アシルピリジンに関する研究 (第1報)

2-アシル-4-アルキルピリジン類の合成

抄録

2-Acylpyridines (acyl=CH₃CO, C₂H₅CO, C₃H₇CO, C₄H₉CO) with alkyl (methyl or ethyl) in the 4-position were prepared by the following route: 2, 4-Lutidine 1-oxide was submitted again to rearrangement by the Boekelheide method to 4-methylpicolin-aldehyde (B), oxidized with silver oxide, and esterified to ethyl 4-methylpicolinate (C). The Claisen condensation of (C) to (D) and ketonic decomposition of (D) afforded 2-acetyl-4-methylpyridine (I). Application of methyl, ethyl, or butyl iodide to (D) and ketonic decomposition of the respective products afforded 2-propionyl- (II), 2-butyryl- (III), and 2-valeryl-4-methylpyridine (IV). Application of methyl iodide to 4-ethylpyridine 1-oxide and reaction of the resultant 1-methoxy-4-ethylpyridinium iodide (E) with potassium cyanide gave 4-ethyl-2-pyridinecarbonitrile (F). Application of the Grignard reagents obtained from methyl iodide, ethyl bromide, propyl iodide, and butyl iodide to (F), afforded 2-acetyl- (V), 2-propionyl- (VI), 2-butyryl- (VII), and 2-valeryl-4-ethylpyridine (VIII).