The two higher analogues of 5-hydroxy flavone (primuletin) containing two and three methoxyl groups in the side phenyl nucleus have been synthesised and subjected to persulphate oxidation. 5-Hydroxy-3′:4′-dimethoxy flavone gave poor yield of dimethoxy primetin while the higher member could not be oxidised under these conditions. Alternatively, oxidation of 8-hydroxy flavones has been attempted and found to proceed more satisfactorily to yield primetin and its higher members. The required 8-hydroxy flavones have been made from 2:3-dihydroxy acetophenone for the preparation of which a convenient method has been worked out starting from ortho vanillin.

8-Methyl baicalein has been made (1) from 8-methyl chrysin by the preparation of the 6-aldehyde and subsequent Dakin’s reaction and (2) from C-methyl phloracetophenone dimethyl ether by steps involving persulphate oxidation and flavone ring closure. The isomeric 6-methyl compound has been obtained by the nuclear methylation of norwogonin and demethylation with aluminium chloride. The methyl ethers of the former undergo only demethylation when boiled with hydriodic acid whereas those of the latter undergo isomeric change besides demethylation.

In order to get fuller information on the influence of hydroxyl groups on alkali colour reactions a number of flavonols of types uncommon in Nature have been prepared and examined. Though the correlation between structure and alkali colour reactions is complex, when applied with care the reactions can be used for diagnostic purposes. The alkali colour reactions of the flavonols with 2′∶3′ and 2′∶3′∶4′ disposition of hydroxyl groups are not prominent and their fluorescence properties are also very feeble.

In the case of nor-wogonin and 5:7:8-trihydroxy-2-methylchromone, Gattermann method is efficient in yielding the corresponding aldehydes, whereas with their 8-methyl ethers hexamine method works satisfactorily.