Reaktion #2126903

Reaktionsgleichung

compound 1031

6-bromo-4′-hydroxy-3′,4′,5′,6′-tetrahydro-2′H-[2,4′]bipyridinyl-1′-carboxylic acid tert-butyl ester

TFA

triethylamine

di-tert-butyl dicarbonate

→

6-bromo-3′,6′-dihydro-2′H-[2,4′]bipyridinyl-1′-carboxylic acid, tert-butyl ester

Ausbeute 50.5%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeRemoval of the TFA
2. 2
   Sonstigegave a residue, which
3. 3
   Sonstigethe volatiles were removed in vacuo and water (100 mL)
4. 4
   workup.ADDITIONwas added
5. 5
   ExtraktionExtraction
6. 6
   Einengenwith dichloromethane (3×), concentration, and purification by chromatography (SiO2, 20% ethyl acetate/hexane)

Vorschrift

As shown in FIG. 7—step ii, compound 1031 (2.0 g) was mixed with TFA (25 mL) in a sealed tube and heated at 128° C. for 2 days. Removal of the TFA gave a residue, which was dissolved in methanol (30 mL) and treated with triethylamine (2 mL) and di-tert-butyl dicarbonate (1.4 mL). After 1 hour, the volatiles were removed in vacuo and water (100 mL) was added. Extraction with dichloromethane (3×), concentration, and purification by chromatography (SiO2, 20% ethyl acetate/hexane) gave 6-bromo-3′,6′-dihydro-2′H-[2,4′]bipyridinyl-1′-carboxylic acid, tert-butyl ester (compound 1032) (0.96 g).

Quelle