Diisopropylamine → (4-Carboxybenzo[b]thiophen-2-yl)boronic acid

HRID 250241Notes

Reaction equation

[Li]CCCC.C(NC(C)C)(C)C.[S:13]1[CH:17]=[CH:16][C:15]2[C:18]([C:22]([OH:24])=[O:23])=[CH:19][CH:20]=[CH:21][C:14]1=2.[B:25](OC(C)C)([O:30]C(C)C)[O:26]C(C)C>C1COCC1>[C:22]([C:18]1[C:15]2[CH:16]=[C:17]([B:25]([OH:30])[OH:26])[S:13][C:14]=2[CH:21]=[CH:20][CH:19]=1)([OH:24])=[O:23]

Participants

Conditions

Temperature: -30 °C

Procedure

A solution of n-BuLi (2.5M in hexane, 1.69 mol, 676 mL) is added slowly at −78° C. to a solution of diisopropylamine (1.69 mol, 236 mL) in 2 L of anhydrous THF. The mixture is stirred for 30 min. A solution of benzo[b]thiophene-4-carboxylic acid (0.8 mol, 143 g) in 2 L of anhydrous THF is added slowly and the mixture is allowed to reach 0° C. The reaction is cooled to −30° C. and the triisopropyl borate (2 mol, 463 mL) is added slowly. The cooling bath is removed and the mixture is allowed to reach room temperature. The reaction is quenched with 1.3 L of concentrated HCl and 1 L of water. The mixture is stirred overnight. The organic solvent is removed under reduced pressure. The precipitate is collected by filtration, washed with water, and dried under vacuum to yield the title compound (170.5 g, 96%). ES/MS m/e 221 (M−1).

Workup

customto reach 0° C
customThe cooling bath is removed
customto reach room temperature
customThe reaction is quenched with 1.3 L of concentrated HCl and 1 L of water
stirringThe mixture is stirred overnight
customThe organic solvent is removed under reduced pressure
filtrationThe precipitate is collected by filtration
washwashed with water
customdried under vacuum

Sources & evidence

ORD record: ord-0acf80ccbd0c42a4a68f85c323069aac
Source dataset: uspto-grants-2011_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07863302B2

Reaction notes

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