Water → HCID 68800773, compound

Temperature

75 °C

To a solution of crude 3-(3-amino-4-hydroxy-phenyl)-2-tert-butoxycarbonylamino-propionic acid ethyl ester (0.89 g, 2.74 mmol) in toluene (20 mL) was added triethyl orthoformate (0.57 mL, 3.36 mmol) and the mixture was heated to 75° C. under an atmosphere of argon for 3 hours at which time all starting material had been consumed. The reaction mixture was concentrated in vacuo to a black waxy solid which was dissolved in acetonitrile (25 mL) and di-tert-butyldicarbonate (0.80 g, 3.67 mmol) added. The mixture was stired at ambient temperature under an atmosphere of argon for 16 hours then poured into water (100 mL), diluted with brine (50 mL) and extracted with ethyl acetae (3×50 mL). The combined organic extracts were washed with brine (100 mL), dried over sodium sulfate and concentrated in vacuo to a black viscous oil. Purification by chromatography over silica gel eluted with 35% ethyl acetate/65% hexanes gave (S)-3-benzooxazol-5-yl-2-tert-butoxycarbonylamino-propionic acid ethyl ester as a colorless solid (0.54 g, 59%).

1. customhad been consumed
2. concentrationThe reaction mixture was concentrated in vacuo to a black waxy solid which
3. dissolutionwas dissolved in acetonitrile (25 mL)
4. extractionextracted with ethyl acetae (3×50 mL)
5. washThe combined organic extracts were washed with brine (100 mL)
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated in vacuo to a black viscous oil
8. customPurification by chromatography over silica gel
9. washeluted with 35% ethyl acetate/65% hexanes

ORD record

ord-1162309c5e83443f935224cf01d5890d

Source dataset

uspto-grants-2008_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07371869B2