反应详情

1.3 l of a 1.3 molar lithium aluminium hydride solution in THF are added dropwise under reflux to a solution of 100 g (0.66 mol) of 2-amino-5-methylbenzoic acid in 400 ml of anhydrous tetrahydrofuran. After addition is complete, the mixture is additionally heated under reflux for 1.5 h and hydrolysed at this temperature using a solution of 36 g of potassium hydroxide in 145 ml of water. After boiling under reflux for a further 15 min, the hydroxide precipitate is filtered off while hot, the precipitate is washed with ethyl acetate, the organic solution is concentrated in vacuo, the residue is dissolved in ethyl acetate and the solution is washed with dilute sodium hydroxide solution and water. After drying with sodium sulphate and concentrating the solution, the residue is recrystallised from ethyl acetate.

1. additionAfter addition
2. temperaturethe mixture is additionally heated
3. temperatureunder reflux for 1.5 h and hydrolysed at this temperature
4. temperatureunder reflux for a further 15 min
5. filtrationthe hydroxide precipitate is filtered off while hot, the precipitate
6. washis washed with ethyl acetate
7. concentrationthe organic solution is concentrated in vacuo
8. dissolutionthe residue is dissolved in ethyl acetate
9. washthe solution is washed with dilute sodium hydroxide solution and water
10. dry with materialAfter drying with sodium sulphate
11. concentrationconcentrating the solution
12. customthe residue is recrystallised from ethyl acetate