Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Reaction of thiosemicarbazide with carboxylic acids, including N-substituted amino acids, in ionic liquids with H 2 SO 4 as a catalyst affords 5-R-2-amino-1,3,4-thiadiazoles. On using alkanedicarboxylic acids, α,ω-bis(2-amino-1,3,4,-thiadiazol-5-yl)alkanes were obtained.