Propargyl bromide → 2-(t-Butyl)-5-(2,6-dichloro-4-pyridyl)-4-propargyl-1,2,4-triazolin-3-one

HRID 3620

Reaction equation

HRID 3620 reaction equation
[C:1]([N:5]1[C:9](=[O:10])[NH:8][C:7]([C:11]2[CH:16]=[C:15]([Cl:17])[N:14]=[C:13]([Cl:18])[CH:12]=2)=[N:6]1)([CH3:4])([CH3:3])[CH3:2].C([O-])([O-])=O.[K+].[K+].[CH2:25](Br)[C:26]#[CH:27]>O.C1(C)C=CC=CC=1.C(OCC)(=O)C>[C:1]([N:5]1[C:9](=[O:10])[N:8]([CH2:27][C:26]#[CH:25])[C:7]([C:11]2[CH:12]=[C:13]([Cl:18])[N:14]=[C:15]([Cl:17])[CH:16]=2)=[N:6]1)([CH3:4])([CH3:2])[CH3:3]

Participants

7

Reactant 3

HCID 7842Propargyl bromideHCID 11430Potassium CarbonateHCID 1363512752-(t-Butyl)-5-(2,6-dichloro-4-pyridyl)-1,2,4-triazolin-3-one

Product 1

HCID 867523412-(t-Butyl)-5-(2,6-dichloro-4-pyridyl)-4-propargyl-1,2,4-triazolin-3-one

Reagents, catalysts & solvents 3

HCID 962WaterCatalystHCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent2×

Procedure

To 2.06 g (7.2 mmol) of crude 2-(t-butyl)-5-(2,6-dichloro-4-pyridyl)-1,2,4-triazolin-3-one were added 30 mL of ethyl acetate, 1 drop of water, and 1.00 g (7.30 mmol) of powdered K2CO3. The mixture was heated to reflux and after 15 min 1.10 g (7.4 mmol) of an 80% by weight solution of propargyl bromide in toluene was added. Refluxing was continued for 2.5 hours. The mixture was cooled, diluted with 175 mL of ethyl acetate, washed with 25 mL of water, and dried over MgSO4. Reomoval of the solvent left 2.18 g of crude product as a reddish solid. The crude product was combined with 0.69 g of material from another run and purified by flash chromatography first on a silica gel column and then on a neutral alumina column eluted portionwise in both cases with ether hexane mixtures containing successively greater percentages of ether to afford 0.97 g of 2-(t-butyl)-5-(2,6-dichloro-4-pyridyl)-4-propargyl-1,2,4-triazolin-3-one (Compound 1) as a white solid, m.p. 107°-109° C. 1H-NMR (CDCl3)∂1.6 (9H,s), 2.45 (1H,t), 4.6 (2H,d), 7.75 (2H,s).

Workup

  1. temperatureThe mixture was heated
  2. additionwas added
  3. temperatureRefluxing
  4. temperatureThe mixture was cooled
  5. washwashed with 25 mL of water
  6. dry with materialdried over MgSO4
  7. waitReomoval of the solvent left 2.18 g of crude product as a reddish solid
  8. custompurified by flash chromatography first on a silica gel column
  9. washon a neutral alumina column eluted portionwise in both cases with ether hexane mixtures
  10. additioncontaining successively greater percentages of ether

Sources & evidence

ORD record
ord-88c4d02c8563491e94268fb63352bd18
Source dataset
uspto-grants-1998_03
Patent number
US05733849

Linked notes

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