A new approach to the synthesis of 3,6- and 5,6-dialkyl derivatives of 4-hydroxy-2-pyrone. Synthesis of rac-germicidin

Article abstract of DOI:10.1016/S0040-4020(99)00150-7

A new approach to the synthesis of 3,6- and 5,6-dialkyl-4-hydroxy-2- pyrones has been developed. The method includes the formation of acylated Meldrum's acids (5-(2-alkyl-3-oxoacyl)-2,2-dimethyl-1,3-dioxane-4,6-diones) followed by their thermal transformation. Introduction of 3-alkyl substituents was accomplished by acylation of 4-hydroxy-2-pyrones and ionic hydrogenation of the 3-acyl derivatives obtained. The effectiveness of this new approach has been demonstrated in the synthesis of rac-germicidin, an autoregulative germination inhibitor of Streptomyces viridochromogenes NRRL B-1551.