ChemicalBook CAS DataBase List 2,3-Difluoropyridine

2,3-Difluoropyridine synthesis

5synthesis methods

Product Name:2,3-Difluoropyridine
CAS Number:1513-66-2
Molecular formula:C5H3F2N
Molecular Weight:115.08

89402-43-7 Synthesis

89402-43-7
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1513-66-2
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Yield:-

Reaction Conditions:

palladium-carbon

Steps:

4 EXAMPLE 4

EXAMPLE 4 For the preparation of 2,3-difluoropyridine, 179.4 g (1.2 mol) of 5-chloro-2,3-difluoropyridine, and 4.5 g of 5% Pd/C (50% water-moist) as catalyst, are placed, together with 598.5 g (1.5 mol) of tri (C₈ /C₁₀) alkylamine as base, in a reaction vessel (autoclave). The reaction solution is heated to 90° C. and reductively dechlorinated with hydrogen at this temperature. After the uptake of hydrogen has ended, the reaction solution is stirred for a short time before being cooled to room temperature and neutralized with sodium hydroxide solution, and the catalyst is filtered off with suction from the reaction mixture. The organic phase is separated off and distilled at atmospheric pressure, and the resulting distillate is dried and then fractionated. The remaining mother liquor, forerunnings, intermediate runnings and residues from distillation are recycled without further pretreatment to the subsequent batch. Conversion: 95.0% (by GC) Yield: 127.7 g (1.1 mol) of 2,3-difluoropyridine 91.7% based on the 5-chloro-2,3-difluoropyridine employed. Purity: >99 (GC area-%) 2,3 -difluoropyridine

References:

US5498807,1996,A