Water → Ethyl 2-(6-(5-amino-1,3,4-thiadiazol-2-yloxy)-1-hydroxy-4-methyl-1,3-dihydrobenzo[c][1,2]oxaborol-3-yl)acetate

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Reaction Conditions

Reaction Steps

Concentrated HCl (10 drops) and water (12 ml) were added to a mixture of [6-(5-nitro-[1,3,4]thiadiazol-2-yloxy)-1-hydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl]-acetic acid ethyl ester (0.65 g, 1.71 mmol) and iron powder (0.479 g; 8.55 mmol) in ethanol (30 mL) at room temperature. The resulting mixture was stirred at 85° C. for 1.5 hours, cooled to room temperature and filtered through a pad of celite. The filtrate was evaporated and the residue dissolved in EtOAc (300 mL), washed with brine, dried over Na2SO4 and concentrated to give [6-(5-amino-[1,3,4]thiadiazol-2-yloxy)-1-hydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl]-acetic acid ethyl ester (0.650 g, 100%) which was used without further purification. 1HNMR (400 MHz, DMSO-d6) δ 9.33 (s, 1H), 7.33 (d, J=12.4 Hz, 1H), 7.18 (d, J=16.8 Hz, 1H), 5.51 (d, J=6.0 Hz, 1H), 4.02 (q, J=7.2 Hz, 2H), 3.10 (d, J=14.4 Hz, 1H), 2.33-2.31 (m, 1H), 2.30 (s, 3H), 1.10 (t, J=7.6 Hz, 3H). MS (ESI) m/z=350 [M+H]+.

Provenance & Evidence