3-(1-hydroxy-pentylidene)-5-nitro-3H-benzofuran-2-one a process for the preparation thereof and the use thereof
A product corresponding to formula (I) or its ketonic tautomer form (II) which is 3-(1-hydroxy-pentylidene)-5-nitro-3H-benzofuran-2-one, a process for the preparation and use of the product corresponding to formula (I) or its tautomeric form (II), a process for the preparation and use, particularly for the production of synthesis intermediates.
1. A compound having the formula (I) or its ketonic tautomer form (II)
2. A compound having the formula I according to claim 1 , which is 3(1-hydroxy-pentylidene)-5nitro-3H-benzofuran-2-one.
3. A compound to formula II according to claim 2 which is 3-(1-oxopentyl)-5-nitro-3H-benzofuran-2-one.
4. A process for the preparation of the compound having the formula (I) or (II),
in which 5-nitro-3H-benzofuran-2-one is reacted, at a temperature above 30° 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 above compound is isolated.
5. A process according to claim 4 , in which 1 mole of 5-nitro-3H-benzofuran-2-one is reacted with 1 to 5 moles of pentanoic anhydride, 0.1 to 2 moles of a salt of pentanoic acid and 0 to 1.5 moles of pentanoic acid, then the resulting reaction mixture is acidified and then the above compound is isolated.
6. A process according to claim 4 , in which 1 mole of 5-nitro-3H-benzofuran-2-one is reacted with 2 moles of pentanoic anhydride and 1 mole of a salt of pentanoic acid, then the resulting reaction mixture is acidified, and then the above compound is isolated.
7. A process according to claim 4 , in which the salt of pentanoic acid is the salt of sodium, potassium or a salt of tertiary amine.
8. A prowess process according to claim 4 , in which the salt of pentanoic acid is produced extemporaneously from pentanoic acid and a base.
9. A process according to claim 4 , in which the salt of pentanoic acid is produced in situ from pentanoic acid and sodium carbonate.
10. A process according to claim 4 , in which the reaction mixture is acidified with sulfuric acid.
11. A process according to claim 4 , in which the above formula (I) or its tautomeric form (II) is purified by recrystallisation in acetic acid.
12. Synthesis intermediate produced using the compound of formula (I) or of its tautomeric form (II) as claimed in claim 1 .
13. 2-butyl-5-nitro-benzofuran-2-one produced using the compound of formula (I) or of its tautomeric form (II) as claimed in claim 1 .