تفاعل #2254201

معادلة التفاعل

tetrahydro-4H-pyran-4-one

methyl cyanoacetate

ammonium acetate

acetic acid

→

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

المذيبات

benzene

water

ظروف التفاعل

المعالجة

1. 1
   أخرىA 50 ml round-bottom flask equipped with a Dean-Stark distillation setup and condenser
2. 2
   أخرىcollected in the Dean-Stark (2 hours)
3. 3
   درجة الحرارةcooled
4. 4
   workup.ADDITIONbenzene (30 ml) added
5. 5
   غسيلthe organic layer washed with water (50 ml)
6. 6
   استخلاصThe aqueous layer was extracted with CH2Cl2 (3×50 ml)
7. 7
   غسيلThe combined organic phase was washed with sat. NaHCO3 (100 ml), brine (100 ml)
8. 8
   تجفيفdried (MgSO4)
9. 9
   ترشيحfiltered
10. 10
    تركيزconcentrated
11. 11
    أخرىPurified by normal phase SiO2 chromatography (10 to 60% EtOAc/hexanes)

الإجراء التجريبي

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).

المصدر