ISSN:
1573-8353
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The reaction of β-diketones with 2-unsubstituted thiosemicarbazides leads to the formation of the corresponding 1-thiocarbamoyl-5-hydroxy-2-pyrazolines, which readily undergo aromatization to give pyrazoles, while the reaction of benzoylacetaldehyde leads to the formation of the corresponding hydrazone. Acetylacetone 2-methyl- and 2,4-dimethylthiosemicarbazones are inclined to undergo tautomerization and, depending on the conditions, can exist in enehydrazine, hydrazone, 1,2,4-triazoline, and 1,3,4-thiadiazoline forms or mixtures of these forms. Upon heating these substances are converted to mixtures of the 1,3,5-trimethylpyrazole and the corresponding 1,2,4-triazoline-5-thione. The structures of the compounds were studied by means of IR and 1H, 13C, and 15N NMR spectroscopy and mass spectrometry.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00472492
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