Pyridine derivatives and methods of using them for the preparation of intermediate compounds for the production of sulfonylurea herbicides
A technology of compounds and derivatives, applied in the field of pyridine derivatives and intermediate compounds used to produce sulfonylurea herbicides, which can solve the problem of difficulty in completely removing Cu by-products, reducing yields, affecting fluorination reactions, etc. question
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Embodiment 1
[0140] Embodiment 1: preparation formula 3a compound
[0141] [Formula 3a]
[0142]
Embodiment 1-1
[0143] Example 1-1: Preparation of 1-(3-chloropyridin-2-yl)-2-fluoropropan-1-one (D=chloro, Y=fluoro)
[0144] Under nitrogen atmosphere, hexane (40 mL) and N,N-dimethylaminoethanol (3.14 g, 35.2 mmol) were added to the reaction vessel and cooled to -5°C. n-Butyllithium (2.5M in hexane, 70 mmol) was added dropwise to the reaction solution, and the mixture was stirred for 1 hr and cooled to -41°C. 3-Chloropyridine in hexane (2.04 g, 18 mmol) was added dropwise to the mixture. After the addition, the reaction mixture was cooled to -78°C, and 2-fluoropropionic acid morpholinamide (5.64 g, 35 mmol) in hexane was added dropwise to the mixture. The reaction mixture was stirred for 2 hours and then heated to -20°C. Propionic acid (9.13 g, 123 mmol) was added dropwise to the mixture to terminate the reaction. The reaction solution was heated to 0°C. After adding water, the solution was extracted with ethyl acetate. The extracted organic layer was dried over magnesium sulfate, and...
Embodiment 1-2
[0146] Example 1-2: Preparation of 1-(3-fluoropyridin-2-yl)-2-fluoropropan-1-one (D=fluorine, Y=fluorine)
[0147] According to the same procedure of Example 1-1, reaction of 3-fluoropyridine (1.75 g, 18 mmol) instead of 3-chloropyridine provided the title compound (2.00 g, 65%).
[0148] 1 H NMR (CDCl 3 , δ): 8.51-8.50 (m, 1H), 7.60-7.54 (m, 2H), 6.15 (dq, J=6.7, 48.9Hz, 1H), 1.67 (dd, J=6.7, 23.8Hz, 3H)
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