Convenient Synthesis of the Central 3,6-Di(2-thiazolyl)-2-(4-thiazolyl)pyridine Skeleton of a Macrocyclic Antibiotic, GE 2270 A

It was shown that 6-dimethoxymethyl-1,2-dihydro-2-oxo-3-pyridinecarbonitrile (5) is easily convertible into the titled ring system by a stepwise method. Both the 3-cyano and 6-dimethoxymethyl groups of 5 were converted into 2-thiazolyl groups via the thioamide and carbaldehyde groups by Hantzsch and Shioiri methods, respectively. The 2-pyridone function was changed to a bromoacetyl group via the coupling reaction between the corresponding triflate and ethyl vinyl ether, and then converted into the 4-thiazolyl group. Thus, the useful 3,6-di(2-thiazolyl)-2-(4-thiazolyl)pyridine derivative for the total synthesis of GE 2270 A was obtained. In fact, the method was recently applied to the total synthesis of an antibiotic, micrococcin P, which has a similar central skeleton.