反应详情

温度

0 °C

Potassium hydroxide (1.1 g, 0.019 mole) is added in one portion to a stirred 0° C. solution of 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzoic acid hydrazide (5.0 g, 0.019 mole) and carbon disulfide (3.4 g, 0.044 mole) in absolute ethanol (60 ml). The resulting mixture is stirred 30 minutes at 0° C. before warming to room temperature and stirring one hour. The solution is then heated to reflux for 2.5 hours. The solvent is removed in vacuo and the residue dissolved in water (100 ml) and washed with ether. The aqueous layer is made acidic with 2M HCl and the product extracted with a 1:1 mixture of ethyl acetate/ether. The organic layer is washed with saturated aqueous NaCl and dried over MgSO4. Filtration and concentration gives a solid which is recrystallized from ethyl acetate/isopropyl ether to give 2.2 g (5.8 g theor., 38%) desired 5-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1,3,4-oxadiazole2(3H)-thione, mp 253.5° C.

1. temperaturebefore warming to room temperature
2. stirringstirring one hour
3. temperatureThe solution is then heated
4. temperatureto reflux for 2.5 hours
5. customThe solvent is removed in vacuo
6. dissolutionthe residue dissolved in water (100 ml)
7. washwashed with ether
8. extractionthe product extracted with a 1:1 mixture of ethyl acetate/ether
9. washThe organic layer is washed with saturated aqueous NaCl
10. dry with materialdried over MgSO4
11. filtrationFiltration and concentration
12. customgives a solid which
13. customis recrystallized from ethyl acetate/isopropyl ether