It was shown that N-(4-methoxybenzyl) group on 2,5-piperazinediones can be oxidatively removed with cerium(IV) diammonium nitrate under mild conditions, and the oxidative removal was performed in some model compounds which have several functional groups.

No abstract

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.

Two 4-ethoxycarbonyl thiazolyl groups were introduced into 2- and 5-positions of 3-hydroxypyridine in 8 steps using 5-cyano-3-hydroxypyridine (2) as the starting material. The pyridine derivative obtained in the last step was converted to a fragment A derivative (21) by stepwise introduction of the 2-substituted 4-thiazolyl group into the 6-position. The total yield for the formation of 21 via 14 steps was 7.6%.