Colouring matters of the Aphididae. Part XIX. Further reactions of the Erythroaphins

Abstract

In addition to the ery throaphins-/6 and -si a third isomer, -tt {trans-trans), is known. This isomer and several of its derivatives have now been studied in more detail. Its reactions are similar to those of the sl isomer, in that it undergoes dihalogenation without, and diamination with, epimerisation to fb derivatives. The erythroaphins have been reductively methylated to tetramethyl ethers. Unlike other halogeno-atoms, chloro-substituents in erythroaphins are stable to reduction and tetra-acetyldichlorodihydro- and tetramethyldichlorodihydro-derivatives have been synthesised. Mild acetyl-ation of diaminoerythroaphins yields diacetamido-derivatives, and more vigorous treatment is necessary to acetylate the peri-hydroxyl groups.