Pyridine → diethyl 4-(4-chloro-2-nitrobenzoyl)-1H-pyrazole-3,5-dicarboxylate

HRID 428410Notes

Reaction equation

HRID 428410 reaction equation
N1C=CC=CC=1.[Cl:7][C:8]1[CH:13]=[CH:12][C:11]([CH:14]([OH:30])[C:15]2[C:16]([C:25]([O:27][CH2:28][CH3:29])=[O:26])=[N:17][NH:18][C:19]=2[C:20]([O:22][CH2:23][CH3:24])=[O:21])=[C:10]([N+:31]([O-:33])=[O:32])[CH:9]=1>ClCCl.[O-2].[Cr+6].[O-2].[O-2]>[Cl:7][C:8]1[CH:13]=[CH:12][C:11]([C:14]([C:15]2[C:19]([C:20]([O:22][CH2:23][CH3:24])=[O:21])=[N:18][NH:17][C:16]=2[C:25]([O:27][CH2:28][CH3:29])=[O:26])=[O:30])=[C:10]([N+:31]([O-:33])=[O:32])[CH:9]=1

Participants

5

Reactant 2

HCID 1049PyridineHCID 18358881Diethyl 4-[(4-chloro-2-nitrophenyl)hydroxymethyl]-1H-pyrazole-3,5-dicarboxylate

Product 1

HCID 18358912diethyl 4-(4-chloro-2-nitrobenzoyl)-1H-pyrazole-3,5-dicarboxylate

Reagents, catalysts & solvents 2

HCID 10219390chromium (VI) trioxideCatalystHCID 6344DichloromethaneSolvent

Procedure

Chromium (VI) oxide (17.48 g, 174.8 mmol) was added over 37 minutes to a solution of pyridine (27.6 mL, 349.5 mmol) in dichloromethane (400 mL). Diethyl 4-[(4-chloro-2-nitro-phenyl)hydroxymethyl]-1H-pyrazole-3,5-dicarboxylate (11.56 g, 25 29.1 mmol) was added as a solid over 9 minutes. The reaction mixture was allowed to stir at room temperature 44 hours. The solution was filtered and the organic layer was washed with aqueous hydrochloric acid (500 mL, 3N). The aqueous layer was extracted with ethyl acetate (3×250 mL) and dichloromethane (3×250 mL). The resulting organic extracts were combined and concentrated on the rotary evaporator to give a crude solid (10.92 g). The product was purified by chromatography eluting with dichloromethane:2-propanol (98:2, 96:4, and 94:6). The desired product was obtained from the mixed fractions by recrystallization from toluene (250 mL). Clean fractions from chromatography were combined with recrystallized product to give the title compound as a white solid (9.85 g, 86%, mp 168° C.).

Workup

  1. filtrationThe solution was filtered
  2. washthe organic layer was washed with aqueous hydrochloric acid (500 mL, 3N)
  3. extractionThe aqueous layer was extracted with ethyl acetate (3×250 mL) and dichloromethane (3×250 mL)
  4. concentrationconcentrated on the rotary evaporator
  5. customto give a crude solid (10.92 g)
  6. customThe product was purified by chromatography
  7. washeluting with dichloromethane:2-propanol (98:2, 96:4, and 94:6)

Sources & evidence

ORD record
ord-f833a00aa1ba4d85834b8f2106a133f3
Source dataset
uspto-grants-2001_11
Patent number
US06313290B1

Reaction notes

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