bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and Configurational Dependence of the Sensory Process in Steroids
Authors: Ohloff Günther , Maurer Bruno , Winter Beat , Giersch Wolfgang 
Published: December 2004

Structural modifications of testosterone and 19‐nortestosterone have led to the synthesis of over 60 androstane and estrane derivatives whose sensory evaluation has allowed molecular parameters to be established for release of a ‘steroid‐type’ scent. Odor perception with O‐containing compounds in both classes has been found to be regioselective. Osmophoric groups at C(3) were found to be the most active and specific. Functionality at C(2) is accompanied to a large extent by anosmic defects, and O‐containing substituents at C(1) and C(4) appear to affect the receptor membrane in exceptional cases.A further characteristic of the ‘steroid‐type’ scent is diastereoselectivity. The odor intensity of axial 2‐ and 3‐hydroxysteroids is far greater than that of the equatorial epimers, and epimeric hydroxy‐groups in the 1‐, 4‐, and 5‐positions lead to almost complete absence of odor. In addition, only steroids with ‘normal’ ring junctions and configuration were found to be odorants, whereas compounds with cis‐junctions between rings A and B, or C and D, were found to be practically inactive, Steroids therefore folow the ‘triaxial rule of odor sensation’.The most remarkable feature of our findings with steroid odorants is enantioselectivityThe term ‘regioselective’ is currently used for a reaction in which formation of one structural (or positional) isomer is favored over another. For convenience we use ‘regioselective’, ‘diastereoselective’ or ‘enantioselective’ for substrate‐receptor interactions in which one positional isomer, diastereoisomer or enantiomer leads to a different sensory response (in quality and/or intensity) than another.

. Whereas with C
19
‐steroids of the ‘natural’ enantiomeric series the perception threshold is extremely low (<6 ppb), the corresponding ‘unnatural’ enantiomers have been found essentially odorless by a panel of 30 persons. This appears to be the first reported instance of a total enantioselective response to an odorant.
[2+2]‐Cycloaddition von Ketenen an «Maleinisoimide» und Überführung der spiroverknüpften b̃‐Laktame in Muconsäure‐ und Tetramsäurederivate
Authors: Capraro Hans‐Georg , Martin Pierre , Winkler Tammo 
Published: December 2004

[2+2]‐Cycloaddition of ‘Maleic Isoimides’ with Ketenes and Reactions of Spiro‐b̃‐lactams to Muconic and Tetramic AcidsThe [2 + 2]‐cycloaddition of iminolactones of type 2 (‘maleic isoimides’) with various ketenes affords spiro‐b̃‐lactams 4–6. These highly functionalized compounds react with CH3ONa giving ketoadipinic acid derivatives 12 and/or pyrrolidinediones 7, depending on the reaction temperature and the nature of substituents.
Total Synthesis of (±)‐α‐Acoradiene via Intramolecular Photoaddition and Reductive Cyclobutane Cleavage
Authors: Oppolzer Wolfgang , Zutterman Freddy , Bättig Kurt 
Published: December 2004

Abstract(±)‐α‐Acoradiene (4) has been synthesized from 3‐methoxy‐2‐cyclohexenone by a sequence of 8 steps. The key steps (Scheme 6) are the regio‐ and stereoselective photo[2+2]addition 7→6 and the reductive fragmentation 6→5.
The Synthesis of Some 1, 8‐Phenanthrolines and Related Compounds
Authors: Markees Diether G. 
Published: December 2004

AbstractThe synthesis of ethyl 4‐oxo‐1, 4‐dihydro‐1, 8‐phenanthroline‐3‐carboxylate (2a) and some other 1, 8‐phenanthrolines is reported. The ethylation of the above ester yields a thermochromic product 2b and some ethyl 4‐ethoxy‐1, 8‐phenanthroline‐3‐carboxylate (3b). Reexamination of similar ethylations of analogous esters derived from 1, 7‐phenanthroline and 1, 10‐phenanthroline indicated formation of the O‐ethyl derivative of the former and the N‐ethyl derivative of the latter.
Anwendung der α‐Alkinon‐Cyclisierung: Totalsynthese von (±)‐Alben
Authors: Manzardo Giuseppe G. G. , Karpf Martin , Dreiding André S. 
Published: December 2004

Application of the α‐Alkynone Cyclization: Total Synthesis of (±)‐AlbeneA synthesis of the racemic form of the natural tricyclic hydrocarbon albene (1) from the Diels‐Alder adduct 2 of tiglyl chloride and cyclopentadiene is described (24% yield). The key step 5→6 involves a thermal α‐alkynone cyclization (Scheme 3), which is able to establish a new quarternary C‐atom at an unactivated position with a high degree of regiospecificity.
Synthesis and Photochemical Behaviour of 2‐Amino‐1,3‐Cyclohexadienes
Authors: Kilger Ralf , Margaretha Paul 
Published: December 2004

AbstractThe reaction of the 4,4‐dialkylated 2‐cyclohexenones 1 or 2 with a twofold excess of a secondary amine 3 affords the 2‐amino‐1,3‐cyclohexadienes 4 and 5, respectively. Irradiation (λ ≧ 300 nm) of the morpholino derivative 4a yields a mixture of the isomeric 3‐morpholino‐6‐methyl‐1,3,5‐heptatrienes 6 and 7, while 5 gives only one corresponding product 8. The reaction of enone 1 with an equimolar amount of pyrrolidine (3c) affords the bis‐enamine 9 which is converted to the unsaturated diketone 10 by oxidative hydrolysis.
Platin(II)‐Chromophore mit σ‐gebundenen Ligatoratomen
Authors: Kozelka Jiří , Ludwig Werner 
Published: December 2004

Platinum(II) Chromophores with σ‐Bonded Ligating AtomsThe absorption spectra of the platinum(II) complexes PtLxL′4−x (L = NH3, amine, hydride, alkyl; L′ = trialkylphosphine) consist of three band systems: (i) ligand‐field bands, partially of fully screened by more intensive absorptions; (ii) at least three comparatively sharp bands of low to intermediate intensity (ϵ = 400–10000), which are assigned to Rydberg transitions from 5d(Pt) to a linear combination of the (n+1)s‐orbitals of the ligands (with a contribution of metal 6s‐ or 6p‐orbitals, respectively); (iii) (only in the case of chromophores with two phosphorus ligands in trans‐position) one high intensity band (ϵ = 20000–50000), presumably due to a transition from the asymmetric linear combination of the trans‐lying phosphorus lone‐pairs to 5dx2−y2(Pt). There is no evidence of low‐lying π‐combinations of phorphorus 3d‐orbitals in the absorption spectra.
Angiotensin‐II Analogues. I: Synthesis and incorporation of the halogenated amino acids 3‐(4′‐iodophenyl)alanine, 3‐(3′,5′‐dibromo‐4′‐chlorophenyl)alanine, 3‐(3′,4′,5′‐tribromophenyl)alanine, and 3‐(2′,3′,4′,5′,6′‐pentabromophenyl)alanine
Authors: Leduc Richard , Bernier Michel , Escher Emanuel 
Published: December 2004

AbstractThe synthesis of the polyhalogenated phenylalanines Phe(3′,4′,5′‐Br3) (3), Phe(3′,5′‐Br2‐4′‐Cl) (4) and DL‐Phe (2′,3′,4′,5′,6′‐Br5) (9) is described. The trihalogenated phenylalanines 3 and 4 are obtained stereospecifically from Phe(4′‐NH2) by electrophilic bromination followed by Sandmeyer reaction. The most hydrophobic amino acid 9 is synthesized from pentabromobenzyl bromide and a glycine analogue by phase‐transfer catalysis. With the amino acids 4, 9, Phe(4′‐I) and D‐Phe, analogues of [1‐sarcosin]angiotensin II ([Sar1]AT) are produced for structure‐activity studies and tritium incorporation. The diastereomeric pentabromo peptides L‐ and D‐13 are separated by HPLC. and identified by catalytic dehalogenation and comparison to [Sar1]AT (10) and [Sar1, D‐Phe8]AT (14).
1,3‐Dipolare Addition von 2‐Benzonitrilio‐2‐propanid an 7‐Methylthieno[2,3‐c]pyridin‐1,1‐dioxid und Folgereaktionen
Authors: Fischer Ulf , Schneider Fernand 
Published: December 2004

1,3‐Dipolar Addition of 2‐Benzonitrilio‐2‐propanid to 7‐Methylthieno[2,3‐c]pyridine 1,1‐Dioxide and Subsequent ReactionsThe addition of dipole 2, generated photochemically from 2,2‐dimethyl‐3‐phenyl‐2H‐azirine (1), to 7‐methylthieno[2,3‐c]pyridine 1,1‐dioxide yields the pyrroline derivative 4 as a major product and regioisomer 5 in low yield. Compound 4 can be transformed into the pyrrolidine derivative 11 by ring opening, loss of SO2 and hydrogenation. Bromopyrroline derivative 14 gives either by dehydrohalogenation compound 18 or, by substitution, nitrile 17 or ethoxy derivative 19. Substitution of 14 and ring opening yields methoxypyrrole derivative 20, which gives access to the unstable hydroxypyrrole and hydroxypyrrolidine derivative 28 resp. 30. The vinylsulfone 18 is the starting material for addition‐ring‐cleavage reactions. Oxidation of pyrroline derivative 4 gives epoxy‐substituted N‐oxide 39 and di‐N‐oxide 40; and oxidative transformation of pyrrolidine derivative 11 yields the (hydroxymethyl)pyridylpyrrolidine derivative 45.
Stromloser Ionentransport und Potentiometrie an Membranen mit Chromoionophoren für Li+und UO
Authors: Villiger Alois , Morf Werner E. , Simon Wilhelm 
Published: December 2004

Zero‐current Ion‐transport Studies and Potentiometric Measurements on Membranes Containing Chromoionophores for Li+and UONon‐macrocyclic ionophores for Li+and UOhave been substituted with a diphenylmaleimide unit. In membranes the obtained chromoionophores induce the same ion‐selectivity and ion‐transport behavior as the unsubstituted ligands.
Synthesis and Anaphylactogenicity of Monohaptenic Carbohydrate Conjugates
Authors: Guenin Raymond , Schneider Conrad H. 
Published: December 2004

AbstractPeptidic model conjugates carrying a single 2‐carboxy‐4,6‐dinitrophenyl haptenic group, and as carbohydrate moieties D‐gluconoyl, β‐D‐mannopyranosyl, 2‐deoxy‐β‐D‐glucopyranos‐2‐yl, or lactobionoyl residues, including the pseudocarbohydrate residue 1,3,4,5‐tetrahydroxycyclohexane‐1‐carbonyl, were synthesized. Conjugates carrying the lactobionoyl of the bis(2‐deoxy‐β‐D‐glucopyranos‐2‐yl) moiety were anaphylactogenic in the guinea pig, passively sensitized against 2‐carboxy‐4,6‐dinitrophenyl antigen.
Highly Stereoselective Total Syntheses of (±)‐Chelidonine and of (±)‐Norchelidonine by an Intramolecular o‐Quinodimethane/Nitrostyrene‐Cycloaddition
Authors: Oppolzer Wolfgang , Robbiani Christian 
Published: December 2004

AbstractConversion of 2‐bromomethylstyrene 22 and benzocyclobutenyl carbamate 28 to the benzophenanthridine alkaloids (±)‐chelidonine (1, five steps, 25% from 28) and to (±)‐norchelidonine (2, six steps, 24% from 28) are described. The key step 29 → 31 involves a highly regio‐ and stereocontrolled intramolecular Diels‐Alder reaction of the (E)‐quinodimethane 30.
The Formulation of Four‐Components Practically Perfluorinated Microemulsions
Authors: Oliveros Esther , Maurette Marie‐Thérèse , Braun André M. 
Published: December 2004

AbstractMicroheterogeneous systems consisting of sodium perfluorooctanoate (1), 2, 2, 3, 3, 4, 4, 4‐heptafluoro‐1‐butanol (2), perfluorohexane (3) and water, representing the first practically perfluorinated microemulsions based on ionic surfactants have been formulated. A pseudoternary phase diagram shows a central region of turbid or transparent gels and two regions of monophasic systems (O/W‐ and W/O‐microemulsions) which have been characterized by NMR. spectroscopy.
The Adamantane Rearrangement of 1,2‐Trimethylenenorbornanes. III. AlBr3‐catalyzed rearrangement to 2,6‐trimethylenenorbornane
Authors: Klester Alfred Michael , Ganter Camille 
Published: December 2004

AbstractFrom treatment of D‐labelled 1, 2exo‐, 1, 2endo‐ and 2endo, 6endo‐trimethylene‐norbornane (1, 2 and 3, resp.) with aluminum bromide in carbon disulfide, the evidence is gained that a degenerate rearrangement is involved in the admantane rearrangement of both 1 and 2 to 3.
Photochemical Reactions. 129th Communication. Photochemistry of a conjugated diepoxydiene: Product formation via carbonyl ylide and carbene intermediates with participation of neighbouring epoxy functions
Authors: Bischofberger Norbert , Frei Bruno , Jeger Oskar 
Published: December 2004

AbstractOn singlet excitation (λ=254 nm, acetonitrile) the diepoxydiene (E)‐7 undergoes photocleavage to the carbonyl ylide VII and the carbenes X and XI. The carbonyl ylide VII rearranges to the thermally labile dioxabicyclo [3.2.1]octene 20 or fragments via VIII to the aldehyde 9 and propyne. The carbene X, showing behaviour typical of vinyl carbenes, undergoes addition to the adjacent double bond furnishing the cyclopropene 11. The carbene XI, however, undergoes an insertion reaction into the neighbouring oxirane C,C‐bond leading to the oxetene (E)‐21 which can be isolated at −78°, but at room temperature is rapidly transformed to the aldehyde 10. On triplet excitation (acetone, λ>280 nm), however, (E)‐7 shows the typical behaviour of epoxydienes, undergoing C, O‐cleavage of the oxirane and isomerization to 22, 23 and (E/Z)‐24.
31P‐NMR and X‐Ray Studies of the Complexes [HgX2 (1)]. (1=2, 11‐bis (diphenylphosphinomethyl)benzo [c]phenanthrene, X=Cl, I)
Authors: Kunz Roland W. , Pregosin Paul S. , Camalli Mercedes , Caruso Francesco , Zambonelli Luigi 
Published: December 2004

AbstractThe 31P{1H}‐NMR characteristics of the complexes [HgX2(1)] and [HgX2‐(PPh2Bz)2] (X = NO3, Cl, Br, I, SCN, CN) and the solid state structures of the complexes [HgCl2(1)] and [HgI2(1)] (1 = 2,11‐bis (diphenylphosphinomethyl)benzo‐[c]phenanthrene) have been determined.The 1J(199Hg, 31P) values increase in the order CN < I < SCN < Br < Cl < NO3. The two molecular structures show a distorted tetrahedral geometry about mercury. Pertinent bond lengths and bond angles from the X‐ray analysis are as follows: HgP = 2.485(7) Å and 2.509 (8) Å, HgCl = 2.525 (8) Å and 2.505 (10) Å, PHgP = 125.6(3)°, ClHgCl = 97.0(3)° for [HgCl2(1)] and HgP = 2.491 (10) Å and 2.500(11) Å, HgI = 2.858(5) Å and 2.832(3) Å, PHgP = 146.0(4)°, IHgI = 116.9(1)° for [HgI2(1)]. The equation, derived previously, relating 1J(199Hg, 31P) and the angles PHgP and XHgX is shown to be valid for 1.
The Tautomerism of 1,3,4‐Thiadiazol‐2 (3H)‐ones. A 15N‐NMR‐Study
Authors: Fritz Hans , Kristinsson Haukur , Winkler Tammo 
Published: December 2004

Abstract5‐Substituted 1,3,4‐thiadiazol‐2(3H)‐ones were shown to exist almost exclusively in the oxo tautomeric form with the aid of proton‐coupled 15N‐NMR spectra using the corresponding 3‐methyl‐1,3,4‐thiadiazol‐2(3H)‐ones and 5‐substituted‐2‐methoxy‐1,3,4‐thiadiazoles as reference compounds.
New Synthetic Routes to β‐Olefinic Triphenylphosphonium Salts via (Diolefin)tricarbonyliron Complexes
Authors: Salzer Albrecht , Hafner Andreas 
Published: December 2004

AbstractThe regio‐ and stereospecific preparation of β‐olefinic triphenylphosphonium salts, starting from (diolefin)tricarbonyliron compounds is described. The latter are converted by various routes into either [(allyl)Fe(CO)4]+ ‐ or [(dienyl)Fe(CO)3]+ ‐ derivatives. The allylic cations, when reacted with P (C6H5)3, yield uncomplexed (2‐en‐l‐yl)triphenylphosphonium salts in good yields, while treatment of the dienyl cations with P(C6H5)3 leads to the quantitative formation of (2,4‐diene‐l‐yl)triphenylphosphonium ions still coordinated to the Fe (CO)3‐moiety. A method of oxidative decomplexation is described, by which the free phosphonium salts can be obtained.All new compounds were characterized by 13C‐NMR spectra and also, where necessary, by 1H‐NMR decoupling experiments to confirm the stereochemical assignments. Many of the new phosphonium salts, potentially useful as Wittig reagents for natural product syntheses, are difficult to obtain by conventional unequivocal routes.
Die Synthese von 7‐anti‐substituierten 2‐exo‐ und 2‐endo‐Norbornanolen. Norbornanreibe. 13. Mitteilung
Authors: Flury Peter , Grob Cyril A. 
Published: December 2004

The Synthesis of 7‐anti‐Substituted 2‐exo‐ and 2‐endo‐NorbornanolsThe title compounds and the corresponding p‐toluenesulfonates were prepared in connection with a mechanistic study of C‐participation in carbocations.
Neue Heteroarene: Synthese und spektrale Daten von Indolizino[6,5,4,3‐aij]chinolin («Ullazin») und einigen Derivaten
Authors: Balli Heinz , Zeller Martin 
Published: December 2004

New Heteroarenes: Synthesis and Spectroscopic Properties of Indolizino[6,5,4,3‐aij]quinoline (‘Ullazine’) and of some DerivativesThe synthesis, 1H‐NMR, 13C‐NMR and electronic absorption spectra of indolizino[6,5,4,3‐aij]quinoline (6a), a new π‐excess heteroarene, and of three 3,9‐disubstituted derivatives are described.
Michael Addition of Lithio‐α‐(methyldiphenylsilyl)acetate to Cyclopentenone: A direct synthesis of (±)‐methyl jasmonate
Authors: Oppolzer Wolfgang , Guo Modao , Baettig Kurt 
Published: December 2004

AbstractAprotic 1,4‐addition of a lithiated α‐(methyldiphenylsilyl)acetate to cyclopentenone andin situenolate alkylation provides a direct synthesis of (±)‐methyl jasmonate(Scheme 3).
Zur Verwendbarkeit von 13C‐Substituenteninkrementen bei 1,4‐Benzo‐ und 1,4‐Naphthochinonen
Authors: Neidlein Richard , Kramer Walter , Leidholdt Rolf 
Published: December 2004

About the Availability of 13C‐NMR Substituent Increments in 1,4‐Benzo‐ and 1,4‐NaphthoquinonesThe 13C‐NMR spectra of a number of substituted 1,4‐benzo‐ and 1,4‐naphthoquinones have been obtained and assigned. Effects of CH3‐, O‐alkyl‐, Cl‐, NH2‐ and N3‐ substituents have been deduced for the quinoid part of the molecules and used for the calculation of 13C‐chemical shifts.
Cyclometalated Arylazo Compounds. Part 4. ortho‐cyano‐1‐arylazonaphthalenes and 3‐amino‐2‐arylbenzo [g]indazoles from cyclopalladated 1‐arylazonaphthalenes. 4th communication on compounds with a metal‐arene σ‐bond
Authors: Gehrig Kurt , Klaus Alfred J. , Rys Paul 
Published: December 2004

AbstractThe reaction of a cyclopalladated 1‐arylazonaphthalene with tetrabutylammonium cyanide leads to an ortho‐cyano‐1‐arylazonaphthalene and a 3‐amino‐aryl‐benzo[g]indazole, depending upon whether triphenylphosphine or 1,2‐bis(diphenyl‐phosphino)ethane (DIPHOS) is used to monomerize the binuclear Pd(II)‐complex. In a similar insertion reaction with cyclohexyl isocyanide the corresponding 3‐(N‐cyclohexyl)‐aminoindazole is formed. A Pd(II)‐isocyano complex is shown to be a possible intermediate in that conversion.
Zum Mechanismus der Photoreduktion von Wasser mit Ruthenium‐trisbipyrazil als Sensibilisator
Authors: Dürr Heinz , Dörr Gisela , Zengerle Klaus , Curchod Jean‐Marc , Braun Andre M. 
Published: December 2004

On the Mechanism of the Photoreduction of Water with Ruthenium‐trisbipyrazil as SensitizerOxidative and reductive primary steps can be differentiated in using Ru(bipy) and Ru(bipz), respectively, as sensitizers in a photochemically induced, Pt‐catalyzed sacrificial water reduction. Experimental evidence for the reductive primary step and kinetic data are given for the electron transfer to methylviologen as relay compound.
Intramolecular Carbenoid Reactions of Pyrrole Derivatives Efficient Syntheses of Pyrrolizinone and Dihydroindolizinone
Authors: Jefford Charles W. , Johncock William 
Published: December 2004

AbstractThe copper‐catalyzed pyrolysis of 1‐diazo‐3‐(pyrrol‐1‐yl)‐2‐propanone (1a) and 1‐diazo‐4‐(pyrrol‐1‐yl)‐2‐butanone (1b) in benzene solution gave 1 H‐pyrrolizin‐2‐(3H)‐one (4a) and 5,6‐dihydroindolizin‐7 (8H)‐one (4b), respectively, in quantitative yield. Similar pyrolysis of 1‐diazo‐4‐(3‐methylindol‐1‐yl)‐2‐butanone (9) was less efficient giving 1‐methylbenzo[b]‐5,6‐dihydroindroindolizin‐7 (8H)‐one (10) and 4‐(3‐methylindol‐1‐yl)‐but‐l‐en‐3‐one (11) in 7% and 24% yield, respectively.
Ringtransformationen von 3‐substituiertem 5‐Trifluormethyl‐1,3,4‐thiadiazol‐2(3H)‐on mit Nucleophilen
Authors: Kristinsson Haukur , Winkler Tammo , Mollenkopf Max 
Published: December 2004

Ring Transformations of 3‐Substituted 5‐Trifluoromethyl‐1,3,4‐thiadiazol‐2(3H)‐one with NucleophilesThe 3‐chlormethyl‐5‐trifluoromethyl‐1,3,4‐thiadiazolone 3 undergoes a ring transformation to 3‐acylated 2,3‐dihydro‐1,3,4‐thiadiazoles 4 with many nucleophiles. Upon formal replacement of the chloromethyl group in the 3‐position of 3 by an extended bromoalkyl chain (→9a‐c), the reaction with nucleophiles yields 4‐acylated 5,6‐dihydro‐4H‐1,3,4‐thiadiazines 10 (from 9a), 4,5,6,7‐tetrahydrothiadiazepines 13 (from 9b) and 5,6,7,8‐tetrahydro‐4H‐1,3,4‐thiadiazocines 14 (from 9c) by ring enlargement. The 3‐propargyl‐thiadiazolone 17 rearranges with nucleophiles to 4‐acylated 6‐methylidene‐5,6‐dihydro‐4H‐1,3,4‐thiadiazines 18. The structures of the new compounds were elucidated by 1H‐ and 13C‐NMR spectroscopy.
Immobilized Enzyme Particles Prepared by Radiation Polymerization of Polyurethane Prepolymer
Authors: Kumakura Minoru , Kaetsu Isao 
Published: December 2004

AbstractThe immobilization of enzymes such as cellulase by radiation polymerization of dispersed polyurethane prepolymer was studied using tolylene‐2,4‐diisocyanate and 2‐hydroxyethyl methacrylate. The polyurethane particles were obtained by the dispersion of polyurethane prepolymer followed by radiation polymerization, in which the enzyme was immobilized on its surface by convalent bonding. The particle diameter of immobilized enzyme particles varied with monomer concentration and composition. The enzymatic activity of immobilized enzyme particles varied with the temperature of dispersion and irradiation, and decreased with increasing particle diameter.
Interactions between Functional Groups. Part I. Crystal Structure of 2‐Phenylethynyl‐N,N‐dimthlaniline at 98 K: A Remarkably Short CH …︁ C Distance
Authors: Wallis John D. , Dunitz Jack D. 
Published: December 2004

AbstractIn the crystal structure of the title compound at 98 K the dimethylamino group has pyramidal geometry. The nitrogenlone pair is not directed towards the triple bond; instead, one NCH3 bond lies almost in the plane of the disubstituted ring, directed away from the triple bond, while the other NCH3 bond and the lone pair are directed to opposite sides of the plane, nearer to the acetylene. There is a remarkably short intramolecular contact (2.39 Å) between a methyl H‐ and an acetylenic C‐atom. The Taft σI parameter of the arylethynyl substituent appears to be similar to that of a carboxylic ester, judging from the bond‐angle deformation at the ipso‐C‐atom.
On the Structure of Oxirane Molecular Cation. Preliminary Communication
Authors: Bally Thomas , Nitsche Stephan , Haselbach Edwin 
Published: December 2004

AbstractA recent controversy on the interpretation of the ESR spectrum of ionized oxirane is clarified on the basis of the electronic absorption spectra of ionized tetramethyloxirane and 9,10‐octalineoxide. The results favour a ring‐opened structure for oxirane molecular cation, resulting from CC bond cleavage and being iso‐π‐electronic to allyl radical.
Palladium‐promoted Cyclization of Tetra‐alkylated 1‐Arylazonaphthalenes to 2‐Aryl‐benzo[g]indazoles
Authors: Hugentobler Max , Klaus Alfred J. , Ruppen Peter , Rys Paul 
Published: December 2004

Abstract1‐Arylazonaphthalenes with all the potential cyclopalladation sites (one peri‐ and three ortho‐positions) substituted by methyl or ethyl groups react with stoicheiometric or catalytic amounts of sodium tetrachloropalladate(II) to the corresponding 2‐arylbenzo[g]indazoles. Possible mechanisms for the catalytic cyclization reaction are proposed.
Über Poterinchemie. 82. Mitteilung. Bildung von Formimidoyl‐Derivaten aus Aminen und Benzylisocyanid; Eine neue Umpolungsmöglichkeit für bestimmte C‐Atome
Authors: Ganguly Subhendu N. , Viscontini Max 
Published: December 2004

Formation of Formimidoyl Derivatives from Amines and Benzylisocyanide; A New Possibility of Umpolung for Certain C‐AtomsCu(I)Cl can give a colorless and well‐crystallized complex with 4 molecules of benzylisocyanide. This complex is able to transfer the benzylisocyanide ligands to primary and secondary amines and to form N‐benzylformimidoyl derivatives. Catalyic hydrogenolysis removes the benzyl group, and free formimidoyl compounds are obtained in good yield. The method which succeeds with aliphatic amines, could not be applied to the secondary amino group of tetrahydropterines.