反应详情

A mixture of (4-cyano-3-mercapto-isothiazol-5-yl)-carbamic acid phenyl ester (0.70 g, 2.5 mmol), 2,6-di-tert-butyl-4-methylphenol (BHT) (one crystal) and concentrated sulfuric acid (3 mL) was stirred for 18 hours at room temperature. The mixture was diluted with ice water, extracted 3× with ethyl acetate, and the combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. The residue was dissolved in 10 mL of ethanol at 0° C. and was treated with 0.096 g (2.5 mmol) of NaBH4. After stirring for 30 minutes, the mixture was acidified with 1 M HCl, extracted into ethyl acetate, dried over Na2SO4, filtered and concentrated in vacuo, affording 0.60 g (81%) of (4-carbamoyl-3-mercapto-isothiazol-5-yl)-carbamic acid phenyl ester as a yellow solid. 1H NMR (400 MHz, acetone-d6) δ 13.0 (s, 1H), 11.0-10.9 (bs, 1H), 10.3 (s, 1H), 7.47 (t, 2H, J=6.8 Hz), 7.37-7.30 (m, 4H) ppm; MS (APCl, m/z): 296 [M+H]−.

1. extractionextracted 3× with ethyl acetate
2. dry with materialthe combined organic layers were dried over Na2SO4
3. filtrationfiltered
4. concentrationconcentrated in vacuo
5. dissolutionThe residue was dissolved in 10 mL of ethanol at 0° C.
6. stirringAfter stirring for 30 minutes
7. extractionextracted into ethyl acetate
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. concentrationconcentrated in vacuo