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The increasing clinical importance of drug‐resistant fungal pathogens has lent additional urgency to microbiological and antifungal research. Various thiazolo(or 1,2,3‐thiadiazolo)thiosemicarbazides (2a—2e), 3‐thiono‐1,4‐dihydrotriazolothiazoles‐(or 1,2,3‐thiadiazoles) (3a—3e), their related substituted thio‐4H‐1,2,4‐triazoles (4a—4p) and sulfones (5a—5o) were synthesized. Most of the compounds tested for antifungal activity exhibited significant effects against Cryptococcus neoofrmans and Sacchromyces cerevisiae at MIC ranges of 0.53 to 12.5μg/mL, whereas their activities were moderate against Candida albicans and weak against Aspergillus fumigatus. At 10 ppm concentration, all compounds showed low toxicity on brine shrimps (higher than 80% survival), except compounds 4c and 2c. At 100 ppm concentration most of the compounds showed toxicity except compounds 2b, 2e, 3c, 3d, 3e, and 4e. Compounds 4b, 4c, and 4h showed in vitro cytotoxicity against Kbalb cell lines and compounds 4c and 4g against 143B cell lines at 0.1 mM concentration.

5‐(2‐Phenoxy)phenyl‐1,3,4‐oxadiazole‐2‐yl‐4‐fluorobenzoate, a non‐classical benzodiazepine receptor ligand, has shown anticonvulsant activity against pentylenetetrazole‐induced convulsion. In order to perform biological studies, we decided to label the compound with positron‐emitting fluorine‐18 (t1/2=109.7 min). The latter compound was prepared in no‐carrier‐added form from [18F]fluoride and 5‐(2‐phenoxy)phenyl‐1,3,4‐oxadiazole‐2‐yl‐4‐N,N,N‐trimethylanilinium triflate in one step. The best results were obtained using Kryptofix2.2.2/[18F]fluoride with dimethylsulfoxide as the solvent at 90°C. Column chromatography afforded the desired compound in 15 min in an overall radiochemical yield of 70–75% corrected to the end of radionuclide production with a specific radioactivity of about 3000 Ci/mmol and a radiochemical purity of more than 95% and high chemical purity. Copyright © 2000 John Wiley & Sons, Ltd.

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Summary[ 18 F]Cholesteryl 4-(fluoromethyl)benzoate 6b was prepared from 3-cholesteryl [(4-nitrobenzenesulfonyl)oxymethyl]benzoate in one step using K + -Kryptofix 2.2.2, as counter ion and acetonitrile as the solvent at 40-608C. The product was isolated by HPLC in 75% (decay corrected) radiochemical yield with a radiochemical purity of more than 90% in 30 min (specific radioactivity 2000-2500 Ci/mmol). Biodistribution studies in mice showed that a high target/non-target ratio of radioactivity was obtained in adrenal and ovaries.