Ammonia → Ethyl acetate hexane

Temperature

-30 °C

Pseudopeptide Boc--Nalψ[CH2S]Ala--OH (1.33 g; 3.4 mmol) was dissolved in THF (25 ml) and the solution was cooled to -30° C. Et3N (0.48 ml; 3.4 mmol) was added, followed by isobutyl chloroformate (0.46 ml; 3.5 mmol). After 15 min an excess of NH3 in CHCl3 was added and the reaction was stirred for 30 min at -30° C. and at room temperature for 3 h. The solvent was removed in vacuo and the residue was dissolved in AcOEt (250 ml). The organic solution was washed with H2O (1×50 ml), NaHCO3 5% (2×50 ml), H2O (1×50 ml), 0.5M citric acid (2×50 ml) and saturated NaCl, then was dried over Na2SO4 and filtered. After evaporation in vacuo of AcOEt, the residue was crystallized from AcOEt/hexane (1.2 g; 90% yield).

1. customThe solvent was removed in vacuo
2. dissolutionthe residue was dissolved in AcOEt (250 ml)
3. washThe organic solution was washed with H2O (1×50 ml), NaHCO3 5% (2×50 ml), H2O (1×50 ml), 0.5M citric acid (2×50 ml) and saturated NaCl
4. dry with materialwas dried over Na2SO4
5. filtrationfiltered
6. customAfter evaporation in vacuo of AcOEt

ORD record

ord-4dfcaba0ac334c37bf2df8e412a13c1b

Source dataset

uspto-grants-1995_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05387610