| 摘要 |
Substituted 1,3,4-thiadiazoles of the formula <FORM:1016520/C2/1> wherein R1 and R2, which may be the same or different, represent substituted or unsubstituted aromatic carbocyclic or aromatic heterocyclic radicals, are produced by heating a carboxylic acid derived from a substituted or unsubstituted aromatic carbocyclic or aromatic heterocyclic compound with hydrazine, a hydrate of hydrazine, an inorganic salt of hydrazine or a monohydrazide of a substituted or unsubstituted aromatic carboxylic or heterocyclic carboxylic acid and a sulphide of phosphorus in the presence of a basic organic tertiary nitrogen compound. The basic nitrogen compounds may be used in admixture with smaller amounts of inert organic solvents and the reaction is generally performed at 90 DEG to 160 DEG C. On completion of the reaction the mixture may be poured into water, rendered alkaline to pH 8 to 12 whilst vigorously stirring and the thiadiazole precipitate so formed washed with water prior to drying. Specified substituents in the aromatic radicals are halogen atoms and alkyl, cycloalkyl, alkoxy, amino and heterocyclic groups. |
