Phosgene → 6-Fluoro-5-isocyanato-3-propargyl-2-benzothiazolone

Participants

Reaction Conditions

Reaction Steps

A solution of 22.5 g of 5-amino-6-fluoro-3-(2-propynyl)-2-benzothiazolinone in 350 ml of ethyl acetate is added dropwise at 30° C. during 2 hours while stirring to a solution of 60.0 g of phosgene in 300 ml of ethyl acetate. The resulting suspension is stirred at 50° C. for 2 hours and subsequently heated slowly to the boiling point. The clear solution is then evaporated to dryness and there is thus obtained as the residue 6-fluoro-5-isocyanato-3-(2-propynyl)-2-benzothiazolinone, yellow crystals. This product serves, inter alia, as the starting material in the manufacture of 3-[6-fluoro-2-oxo-3-(2-propynyl)-5-benzothiazolinyl]-6-trifluoromethyl-2,4-(1H,3H)-pyrimidinedione (see Example 1).

Provenance & Evidence