Triethylamine → Tert-butyl 2,6-dioxomorpholine-4-carboxylate

Iminodiacetic acid (5.0 g, 37.6 mmol) in THF-water (1:1, 100 ml) was treated with Na—HCO3 (12.6 g, 150 mmol) portion-wise over 15 minutes. Boc anhydride (9.85, 45.1 mmol) was added and the mixture was stirred at room temperature for 2 days. THF was removed by evaporation in vacuo and the aqueous solution was washed with ether (2×), acidified using conc. HCl to pH 1 under cooling with ice bath and extracted with AcOEt (3×). The organic phase was washed with brine, dried (Na2SO4) and evaporated in vacuo to yield 2.55 g (29%). Crude N-Boc-iminodiacetic acid (2.0 g, 8.6 mmol) was dissolved in AcOEt (100 ml), cooled to 0° C., and treated with triethylamine (2.43 ml, 17.4 mmol) and powdered triphosgene (0.84 g, 2.83 mmol). The suspension was stirred 15 minutes under cooling, and 15 minutes at room temperature. The solution was washed with brine, dried (MgSO4) and evaporated in vacuo to yield 17, 1.53 g (83%).

1. customTHF was removed by evaporation in vacuo
2. washthe aqueous solution was washed with ether (2×)
3. temperatureunder cooling with ice bath
4. extractionextracted with AcOEt (3×)
5. washThe organic phase was washed with brine
6. dry with materialdried (Na2SO4)
7. customevaporated in vacuo
8. customto yield 2.55 g (29%)
9. temperaturecooled to 0° C.
10. stirringThe suspension was stirred 15 minutes
11. temperatureunder cooling
12. custom15 minutes
13. customat room temperature
14. washThe solution was washed with brine
15. dry with materialdried (MgSO4)
16. customevaporated in vacuo

ORD record

ord-186cb6b011214b268a16d0b9adbc5252

Source dataset

uspto-grants-2008_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07317000B2