Method for preparing pyrazolecarboxylic acid derivative, and intermediate thereof
AssigneeZhejiang Yongtai Technology Co., Ltd.
InventorsHongming Shao, Renbao He, Yizhong Jin, Lei Wang
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Abstract
Provided are a preparation method for synthesizing a pyrazolecarboxylic acid derivative of the following formula (I), which is suitable for industrial production, and an intermediate as shown by the following formula (II). The method is high in reaction yield in each step, low in waste gas and waste water and low in cost, and requires no special reaction equipment.
Claims20
A compound of the following formula (II),
- wherein,
- R1 is selected from methyl or ethyl;
- R4 is selected from hydrogen or methyl;
- n is 1-4;
- X is F, Cl or CF3.
A method for preparing the compound of formula (II), said method comprising the following steps of:
- (1) in the presence of Lewis acid, reacting α-fluoride amine of formula (III) with ethylene derivative of formula (IV) to obtain vinamidinium salt of formula (V) (i.e. 1,5-diaza-pentadiene salt),
- said α-fluoride amine of formula (III) is as follows:
- wherein, X is defined as described previously, R2 and R3 are independently selected from C1-C4 alkyl;
- said ethylene derivative of formula (IV) is as follows:
- wherein, R4 is hydrogen or methyl, n is 1-4;
- said 1,5-diaza-pentadiene salt of formula (V) is as follows:
- wherein, n, R2, R3, and R4 are defined as described previously, Y− is an anion, said anion is selected from [BF4]−, [AlCl3F]−, [AlF4]−, [ZnCl2F]−, [SbF6]−, [SnCl4F]−, [BiCl3F]−, [GaCl3F]− and [SiCl4F]−, which are derived from the corresponding Lewis acids;
- (2) reacting the 1,5-diaza-pentadiene salt of formula (V) with hydrazine to obtain the compound of formula (II).
A method for preparing compound of formula (I), said compound of formula (I) is as follows,
- wherein, R1 is methyl or ethyl;
- X is F, Cl or CF3;
- said method comprising the following steps of:
- (1) in the presence of Lewis acid, reacting α-fluoride amine of formula (III) with ethylene derivative of formula (IV) to obtain vinamidinium salt of formula (V) (i.e. 1,5-diaza-pentadiene salt),
- said α-fluoride amine of formula (III) is as follows:
- wherein, X is defined as described previously, and R2 and R3 are independently selected from C1-C4 alkyl;
- said ethylene derivative of formula (IV) is as follows:
- wherein, R4 is hydrogen or methyl, and n is 1-4;
- said 1,5-diaza-pentadiene salt of formula (V) is as follows:
- wherein, n, R2, R3, and R4 are defined as described previously, and Y− is an anion, said anion is selected from [BF4]−, [AlCl3F]−, [AlF4]−, [ZnCl2F]−, [SbF6]−, [SnCl4F]−, [BiC13F]−, [GaCl3F]− and [SiCl4F]−;
- (2) reacting the 1,5-diaza-pentadiene salt of formula (V) with hydrazine to obtain the compound of formula (II),
- said compound of formula (II) is as follows:
- wherein, X, n, R1, and R4 are defined as described previously;
- (3)hydrolyzing and oxidizing one of the compounds of formula (II) with n=1-4 to obtain the compound of formula (I).
Dependencies are inferred from the claim text.