4-Pentynoic acid → 5-(But-3-ynyl)-3-o-tolyl-1,2,4-oxadiazole

HRID 334543Notes

Reaction equation

HRID 334543 reaction equation
[OH:1][N:2]=[C:3]([NH2:11])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=1[CH3:10].[C:12](O)(=O)[CH2:13][CH2:14][C:15]#[CH:16].C1C=CC2N(O)N=NC=2C=1.CCN=C=NCCCN(C)C.Cl>O1CCOCC1>[CH2:15]([C:16]1[O:1][N:2]=[C:3]([C:4]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=2[CH3:10])[N:11]=1)[CH2:14][C:13]#[CH:12]

Participants

6

Reactant 4

HCID 224644-Pentynoic acidHCID 757711-HydroxybenzotriazoleHCID 27239391,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochlorideHCID 3098087N-Hydroxy-2-methyl-benzamidine

Product 1

HCID 860869225-(But-3-ynyl)-3-o-tolyl-1,2,4-oxadiazoleYield 32%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Conditions

Temperature
80 °C

Procedure

In a reactor tube, a mixture of N′-hydroxy-2-methylbenzamidine (555 mg, 3.7 mmol), 4-pentynoic acid (363 mg, 3.7 mmol), HOBT (0.56 g, 3.7 mmol) and EDCI.HCl (1.06 g, 5.55 mmol) in dioxane (7.4 mL) was stirred at R.T for 3 h. After this time the mixture was heated at 80° C. overnight in a reaction block. The mixture was concentrated. The organic layer was washed with water, NaOH 1N and water. The solvent was evaporated in a Genevac for 75 min at 40° C. using the low boiling point program. The crude product was purified by flash chromatography (Prepacked 10 g silicagel column) with DCM as eluent to afford 250 mg of 5-(but-3-ynyl)-3-o-tolyl-1,2,4-oxadiazole (Yield: 32%) as yellow oil.

Workup

  1. concentrationThe mixture was concentrated
  2. washThe organic layer was washed with water, NaOH 1N and water
  3. customThe solvent was evaporated in a Genevac for 75 min at 40° C.
  4. customThe crude product was purified by flash chromatography (Prepacked 10 g silicagel column) with DCM as eluent

Sources & evidence

ORD record
ord-e0bc7b7164a643f1ab69d0ca1d2d694e
Source dataset
uspto-grants-2014_11
Patent number
US08883826B2

Reaction notes

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