A solution of pentafluoropyridine (3) (0.6 g, 3.6 mmol) in tetrahydrofuran (5 cm3) was added to a mixture of lithium aluminium hydride (5 cm3, 5 mmol of 1.0 M solution in ether) and 12-crown-4 (1.0 g, 5.7 mmol) in THF (10 cm3) at 0 "C, with stirring, under an atmosphere of dry nitrogen. The mixture was stirred at 0 "C for 10 min, then at room temperature for 19 h, then iced water added and the mixture extracted into ether. The ether solution was dried (MgS04), evaporated and the products were isolated by preparative scale GLC (1 0% SE, 40"C), giving 2,3,5-trifluoropyridine (7, 92%) 50(Found: C, 44.9; H, 1.3; N, 10.5. Calc. for C5H2F3N: C, 45.1; H, 1.5; N, 10.5); IR spectrum no. 2; mass spectrum no. 3; nmr spectrum no. 3.
[1] Journal of Fluorine Chemistry, 2013, vol. 155, p. 132 - 142
