Trityl chloride → 4-Bromo-1-trityl-1H-pyrazole

HRID 1531804Notes

Reaction equation

HRID 1531804 reaction equation
[C:1](Cl)([C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Br:21][C:22]1[CH:23]=[N:24][NH:25][CH:26]=1>CN(C)C1C=CN=CC=1.N1C=CC=CC=1>[Br:21][C:22]1[CH:23]=[N:24][N:25]([C:1]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)[C:2]2[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=2)[CH:26]=1

Participants

5

Reactant 2

HCID 6456Trityl chlorideHCID 163754-Bromopyrazole

Product 1

HCID 108341884-Bromo-1-trityl-1H-pyrazoleYield 35.6%

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 1049PyridineSolvent

Conditions

Temperature
85 °C

Procedure

Trityl chloride (9.02 g) was added to a stirred solution of 4-bromopyrazole (4.24 g) and 4-dimethylaminopyridine (0.711 g) in pyridine (90 ml). The reaction mixture was heated to 85° C. for 20 hrs, cooled to room temperature and partitioned between diethyl ether and water. The organic layer was separated, dried (MgSO4) and evaporated under reduced pressure. The crude product was recrystallized from hexane/toluene (5/1, 180 ml) to afford the title compound (4.0 g). The remaining solids and the mother liquors were combined and purified by column chromatography on silica gel eluting with pentane/ether (30/1, v/v) to afford a second batch of title compound (3.0 g).

Workup

  1. temperaturecooled to room temperature
  2. custompartitioned between diethyl ether and water
  3. customThe organic layer was separated
  4. dry with materialdried (MgSO4)
  5. customevaporated under reduced pressure
  6. customThe crude product was recrystallized from hexane/toluene (5/1, 180 ml)

Sources & evidence

ORD record
ord-ae0968c9107b4b17b084c43efff398db
Source dataset
uspto-grants-2001_03
Patent number
US06200978B1

Reaction notes

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