| 摘要 |
PURPOSE: Provided are 3-(1-hydroxy-pentylidene)-5-nitro-3H-benzofuran-2-one and its ketonic tautomer form 3-(1-oxo-pentyl)-5-nitro-3H-benzofuran-2-one. The 3-(1-hydroxy-pentylidene)-5-nitro-3H-benzofuran-2-one is used as a synthesis intermediate. In particular, it may be converted to 2-butyl-5-nitrobenzofuran by hydrolysis, decarboxylation and cyclization, by simple heating in an acid medium. 2-butyl-5-nitrobenzofuran may act as an intermediate in the synthesis of an antiarrhythmic, dronedarone. CONSTITUTION: 3-(1-hydroxy-pentylidene)-5-nitro-3H-benzofuran-2-one and its ketonic tautomer form, 3-(1-oxo-pentyl)-5-nitro-3H-benzofuran-2-one are represented by the formula(1) and formula(2) respectively. Their preparation process is characterized in that 5-nitro-3H-benzofuran-2-one is reacted, at a temperature 30 deg.C, with pentanoic anhydride and a salt of pentanoic acid, optionally in the presence of pentanoic acid, then the resulting reaction mixture is acidified, and then the expected product is isolated.
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