| US 7,585,998 B2 | ||
| Method for producing difluoro-acetyl-acetic acid alkylesters | ||
| Bernd Gallenkamp, Wuppertal (Germany); and Lubbertus Mulder, Hagen (Germany) | ||
| Assigned to Bayer CropScience AG, Monheim (Germany) | ||
| Appl. No. 10/561,031 PCT Filed Jun. 18, 2004, PCT No. PCT/EP2004/006607 § 371(c)(1), (2), (4) Date Dec. 16, 2005, PCT Pub. No. WO2005/003077, PCT Pub. Date Jan. 13, 2005. |
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| Claims priority of application No. 103 29 450 (DE), filed on Jul. 01, 2003; and application No. 103 31 496 (DE), filed on Jul. 11, 2003. | ||
| Prior Publication US 2006/0149091 A1, Jul. 06, 2006 | ||
| Int. Cl. C07C 69/66 (2006.01) | ||
| U.S. Cl. 560—174 | 9 Claims |
1. A method of preparing alkyl esters of 4,4-difluoroacetoacetic acid of formula (I)
 in which R represents alkyl,
comprising
(a) in a first step, reacting an alkyl ester 4-chloro-4,4-difluoroacetoacetic acid of formula (II)
 in which R represents alkyl,
with a trialkylphosphite of formula (III)
P(OR1)3 (III)
in which each R1 independently of the others represents C1-C4-alkyl, to give a alkylphosphonate of formula (IV)
 in which R and R1 have the meanings described above,
(b) in a second step, reacting the alkylphosphonate of formula (IV) with an amine of formula (V)
 in which
R2 and R3 independently of each other represent hydrogen or C1-C8-alkyl, or R2 and R3 together represent —CH2—CH2—O—CH2—CH2—, —CH2—CH2—S—CH2—CH2—, or —CH2—CH2—N(R4)—CH2—CH2—, and
R4 stands for hydrogen or C1-C8-alkyl,
optionally in the presence of a diluent,
to give an enamine of formula (VI)
 in which R, R2, and R3 have the meanings described above, and
(c) in a third step, condensing the enamine of formula (VI) in the presence of an acid.
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