反应详情

) A solution of N,N-diethylethanamine (0.544 mol) in ethanol (600 ml) was added dropwise to a stirred suspension of N-hydroxy-3-pyridinecarboximidoyl chloride (0.259 mol) and methyl 2-propenoate (1.295 mol) in ethanol (1500 ml) over a period of 1 hour. The reaction mixture was stirred for 1 hour at RT. The reaction mixture was evaporated. The residue was mixed with diethyl ether and filtered. The organic layer was separated, washed three times with water, separated again, dried (MgSO4), filtered and left overnight. Partial crystallization occurred on overnight standing. The crystals were filtered and dried and the filtrate was evaporated, yielding 52.6 g (98%) of (±)-methyl 4,5-dihydro-3-(3-pyridinyl)-5-isoxazolecarboxylate (interm. 1).

1. customThe reaction mixture was evaporated
2. additionThe residue was mixed with diethyl ether
3. filtrationfiltered
4. customThe organic layer was separated
5. washwashed three times with water
6. customseparated again
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. waitleft overnight
10. customPartial crystallization
11. waitoccurred on overnight
12. filtrationThe crystals were filtered
13. customdried
14. customthe filtrate was evaporated