S K Mukerjee
Articles written in Proceedings – Section A
Volume 35 Issue 1 January 1952 pp 34-44
Methods of nuclear oxidation are applied for the preparation of chromone derivatives, many of which have been required for the study of isomeric change. Just as in the flavone group the presence of a methoxyl (hydroxyl) in the 3-position prevents isomeric change from the 5:7:8 to the 5:6:7 arrangement of hydroxyl groups; in its absence the isomeric change takes place.
Volume 35 Issue 2 February 1952 pp 82-88
When boiled with hydriodic acid, 2:3-dimethyl-5:7:8-trimethoxy chromone undergoes besides demethylation, isomeric change also, yielding 2:3-dimethyl-5:6:7-trihydroxy chromone, thus showing that a free hydrogen atom in the 3-position is not essential for this isomeric change to take place and that the nature of the substituent is also important. For purposes of comparison, 2:3-dimethyl-5:7:8-trihydroxy chromone has been obtained by demethylation of the above trimethyl ether with aluminium chloride and 2:3-dimethyl-5:6:7-trimethoxy chromone by independent synthesis using nuclear oxidation as a stage.
Volume 35 Issue 6 June 1952 pp 323-326
A new method of conversion of visnagin into kellin is described. It involves only three steps and gives much better yields. Nor-visnagin is subjected to nuclear oxidation with alkaline persulphate to yield nor-kellin which is conveniently methylated to kellin by means of dimethyl sulphate and potassium carbonate in acetone solution.
Volume 37 Issue 1 January 1953 pp 127-144
A review of ring isomeric change of flavones and chromones is made as also of the reactivity of C-hydroxy phloroglucinol and C-hydroxy phloracetophenone derivatives in methylation, benzoylation and ring closure. The results are consistent showing the greater reactivity of a hydroxyl group of the quinol unit as compared with that of the catechol unit. A tentative explanation is given.
A synthetic study has been made of the chromones of
An attempt has been made to develop a comprehensive scheme of biogenesis which includes all the five components occurring in
Volume 38 Issue 3 September 1953 pp 207-219
Volume 46 Issue 1 July 1957 pp 19-24
A number of α-methyl-furano-flavones and their dihydro derivatives have been prepared using 7-hydroxy-8-allyl flavone derivatives. Ring closure is effected with anhydrous hydrogen bromide followed by pyridine and dehydrogenation with N-bromosuccinimide. 2-Methyl cromone derivatives have also been made. Tests with fish of select compounds indicate that dihydrofurano compounds are better poisons and an α-methyl group reduces toxicity in the furano compounds.
Volume 47 Issue 4 April 1958 pp 230-237
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.