Type 6 meso-ionic [1,2,4]triazolo[5,1-c]thiadiazoles were synthesised by oxidation of the corresponding N-methyl-N'-(substitutedbenzal)-5-amino-3- substituted-1,2,4-triazol-1-yl)thiohydrazide (3) type bases or their [1,2,4]triazolo[5,1-d][1,2,3,6]tetrazepin-5-thion (4) type ring tautomers. Besides spectroscopical evidence a preparative proof of their structure was also provided. X-ray diffraction analysis of 3-methylthio-6-morpholino-1,2,4- triazolo[5,1-c]thiadiazole (8) showed quite unusual bond lengths for the N1- S and S-C3 bonds of the thiadiazole ring proving the meso-ionic character of these derivatives unequivocally.
ASJC Scopus subject areas
- Organic Chemistry