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温度

0 °C

2,3,6-trimethylphenol (1.6 g, 11.8 mmol) was disolved in 50 mL of anhydrous methanol which had been deoxygenated by bubbling with nitrogen. Ammonium thiocyanate (2.2 g, 28,9 mmol) was added to this solution which was then cooled to 0° C. and bubbled with chlorine gas. The initially colorless homogeneous solution becomes pink and then green with the formation of a white precipitate. The solution was stirred for 1 h at 0° C. and then for a further hour at 20° C. The dissolved chlorine was removed by bubbling with nitrogen and the precipitate removed by filtration. Evaporation of the filtrate under reduced pressure followed by drying under high vacuum (0.1 torr) yielded 2.20 g (97%) of 2,3,5-Trimethyl-4-hydroxyphenylthiocyanate in a form pure enough for the next step in the synthesis. An analytical sample was recrystallized from hexanes: white crystals, mp 100.3° C. 1H NMR (CDCl3) δ 7.2 (s, 1H), 5.0 (s, 1H) 2.4 (s, 3H), 2.2 (s, 6H).

1. customhad been deoxygenated
2. customby bubbling with nitrogen
3. custombubbled with chlorine gas
4. waitfor a further hour at 20° C
5. customThe dissolved chlorine was removed
6. customby bubbling with nitrogen
7. customthe precipitate removed by filtration
8. customEvaporation of the filtrate under reduced pressure
9. customby drying under high vacuum (0.1 torr)