No abstract

No abstract

No abstract

No abstract

Methyl O-dimethylcitromycetin ( I ; R = Me), which is shown to have basic properties, is oxidised with lead tetra-acetate and chromic acid respectively to give methyl O-dimethylcitromycetinol (11) and methyl O-dimethylcitromycetinone (111). Unlike O-dimethylcitromycin, (I ; R = Me) is not oxidised to give (11) and ( 111) with ozone. The phenylpyrone (IV; R = H) is formed from (11) with alkali, whilst with warm dilute acid (111) gives (V) which on cyclisation regenerates the parent compound. With warm alkali (111) gives rise to (VI), (VIII), and probably (IX), along with acetone and acetic acid.Attempts to employ the ester (XIV; R = Me, R' = OH) as the starting material for the synthesis of (VI), (VIII), and (IX) were unsuccessful because (XIV; R = Me, R' = OH) could not be C-formylated or -acetylated. A new route to the synthesis of the acid (XIV; R = H, R' = OH) is described.