反应详情

2-Azido-6,7-diethyl-1,4-naphthoquinone (6.0 g; 0.024 mole) was added portionwise to cold (0°-5° C.), stirred concentrated sulphuric acid (100 ml) over 2 hours and the red solution stirred at this temperature till no further nitrogen evolution was noticed (ca. 15 mins.). The products from two such reactions carried out simultaneously were poured into 1200 ml of ice-water and the lilac solid filtered off and washed well with water. Recrystallisation from ethanol in the presence of charcoal give the title compound 5.00 g (47%) as an off-white solid of m.p. 147°-158° C. Further recrystallisation gave a white sample of m.p. 159°-168° C. shown by nmr to be a mixture of E and Z isomers. (Found; C, 73.70; H, 5.95; N, 5.94; C14H13NO2 requires; C, 73.99; H, 5.77; N, 6.16%).

1. custom(ca. 15 mins.)
2. filtrationthe lilac solid filtered off
3. washwashed well with water
4. customRecrystallisation from ethanol in the presence of charcoal