Ammonium Chloride → 2-(3-Ethylureido)-7-(pyridin-2-yl)benzothiazol-5-ylboronic acid

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of [2-(ethylcarbamoylamino)-7-(2-pyridyl)-1,3-benzothiazol-5-yl]trifluoromethanesulfonate (25 g, 56.1 mmol) in DMSO (250 mL) at rt was added bis(neopentylglycolato) diboron (25.20 g, 112.10 mmol) and potassium acetate (16.5 g, 168.2 mmol). The resulting reaction mixture was de-gassed by purging N2 for 15-20 min followed by addition of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) DCM adduct (6.8 g, 8.4 mmol). The reaction mixture was again purged with N2for 15-20 min then heated to 80° C. for 90 min. After the completion of reaction (by TLC), the reaction mixture was poured onto saturated NH4Cl solution (1 L). The resulting precipitate was filtered and dried under vacuum. The solid cake was taken up in 2N NaOH (200 mL) and stirred for 45 min at rt. The solution was filtered and the filtrate acidified up to pH 5-6. The solid thus obtained was filtered and dried to obtain the desired product (17 g, 88%). 1H-NMR (DMSO-d6): δ 1.10 (t, J=7.20 Hz, 3H), 3.20 (m, 2H), 6.84 (br s, 1H), 7.41 (m, 1H), 8.01 (m, 1H), 8.12 (s, 1H), 8.25 (m, 3H), 8.40 (s, 1H), 8.79 (d, J=4.0 Hz, 1H) and 10.57 (br s, 1H). MS: 343.25 [M+H]+.

Provenance & Evidence