Reaktion #1595518

Reaktionsgleichung

N2

tert-Butyl carbazate

2-bromo-4-chloropyridine

Cs2CO3

→

tert-butyl 2-(4-chloropyridin-2-yl)hydrazinecarboxylate

Ausbeute 35.0%

Lösungsmittel

brine

water

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwere added
2. 2
   Extraktionthe mixture was extracted with EtOAc (2×)
3. 3
   EinengenThe combined organic layer was concentrated
4. 4
   Sonstigepurified by silica gel chromatography

Vorschrift

4-Chloro-2-hydrazinylpyridine, 2HCl: In microwave vial was added toluene (4 mL) and purged with N2 for 5 min. tert-Butyl carbazate (66.6 mg, 0.494 mmol), 2-bromo-4-chloropyridine (95 mg, 0.494 mmol), Cs2CO3 (161 mg, 0.494 mmol), and PdCl2(dppf)-CH2Cl2 adduct (4.03 mg, 4.94 μmol) were added. The sealed tube was heated at 100° C. for 5 h. To the reaction mixture was added water, brine and the mixture was extracted with EtOAc (2×). The combined organic layer was concentrated and purified by silica gel chromatography to provide tert-butyl 2-(4-chloropyridin-2-yl)hydrazinecarboxylate (42 mg, 35%) as red oil. MS(ESI) m/z: 244.2 (M+H)+. To the above oil was added 4 N HCl in dioxane (2 mL) and the reaction was stirred at rt for 2 h. The mixture was concentrated to dryness to give the desired (36 mg, 34%) as a white solid. MS(ESI) m/z: 144.0 (M+H)+.

Quelle