Reaction #1884992

Reaction equation

tert-butylamine

acetonitrile

tert-butyl chloride

NaOH

→

N,N′-di-tert-butyl acetamidine

Solvents

CH2Cl2

water

Conditions

Workup

1. 1
   TemperatureWhile the solution was cooled below −70° C.
2. 2
   workup.WAITThe solution was then left
3. 3
   workup.STIRRINGstirring at −70° C. for a few hours
4. 4
   Temperaturewarmed up to −20° C.
5. 5
   OtherThe organic layer was separated
6. 6
   Extractionthe aqueous phase was then extracted with fresh CH2Cl2
7. 7
   WashCombined CH2Cl2 fractions were washed twice with water
8. 8
   Dryingdried over anhydrous MgSO4
9. 9
   OtherThe dried organic solution was evaporated
10. 10
    Otherto yield a light yellow liquid

Procedure

N,N′-di-tert-butyl acetamidine was synthesized as follows. Anhydrous FeCl3 (1.04 mol.) was suspended in 1 L of CH2Cl2 under N2 at room temperature. The suspension was cooled to −40 to −50° C. and acetonitrile (1 mol) was quickly added with stirring. While the solution was cooled below −70° C., tert-butyl chloride (1.04 mol) was added, followed by tert-butylamine (1.05 mol). The solution was then left stirring at −70° C. for a few hours and then warmed up to −20° C., followed by pouring it into a diluted aqueous NaOH solution (12.5 wt %, 1 L). Additional water was added to ensure complete formation of precipitate. The organic layer was separated and the aqueous phase was then extracted with fresh CH2Cl2. Combined CH2Cl2 fractions were washed twice with water and dried over anhydrous MgSO4. The dried organic solution was evaporated to yield a light yellow liquid. The crude amidine thus obtained was then purified by fractional distillation. Yield of the main fraction was >70%, and free of organic and metallic impurities as detected by 1H NMR and ICP-MS. 1H NMR (in C6D6, δ ppm): 3.02 (br. s, 1H), 1.41 (s, 3H), δ 1.34 (s, 18H).

Source