反应详情

5.4 grams of methyl 3,5-dimethyl-4-hydroxybenzoate (0.03 moles) is dissolved in 30.8 ml of a 0.99 molar toluene solution of 3,5-di-tert.butyl-4-hydroxybenzoyl chloride and heated at reflux (119° C.) for 2 and 1/2 hours the evolved hydrogen chloride being swept out of the reaction by a stream of nitrogen. After this period, sufficient toluene (ca 5 to 10 ml) is removed so as to raise the reaction temperature to 128° to 132° C. and heating continued under a nitrogen atmosphere for an additional 2 hours. After cooling to room temperature, the reaction mixture is dissolved in 100 ml of toluene and successively washed with 2N aqueous sodium hydroxide and then with water until the wash waters were neutral. The washed toluene solution was dried over anhydrous sodium sulfate, filtered and the solvent removed by distillation under vacuum at 50°-60° C. initially at about 20 mm Hg. and finally at 0.3 mm Hg. The resulting residue is ground to a powder and triturated with boiling hexane. The ice-cold slurry is then filtered to yield light yellow crystals, which are then recrystallized from a solvent mixture of 50 ml of toluene and 40 ml of n-hexane. The crystals were filtered, washed with same solvent mixture and dried in vacuum. Methyl-4-(3,5-di-tert.butyl-4-hydroxybenzoyloxy)-3,5-dimethylbenzoate is then obtained as white crystals melting at 180°-182° C.

1. temperatureheated
2. customswept out of the reaction by a stream of nitrogen
3. waitAfter this period
4. customsufficient toluene (ca 5 to 10 ml) is removed so as
5. temperatureto raise the reaction temperature to 128° to 132° C.
6. temperatureheating
7. dissolutionthe reaction mixture is dissolved in 100 ml of toluene
8. washsuccessively washed with 2N aqueous sodium hydroxide
9. dry with materialThe washed toluene solution was dried over anhydrous sodium sulfate
10. filtrationfiltered
11. customthe solvent removed by distillation under vacuum at 50°-60° C. initially at about 20 mm Hg
12. customtriturated with boiling hexane
13. filtrationThe ice-cold slurry is then filtered
14. customto yield light yellow crystals, which
15. customare then recrystallized from a solvent mixture of 50 ml of toluene and 40 ml of n-hexane
16. filtrationThe crystals were filtered
17. washwashed with same solvent mixture
18. customdried in vacuum