Reaction #1605770

Reaction equation

2,4-dimethoxybenzylamine

triethylamine

Ethyl chlorooxoacetate

→

N-(2,4-dimethoxy-benzyl)-oxalamic acid ethyl ester

Yield 92.8%

Solvents

THF

Conditions

Workup

1. 1
   OtherA clean and dry jacketed reactor
2. 2
   Otherwas equipped with a condenser
3. 3
   OtherThe reactor was flushed with nitrogen gas for at least 15 minutes
4. 4
   workup.ADDITIONhead column and charged to the batch at such a rate that the internal temperature
5. 5
   Otherdid not exceed 10° C
6. 6
   OtherSolids formed approximately ⅓ into the addition
7. 7
   workup.ADDITIONAfter the addition
8. 8
   TemperatureWhen complete, the reaction was warmed to from 20° C. to 25° C
9. 9
   WashThe organic phase was washed twice with 22,580 mL of 1 N HCl
10. 10
    WashThe organic phase was then washed with 12,600 mL saturated sodium bicarbonate
11. 11
    WashNext, the organic phase was washed with 12,463 mL of brine
12. 12
    Dryingdried over magnesium sulfate
13. 13
    FiltrationThe mixture was filtered through a thin pad of celite
14. 14
    Concentrationconcentrated at from 40° C. to 45° C. to a yellow oil

Procedure

A clean and dry jacketed reactor was equipped with a condenser, a Claisen adapter, a temperature probe, and an addition funnel or head column. The reactor was flushed with nitrogen gas for at least 15 minutes. The reactor was then charged with 1,396 g (1 equiv., 8.3 mol) of 2,4-dimethoxybenzylamine, 1,693 g (2 equiv., 16.7 mol) of triethylamine, and 25,086 mL of THF. The mixture was cooled to from 0 to 5° C. Ethyl chlorooxoacetate (1140 g, 1 equiv., 8.3 mol) was added to an addition funnel or head column and charged to the batch at such a rate that the internal temperature did not exceed 10° C. Solids formed approximately ⅓ into the addition. After the addition was complete, the cooling was turned off and the slurry was allowed to stir for 30 minutes at from 5° C. to 15° C. When complete, the reaction was warmed to from 20° C. to 25° C. The organic phase was washed twice with 22,580 mL of 1 N HCl. The organic phase was then washed with 12,600 mL saturated sodium bicarbonate. Next, the organic phase was washed with 12,463 mL of brine and dried over magnesium sulfate. The mixture was filtered through a thin pad of celite and concentrated at from 40° C. to 45° C. to a yellow oil. A total of 2,052 g (7.7 mol, 92%) of the crude N-(2,4-dimethoxy-benzyl)-oxalamic acid ethyl ester was isolated.

Source