HCID 19745792, compound → HCID 19745785, compound

Participants

Reaction Conditions

Reaction Steps

34.94 g of 1,6-dimethyl-3-(6-fluoro-3-isopropyl-2-oxo-5-benzothiazolinyl)-2,4(1H,3H)-pyrimidinedione (see Example 49) are dissolved in 200 ml of concentrated sulphuric acid while stirring and gassing with nitrogen and the solution is heated to 150° C. for 45 minutes. The reaction mixture is cooled to 25° C. and poured on to 1 kg of ice, and the precipitated product is filtered off under suction and washed neutral with water. The filter cake is suspended in 500 ml of ethyl acetate at 60° C., the suspension is concentrated to 250 ml, the product, after cooling, is filtered off under suction, the filtrate is back-washed with ethyl acetate and dried at 50° C. under reduced pressure. In this manner there is obtained 1,6-dimethyl-3-(6-fluoro-2-oxo-5-benzothiazolinyl)-2,4-(1H,3H)-pyrimidinedione, m.p.>250° C.

Provenance & Evidence