Furancarbonsäuren aus Rinderharn

Furancarboxylic Acids in Cattle Urine The urine of cattle contains large amounts of furancarboxylic acids. The same acids were isolated from rats after feeding with methyl esters of the so-called F-acids. Since the F-acids were not detected in cattle-food, they must be produced somewhere in the body of cattle.     

Halogenierte Pyridine IV. Kernchlorierte Pyridin-3-carbonsäuren

Halogenated pyridines IV. Nuclear chlorinated pyridine-3-carboxylic acids . Chlorinated pyridine-3-carboxylic acids (nicotinic acids) are readily accessible by oxidation of nuclear chlorinated 3-chloromethyl-pyridines. The catalytic oxidation procedures proved to be by far the best ones of the methods tested.     

NMR.-spektroskopische Methoden als Reinheitskriterien isomerer Weinsäuren und Weinsäureester

NMR.-spectroscopic Methods as Criteria of the Purity of Isomeric Tartaric Acids and Their Esters meso-Tartaric acid ( 2 ) can be distinguished either from the natural (+)-(2R, 3R)-tartaric acid ( 1 ) or the ‘unnatural’ (?)-(2S, 3S)-tartaric acid ( 1 ′) or their racemic mixture, by ¹H-NMR.-spectral resolution using europium chloride in aqueous solution. Diastereomeric esters have been prepared from different esters of tartaric acid 3 and the Mosher reagent 4 and the purities of the enantiomers of 3 have been checked by ¹H-NMR. spectroscopy.     

Zur herstellung aromatischer phosponsäureester aus arylhalogeniden und trialkylphosphiten

Aromatic iodo- or bromo-compounds react with with an excess of trialkylphosphite and copper to give the dialkylarylphosphonates 1a–1h. A radical mechanism is proposed for this reaction.