J. Kalvoda

  • Citations Per Year
Learn More
We have measured five deep-water carbonate and carbonate-siliciclastic sections at the Tournaisian-Viséan (Tn/V) boundary in western Europe, using petrophysical outcrop logging techniques (gamma-ray spectrometry /GRS/ and magnetic susceptibility /MS/). The aim was to trace correlatable log patterns across the flanks of the London-Brabant Massif from eastern(More)
The intramolecular substitution of the angular methyl groups in steroids by attack of O-radicals derived from 6β-, 11β, and 20-alcohols is discussed. Irrespective of their genesis, these radicals abstract a hydrogen atom from one of the said methyl groups, suitably oriented inδ-position. The C-radicals thus formed give different products depending on the(More)
Through its collaboration with the ETH in Zurich (Ruzicka's group) and later on with the University of Basel (Reichstein's group). Ciba became involved very early in steroid chemistry. The main task of the chemists consisted at that time of the synthesis of natural hormones and their derivatives. Cholesterol served for several years as the preferred(More)
The new methods for the production of 19-norsteroids described involve the conversion of 5α-halogen-6β-hydroxy-steroids into the corresponding 5α-halogen-6β:19-ethers either with lead tetraacetate or by the hypoiodite reaction8,10. The 6β:19-oxygen bridge is then opened reductively either directly or after oxidation of the 6β:19-ethers to lactones or(More)