Lithium Hydroxide → 2-(1,6-Dihydroxy-4-methyl-1,3-dihydrobenzo[c][1,2]oxaborol-3-yl)acetic acid

HRID 1798037Notes

Reaction equation

C([O:3][C:4](=[O:18])[CH2:5][C@@H:6]1[O:10][B:9]([OH:11])[C:8]2[CH:12]=[C:13]([OH:17])[CH:14]=[C:15]([CH3:16])[C:7]1=2)C.[OH-].[Li+]>C1COCC1.O>[OH:11][B:9]1[C:8]2[CH:12]=[C:13]([OH:17])[CH:14]=[C:15]([CH3:16])[C:7]=2[CH:6]([CH2:5][C:4]([OH:18])=[O:3])[O:10]1

Participants

Conditions

Temperature: 0 °C

Procedure

A solution of (3S)-(1,6-dihydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester (1.04 g, 4.16 mmol) in THF (5 mL) was treated with lithium hydroxide (0.478 g, 2.08 mmol) in water (5 mL) at 0° C. The solution was stirred at 0° C. for 1 hour then quenched with 2N HCl to pH 2 and concentrated to approximately half of the entire volume. The precipitated solid was collected by vacuum filtration, then rinsed with cold water and dried to give (1,6-dihydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid. The filtrate was neutralized with NaHCO3 and lyophilized. The residue was suspended in water (5-10 mL) and stirred for 10 minutes. The solid was collected by vacuum filtration to give a second portion of (1,6-dihydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid as a yellow solid (total product; 0.49 g, 53%). 1H NMR (400 MHz, DMSO-d6) δ 12.31 (s, 1H), 9.30 (s, 1H), 9.08 (s, 1H), 6.88 (s, 1H), 6.66 (s, 1H), 5.38 (d, J=9.38 Hz, 1H), 3.00 (d, J=15.24 Hz, 1H), 2.20 (s, 3H), 2.00 (dd, J=15.24, 10.16 Hz, 1H). MS (ESI) m/z: 221 [M−1].

Workup

customthen quenched with 2N HCl to pH 2
concentrationconcentrated to approximately half of the entire volume
filtrationThe precipitated solid was collected by vacuum filtration
washrinsed with cold water
customdried

Sources & evidence

ORD record: ord-941368e3f2e14838a718a027fdd2bfc1
Source dataset: uspto-grants-2013_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08343944B2

Reaction notes

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