Gerhard Hojas
University of Graz
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Publication
Featured researches published by Gerhard Hojas.
Molecules | 2001
Wolfgang Stadlbauer; El-Sayed A. M. Badawey; Gerhard Hojas; Peter Roschger; Thomas Kappe; Karl-Franzens-University Graz
The use of malonates such as diethyl malonates 9, (chlorocarbonyl)ketenes 15 and bis(2,4,6-trichlorophenyl) malonates 18 as reagents for cyclocondensation with 1,3-dinucleophiles to give six-membered heterocycles is described. Further attempts to use malonates such as bis(trimethylsilyl) malonates 19 and bis(carbamimidoyl) malonates 29 as new cyclocondensation agents are described .
Journal of Biochemical and Biophysical Methods | 2002
Wolfgang Stadlbauer; Gerhard Hojas
Thermal properties of azidohetarenes without reactive ortho-substituents, obtained by DSC analysis, were compared with the DSC data of ortho-phenyl and ortho-acyl substituted azidohetarenes, which give ring closure reactions either to indoles or to five-membered heterocycles such as isoxazoles. The reaction temperatures and reaction enthalpies give both information to prepare the reaction conditions and important safety information and were, in addition, used to find out relations between the temperatures or enthalpies with the three different reaction mechanisms.
Journal of The Chemical Society-perkin Transactions 1 | 2000
Wolfgang Stadlbauer; Gerhard Hojas
The reaction of 3-amino-4-hydrazino-1H-pyrazolo[3,4-b]quinoline 8 with nitrous acid did not give 2,4-diazidoquinoline-3-carbonitrile 5 as reported previously, but afforded in 60% yield 4-azido-3-diazopyrazolo[3,4-b]quinoline 10, which gave by azo coupling with 2-naphthol 4-azido-3-(2-hydroxy-1-naphthylazo)-1H-pyrazolo[3,4-b]quinoline 11.
Journal Fur Praktische Chemie-chemiker-zeitung | 2000
Wolfgang Stadlbauer; Werner Fiala; Michaela Fischer; Gerhard Hojas
4-Azidopyridines such as 3-acetyl-4-azido-2-pyridones 3 or 4-azido-3-ethoxycarbonylpyridine 7 with reactive ortho-acyl substituents were obtained from the 4-hydroxy-2-pyridones 1, resp. 5via 4-tosyloxy-2-pyridones 2 or the 2,4-dichloropyridine 6. DSC-assisted thermolysis of the azides 3 and 7 resulted in electrocyclization and elimination of nitrogen to the isoxazolo[4,3-c]pyridines 4 and 8.
Journal of Heterocyclic Chemistry | 2004
Wolfgang Stadlbauer; Gerhard Hojas
Journal of Heterocyclic Chemistry | 2000
Gerhard Hojas; Werner Fiala; Wolfgang Stadlbauer
Journal of Heterocyclic Chemistry | 2000
Wolfgang Stadlbauer; Werner Fiala; Michaela Fischer; Gerhard Hojas
Journal of Heterocyclic Chemistry | 2003
Wolfgang Stadlbauer; Gerhard Hojas
ChemInform | 2010
Gerhard Hojas; Werner Fiala; Wolfgang Stadlbauer
ChemInform | 2004
Wolfgang Stadlbauer; Gerhard Hojas