Реакция #2254201

Уравнение реакции

tetrahydro-4H-pyran-4-one

methyl cyanoacetate

ammonium acetate

acetic acid

→

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

Растворители

benzene

water

Условия реакции

Обработка

1. 1
   ДругоеA 50 ml round-bottom flask equipped with a Dean-Stark distillation setup and condenser
2. 2
   Другоеcollected in the Dean-Stark (2 hours)
3. 3
   Температураcooled
4. 4
   workup.ADDITIONbenzene (30 ml) added
5. 5
   Промывкаthe organic layer washed with water (50 ml)
6. 6
   ЭкстракцияThe aqueous layer was extracted with CH2Cl2 (3×50 ml)
7. 7
   ПромывкаThe combined organic phase was washed with sat. NaHCO3 (100 ml), brine (100 ml)
8. 8
   Сушкаdried (MgSO4)
9. 9
   Фильтрацияfiltered
10. 10
    Концентрированиеconcentrated
11. 11
    ДругоеPurified by normal phase SiO2 chromatography (10 to 60% EtOAc/hexanes)

Методика

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).

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