反应详情

12.9 g of γ-ethoxy-γ-butyrolactam, 10 ml of conc. sulphuric acid and 90 ml of glacial acetic acid were initially charged at 0° C. and admixed a little at a time with a total of 18.8 g of phenol. After thawing, the mixture was stirred at room temperature for 2 days. For work-up, the mixture was poured onto ice and extracted three times with ethyl acetate, and the combined extracts were washed once each with water and saturated sodium chloride solution, dried and evaporated. After some time, γ-2-hydroxyphenyl-γ-butyrolactam (X-2b) of melting point 220° C. (6.4 g 36% of theory) crystallized form the aqueous phase. The evaporation residue was stirred with a 1:1 mixture of cyclohexane/ethyl acetate and gave, after filtration with suction, 4.65 g of γ4-hydroxyphenyl-γ-butyrolactam (X-2a) of melting point 183° C. The filtrate was concentrated. Recrystallization from dichloromethane/hexane gave a further 3.35 g (total: 45% of theory) of γ-4-hydroxyphenyl-γ-butyrolactam.

1. additionFor work-up, the mixture was poured onto ice
2. extractionextracted three times with ethyl acetate
3. washthe combined extracts were washed once each with water and saturated sodium chloride solution
4. customdried
5. customevaporated
6. customAfter some time, γ-2-hydroxyphenyl-γ-butyrolactam (X-2b) of melting point 220° C. (6.4 g 36% of theory) crystallized form the aqueous phase
7. stirringThe evaporation residue was stirred with a 1:1 mixture of cyclohexane/ethyl acetate
8. customgave
9. filtrationafter filtration with suction, 4.65 g of γ4-hydroxyphenyl-γ-butyrolactam (X-2a) of melting point 183° C
10. concentrationThe filtrate was concentrated
11. customRecrystallization from dichloromethane/hexane