반응 #2254201

반응 방정식

tetrahydro-4H-pyran-4-one

methyl cyanoacetate

ammonium acetate

acetic acid

→

methyl 2-cyano-2-(oxan-4-ylidene)acetate

용매

benzene

water

반응 조건

후처리

1. 1
   기타A 50 ml round-bottom flask equipped with a Dean-Stark distillation setup and condenser
2. 2
   기타collected in the Dean-Stark (2 hours)
3. 3
   온도cooled
4. 4
   workup.ADDITIONbenzene (30 ml) added
5. 5
   세척the organic layer washed with water (50 ml)
6. 6
   추출The aqueous layer was extracted with CH2Cl2 (3×50 ml)
7. 7
   세척The combined organic phase was washed with sat. NaHCO3 (100 ml), brine (100 ml)
8. 8
   건조dried (MgSO4)
9. 9
   여과filtered
10. 10
    농축concentrated
11. 11
    기타Purified by normal phase SiO2 chromatography (10 to 60% EtOAc/hexanes)

실험 절차

A 50 ml round-bottom flask equipped with a Dean-Stark distillation setup and condenser was charged with tetrahydro-4H-pyran-4-one (4.61 ml, 50 mmol), methyl cyanoacetate (5.3 ml, 60 mmol), ammonium acetate (1 g, 13 mmol), acetic acid (0.57 ml, 10 mmol) and benzene (30 ml). The mixture was refluxed until no more water collected in the Dean-Stark (2 hours), cooled, benzene (30 ml) added and the organic layer washed with water (50 ml). The aqueous layer was extracted with CH2Cl2 (3×50 ml). The combined organic phase was washed with sat. NaHCO3 (100 ml), brine (100 ml) dried (MgSO4), filtered and concentrated. Purified by normal phase SiO2 chromatography (10 to 60% EtOAc/hexanes) to afford methyl 2-cyano-2-(oxan-4-ylidene)acetate as a colorless oil (6.30 g, 70%, m/z: 181.1 [M+H]+ observed).

출처