Kurt Polborn

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1,5-Diamino-1H-tetrazole (2, DAT) can easily be protonated by reaction with strong mineral acids, yielding the poorly investigated 1,5-diaminotetrazolium nitrate (2a) and perchlorate (2b). A new synthesis for 2 is introduced that avoids lead azide as a hazardous byproduct. The reaction of 1,5-diamino-1H-tetrazole with iodomethane (7a) followed by the(More)
Chloro-(eta6-arene) complexes of ruthenium(II) with N-sulfonyl-1,2-ethylenediamine ligands that have one or two styrene side chains have been synthesised and characterised. The chloro ligand was substituted with a diphenylphosphinato ligand and the resulting organometallic complexes are transition state analogues for the ruthenium-catalysed transfer(More)
The new large scale synthesis of the yellow colored vitamin B6 analogue 5'-O-phosphono-pyridoxylidenerhodanine (2) (B6PR) leads to oligohydrates of its monosodium salt (4). The light-red hemiheptadecahydrate (8 1/2 hydrate) (4a) was crystallized and its three-dimensional structure determined by X-ray crystallography. Special nucleotide and protein(More)
2-Triphenylphosphanimino-4-azidotetrazolo[5,1-a]-[1,3,5]triazine (6) was obtained by reaction of 2,4,6-triazido-1,3,5-triazine (1) with 1 equiv of triphenylphosphane. Raman and X-ray data revealed that only one azide group formed a tetrazole ring system whereas the second azide group did not undergo ring closure. To investigate the equilibrium between the(More)
N-Nitroso- (5a,c) and N-nitraminotetrazoles (6a-c) were synthesized from the corresponding aminotetrazoles (3a-c) either by the direct nitration with acetic anhydride/HNO3 or by dehydration of the corresponding nitrates (4a-c) with concentrated sulfuric acid. The conversion of the N-nitrosoaminotetrazoles (5a,c) with peroxytrifluoroacetic acid (CF3CO3H)(More)
The yeast Malassezia furfur converts tryptophan into several indole compounds. One of these, malassezin, was identified as 2-(1H-indol-3-ylmethyl)-1H-indole-3-carbaldehyde (1). It was synthesized from N-Boc-indole-3-carbaldehyde in five steps with 12% overall yield. The compound easily cyclizes to indolo[3,2-b]carbazole (7) which is known to interact with(More)
The kinetics of reactions of acceptor-stabilized carbanions 2a-m with benzylidenebarbituric and -thiobarbituric acids 1a-e has been determined in a dimethyl sulfoxide solution at 20 degrees C. Second-order rate constants were employed to determine the electrophilicity parameters E of the benzylidenebarbituric and -thiobarbituric acids 1a-e according to the(More)