Bromine → 2-amino-4H,5H,6H,7H,8H-cyclohepta[d][1,3]thiazol-8-one

Participants

Reaction Conditions

Reaction Steps

Cycloheptane-1,3-dione (20.0 g, 159 mmol) [prepared according to Organic Process Research & Development 1998, 2, 379] is taken up in 200 mL acetic acid and sodium acetate (14.3 g, 174 mmol) is added. The reaction mixture is stirred for 10 min, cooled to 10° C. and than bromine (8.99 mL, 174 mmol) is added dropwise over a period of 20 min. The reaction mixture is allowed to come to RT and stirred for 2 h. Thiourea (13.2 g, 174 mmol) is added and the reaction mixture is heated to 85° C. and stirred for 1 h. The reaction mixture is stirred overnight at RT, filtered and the solids are washed with 200 mL petroleum ether. The solids are taken up in water, filtered and the filtrate is basified to pH 8 with aqueous ammonia. The precipitated solids are filtered off and dried in vacuo. Yield: 10.0 g. HPLC-MS: tR=0.14 min, (M+H)+=183. 1H NMR (DMSO-d6): δ 7.81 (s, 2H), 2.84 (t, 2H), 2.58 (t, 2H), 1.81 (m, 4H).

Provenance & Evidence