Isopropanol → 1-Isopropyl-4-nitro-1H-pyrazole

HRID 2400519Notes

Reaction equation

HRID 2400519 reaction equation
N(C(OC(C)(C)C)=O)=NC(O[C:6](C)([CH3:8])[CH3:7])=O.[N+:17]([C:20]1[CH:21]=[N:22][NH:23][CH:24]=1)([O-:19])=[O:18].CC(O)C.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>O1CCCC1>[CH:6]([N:22]1[CH:21]=[C:20]([N+:17]([O-:19])=[O:18])[CH:24]=[N:23]1)([CH3:8])[CH3:7]

Participants

6

Reactant 4

HCID 3776IsopropanolHCID 11776TriphenylphosphineHCID 163764-nitro-1H-pyrazoleHCID 97268Di-tert-butyl azodicarboxylate

Product 1

HCID 134698241-Isopropyl-4-nitro-1H-pyrazoleYield 149%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Di-tert-butyl azodicarboxylate (1.59 g, 6.91 mmol) was added to a solution of 4-nitro-1H-pyrazole (601 mg, 5.32 mmol), 2-propanol (319 mg, 5.32 mmol) and triphenylphosphine (1.67 g, 6.36 mmol) in tetrahydrofuran (25 mL) over 3 minutes and the mixture was stirred at room temperature for 16 h. After this time, the reaction was concentrated under reduced pressure and the resulting residue purified by chromatography (silica, gradient, 1:4 ethyl acetate/heptane to 7:3 ethyl acetate/heptane) to afford 1-isopropyl-4-nitro-1H-pyrazole (1) (1.23 g, >100%) as an impure off-white solid, which was used without further purification: 1H NMR (300 MHz, DMSO-d6) δ 8.91 (s, 1H), 8.24 (s, 1H), 4.58 (m, 1H), 1.42 (d, J=6.6 Hz, 6H).

Workup

  1. concentrationAfter this time, the reaction was concentrated under reduced pressure
  2. customthe resulting residue purified by chromatography (silica, gradient, 1:4 ethyl acetate/heptane to 7:3 ethyl acetate/heptane)

Sources & evidence

ORD record
ord-2b3fe7a65bdb49c5ae562cd3d5fa0803
Source dataset
uspto-grants-2014_08
Patent number
US08796270B2

Reaction notes

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