Reacción #3764

Ecuación de reacción

4-heptanone

ethyl cyanoacetate

Acetic

→

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

Disolventes

cyclohexane

ethyl acetate

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwere added
2. 2
   Temperaturaheated
3. 3
   Temperaturato reflux with a Dean-Stark trap in place overnight under N2
4. 4
   TemperaturaThe reaction was cooled to ambient,
5. 5
   Lavadowashed with H2O (2×50 mL) and brine (25 mL)
6. 6
   SecadoThe organic extracts were dried (Na2SO4
7. 7
   Filtraciónfiltered
8. 8
   Concentraciónconcentrated under vacuum
9. 9
   Otroto give an oil that
10. 10
    workup.DISTILLATIONwas distilled (bp. 135°-137° C., 20 mmHg)

Procedimiento

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.

Fuente