The preparation of adrcnoluti~i monohydrate in pure crystallirie for111 has been carried out fly the a1l;alinc rearrangement of aqlreous solutions of adrcriochro~nc, prepared from the silver oxide oxidntio~l of aclrenaline in aqueous solution. AII anion-exchange resin (Dowes-l (C1-)) was employeti to renlove inorganic coutan~inarits froni the reaction mixture prior to treatment with allcali. The pure anhydrous material has been prepared by the high vacuum sublimation of the rnoriol~ydrate. The paper cl~rou~atograptiic, spectroscopic, and Rc~orin~etric characteristics of aclrenolutin have been invcstigatecl. On the basis of the ilifrarecl s p c c t r~~~n it is suggestecl that ill the solicl state, atlrcnolutiri exists in the Iccto form, i.e. 2,s-dit~ydro- 5,6-dil~ydrox)~-N-~netl~yl-3-lictoincloleThe infrared spectrum of adrenochron~e, in the solid statc, agrees with the zwitterionic for~nulatiori si~ggestccl for this compound.Adrenoluti11 (usually formulated as 3,5,6-trihydroxy-i\i-methylindole, I ) , the substance mainly responsible for the intense yellow-green fluorescence that develops in adrenaline solutions that have undergone oxidation in alltaline media, ~v a s first isolated in crystalline form and correctly identified by Lund in 1949 (I), from the alltaline real-rangement products of adrenochrome (11), although the correct structure had been assigned to the substance on theoretical grou~lds a year earlier (Ehrlen (2)).

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The paper chro~natographic behavior of several 5,6-dihydrosyindoles has been studied. The colors given by nine dihydroxyindoles with 16 chrornogenic reagents are reported. The R, values of this group of compounds on Whatman No. 1 paper with 2% acetic acid in water or n-butanollacetic acid/water (6:1:2) as running solvents have been determined. The 5,6-dihydroxyindoles can be chromatographed satisfactorily using ZaHaroni-type systems (i.e. formamide-treated paper and non-polar running solvents). Satisfactory R, values can also be obtained for the 5,6-diacetoxyindoles on formamide-treated paper using a suitable non-polar mobile phase. The preparations of several new 5,6-dihydroxyindoles and 5,6-diacetoxyindoles are described and improved procedures for the syntheses of some known members of these groups are reported.The importance of the 5,6-dihydroxindoles as intermediates in the production of the dark pigillents known as melanins, in plants and animals, has been recognized for some time (for references see reviews by Lerner (I), Mason (2), and Thoinas (3)), but it is only in relatively recent years that many of these highly reactive compounds have been obtained in pure crystalline form (see (3) and (4) for references). Although there has been a considerable voluine of work carried out on the chromatography of the indoles in the past decade, there have been relatively few studies reported of the paper chromatographic behavior of the 5,6-dihydroxyindoles and their derivatives. In a study of the urine melanogens observed in cases of malignant melanoma of the liver, Leonhardi reported the R J values of some 5,6-dihydroxyindole derivatives (e.g. 0-acetyl, 0-methyl, 0-sulphatoxy, etc.) in several different solvent systems. These compounds were employed as models for the urinary melanogens which were considered by Leonhardi to be 5,G-dihydroxyindole derivatives (5). During an investigation into the metabolism of P-(3,4-dihydroxyphei1yl)-alanine in albino rats Pellerin and D'Iorio obtained a product with a RJ of 0.85 in a n-butanol/acetic acid/water system which they suggested was possibly 5,G-dihydroxyindole (6).One of the main difficulties encountered in carrying out paper chromatographic studies with the 5,G-dihydroxyindoles is the ease with which they undergo destructive oxidation to inelanitic pigments, especially under alkaline conditions; consequently basic solve~lt systems, including the isopropanol/aqueous ammonia systeills widely favored for indole chromatography, are quite useless with this group of indole derivatives. In an investigation of the reduction of adrenochrome with various reducing agents, carried out in these laboratories (7,8,9), we have made extensive use of paper chromatographic procedures in the examination of the reaction products. R4any of the products encountered in this program were either 5,G-dihydroxyindoles or their derivatives, and one of the most satisfactory systems for the study of these reaction mixtures was found to be 2% acetic acid in water using chromatographic paper ...

The mixture of products obtained when skatole is oxidized with the ferrous sulphate – ascorbic acid – EDTA – air system has been examined by means of paper and thin layer chromatographic techniques. 3-Methyloxindole, o-aminoacetophenone, N-formyl-o-aminoacetophenone, and the four isomeric hydroxyskatoles have been definitely identified. A number of, as yet, unidentified compounds, which react positively with Ehrlich's reagent, are also present in the reaction mixture. The mechanism of the hydroxylation reaction and its possible physiological significance are discussed.