Triethyl borate → B-2,1,3-Benzoxadiazol-4-ylboronic acid

HRID 369037Notes

Reaction equation

HRID 369037 reaction equation
[N:1]1[O:2][N:3]=[C:4]2[C:9](Br)=[CH:8][CH:7]=[CH:6][C:5]=12.C([O:13][B:14](OCC)[O:15]CC)C.[Li]CCCC.[Cl-].[NH4+]>O1CCCC1.CCCCC>[N:1]1[O:2][N:3]=[C:4]2[C:9]([B:14]([OH:15])[OH:13])=[CH:8][CH:7]=[CH:6][C:5]=12

Participants

7

Reactant 4

HCID 9009Triethyl borateHCID 25517Ammonium ChlorideHCID 6078234-Bromo-2,1,3-benzoxadiazoleHCID 178418339Butyllithium

Product 1

HCID 21186805B-2,1,3-Benzoxadiazol-4-ylboronic acidYield 32%

Reagents, catalysts & solvents 2

HCID 8003PentaneSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 4-benzo[c]furazanyl bromide (4 g, 0.020 mol) in tetrahydrofurane (80 ml) and n-pentane (20 ml) is added triethylborate (3.8 ml, 0.022 mol) and N,N,N,N-tetraethylendiamine (3 ml, 0.02 mol). Then, n-BuLi (8.8 ml, 2.5N in hexane, 0.022 mol) is added dropwise at -100° C. and the solution is stirred for 5 minutes more. The reaction mixture is poured into an aqueous solution of saturated ammonium chloride and the water phase is extracted with ethyl acetate. The organic solvent is removed and the crude product is taken up in dichloromethan/n-hexane (5:6). The suspension is filtered to yield the title compound (1.05 g) which is used without further purification.

Workup

  1. extractionthe water phase is extracted with ethyl acetate
  2. customThe organic solvent is removed
  3. filtrationThe suspension is filtered

Sources & evidence

ORD record
ord-4ebbced45bb6440c905812d638390ec3
Source dataset
uspto-grants-2000_10
Patent number
US06136821

Reaction notes

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