Hans Berbalk

Synthesen von 2-Anilinocyclopentanonen

The syntheses of the 2-anilinocyclopentanones2 a–2 e in yields about 50% by reaction of 2-chlorocyclopentanone with 4-chloroaniline, N-methyl-4-chloroaniline, α,α,α-trifluoro-3-toluidine, N-methyl-α,α,α-trifluoro-3-toluidine and 3,4,5-trimethoxyaniline, are described.

Der massenspektrometrischeortho-Effekt bei 2-Nitro-benzophenon

An attempt has been made to interpret the mass spectrometric ortho-effect observed for 2-nitrobenzophenone. Asterically hindered planar conformation, stabilized by an intramolecular donor-acceptor complex, is proposed for the ground state.

p-(5-Fluor-2,4-dinitro-1-phenylazo)-N,N-dimethylanilin, ein neues Reagens zur flüssigchromatographischen Bestimmung von Phenolen

The synthesis ofp-(5-fluoro-2,4-dinitro-1-phenylazo)-N,N-dimethylaniline and its reactions with phenoles top-(2,4-dinitro-5-phenoxy-1-phenylazo)-N,N-dimethylanilines and the use of the resulting coloured products for the TLC determination of phenoles is described.

Reaktionswege zu 3-Acyl-2-oxo-cholest-5-enen / Reaction Ways to 3-Acyl-2-oxo-cholest-5-enes

Two reaction ways to 3-phenylacetyl-2-oxo-cholest-5-ene (10) as model compound for similar A-ring derivatives of steroids are investigated. The first way starts from the known 6,6-ethylenedioxy-3-oxo-5α-cholestane (1) which is reacted with phenylethinyl-magnesiumbromide to the mixture of epimeric alkinols. The crude mixture of epimers is dehydrated to 6,6-ethylenedioxy-3-phenylethinyl-5α-cholest-2-ene (2), which gives after epoxidation of the double bond and reaction of the resulting crude epoxide with 95 proz. HCOOH the fully enolic 2,6-dioxo-3-phenylacetyl-5α-cholestane (3). Because of a very low total yield of this approach to 10 this way is not further investigated. A successful reaction way starts from the known 6β-hydroxy-5α-cholestane-3-one (4). 4 is reacted with phenylethinylmagnesiumbromide, the 6β-OH group is benzoylated and the tert. alkinols dehydrated in successive steps without isolation of the non crystalline intermediate products to 6β-benzoyloxy-3-phenylethinyl-5α-cholest-2-ene (6). Hydrolysis of 6 yields 6β-hydroxy-3-phenylethinyl-5α-cholest-2-ene (7) which is epoxidated at the double bond and the crude epoxide reacted with 95 proz. HCOOH to 6β-formyloxy-3-phenylacetyl-5α-cholestan-2-one (8). Hydrolysis of the formylgroup in 8 yields 9, which gives by acid catalysed dehydratisation the desired model compound 10. The structure of 10 is confirmed by its 1H NMR and UV spectra.

Stereochemie vonGrignard-Reaktione mit 2-(N-Methylanikino)-cyclopentanonen

TheGrignard reactions of the 2-anilinocyclopentanones (1 a and1 b) with CH3MgI and C6H5C≡CMgBr, giving the 2-anilinocyclopentanols2 a, 2 b, and2 c, and the synthesis oftrans-1-methyl-2-(4-chloro-N-methylanilino)-cyclopentanol (4), which was used as a reference compound of known stereochemistry, are described. IR spectroscopic investigations of2 a, 2 b, and2 c as compared with4 lead to the conclusion that2 a, 2 b, and2 c have the structures ofcis-2-(N-methylanilino)-cyclopentanols.

Untersuchungen über die gaschromatographische Bestimmung von Am eisensäure und Essigsäure neben SO2 in wäßrigen Lösungen

Preparation in an analytical scale from aquous SO2 containing solutions of the free acids and use of some esters and amides of formic and acetic acid are described. The piperidides of acetic and formic acid are obtained without interference from SO2 and are easily determined with the column SP 1000 and a flame ionisation detector.

Infrarotspektroskopische Untersuchungen an 1-Alkynylcyclopentanen

Frequencies and intensities of the C≡C stretching vibration band in the infrared spectra of 15 1-alkynylcyclopentanes are reported and correlated with the substituents at the triple bond. The syntheses of substituted 7-(1-cyclopentenyl)-6-heptynoic acids, used as reference compounds, are described.

Untersuchungen über die zusammensetzung der unverseifbaren Bestandteile in Fettsäuredestillaten aus Tallöl

The unsaponifiable, non-acidic constituents of commercial fatty acid distillates were isolated. The resulting complex mixture was further separated viaGirard-compounds.Some of the constituents of these still complex fractions were identified as α-pinene, pimarol, isopimarol, abietol,trans-3,5-dimethoxystilbene, abietal, pimaral and isopimaral by gas chromatography, mass spectrometry and isolation of crystalline derivatives.

Die Isopropylgruppe als Ursache und Sonde für sterische Mesomeriehinderung in Benzocyclen-3-onen

Abstract The syntheses of new isopropylsubstituted benzocyclenones are reported. Ultraviolet-spectra of this compounds allow the calculation of the torsion angle of the plane of the carbonyl group relative to the plane of the aromatic system. Torsion angles due to steric interaction between isopropyl group and carbonyl group alone are reported. It is found that the 1 H-NMR chemical shift of the tert. H-atom of the isopropyl group may be correlated with the torsion angle according to the McConnell equation.