Helvetica Chimica Acta

doi: 10.1002/hlca.19740570401pmid: N/A

Garmatter, Jacques; Siegrist, Adolf Emil

doi: 10.1002/hlca.19740570402pmid: N/A

Schiff'sche Basen des Dibenzofuran‐2‐ bzw. ‐3‐carbaldehydes mit p‐Chloranilin können mit p‐tolyl‐substituierten heterocyclischen und carbocyclischen Aromaten in Gegenwart von Dimethylformamid und Kaliumhydroxid bzw. Kalium‐t‐butylat in die entsprechenden Styryl‐Derivate übergeführt werden (« Anil‐Synthese »).

Schiess, Peter; Wisson, Markus

doi: 10.1002/hlca.19740570403pmid: N/A

8‐Oxabicyclo[5.1.0]octa‐2,4‐diene (1) is obtained from cycloheptatriene with commercial 40% peracetic acid. Upon catalytic and LiAlH4 reduction the allylic CO‐bond in 1 is cleaved. Acid catalised hydrolysis leads to a mixture of all six possible isomeric cycloheptadienediols. With BF3 in the absence of water isomerization to 3,5‐cycloptadienone is observed.

Müller, Paul; Siegfried, Bernard

doi: 10.1002/hlca.19740570404pmid: N/A

Sodium cyanide in hexamethylphosphoric triamide selectively cleaves methyl esters in the presence of ethyl esters with yields of ca. 80%. The mechanism of the reaction has been investigated. It consists of nucleophilic displacement by cyanide of the carboxylate ion from the alcohol carbon atom (BAl2 mechanism).

Maier, John P.

doi: 10.1002/hlca.19740570405pmid: N/A

The He I photoelectron spectra of peri‐amino and dimethylamino naphthalenes are presented. The differences in the ionization energies of the π‐bands are interpreted by separation of the perturbation of the amino substituent into an inductive destabilization and conjugative stabilization. This affords the assignment of the photoelectron bands of ionization energies below 11 eV and an estimation of the dihedral angle in the peri‐dimethylamino derivatives. The data on the peri‐amino naphthalenes indicate some angular distortion in contrast to 2‐aminonaphthalene.

Blackstock, Walter P.; Kuenzle, Clive C.; Eugster, Conrad H.

doi: 10.1002/hlca.19740570406pmid: 4416931

A novel carbohydrate has previously been isolated from human bile as a complex glycoside of bilirubin [1]. This compound has been tentatively identified as 3‐C‐hydroxymethyl‐D‐riburonic acid. To test this structural assignment the proposed branched‐chain uronic acid was synthesized. Gas chromatographic and mass spectrometric comparison of the natural and synthetic materials indicated that the proposed structure, 3‐C‐hydroxymethyl‐D‐riburonic acid, did not apply to thc natural product.

Fink, Walter

doi: 10.1002/hlca.19740570407pmid: N/A

Poly(dimethylsilyl)benzenes have been prepared by ‘in situ’ reactions of polybromobenzenes with magnesium and dimethylchlorosilane in tetrahydrofuran. The hydrolysis of these compounds yields benzo[c][1,2,5]oxadisiloles.

Mihailovič, Mihailo Lj.; Bošnjak, Jovan; Čeković, Živorad

doi: 10.1002/hlca.19740570408pmid: N/A

The stereochemistry of β‐fragmentation products formed in the oxidation of cis‐and trans‐4‐t‐butylcyclohexaanemethanol with lead tetraacetate and with lead tetraacetate‐metal chloride combinations, under various reaction conditions, has been investigated, and the results compared with those obtained, under similar conditions, in the oxidative decarboxylation of cis‐and trans‐4‐t‐butylcyclohexanecarboxylic acid with the same reagents. It was found that all four substrates afford, under comparable conditions, identical cis‐trans proportions of the respective fragmentation products, and that, therefore, so far as steric course is concerned, both the initial homolytic and subsequent heterolytic processes involved in the lead tetraacetate fragmentation reaction are independent of the nature and configuration of the starting material.

Buxtorf, Rudolf; Kaden, Thomas A.

doi: 10.1002/hlca.19740570409pmid: N/A

The synthesis, properties and complexation of 1‐methyl‐1,4,8,11‐tetraazacyclotetradecane (1‐MeCyclam‐14), 1,5‐dimethyl‐1,5,8,12‐tetraazacyclotetradecane (2‐MeCyclam‐14) and 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane (4‐MeCyclam‐14) are described.

Fink, Walter

doi: 10.1002/hlca.19740570410pmid: N/A

Es wird eine einfache Darstellung von N‐Trimethylsilylmethyl‐glycin durch Hydrolyse von N‐Trimethylsilylmethyl‐glycinamid beschrieben.