Reaktion #59644

Reaktionsgleichung

sodium borohydride

acetate

[1-((S)-2-Benzyloxycarbonylamino-propyl)-7-bromo-1H-indazol-6-yloxy]-acetic acid ethyl ester

sodium borohydride

calcium chloride

→

solid

Ausbeute 82.0%

{(S)-2-[7-Bromo-6-(2-hydroxy-ethoxy)-indazol-1-yl]-1-methyl-ethyl}-carbamic acid benzyl ester

Ausbeute 82.0%

Lösungsmittel

tetrahydrofuran

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe suspension was stirred at ambient temperature for 1 h
2. 2
   SonstigeThe volatiles were evaporated
3. 3
   workup.ADDITIONthe residue mixed with water
4. 4
   Extraktionextracted with ethyl acetate (3×50 mL)
5. 5
   TrocknenThe combined extracts were dried over magnesium sulfate
6. 6
   Filtrationfiltered
7. 7
   Sonstigeevaporated to dryness

Vorschrift

To a solution of the acetate from Step B (0.90 g, 1.84 mmol) in a mixture of tetrahydrofuran (20 mL) and ethanol (20 mL) was added sodium borohydride (70 mg, 1.84 mmol) and calcium chloride (0.21 g, 1.84 mmol) with stirring. The suspension was stirred at ambient temperature for 1 h and more sodium borohydride (70 mg, 1.84 mmol) was added. The reaction was monitored by TLC until no starting material remained. The volatiles were evaporated and the residue mixed with water and extracted with ethyl acetate (3×50 mL). The combined extracts were dried over magnesium sulfate, filtered and evaporated to dryness. Chromatography on silica eluting with a gradient of 20% to 50% EtOAc/hexane gave a solid (0.67 g, 82%): mp 97-99° C.; LCMS (+APCI) 448, 450 (M+H).

Quelle