Reaction #3764

Reaction equation

4-heptanone

ethyl cyanoacetate

Acetic

→

Ethyl α-cyano-α-(4-heptylidene)acetate

Solvents

cyclohexane

ethyl acetate

Conditions

Workup

1. 1
   workup.ADDITIONwere added
2. 2
   Temperatureheated
3. 3
   Temperatureto reflux with a Dean-Stark trap in place overnight under N2
4. 4
   TemperatureThe reaction was cooled to ambient,
5. 5
   Washwashed with H2O (2×50 mL) and brine (25 mL)
6. 6
   DryingThe organic extracts were dried (Na2SO4
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated under vacuum
9. 9
   Otherto give an oil that
10. 10
    workup.DISTILLATIONwas distilled (bp. 135°-137° C., 20 mmHg)

Procedure

In a 100 mL round-bottom flask was dissolved 4-heptanone (11.4 g, 0.10 mmole) and ethyl cyanoacetate (11.30 g, 0.100 mole) in cyclohexane (25 mL). Acetic add (1.0 mL) and NH4OAc (2.0 g) were added. The solution was magnetically stirred and heated to reflux with a Dean-Stark trap in place overnight under N2. The reaction was cooled to ambient, diluted with ethyl acetate (100 mL) washed with H2O (2×50 mL) and brine (25 mL). The organic extracts were dried (Na2SO4, filtered and concentrated under vacuum to give an oil that was distilled (bp. 135°-137° C., 20 mmHg) to give Ethyl α-cyano-α-(4-heptylidene)acetate (16.65 g, 0.080 mole, 80%). IR (neat film) 2950, 2910, 2860, 2200, 1725, 1570, 1235, 1085 cm-1 ; 1H NMR (400 MHz, CDCl3 δ 4.15 (q, J=9 Hz, 2H), 2.60 (t, J=10 Hz, 2H), 2.38 (t, J=10 Hz, 2H), 1.25 (t, J=9 Hz, 2H), 1.40 (sextet, J=9 Hz, 2H), 1.25 (t, J=9 Hz, 3H), 0.88 (m, 6H); 13C NMR (100 MHz, CDCl3) δ 181.2, 161.5, 115.5, 104.6, 61.4, 40.2, 35.2, 21.9, 21.4, 14.1, 13.8 (one carbon not observed due to overlap); MS (CI) m/e 211 (14.5), 210 (100), 209 (3.59), 182 (3.5), 164 (2.8); HRMS (CI) calcd for C12H20NO2 (M+H) m/e 210.1484, found 210.1491.

Source