Acetic Anhydride → 2-Acetamidopyridine-5-boronic acid pinacol ester

HRID 1910691Notes

Reaction equation

HRID 1910691 reaction equation
[CH3:1][C:2]1([CH3:16])[C:6]([CH3:8])([CH3:7])[O:5][B:4]([C:9]2[CH:10]=[CH:11][C:12]([NH2:15])=[N:13][CH:14]=2)[O:3]1.C(N(CC)CC)C.[C:24](OC(=O)C)(=[O:26])[CH3:25]>ClCCl.CN(C)C1C=CN=CC=1>[CH3:8][C:6]1([CH3:7])[C:2]([CH3:16])([CH3:1])[O:3][B:4]([C:9]2[CH:10]=[CH:11][C:12]([NH:15][C:24](=[O:26])[CH3:25])=[N:13][CH:14]=2)[O:5]1

Participants

6

Reactant 3

HCID 7918Acetic AnhydrideHCID 8471TriethylamineHCID 27565555-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-amine

Product 1

HCID 177502022-Acetamidopyridine-5-boronic acid pinacol esterYield 52.5%

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 6344DichloromethaneSolvent2×

Procedure

5-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-amine (0.3 g, 1.36 mmol) was dissolved in dichloromethane (5 mL) and 4-dimethylaminopyridine 17 mg, 0.136 mmol) was added, followed by triethylamine (0.38 mL, 2.73 mmol) then acetic anhydride (0.153, 1.5 mmol). The mixture was stirred at room temperature for 3.5 h then diluted with dichloromethane and washed with NH4Cl (sat aq) then brine. The organic layer was dried (MgSO4), filtered and concentrated. Chromatography eluting with ethyl acetate gave the desired product (187 mg, 52% yield). 1H-NMR (300 MHz, CDCl3) δ 9.3 (s, 1H), 8.6 (s, 1H), 8.2 (d, 1H), 8.05 (d, 1H), 2.2 (s, 3H), 1.2 (s, 12H).

Workup

  1. washwashed with NH4Cl (sat aq)
  2. dry with materialThe organic layer was dried (MgSO4)
  3. filtrationfiltered
  4. concentrationconcentrated
  5. washChromatography eluting with ethyl acetate

Sources & evidence

ORD record
ord-9dc61c2a16784e68bcc196a552c7dd81
Source dataset
uspto-grants-2013_12
Patent number
US08604023B2

Reaction notes

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