Method for producing 1-substituted 5-hydroxypyrazoles
AssigneeBASF SE
InventorsNorbert Götz, Roland Götz, Michael Rack
Life of this patent
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Abstract
A process for preparing compounds of the formula I in which R1 is hydrogen, an aliphatic group having 1-8 carbon atoms, C1-C6-alkoxycarbonyl, C1-C6-alkylthiocarbonyl or a cyclic ring system having 3-14 ring atoms, and R2 is hydrogen, an aliphatic group having 1-8 carbon atoms, or R1 and R2 together with the carbon atom to which they are bound form a cyclic or bicyclic ring system having 3-14 ring atoms, comprises the preparation of compounds of the formula II in which R3 and R4 are readily detachable groups and R1 and R2 are as defined above, as starting materials or intermediates and the cyclization of these under suitable reaction conditions to give compounds of the formula I.
Claims13
A process for preparing hydroxypyrazole of the formula I
- where
- R1 is hydrogen, straight-chain or branched alkyl, alkenyl or alkynyl having in each case 1 to 8 carbon atoms, where these groups may be substituted by one or more halogen atoms, halogen-C1-C6-alkyl groups, C1-C6-alkoxy or aryloxy, C1-C6-alkoxycarbonyl, C1-C6-alkylthiocarbonyl or a cyclic ring system having 3 to 14 ring atoms, and
- R2 is hydrogen, straight-chain or branched alkyl, alkenyl or alkynyl, having in each case 1 to 8 carbon atoms, where these groups may be substituted by one or more halogen atoms, halogen-C1-C6-alkyl groups, C1-C6-alkoxy or aryloxy, R1 and R2 together with the carbon atom to which they are bound form a cyclic ring system having 3 to 14 ring atoms or a bicyclic ring system having 7 to 14 ring atoms,
- comprising:
- i. the preparation of a compound of the formula IlIl
- in which R1 and R2 are as defined above, and the group R3 is a C1-C6-alkylcarbonyl group, by reacting a compound of the formula V
- with a compound of the formula VI
- and subsequently hydrogenating the resulting compound of the formula VII
- to form a compound of the formula III,
- ii. reacting the compound of formula III with an activated alkenylcarboxylic acid derivative of the formula IV
- in which R4 is a C1-C4-alkoxy group and X is a suitable leaving group, to form a compound of formula 11,
- wherein R1, R2, R3 and R4 are as defined above, and
- iii subsequent cyclization of the compound of the formulation II to form a compound of the formula I.
Dependencies are inferred from the claim text.