Hydrochloric Acid → 8-Bromo-4,5-dihydrobenzo[2,3]oxepino[4,5-d]thiazole-2-carboxylic acid

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Reaction Steps

To a stirred solution of 8-Bromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid ethyl ester in THF (10 ml) and MeOH (5 ml) was added a solution of NaOH (117 mg, 2.9 mmol) in water (2 ml). The reaction mixture was stirred at room temperature for 2 h upon which time it was acidified with 2M HCl. The aqueous was extracted with CH2Cl2 and the combined organics dried (MgSO4) and concentrated to give 8-Bromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid as a colorless solid (396 mg; 83%). 1H NMR (400 MHz, CDCl3) δ 8.22 (d, J=8.4, 1H), 7.19-7.24 (m, 2H), 4.33 (t, J=5.2, 2H), 3.36 (t, J=5.2, 2H).

Provenance & Evidence