Hydrochloric Acid → (6-Methoxy-1-benzothiophen-2-yl)boronic acid

HRID 581020Notes

Reaction equation

[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[CH:10]=[CH:9][S:8][C:7]=2[CH:11]=1.C([Li])CCC.[B:17](OC(C)C)([O:22]C(C)C)[O:18]C(C)C.Cl>O1CCCC1.C(OCC)(=O)C>[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[CH:10]=[C:9]([B:17]([OH:22])[OH:18])[S:8][C:7]=2[CH:11]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 6-methoxybenzo[b]thiophene (18.13 g, 0.111 mol) in 150 mL of anhydrous tetrahydrofuran (THF) at -60° C. was added n-butyllithium (76.2 mL, 0.122 mol, 1.6M solution in hexanes), dropwise via syringe. After stirring for 30 minutes, triisopropyl borate (28.2 mL, 0.122 mol) was introduced via syringe. The resulting mixture was allowed to gradually warm to 0° C. and then distributed between 1N hydrochloric acid and ethyl acetate (300 mL each). The layers were separated, and the organic layer was dried over sodium sulfate. Concentration in vacuo produced a white solid that was triturated from ethyl ether hexanes. Filtration provided 16.4 g (71%) of 6-methoxybenzo[b]thiophene-2-boronic acid as a white solid. mp 200° C. (dec). 1H NMR (DMSO-d6) d 7.83 (s, 1H), 7.78 (d, J=8.6 Hz, 1H), 7.51 (d, J=2.0 Hz, 1H), 6.97 (dd, J=8.6, 2.0 Hz, 1H), 3.82 (s, 3H). FD mass spec: 208.

Workup

customThe layers were separated
dry with materialthe organic layer was dried over sodium sulfate
concentrationConcentration in vacuo
customproduced a white solid
customthat was triturated from ethyl ether hexanes
filtrationFiltration

Sources & evidence

ORD record: ord-ad6543b270ee4e3e881cff4eef8ef5e1
Source dataset: uspto-grants-1999_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05919800

Reaction notes

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