Ammonium Chloride → HCID 178451026, compound

A mixture of tert-butyl (4R)-4-(benzyloxycarbonylamino)-4-cyanobutyrate (1.53 g, 4.8 mmol), ammonium chloride (0.28 g, 5.2 mmol), sodium azide (0.345 g, 5.3 mmol) and dry DMF (6 ml) was stirred and heated at 90°-95° C. under argon for 20 hours. The mixture was cooled and concentrated and the residue partitioned between ice-cooled water (40 ml) and ethyl acetate (30 ml) with the pH of the aqueous phase being adjusted to 3 by the addition of 10% aqueous citric acid solution (ca. 10 ml). The aqueous layer was extracted with further ethyl acetate (3×30 ml) and the combined organic solution washed with water (4×25 ml), dried (MgSO4) and evaporated. A solution of the residue in dichloromethane (3 ml) was added dropwise to stirred hexane (20 ml) and the precipitate was collected, washed with hexane and dried to give tert-butyl (4R)-4-(benzyloxycarbonylamino)-4-(tetrazol-5-yl)butyrate (1.462 g, 84%), m.p. 99°-101° C.

1. temperatureheated at 90°-95° C. under argon for 20 hours
2. temperatureThe mixture was cooled
3. concentrationconcentrated
4. customthe residue partitioned between ice-
5. temperaturecooled water (40 ml) and ethyl acetate (30 ml) with the pH of the aqueous phase
6. additionbeing adjusted to 3 by the addition of 10% aqueous citric acid solution (ca. 10 ml)
7. extractionThe aqueous layer was extracted with further ethyl acetate (3×30 ml)
8. washthe combined organic solution washed with water (4×25 ml)
9. dry with materialdried (MgSO4)
10. customevaporated
11. additionA solution of the residue in dichloromethane (3 ml) was added dropwise
12. stirringto stirred hexane (20 ml)
13. customthe precipitate was collected
14. washwashed with hexane
15. customdried

ORD record

ord-166d4feeb7d8485898e6ac3840d5025d

Source dataset

uspto-grants-1998_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05747499