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HuagongsheHuagongshe Chemistry Print Report · For research reference only
HRID 490551Generated: October 29, 2026

Hydrochloric Acid → 1,2-Dihydro-5-nitro-1-(phenylmethyl)-3H-indazol-3-one

https://huagongshe.com/reaction/490551

Reaction equation

Participants

RoleNameHCIDCharge
ReactantHydrochloric AcidHCID 313—
ReactantDiisopropylethylamineHCID 81531—
ReactantBenzylhydrazine dihydrochlorideHCID 146540—
Reactant2-Fluoro-5-nitrobenzoic acidHCID 280997—
ReactantO-(Benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborateHCID 2733207—
SolventDimethylformamideHCID 6228—
Product1,2-Dihydro-5-nitro-1-(phenylmethyl)-3H-indazol-3-oneHCID 38499535.7%

Reaction Steps

To a solution of 2-fluoro-5-nitrobenzoic acid (0.5 g) in DMF (9 mL) was added TBTU (1.04 g) followed by N-ethyldiisopropylamine (2.3 mL). After 10 minutes benzylhydrazine.2HCl (0.63 g) was added. The reaction mixture was stirred at ambient temperature for 22 hours and the reaction was poured onto aqueous 1N HCl solution and extracted with EtOAc. The organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo. Purification via ISCO combiflash chromatography afforded pure desired 1-benzyl-5-nitro-1,2-dihydro-indazol-3-one (0.26 g) as a yellow solid. MS (ESI−):268.3 ([M−H]−).

Provenance & Evidence

DOI10.6084/m9.figshare.5104873.v1
Patent numberUS07528158B2
Source datasetuspto-grants-2009_05
ORD IDord-c29723ba24224e10a59bfe12c3fb473a
Source noteuspto-grants-2009_05