Benzyl Bromide → 2-Benzyl-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid amide

HRID 475503Notes

Reaction equation

HRID 475503 reaction equation
[NH:1]1[C:5]2[CH2:6][CH2:7][CH2:8][C:4]=2[C:3]([C:9]([NH2:11])=[O:10])=[N:2]1.[OH-].[Na+].[CH2:14](Br)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1>C1COCC1>[CH2:14]([N:1]1[C:5]2[CH2:6][CH2:7][CH2:8][C:4]=2[C:3]([C:9]([NH2:11])=[O:10])=[N:2]1)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1.[CH2:14]([N:2]1[CH:3]([C:9]([NH2:11])=[O:10])[C:4]2[CH2:8][CH2:7][CH2:6][C:5]=2[NH:1]1)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1

Participants

6

Reactant 3

HCID 7498Benzyl BromideHCID 14798Sodium HydroxideHCID 451212581H,4H,5H,6H-cyclopenta[c]pyrazole-3-carboxamide

Product 2

HCID 587136291-Benzyl-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid amideHCID 693044772-Benzyl-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid amideYield 196.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid amide (41.5 g, 275 mmol) in THF (460 mL) at rt was added a solution of NaOH (5N aq., 110 mL, 0.54 mol). After stirring for 5 min benzyl bromide (49.2 g, 0.29 mol) was added and the reaction was stirred for 16 h. The volatiles were removed in vacuo and the resulting solid was washed with H2O (3×250 mL). Further concentration gave regioisomers of 1-benzyl-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid amide and 2-benzyl-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid amide (65.3 g, 270 mmol, 98% yield) as a 20:1 mixture and was used without separation).

Workup

  1. additionwas added
  2. customThe volatiles were removed in vacuo
  3. washthe resulting solid was washed with H2O (3×250 mL)
  4. concentrationFurther concentration

Sources & evidence

ORD record
ord-82cb83c953dc4b479df7343cf5e60f7f
Source dataset
uspto-grants-2014_01
Patent number
US08637555B2

Reaction notes

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