420 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS /•amino ethyl morpholine or fiamino propyl piperidine. The substitution is followed by quaternization of the tertiary amine. A grey dye has been synthesized by substituting only the hydroxy groups in the 2- and 4-positions of the 1,2,4-trihydroxy anthraquinone by N,Ndimethyl pphenylene diamine, and by subsequent quaternization. We have also widened the range of shades obtained up to now with this type of quaternary compounds, by synthesizing new yellow dyes. These may be obtained from the 2-chloro anthraquinone and diamines mentioned above. Nevertheless, the yields are rather low as the fichlorine atom in the anthraquinone ring is not so mobile as that in a position. It is more advantageous to start with •amino anthraquinone for instance, the reaction of •amino anthraquinone with N,N-diethyl amino ethyl chloride gives an excellent yield. In our opinion these dyes possess the following advantages: Good solubility, possibility of dyeing over a wide pH range, good resistance to sunlight, no dermatological action. It should also be emphasized that solutions of these dyes--in which quaternary amino groups form part of an heterocyclic nucleus such as morpholine or piperidine--have the great advantage of never developing unpleasant odours on storage. This was the main reason for studying these types of dyes. DISCUSSION MR. A. J. M. VERHAAR: The hydroxy anthraquinones which you use as starting materials remind me of two well known hair dyes: Lawsone and Juglone, 2- and 5-hydroxy naphtoquinones, respectively. Have you ever tried to make quaternary ammonium derivatives from these compounds ? (As these molecules are smaller, one would expect a better penetration into the hair shafts than with anthraquinone derivatives). THE LECTURER: No. MR. A. J. M. VERHAAH: Most quaternary surface active substances are rather strong eye irritants. Do you have any data on eye irritating effects of your quaternary dyes ? THE LECTURER: Tests on rabbits' eyes using the Draize method proved these dyes to be completely innocuous. MR. A. J. M. VERHAAR: It is one of the great advantages of oxidation hair dyes that the hair is bleached while it is dyed. This is not only necessary when the hair is to be tinted in a lighter shade, but also when another shade of the same depth is wanted. Are the quaternary anthra- quinone dyes resistant to bleaching conditions, particularly to an alkaline medium and hydrogen peroxide ?

SYNTHESIS O• SOME NEW QUATERNARY DYES 421 THE LECTURER' Simultaneous bleaching and dyeing with these dyes is a perfectly compatible operation. DR. V. B6•.•.ERT ' Can you tell us something about staining of the skin by that sort of dye ? TaE L•.CTUR•.R ' These dyes have indeed a certain affinity for the skin, but it is possible to lower it, as for instance by introducing nonionics into the formulation. DR. J. F. CORBETT' Could you tell us whether there is any significant difference in the dyeing properties between the various yellow dyes des- cribed in your communication ? Was there any particular purpose in your choice of the quaternizing agent ? TaE L•CTURER ' The shade varies with the length of the chain separating the two amino groups, and the presence or absence of a heterocyclic ring does not play any significant part in relation to the shade, e.g. Series I• yellow dyes' (a) Methyl [2-(/•methylmorpholinium) ethylamino-anthraquinone] sul- phate--(n = 2) • max = 455 yellow. (b) Methyl [2-(/•methyldiethylammonium) ethylamino-anthraquinone] sulphate--{n •- 2) A max : 456 yellow. (c) Methyl [2-(/•trimethylammoniurn) propylamino-anthraquinone] sul- phate•(n = 3) ,1 max = 470-472 orange-yellow. Similar observations were made with the violet dyes' (a) Methyl [1-hydroxy 4-(/•methylmorpholinium) ethylamino anthra-- quinone] sulphate--(n = 2) is purple, whereas (b) methyl [1-hydroxy 4-(ymethyl piperidinium) propylamino-anthra-• quinone• sulphate--(n = 3) is violet. On the other hand, the shade is not modified markedly by the choice of quaternizing agent. I wish to mention that our choice of morpholine and piperidine derivatives had been made on the basis of their behaviour on storage, as these substances do not develop unpleasant odours. PRO•. C. S. WHEWV.•.•. ß Could you give any indication of the mechanism by which these dyes are attached to the hair ? Is the positively charged nitrogen atom important, and if this is so, have you prepared any other compounds which are colourless ? Such compounds will obviously be im- portant as softening agents, antistatic agents, a.s.o. THE LECTURER ' It is assumed that the great affinity of these quaternary