Water → 4-Chloro-5-(2-methoxy-5-nitro-phenyl)-1-methyl-1H-pyrazole

HRID 540530Notes

Reaction equation

[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([N+:9]([O-:11])=[O:10])=[CH:5][C:4]=1[C:12]1[N:16]([CH3:17])[N:15]=[CH:14][CH:13]=1.[Cl:18]N1C(=O)CCC1=O.O>CN(C=O)C>[Cl:18][C:13]1[CH:14]=[N:15][N:16]([CH3:17])[C:12]=1[C:4]1[CH:5]=[C:6]([N+:9]([O-:11])=[O:10])[CH:7]=[CH:8][C:3]=1[O:2][CH3:1]

Participants

Conditions

Temperature: 80 °C

Procedure

5-(2-Methoxy-5-nitro-phenyl)-1-methyl-1H-pyrazole (2.37 g, 10.17 mmol) was dissolved in DMF (100 mL). The solution was then heated to 80° C. N-Chlorosuccinimide (1.49 g, 11.1 mmol) was added at 80° C. under Argon gas. After two hours of continuous stirring, the reaction was checked by TLC and LCMS, and found to be incomplete. An additional aliquot of NCS (0.5 g, 3.7 mmol) was added, bringing the reaction to completion after 1.5 hours. While stirring, a portion of water (200 mL) was added to force the product to precipitate out of solution. After the precipitation was complete, the flask containing the solid was cooled in an ice water bath for 10 minutes. The solid was then filtered under vacuum and rinsed with water, yielding 2.4 g (89%) of 4-chloro-5-(2-methoxy-5-nitro-phenyl)-1-methyl-1H-pyrazole. This material was used in the next step without purification. LCMS m/z (%)=267 (M+H, 100). 1H NMR (400 MHz, CDCl3) δ: 8.41 (dd, J1=8 Hz, J2=4 Hz, 1H), 8.22 (d, J=4 Hz, 1H), 7.53 (s, 1H), 7.14 (d, J=12 Hz, 1H), 3.97 (s, 3H), 3.72 (s, 3H).

Workup

customthe reaction to completion after 1.5 hours
customto precipitate out of solution
customAfter the precipitation
additionthe flask containing the solid
temperaturewas cooled in an ice water bath for 10 minutes
filtrationThe solid was then filtered under vacuum
washrinsed with water

Sources & evidence

ORD record: ord-860b039eeb2644e481a86ccc349f0e89
Source dataset: uspto-grants-2014_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08871797B2

Reaction notes

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