Synthesis of new substituted th losemicarbazides and their cyclization to triazole-and thiadiazole derivatives
Nine new thiosemicarbazides substituted with arylsulfonylbenzoyl groups at N1 and with β-phenylethyl, n-butyl and cyclohexyl groups at N4 were obtained in a four-step synthesis involving nucleophilic addition of corresponding acid hydrazides to isocyanates. Cyclization of β-phenylethyl and n-butyl thiosemicarbazides in NaOH solution afforded the corresponding mercaptotriazoles. Cyclization of β-phenylethyl thiosemicarbazides in concentrated H2SO4 gave rise to substituted aminothiadiazoles bearing an -SO3H group in the para- position of the side-chain phenyl ring, whereas Cyclization of n-butyl thiosemicarbazides conducted in a clean way to the expected substituted aminothiadiazoles. The thiosemicarbazides possessing cyclohexyl substituants proved reluctant to Cyclization both in alkaline and acidic medium, probably due to steric hindrance. All the new compounds - extensively characterised by IR, UV, 1H-NMR and 13C-NMR spectra - will be biologically tested.
?aramet, Ioana,Drǎghici, Constantin,Bǎrcutean, Corina,Rǎdulescu, Valeria,Loloiu, Teodora,Banciu, Mircea D.
p. 139 - 153
(2007/10/03)
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