in an Alcoholic Mixture at Low TemperatureThe partial photobleaching of a series of symmetrical triazacarbocyanine dyes with different heterocycles in EtOH/MeOH/i‐PrOH at low temperature (110 to 250 K) was investigated by UV/VIS spectra. Kinetic data of the dark reaction of photobleached compounds are given. The effect of electron‐donating or ‐accepting substituents, respectively, and of protonation of the photobleached compound on kinetic data and on UV/VIS spectra was studied. Products of photobleaching and mechanisms of the dark reaction are discussed.
Enantioselektive α‐Alkylierung von Asparagin‐ und Glutaminsäure über die Dilithium‐enolatocarboxylate von 2‐[3‐Benzoyl‐2‐(tert‐butyl)‐1‐methyl‐5‐oxoimidazolidin‐4‐yl]essigsäure und 3‐[3‐Benzoyl‐2‐(tert‐butyl)‐1‐methyl‐5‐oxoimidazolidin‐4‐yl]propionsäure
Authors: Aebi Johannes D. , Seebach Dieter 
Published: December 2004

Overall Enantioselective α‐Alkylation of Aspartic and Glutamic Acid through Dilithium Enolatocarboxylates of 2‐ [3‐Benzoyl‐2‐(tert‐butyl)‐1‐methyl‐5‐oxoimidazolidin‐4‐yl]acetic and 3‐[3‐Benzoyl‐2‐(tert‐butyl)‐1‐methyl‐5‐oxoimidazolidin‐4‐yl]propionic Acid, respectivelyThe pure methyl esters10of the heterocyclic carboxylic acids specified in the title were prepared in several steps by known methods from aspartic and glutamic acid, with overall yields ofca.20%. The corresponding heterocyclic acids11were doubly deprotonated by LiNEt2/BuLi or LiN(i‐Pr)2/BuLi to give enolatocarboxylates (3). The latter were reacted with electrophiles (MeOD, Mel, C6H5CH2Br) to give the crystalline products14–21diastereoselectively. Hydrolysis of the imidazolidinone ring of three such products gave the corresponding α‐branched aspartic and glutamic acids22–24of known absolute configuration, thus establishing the stereochemical course of the overall enantioselective alkylations.
Photoactive Cryptands. Crystal Structure of the Sodium Cryptate of the Tris(phenanthroline) Macrobicyclic Ligand
Authors: Caron Aimery , Guilhelm Jean , Riche Claude , Pascard Claudine , Alpha Béatrice , Lehn Jean‐Marie , Rodriguez‐Ubis Juan‐Carlos 
Published: December 2004

AbstractThe crystal structure of the complex [phen · phen · phen] · NaBr · 2 CHCl3 of the macrobicyclic ligand 1 has been determined. The complex is of cryptate type, the Na+ cation being contained in the molecular cavity of 1 and coordinated to all eight N‐atoms. The ligand has a propeller shape and interconverts in solution between the two enantiomeric helical forms.
Photochemical reactions. 146th communication. Photochemistry of conjugated methano‐epoxydienes: Participation of the neighboring cyclopropane ring in product formation via carbonyl ylide and carbene intermediates
Authors: Bischofberger Norbert , Frei Bruno , Jeger Oskar 
Published: December 2004

AbstractOn singlet excitation (λ = 254 nm, THF, pentane or hexane), the diastereoisomeric methano‐epoxydienes (E)‐6 and (E)‐7 undergo interconversion and yield the products 8–11. The main process is the cleavage of the oxirane ring to the vinyl carbene intermediate e which undergoes addition to the adjacent double bond furnishing the cyclopropene 8. The alternative carbene intermediate f is evidenced by the formation of the cyclobutene 10. For the fragmentation leading to 11, the carbene f as well as the dipolar species h are considered as possible intermediates. On triplet sensitization (acetone, λ > 280 nm), (E)‐7 shows behavior typical of epoxydienes, undergoing fission of the CO bond of the oxirane ring and isomerization to the compounds 13, 14 and (E/Z)‐15.
Uncinatone, a New Antifungal Hydroquinone Diterpenoid from Clerodendrum uncinatum SCHINZ
Authors: Dorsaz Anne‐Christine , Marston Andrew , Stoeckli‐Evans Helen , Msonthi Jerome D. , Hostettmann Kurt 
Published: December 2004

AbstractA new hydroquinone diterpenoid was isolated from Clerodendrum uncinatum SCHINZ (Verbenaceae) by flash chromatography on silica gel. The structure was established as 7,11‐dihydroxy‐3,4,9,11b‐tetramethyl‐1,2,8,9,11b‐pentahydrophenanthro[3,2‐b]furan‐6(2H)‐one by spectroscopic methods and X‐ray analysis. The diterpene was strongly fungitoxic to spores of Cladosporium cucumerinum.
Über die Strukturaufklärung von (Hydroxy‐oxo‐cyclopentenyl)alkansäuren, den Aldolkondensationsprodukten von Dioxoencarbonsäuren aus Rinderleber
Authors: Schödel Rolf , Spiteller Gerhard 
Published: December 2004

Structure Elucidation of (Hydroxy‐oxo‐cyclopentenyl)alkanoic Acids, the Aldol‐Condensation Products of Dioxoene Acids from Cattle LiverDuring homogenization of cattle liver the highly instable dioxoene acids 13a, 13b, and 13c are formed. These acids cyclize in alkaline solution to yield pairs of stable (hydroxy‐oxo‐cyclopentenyl)alkanoic acids, which were isolated as methyl esters 4a/5a, 4b/5b, and 4c/5c. The structures of these compounds were deduced from an enriched 3‐mg mixture sample by microchemical reactions combined with a GC/MS analysis of the reaction products. Compound 13a was obtained as methyl ester by oxidation of the methyl ester of the corresponding F‐acid with NaOCl. It was not possible to isolate 13a in pure form due to its high sensitivity. Instead of the methyl ester of 13a, 4a and 5a were isolated, of which the structures were established.
Structure and Reactivity of Xanthocorrinoids. Part II. Influence of the c‐acetic‐acid chain on the course of the hydroxylation of the corrin chromophore by oxygen in the presence of ascorbic acid
Authors: Grüning Burghard , Holze Gerhard , Jenny Titus A. , Nesvadba Petr , Gossauer Albert , Ernst Ludger , Sheldrick William S. 
Published: December 2004

AbstractThe yield of the main product from the reaction of heptamethyl dicyanocobyrinate with O2 in the presence of ascorbic acid has been optimised by systematic variation of the reaction conditions, and the structure of the obtained ‘stable yellow corrinoid’ has been established by X‐ray analysis. From the relationship between the structures of analogous xanthocorrinoids obtained likewise from a series of dicyanocobyrinic‐acid derivatives, which has been prepared by systematic modifications of the c‐acetic‐acid chain, and the functionality of the substituent at C(7), a reaction mechanism is suggested.
Bestimmung des Chiralitätssinns der enantiomeren 2,6‐Adamantandiole
Authors: Gerlach Hans 
Published: December 2004

Determination of the Chirality Sense of the Enantiomeric 2,6‐AdamantanediolsThe enantiomers of 2,6‐adamantanediol (1) are resolved via the diastereoisomeric camphanoates. The (2R,6R)‐chirality sense for (−)‐1 and (2S,6S) for (+)‐1 was determined by chemical correlation with (−)‐(1R,5R)‐bicyclo[3.3.1]nonan‐2,6‐dion ((1R,5R)‐3) of known absolute configuration in the following way: alkylation of the bis(pyrrolidine enamine) of (−)‐(1R,5R)‐3 with CD2I2 and hydrolysis of the product gives the enantiomer 4 of (4,4‐D2)‐2,6‐adamantanedione. Reduction of 4 with LiAlH4 leads to one enantiomer (Scheme 2) of each of the three diols 5–7 of known absolute configuration. The three diols are themselves configurational isomers due to the presence of the CD2 group, but correspond otherwise entirely to the enantiomeric diols 1. Accordingly, they can also be separated by means of their diastereoisomeric camphanoates to give the diols 5/6 and 7. These samples are easily distinguished and identified by their characteristic 1H‐NMR spectra (cf. Fig. 2). This allows to identify the (2R,6R)‐ and (2S,6S)‐enantiomer of 1 on the basis of their behavior in the resolution experiment analogous to that of the diols 5/6 and 7, respectively. The diol (−)‐1 must have the (2R,6R)‐configuration because it forms, like the diols 5/6, with (−)‐camphanic acid the diastereoisomeric ester less soluble in benzene. The diol (+)‐1 has (2S,6S)‐configuration, because it forms, like 7, with (+)‐camphanic acid the diastereoisomeric ester less soluble in benzene. The bis(4‐methoxybenzoate) of (−)‐(2R,6R)‐1 shows chiroptical properties which are in accordance with Nakanishi's rule for two chromophores having coupled electric dipol transition moments arranged with a left‐handed torsion angle.
Synthese einiger 8‐substituierter 2‐Methyl‐1,2,3,4‐tetrahydroisochinoline
Authors: Rey Max , Vergnani Tiziana , Dreiding André S. 
Published: December 2004

Synthesis of Some 8‐Substituted 2‐Methyl‐1,2,3,4‐tetrahydroisoquinolinesA general route to 8‐substituted tetrahydroisoquinolines is exemplified by the preparation of the 2‐methyl‐1,2,3,4‐tetrahydroisoquinolin‐8‐ol (11), the ‐8‐carbaldehyde oxime (12) and the ‐8‐carbonitrile (13). It involves the conversion of isoquinoline (1) by partially modified Steps 1, 2, 3, and 5 (see the Scheme) into the 5‐bromo‐8‐nitro derivative 5, reduction of the latter to the 8‐amino derivative 8 and replacement of the NH2‐group with an appropriate substituent by a Sandmeyer‐like reaction. The selective reductions of the N‐containing ring in 6 (Steps 5, 6, and 8) and of the NO2‐group in 5 (Steps 4 and 7) were also studied.