An Easy and Convenient Synthesis of 6-Methyl-4(1<i>H</i>)-pyridone-3-carboxylic Acid
作者:Martin Mittelbach
DOI:10.1055/s-1988-27614
日期:——
A new and easy synthesis of 6-methyl-4-(1H)-pyridone-3-carboxylic acid (5), an important component of broad spectrum cephalosporins, is described. It starts from the readily available ethyl 4-hydroxy-6-methyl-2(1H)-pyridone-3-carboxylate (1), which is treated with phosphoryl chloride to give ethyl 2,4-dichloro-6-methylpyridine-3-carboxylate (2).Selective substitution of the chlorine in 4-position with alkoxide ion leads to the 4-alkoxypyridine derivatives 3. Hydrogenolysis of 3 affords ethyl 4-alkoxy-6-methyl-pyridine-3-carboxylates 4; which are hydrolysed to 5 in one step.