Synthetic Route of 71902-33-5 , The common heterocyclic compound, 71902-33-5, name is 3,5-Difluoropyridine, molecular formula is C5H3F2N, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc., below Introduce a new synthetic route.
General procedure: An oven-dried reaction vessel (4 or 9 ml screw-cap vial) equipped with a stirring bar was allowed to cool to room temperature under vacuum. Activated 4 A molecular sieves (crushed, 50 mg), [Rh-2 ] (and solid substrates, 1.0 equiv.), were added under air. The vial was then depressurized and pressurized with argon gas three times before the addition of dry THF (1 M) (and liquid substrates, distilled over CaH2, 1.0 equiv.). Following the addition of 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.0-4.0 equiv. as indicated), the glass vial was placed in a 150 ml stainless-steel autoclave under an argon atmosphere. The autoclave was pressurized and depressurized with hydrogen gas three times before the indicated pressure was set. The reaction mixture was stirred at 25-40 C for 24 h. After the autoclave was carefully depressurized, trifluoroacetic anhydride (3.0 equiv.) and CH2Cl2 (0.5 ml) were added to the crude mixture and stirring was continued for 10 min at room temperature. Alternatively, di-tert-butyl dicarbonate (3.0 equiv.), triethyl amine (3.0 equiv.) and CH2Cl2 (0.5 ml) were added to the reaction mixture and stirring was continued for 2 h at room temperature. The crude was then filtered over fritted funnel and the remaining solid was washed with ethyl acetate (2x 5 ml). The combined solution was concentrated under reduced pressure and submitted to column chromatography (pentane/ethyl acetate or pentane/dichloromethane) to obtain the final product. The indicated diastereoselectivities were determined by GC analysis or from the 19F NMR spectrum immediately after the reaction. NMR yield was calculated using hexafluorobenzene (20 mul, 0.173 mmol) as internal standard.
The synthetic route of 71902-33-5 has been constantly updated, and we look forward to future research findings.
Reference:
Article; Nairoukh, Zackaria; Wollenburg, Marco; Schlepphorst, Christoph; Bergander, Klaus; Glorius, Frank; Nature Chemistry; vol. 11; 3; (2019); p. 264 – 270;,
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem