反应详情

The method of Smith and Schubert, J. Am. Chem. Soc. 1948, 70, 2656, was followed. 2,3,5-Trimethyl-1,4-benzoquinone-1-mono-oxime (50 g, 0.30 mol) was dissolved in aq. sodium hydroxide solution (49.5 g, 1.24 mol of NaOH in 720 mL of water). The resulting intense red solution was cooled in an ice bath and stirred while sodium dithionite (126.1 g, 0.73 mol) was added. The red color faded and a beige precipitate formed. The mixture was stirred for 2 hours and allowed to come to ambient temperature. It was then cooled in ice and filtered. The crude 25a was pressed dry, rapidly transferred to an evacuated atmosphere and dried further (50° C./0.3 torr, 24 hours), mp 130°-131° C. with dec. (lit.: Smith, L. I.; Schubert, W. M. J. Am. Chem. Soc. 1948, 70, 2656; 132°-134° C. dec.). Spectral data: 1H NMR (CD3 SOCD3): δ 1.90 (s, 3H), 2.05 (2s, 3H each), 4.10 (br s, 2H), 6.25 (s, 1H), 7.10 (br s, 1H); 13C NMR (CD3SOCD3): δ 12.88, 13.25, 16.78, 114.39, 118.43, 122.25, 123.95, 138.81, 144.11.

1. temperatureThe resulting intense red solution was cooled in an ice bath
2. additionwas added
3. customa beige precipitate formed
4. customto come to ambient temperature
5. temperatureIt was then cooled in ice
6. filtrationfiltered
7. dry with materialThe crude 25a was pressed dry
8. customdried further (50° C./0.3 torr, 24 hours), mp 130°-131° C. with dec