Reaction #50055

Reaction equation

water

sodium hydride

1,1-diethoxyethylphosphinic acid ethyl ester

bromomethylcyclohexane

→

1,1-diethoxyethyl(cyclohexylmethyl)phosphinic acid ethyl ester

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   Temperaturethe temperature being maintained at from 20° to 25°
2. 2
   Temperatureheating
3. 3
   Temperatureunder reflux
4. 4
   workup.WAITis effected for 24 hours
5. 5
   TemperatureThe suspension is cooled to 4°
6. 6
   OtherTwo phases are formed
7. 7
   OtherThe tetrahydrofuran phase is separated off
8. 8
   Extractionthe aqueous phase is extracted twice with 250 ml of dichloromethane each time
9. 9
   ConcentrationConcentration
10. 10
    Otherby evaporation
11. 11
    Otheryields a brown oil which
12. 12
    workup.DISTILLATIONafter distillation under reduced pressure

Procedure

21 g of 99% sodium hydride are suspended at room temperature under argon in 1000 ml of anhydrous tetrahydrofuran, and a solution of 172.2 g of 1,1-diethoxyethylphosphinic acid ethyl ester is added dropwise over a period of 2.5 hours, the temperature being maintained at from 20° to 25°. The reaction is exothermic and involves the evolution of gas. The batch is then stirred for 1.5 hours at room temperature, 142.2 g of bromomethylcyclohexane are added and heating under reflux is effected for 24 hours. The suspension is cooled to 4° and 250 rnl of water are carefully added. Two phases are formed. The tetrahydrofuran phase is separated off and the aqueous phase is extracted twice with 250 ml of dichloromethane each time. Concentration by evaporation yields a brown oil which, after distillation under reduced pressure, gives 1,1-diethoxyethyl(cyclohexylmethyl)phosphinic acid ethyl ester having a boiling point of 95° (1.8×10-4 mbar).

Source