Thiourea → HCID 86685413, Verbindung

To a solution of 2-bromo-8-(chloromethyl)-6,7-dihydro-5H-benzo[7]annulene from step A6 (60 mg, 0.221 mmol) in ethanol (1 mL) was added thiourea (16.82 mg, 0.221 mmol). The mixture was heated at reflux for 4 h. The solvent was removed, and the solid residue was triturated with hexanes and dried in vacuo to give (2-bromo-6,7-dihydro-5H-benzo[7]annulen-8-yl)methyl carbamimidothioate hydrochloride (70 mg, 0.201 mmol, 91% yield). To a solution of (2-bromo-6,7-dihydro-5H-benzo[7]annulen-8-yl)methyl carbamimidothioate, hydrochloride (60 mg, 0.173 mmol) in TFA (1 mL) was added triflic acid (0.2 mL) at 0° C. The mixture was stirred at rt for 18 h and then heated to 80° C. for 4 h. Another 2 mL of TFA and 0.2 mL of trifilic acid were added, and the mixture was stirred at 60° C. for 20 h. The solvent was removed. The residue was dissolved in 50 mL of EtOAc and the organic layer was washed with saturated sodium bicarbonate/water, dried over sodium sulfate, filtered, and concentrated in vacuo to afford crude product (60 mg, 0.193 mmol, 112% yield), which was used for the next step without purification.