Reaktion #56713

Reaktionsgleichung

2,2-dimethyl-pent-4-enal

cyano-acetic acid ethyl ester

piperidine

acetic acid

→

2-Cyano-4,4-dimethyl-hepta-2,6-dienoic acid ethyl ester

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturunder reflux for 18 hours in a flask
2. 2
   Sonstigeequipped with a Dean-Stark separator
3. 3
   SonstigeSeveral mL of water was collected in the trap
4. 4
   TemperaturThe reaction was cooled
5. 5
   Waschenwashed with 1N HCl, NaHCO3 and brine
6. 6
   TrocknenThe organic layers were dried over Na2SO4
7. 7
   Einengenconcentrated to an oil
8. 8
   SonstigeThis oil was chromatographed
9. 9
   Wascheneluting with 20% of EtOAc in hexane
10. 10
    Sonstigeto give a combination of two lots total 8.3 g (91%)

Vorschrift

A solution of 2,2-dimethyl-pent-4-enal (5.0 g, 44 mmol), cyano-acetic acid ethyl ester (5.12 mL, 48 mmol), piperidine (1.3 mL, 14 mmol) and acetic acid (4.52 mL, 80 mmol) in 170 mL of toluene was heated under reflux for 18 hours in a flask equipped with a Dean-Stark separator. Several mL of water was collected in the trap. The reaction was cooled and washed with 1N HCl, NaHCO3 and brine, successively. The organic layers were dried over Na2SO4 and concentrated to an oil. This oil was chromatographed eluting with 20% of EtOAc in hexane to give a combination of two lots total 8.3 g (91%). 1H NMR (400 MHz; CDCl3) 1.28 (s, 6H), 1.32 (t, 3H, J=7 Hz),. 2.26 (d, 2H, J=7.6 Hz), 4.27 (q, 2H, J=7.2 Hz), 5.08 (d, 1H, J=12 Hz), 5.10 (d, 1H, J=4 Hz), 5.72 (m, 1H).

Quelle