15.7 g of 5-amino-2-n-butyl-1:3:4-thiadiazole (0.1 mol) was dissolved in 150
ml dry pyridine and treated with 21.1 g of ρ-chlorobenzene sulfonyl chloride
(0.1 mol). The mixture was heated on a steam bath for 4 h and the pyridine
removed by distillation under reduced pressure. The residue was treated with
50 ml 2 N hydrochloric acid, and after filtration the 2-n-butyl-5-ρ-
chlorobenzenesulfonamido-1:3:4-thiadiazole as colourless prisms, melting
point 129-130°C (recrystallised from benzene) was obtained.
