((1,1-Dimethyl-2-propynyl)oxy)trimethylsilane → 1-(Benzo[c][1,2,5]oxadiazol-5-yl)-4-methyl-4-(trimethylsilyloxy)pent-2-yn-1-one

HRID 655437Notes

Reaction equation

HRID 655437 reaction equation
[CH3:1][Si:2]([CH3:10])([CH3:9])[O:3][C:4]([CH3:8])([C:6]#[CH:7])[CH3:5].[Li]CCCC.CON(C)[C:19]([C:21]1[CH:29]=[CH:28][C:24]2=[N:25][O:26][N:27]=[C:23]2[CH:22]=1)=[O:20]>C1COCC1>[N:25]1[O:26][N:27]=[C:23]2[CH:22]=[C:21]([C:19](=[O:20])[C:7]#[C:6][C:4]([CH3:8])([O:3][Si:2]([CH3:10])([CH3:9])[CH3:1])[CH3:5])[CH:29]=[CH:28][C:24]=12

Participants

5

Reactant 3

HCID 87344((1,1-Dimethyl-2-propynyl)oxy)trimethylsilaneHCID 59354764N-methoxy-N-methylbenzo[c][1,2,5]oxadiazole-5-carboxamideHCID 178418339Butyllithium

Product 1

HCID 593547971-(Benzo[c][1,2,5]oxadiazol-5-yl)-4-methyl-4-(trimethylsilyloxy)pent-2-yn-1-oneYield 63%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-78 °C

Procedure

To a −78° C. stirred solution of trimethyl(2-methylbut-3-yn-2-yloxy)silane (0.49 g, 2.367 mmol) in dry THF (20 mL), n-BuLi (3.70 mL, 5.917 mmol, 1.6 M in hexane) was added dropwise over 10 minutes under an inert atmosphere. The reaction mixture was stirred for 30 min at −78° C., and then a solution of N-methoxy-N-methylbenzo[c][1,2,5]oxadiazole-5-carboxamide (0.557 g, 3.550 mmol) in dry THF (10 mL) was added to reaction mixture and stirring was continued for an additional 3 h at −78° C. The reaction mixture was quenched with a saturated NH4Cl solution and extracted with EtOAc (2×20 mL). The combined organic layers were washed with water (10 mL) and brine (10 mL), dried over Na2SO4, filtered and concentrated in vacuo to obtain the crude product. The crude material was purified via silica gel column chromatography eluting with 5% EtOAc in hexanes to afford 1-(benzo[c][1,2,5]oxadiazol-5-yl)-4-methyl-4-(trimethylsilyloxy)pent-2-yn-1-one (0.45 g, 63%) as a colorless oil.

Workup

  1. additionwas added dropwise over 10 minutes under an inert atmosphere
  2. stirringstirring
  3. waitwas continued for an additional 3 h at −78° C
  4. customThe reaction mixture was quenched with a saturated NH4Cl solution
  5. extractionextracted with EtOAc (2×20 mL)
  6. washThe combined organic layers were washed with water (10 mL) and brine (10 mL)
  7. dry with materialdried over Na2SO4
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo
  10. customto obtain the crude product
  11. customThe crude material was purified via silica gel column chromatography
  12. washeluting with 5% EtOAc in hexanes

Sources & evidence

ORD record
ord-d8b84aa59849423992c9809575d6dbfd
Source dataset
uspto-grants-2011_12
Patent number
US08071595B2

Reaction notes

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