bluuebunny/crossref_metadata_2025_split huggingface dataset:
Darstellung, Eigenschaften und Kristallstruktur der N-[2-(4.5.6.7-Tetrahydro-2-benzimidazolyl)-ethyl] -phthalamidsäure / Preparation, Properties and Crystal Structure of N-[2-(4.5.6.7-Tetrahydro-2-benzimidazolyl)-ethyl]-phthalamic Acid
Authors: Elz Sigurd , Buschauer Armin , Dräger Martin , Schunack Walter 
Published: February 2015

Abstract
During syntheses using the phthalimide rest in liquid, ethanolic or aqueous ammonia, phthalamides, phthalimides or phthalamic acids are formed depending on reaction condi-tions and work-up. As demonstrated by the synthesis of the title compound via hydrolysis of 4 with aqueous ammonia, dipolar ions of phthalamic acids are obtained if the phthal-imide-N substituent is sufficiently basic. The crystal structure of 5 • 4H2O has been determined and refined until R = 0.0878. It shows a vast system of hydrogen bonds.
Argon-Matrix Isolation of Bis(carbomethoxy)thiirene: Formation of Acyl and Carbalkoxythioketenes
Authors: Torres M. , Clement A. , Strausz O. P. 
Published: February 2015

Abstract
Photolysis of argon-matrix isolated 4,5-bis(carbomethoxy)-1,2,3-thiadiazole with λ = 254 or 265 nm resulted in the almost quantitative formation of bis(carbomethoxy)-thiirene (3g). Photolysis of 3g could only be carried out by long irradiation times at short wavelength λ = 210 nm and resulted mainly in extensive fragmentation instead of the formation of bis(carbomethoxy)thioketene, confirming earlier predictions that substituents, especially electron-withdrawing ones, should stabilize the thiirene ring. Methylcarboethoxy and methylacetylthioketene were obtained, however, in the argon-matrix photolysis or flow thermolysis of 4-methyl-5-carboethoxy-or 4-carboethoxy-5-methyl-1,2,3-thiadiazole and 4-acetyl-5-methyl-1,2,3-thiadiazole, respectively.
Nematogens for Matrix-Addressed Twisted Nematic Displays, II
Authors: Osman Maged A. , Huynh-Ba T. 
Published: February 2015

Abstract
Nonpolar aromatic nematogens useful in mixtures for high performance matrix-addressed twisted nematic displays were synthesized. Nematic phases were obtained by introducing lateral halo-substituents in purely smectic biphenyls and phenyl pyrimidines. Because of their chemical stability, low viscosity and negative dielectric anisotropy, the substituted biphenyls can also be used in mixtures of negative dielectric anisotropy which are needed for the homeotropic nematic and guest-host displays with positive contrast. The effect of lateral halo-substituents on the mesomorphic properties of rod like molecules is discussed.
Die Elektronenaffinität der Halogene ermittelt aus elektrochemischen und kalorimetrischen Messungen / The Electron Affinity of the Halogens Determined from Electrochemical and Calorimetrical Measurements
Authors: Stanienda Alfred 
Published: February 2015

Abstract
Using a conception given in [1, 3] for single ionic solvation and redox reactions the electron affinities (EA) of halogens are calculated from calorimetric data of their reactions with methyleneblue radical giving the values 8.81 eV; 8.23 eV; and 7.16 eV for Cl, Br and I, respectively. For iodine EA is also obtained from the reaction enthalpy of the reaction between iodide and Mg-porphyrine cation radical. EA calculated from electrochemical standard potentials are only approximately 0.2 eV higher than found from calorimetric data except for iodine, the standard potential of which could be influenced by I3-. The disagreement of the EA values given in the literature and those presented in this work is mainly caused -to the author's opinion -by a different interpretation of single ionic solvation and the size of ionic radii in solutions.
From experimental data [1,3] solvation of anions is regarded as an energy consuming process which is understood as the overall repulsion between the anionic charge and the outer sphere electrons of solvent molecules. For calculation of the solvation energy according to the Born equation different radii have to be used: in the case of anions, the radius is composed of the radius of anions in the crystals extended by the average radius of a solvent molecule, in the case of cations -the solvation of which is an energy supplying process -the radius of atoms must be taken. On this basis the ionisation energy of tetra-methyl-p-phenylenediamine is calculated from calorimetric data for the reaction with bromine. As other examples the reaction enthalpies of the reactions of chlorine with methyleneblue radical, Li, Na, K, Cs, Be, Ca, La, Al and Zr are calculated in the gas phase as well as in water and compared with experimental ⊿G-values obtained from electrochemical standard-potentials. Excellent agreement for all selected examples is found. The discussion includes electron absorption energies of anions and solvation of ionic crystals in a solvent.
Chirale Erkennung von Naturstoffen an optisch aktiven Polysiloxanen Chiral Recognition of Natural Products on Optically Active Polysiloxanes
Authors: Bayer Ernst 
Published: February 2015

Abstract
Polysiloxanes with chiral peptide side chains have been synthesized and used as stationary phases in gas chromatography. With these phases amino acid enantiomers can be separated as N-acyl esters. Due to temperature stability up to 230 °C all protein amino acids can be separated and the racemization of synthetic biologically active peptides controlled. The phases can be used to assign the absolute configuration of amino acids. A variety of other classes of compounds can be separated into their enantiomers using the chiral polysiloxanes, like hydroxy acids, sulfoxides, phosphorous compounds, glycols, atrop isomers, amines and alcohols. Various applications of these phases are described including investigations of enantiomer selectivity in nature.
Notizen: Eine verbesserte Synthese für Bis(trimethylsilyl)magnesium / An Improved Synthesis of Bis (trimethylsilyl)magnesium
Authors: Rösch Lutz , Starke Uwe 
Published: February 2015

Abstract
Mg(SiMe3)2 · DME can be prepared in high yields by reaction of magnesium powder with Hg(SiMe3)2 in 1,2-dimethoxyethane in a supersonic bath.
Notizen: Electronegativity Order of Group IV Elements: Evidence from Molecular Geometry
Authors: Hargittai Istvan , Bliefert Claus 
Published: February 2015

Abstract
Electronegativities, Group IV Elements Electronegativities for Group IV elements A have been estimated from the bond lengths observed in AX2 and AX4 molecules (X = F, Cl, Br). The order of electronegativities established by this method is χC > χGe > χsn > χSi.
Notizen: The Isolation and Structure of Hyderabadine, a New Indole Alkaloid from Ervatamia coronaria
Authors: Atta-ur-Rahman  , Daulatabadi Nader 
Published: February 2015

Abstract
A new indole alkaloid, hyderabadine, has been isolated from the leaves of Ervatamia coronaria to which structure 1 has been assigned.
Synthese, Molekül-und Elektronenstruktur eines Radikal-Kationkomplexes [Cr(CO)4(Carben)2]+ / Synthesis, Molecular and Electronic Structure of a Radical Cationic Complex [Cr(CO)4(Carbene)2]+
Authors: Ackermann Klaus , Hofmann Peter , Köhler Frank H. , Kratzer Hans , Krist Herbert , Öfele Karl , Schmidt Helmut R. 
Published: February 2015

Abstract
A new one-step synthesis for bis-carbene complexes cis-M(CO)4L2 (M = Cr, Mo, W) containing cyclic carbene ligands L has been developed. These compounds can be oxidized by ferrocenium salts to paramagnetic cation complexes [M(CO)4L2]+ which, for M = Cr, are isolable in the form of their PF6 salts. The chromium compounds with L= 1,3-dimethyl-4-imidazolin-2-ylidene permit for the first time a structural and spectroscopic comparison of a diamagnetic carbene complex with the corresponding paramagnetic cation; the experimental facts are interpreted by molecular orbital calculations.
Amino(keto)carbene und Amino(phenyl)carbene als 1.4-dipolare Brückenliganden in einer Fe2(CO)6-Matrix / Amino(keto)carbenes and Amino(phenyl)carbenes as 1,4-Dipolar Bridging Ligands in a Fe2(CO)6 Matrix
Authors: Aumann Rudolf , Heinen Heinrich , Henkel Gerald , Dartmann Mechtild , Krebs Bernt 
Published: February 2015

Abstract
Cyclohexylamino(keto)carbene complexes of group VI B metals which contain a terminally bound carbene ligand, on reaction with Fe2(C0)9 give binuclear oxallyl iron complexes 5, in which the carbene carbon and the keto function form a bridge consisting of three atoms bound to two iron atoms. From a single crystal structure analysis of the phenyl derivative 5b, the Fe-Fe distance was found to be 2.508 Å. The two C atoms are bridging the Fe2 group in a somewhat distorted manner (C(l)-Fe(l) 2.461, C(l)-Fe(2) 1.912, C(2)-Fe(l) 2.024, C(2)-Fe(2) 2.478 Å), whereas the bridging keto oxygen is symmetrically bound to both Fe (1.927 and 2.004 Å).
Alkylamino(phenyl)carbene complexes like 11 react with Fe2(C0)9 to give a four atom bridging ligand by migration of a hydrogen atom from nitrogen and an ortho hydrogen from the phenyl group to the carbene carbon. Free or complexed alkylimines may be intermediates in this reaction.
Vitamin-Synthesen mit Carben-Komplexen, III [1]. Stereospezifische Synthese von Alkenylcarben-Komplexen des Chroms / Vitamin Syntheses via Carbene Complexes, III [1]. Stereospecific Synthesis of Alkenylcarbene Chromium Complexes
Authors: Dötz Karl Heinz , Kuhn Werner , Ackermann Klaus 
Published: February 2015

Abstract
Addition of lithioalkenes to hexacarbonylchromium followed by alkylation with trimethyloxonium tetrafluoroborate provides a stereospecific route to pentacarbonyl-[alkenyl(methoxy)carbene]chromium complexes. For the E-butenylcarbene complex an approximately orthogonal dihedral angle between the carbene and the alkene plane is established by X-ray analysis.
Derivate des Borols, IV [1]. Ein Borol-Dianion durch Lithiierung von 1-Diisopropylamino-3-borolen / Derivatives of Borole, IV [1]. A Borole Dianion via Lithiation of 1-Diisopropylamino-3-borolene
Authors: Herberich Gerhard E. , Ohst Holger 
Published: February 2015

Abstract
1 -Diisopropylamino-3-borolene is readily lithiated by tert-butyllithium in THF to produce lithium (1-diisopropylaminoborolenediide), the second known example of the 6 π-electron borole dianion. Trimethylsilylation of the dianion gives trans-1-diisopropylamino-4,5-bis(trimethylsilyl)-2-borolene. Reaction with [{C6(CH3)6}RuCl2]2 affords the (borole)-ruthenium complex [C6(CH3)6]Ru[C4H4BN{CH(CH3)2}2].
Übergangsmetall-Methylen-Komplexe, LI [1]. Carbocyclische Carbene, Carben-Brücken, kleine Kohlenwasserstoff-Liganden und Metallacyclen: Beispiele einer umfassenden Synthesekonzeption / Transition Metal Methylene Complexes, LI [1]. Carbocyclic Carbenes, Carbene Bridges, Small Hydrocarbon Ligands, and Metallacycles: Examples of a General Synthetic Concept
Authors: Herrmann Wolfgang A. , Plank Johann , Hubbard John L. , Kriechbaum Gangolf W. , Kalcher Willibald , Koumbouris Basile , Ihl Gabriele , Schäfer Adolf , Ziegler Manfred L. , Pfisterer Heike , Pahl Claudia , Atwood Jerry L. , Rogers Robin D. 
Published: February 2015

Abstract
Carbene transfer from aliphatic diazoalkanes upon coordinatively unsaturated metal centers is a general synthetic concept that provides straight-forward routes into organo-metallic hydrocarbon chemistry. A comparison focussing on several key reactions of general applicability demonstrates that mononuclear organometal substrates add carbenes that may act as bridging ligands (e.g., compound 6) if they arise from ω,ω'-bisdiazoalkanes. By way of contrast, metal-metal double bonds cleanly form dimetallacyclo-propane-type derivatives under very mild conditions (7-9). The broadest variety of structures is finally encountered with metal-metal triply bonded precursors such as the molybdenum compounds 3: here, the initial diazoalkane adducts are subject to further rearrangement processes commonly leading to metal-metal single bonds (11) or causing irreversible cleavage of the dinuclear metal systems (10).
Funktionelle Trimethylphosphanderivate, XVIII [1]. Methyl(phosphinomethyl)silane und -stannane / Functional Trimethylphosphane Derivatives, XVIII [1]. Methyl(phosphinomethyl)silanes and -stannanes
Authors: Karsch Hans H. , Appelt Armin 
Published: February 2015

Abstract
Mono-and polydentate phosphanes Me(4-x)E(CH2PMe2)x (E = Si, Sn) are prepared by the reaction of LiCH2PMe2 with Me(4-x)EClx. They are easily deprotonated at the methylen carbon atom. The preparation of BrCH2CMe2CH2PMe2 and Me2C(CH2PMe2)2 is also described. The complex formation ability is shown by the isolation of the tetrahedral nickel(0) complex [Me2Si(CH2PMe2)2]2Ni, where the diphosphane acts as a bidentate chelating ligand with heteroelement bridges. The new compounds are characterized by means of NMR spectroscopy.
Oberflächenverbindungen von Übergangsmetallen, XXV [1]: Redoxreaktionen von Oberfläehen-Chrom(II) auf Silicagel mit Olefinen / Surface Compounds of Transition Metals, XXV [1]: Redox Reactions of Surface Chromium(II) on Silicagel with Olefins
Authors: Krauss Hans-Ludwig , Hums Erich 
Published: February 2015

Abstract
Olefins may react with chromium(II)/silicagel catalysts at temperatures from 100 to 600 °C under formation of C1-C4 n-alkanes and organometallic species; the chromium is oxidized simultaneously. By this reaction the catalytic sites loose the ability for olefin polymerization and 〈CH2〉 transfer.
A following treatment of the catalyst with hydrogen at 400 °C produces a second crop of alkanes from former organometallic species under partial reduction of the chromium back to CrII ; the polymerization activity is restorted correspondingly.
Übergangsmetallketen-Verbindungen, XIX [1]. Umwandlung von η2 -Ketenyl-in η2 -Alkinkomplexe mit Lewis-Säuren / Compounds of Transition Metal Ketenes, XIX [1]. Conversion of η2 -Ketenyl-into η2 -Alkyne Complexes Using Lewis Acids
Authors: Kreißl Fritz R. , Sieber Werner J. , Wolfgruber Mathias 
Published: February 2015

Abstract
Carbonyl(η5 -cyclopentadienyl)(η2 -ketenyl)trimethylphosphine tungsten complexes add Lewis acids to the ketene oxygen atom with concomitant conversion of the η2 -ketenyl into an η2 -alkyne ligand.
Gehinderte Ligandbewegungen in Übergangsmetall-Komplexen, XXI [1]. Isomeric und Dynamik von cis-Dicarbonyl-bis(η4 -2-methyl-1.3-butadien)wolfram(0) / Hindered Ligand Movements in Transitionmetal Complexes, XXI [1]. Isomerism and Dynamics of cis-Dicarbonyl-bis(η4 -2-methyl-1,3-butadiene)tungsten(0)
Authors: Kreiter Cornelius G. , Özkar Saim 
Published: February 2015

Abstract
cis-Dicarbonyl-bis(2-methyl-1,3-butadiene)molybdenum(0) (1) and -tungsten(0) (2) were prepared photochemically from tricarbonylmesitylene-molybdenum(0) and aceto-nitrile-pentacarbonyl-tungsten(0), respectively, as thermolabile yellow oils. 2 is obtained as a mixture of two diastereomeric pairs of enantiomers 2a (2a') and 2c (2c'). From 1H and 13C NMR spectroscopic data 2 a (2a') is shown to have C2 symmetry, whereas 2 c (2c') is asymmetric. The NMR signals of 2 c (2 c') are temperature dependent due to an intramolecular 2c⇄2c'-isomerization (⊿G≠250 = 47 kJ · mol-1). A trigonal prismatic transi-tion state with Cs symmetry explains the D-NMR spectroscopic results. The NMR signals of 2 a (2a') are temperature dependent, too. This is taken as evidence for a ligand movement which brings 2a (2a') on the way to a third diastereomeric form 2b' (2b), with no detectable population. The molybdenum complex 1 forms only the isomers la (la') with C2 symmetry.
Über das [C7H7Fe2(CO)5]--Anion (C7H7 = Cycloheptatrienyl) / About the [C7H7Fe2(CO)5]--Anion (C7H7 = Cycloheptatrienyl)
Authors: Moll Matthias , Behrens Helmut , Popp Werner , Liehr Günther , Fehlhammer Wolf Peter 
Published: February 2015

Abstract
The extremely unstable anionic complex [C7H7Fe2(CO)6]- (C7H7 = cycloheptatrienyl) which decomposes in polar solvents under CO elimination to give [C7H7Fe2(CO)5]- can be prepared by deprotonation of C7H8Fe2(CO)6 (C7H8 = cycloheptatriene) with NaN(SiMe3)2 in C6H6.The NMR spectra of [C7H7Fe2(CO)5]- show the highly fluctional character of this anion in solution. The X-ray structural parameters of Ph4As[C7H7Fe2(CO)5] (space group P21/n) can be interpreted in terms of a rotation of the tub shaped C7H7 ring against the CO bridged Fe2(CO)5 fragment in the solid state. Consequently, each iron atom is alternatingly η3 -or η4-coordinated to the allyl anion and the diene part, respectively, of the anionic 8π system of the cycloheptatrienyl ring.
Metallorganische Lewis-Säuren, XIV [1]. Ethylen-verbrückte Mangan- und Rheniumcarbonyle; Tieftemperatur-Röntgenstrukturanalyse von (OC)5ReCH2CH2Re(CO)5 / Organometallic Lewis Acids, XIV [1]. Ethylene Bridged Manganese and Rhenium Carbonyls; Low Temperature X-Ray Structure of (OC)5ReCH2CH2Re(CO)5
Authors: Raab Klaus , Nagel Ulrich , Beck Wolfgang 
Published: February 2015

Abstract
The tetrafluoroborato complexes (OC)5MFBF3 (M = Mn, Re) which are obtained by methyl abstraction from (OC)5MCH3 using Ph3CBF4 react with ethylene or propene at room temperature and 1 bar to give [(OC)5M(alkene)]+ BF4-. By nucleophilic addition of the carbonylmetalates [M(CO)s] -(M = Mn, Re) to the coordinated alkene in these cationic complexes [(OC)5M(alkene)]+ the alkene bridged complexes (OC)5MCH2CH(R)M(CO)5 (M = Mn, Re; R = H, Me) are formed. Also the mixed-metal complex (OC)5MnCH2CH2Re(CO)5 has been isolated. According to an X-ray structure at low temperature (OC)5ReCH2CH2Re(CO)5 can be considered as a dimetal substituted ethane with a carbon-carbon distance of 152 pm.
Überführung von Triazaphospholen in Diazaphosphole durch Acetylenaddition/Nitrileliminierung [1] / Conversion of Triazaphospholes into Diazaphospholes by Acetylene Addition/Nitrile Elimination [1]
Authors: Schmidpeter Alfred , Klehr Hubert 
Published: February 2015

Abstract
Acetylene di-and (less easily) monocarboxylic esters replace nitriles from the 4,5-position of 1,2,4,3-triazaphosphole rings to give carboxyl derivatives of 1,2,3-diazaphospholes, presumably by a cycloaddition/cycloreversion mechanism. In cases with a mobile N-substituent alternatively the loss of N2 seemed feasible, but was normally not observed.
Hydrido-Silyl-Komplexe, IV [1]. Strukturelle Änderungen in Hydrido-Silyl-Komplexen infolge Si-H-Wechselwirkung; Strukturvergleich von (π-CH3C5H4)(CO)2Mn(H)SiCl3 und trans-(π-CH3C5H4)(CO)2Mn(SiCl3)2 / Hydrido Silyl Complexes, IV [1]. Structural Changes in Hydrido Silyl Complexes Due to Si-H Interaction; Comparison of the Structures of (π-CH3C5H4)(CO)2Mn(H)SiCl3 and trans-(π-CH3C5H4)(CO)2Mn(SiCl3)2
Authors: Schubert Ulrich , Ackermann Klaus , Kraft Gertraud 
Published: February 2015

Abstract
The main difference between the structures of MeCp(CO)2Mn(H)SiCl3 (1) and MeCp(CO)2Mn(SiCl3)2 (2) is that in 1 the SiCl3 ligand is tilted relative to the Mn-Si vector, due to Mn-H-Si three-center two-electron bonding. Mn-Si: 225.4(1) in 1, 232.0(2) pm in 2. Comparison of the structures of MeCp(CO)2Mn(H)SiR3 complexes shows that the Mn-Si distance and the tilt angle of the SiR3 group increases as Si-H interaction increases. A stereochemical pathway of the oxidative addition of HSiR3 to the CpMn(CO)3 fragment is suggested.
Photochemistry of Osmium-Carbyne Complexes
Authors: Vogler Arnd , Kisslinger Josef , Roper Warren R. 
Published: February 2015

Abstract
Upon charge transfer (Os to carbyne) excitation the carbyne complexes Os(CPh)(CO)(PPh3)2Cl and [Os(CPh)(CO)2(PPh3)2]+ with Ph = C6H5 are converted to the carbene complex Os(CHPh)(CO)(PPh3)2Cl2 in solutions containing HCl. It is suggested that the relaxed CT state can be described as square-pyramidal Os(II) complex containing a bent carbyne ligand which carries a lone pair at the coordinating carbon atom. Product formation occurs by the addition of a proton to the carbyne ligand and by attaching a chloride to the osmium completing an octahedral coordination. The cationic carbene complex thus formed is apparently not stable but undergoes a substitut ion of a CO ligand by chloride.
Kristallstruktur und Schwingungsspektren des Thalliumhexathiometadiphosphates Tl2P2S6 / Crystal Structure and Vibrational Spectra of Tl2P2S6
Authors: Wibbelmann Claus , Brockner Wolfgang , Eisenmann Brigitte , Schäfer Herbert 
Published: February 2015

Tl2P2S6 crystallizes in the orthorhombic system, space group Immm, Z = 2 with the lattice constants
a = 793.2(4) pm, b = 689.2(4) pm, c = 901.9(5) pm.
In the structure there are discrete P2S6
2- -anions. The P2S6
2- -ion was found to be a hexa-thiometadiphosphate group where the two P atoms are linked by two S bridges.
Far infrared, infrared and Raman spectra of this compound have been recorded. The observed frequencies are assigned on the basis of P2S6
2- units with D2h symmetry in analogy to the isoelectronic Al2Cl6
Ultraviolet Photoelectron Spectra of Square Planar Complexes of Nickel Triad Metals, I.He(I) and He(II) Spectra of [M{C6H3(CH2NMe2)2o,o′}X], (M = Ni, Pt; X = Cl, Br, I. M = Pd; X = Br)
Authors: Louwen Jaap N. , Grove David M. , Ubbels Henk J. C. , Stufkens Derk J. , Oskam Ad 
Published: February 2015

UV photoelectron spectra of the title compounds are reported. Assignments based on He(I)/He(II) intensity differences, shift effects, and comparison with related molecules allow an assignment of the upper valence bands. Electronic differences between nickel and both platinum and palladium are reflected in the spectra, especially with respect to bands due to ionization of electrons from the metal.
Strong evidence is found for π interaction of the ligand phenyl system with metal orbitals
Über Arthropodenabwehrstoffe, LXV. Die Chemische Ökologie des Grundschwimmers Laccophilus minutus / On Arthropode Defensive Compounds, LXV. The Chemical Ecology of the Water Beetle Laccophilus minutus
Authors: Schildknecht H. , Weber B. , Dettner K. 
Published: February 2015

According to a GC-MS analysis of methylated extracts the abdominal tips of the water beetle Laccophilus minutus (Dytiscidae) contain four β-hydroxyalkanoic acids. On the basis of MS and GC data another compound was assigned the structure of 6-octenoic acid.
The same β-hydroxyalkanoic acids, and in addition, traces of β-hydroxyheptanoic acids were identified in dissected pygidial defensive glands after trimethylsilylation. Methyl 3,4-dihydroxyphenylacetate was recognized as a further main component in the pygidial gland secretion from the mass spectrum of its TMSi ether.
The Laccophilinae occupy unique position among all the dytiscide subfamilies because they are the only water beetles which store β-hydroxyalkanoic acids in their pygidial glands. On the other hand the dytiscides appear to form a monophyletic group which is supported by the occurrence of methyl 3,4-dihydroxyphenylacetate. This class of compound is also commonly encountered in the other dytiscide subfamilies
A New Approach for the Synthesis of Some Pyridine and Pyridone Derivatives
Authors: Hishmat O. H. , Zohair M. M. Y. , Miky J. A. A. 
Published: February 2015

Both visnaginone and khellinone react with malononitrile, ethyl cyanoacetate or cyanoacetamide in presence of ammonium acetate to give substituted furobenzopyrans or furobenzopyridones.
However, the reaction of visnaginone and khellinone with aldehydes, and malononitrile in presence of ammonium acetate leads to the formation of the corresponding 2-amino-4,6-disubstituted pyridine 3-carbonitriles. The latter compounds are also obtained by treating the respective chalcones with malononitrile and ammonium acetate.
3-Substituted 1,3-diketobutyrates form with malononitrile or with cyanoacetamide and ammonium acetate the 2-amino-4,6-disubstituted pyridine-3-carbonitriles or the 4,6-di-substituted cyanopyridones, respectively