[F:1][C:2]1[CH:21]=[CH:20][CH:19]=[C:18]([F:22])[C:3]=1[C:4]([NH:6][NH:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[C:14]([F:17])([F:16])[F:15])=[O:5].[C:23](Cl)(Cl)=[S:24].C(N(CC)CC)C>C1(C)C=CC=CC=1.COC(C)(C)C>[F:1][C:2]1[CH:21]=[CH:20][CH:19]=[C:18]([F:22])[C:3]=1[C:4]1[O:5][C:23](=[S:24])[N:7]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=2[C:14]([F:15])([F:16])[F:17])[N:6]=14.79 g (15 mmol) of 2,6-difluoro-N'-(α,α,α-trifluoro-o-tolyl)-benzhydrazide in 30 ml of toluene are treated with 1.98 g (17 mmol) of thiophosgene and the reaction mixture is heated at the reflux temperature for 5 hours. 4.8 ml (35 mmol) of triethylamine are then added dropwise at 45° C. while cooling and, after cooling, the mixture is stirred at room temperature for about 1 hour. The mixture is subsequently taken up in 100 ml of tert.butyl methyl ether and the solution is washed in each case once with dilute, ice-cold sodium hydroxide solution and saturated sodium chloride solution, dried over anhydrous magnesium sulfate and evaporated under reduced pressure. The residue is purified by chromatography using acetone/n-hexane (1:4) as the eluent and crystallized from diisopropyl ether/n-hexane. In this manner there is obtained 5-(2,6-difluorophenyl)-3-(α,α,α-trifluoro-o-tolyl)-1,3,4-oxadiazole-2(3H) -thione as a white crystallizate, m.p. 128°-130° C.; mass spectrum: 358(58), 298(15 ), 289(17), 159(100).
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