Triphenylphosphine → 5-Cyclopropyl-2-(5-methylpyridin-2-yl)-6-nitro-2H-indazole

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 5-cyclopropyl-2,4-dinitrobenzaldehyde (prepared according to the synthesis of Compound (1)) (50 mg, 0.212 mmol) in EtOH (750 mL) was added 5-methylpyridin-2-amine (25 mg, 0.23 mmol) and the resultant solution stirred at RT for 2d after which time a solid had precipitated from solution. Triphenylphosphine (167 mg, 0.64 mmol) was added in a single portion and the reaction then heated at 100° C. in a sealed tube for 4 h. Upon cooling to RT, the reaction was diluted with DCM (2 mL) and the organics were washed with aq. 30% hydrogen peroxide solution (2 mL). The organics were separated and filtered through a plug of MgSO4 and then purified by automated column chromatography (Biotage SP4, Grace 4 g silica cartridge) eluting with EtOAc:n-heptane (gradient elution, 0% equil. (2 CV), 0% (1CV), 0 to 100% (35 CV), 100% (5 CV)) to give (ii) (27 mg, 43%). ESI-MS: calculated [M+H]+ 295.1. observed [M+H]+ 295.2.

Provenance & Evidence