Formaldehyde → 1,3-Dioxan-5-yl 3-pyridyl ketone

Reaction equation

[C:1]([C:4]1[CH:5]=[N:6][CH:7]=[CH:8][CH:9]=1)(=[O:3])[CH3:2].[CH2:10]=[O:11].B(F)(F)F.C[CH2:17][O:18][CH2:19]C>C(O)(=O)C>[N:6]1[CH:7]=[CH:8][CH:9]=[C:4]([C:1]([CH:2]2[CH2:10][O:11][CH2:19][O:18][CH2:17]2)=[O:3])[CH:5]=1

Participants

Procedure

A 48.4 g. portion of 3-acetylpyridine was combined with 60 g. of paraformaldehyde and 200 ml. of glacial acetic acid, and to the mixture was added, dropwise with stirring, 86 g. of boron trifluoride etherate. The mixture was then heated, and was stirred under reflux for 4 hours. The reaction was cooled and the volatile materials were evaporated under vacuum to obtain 60 g. of an oily yellow solid, which was crystallized by the addition of water. The solids were separated by filtration, washed with water and dried to obtain 25 g. of the desired product, m.p. 91°-100°.