Sir Wyndham Rowland Dunstan 1861-1949 / [Thomas Anderson Henry].

  • Henry, Thomas Anderson, 1873-1958.
Date:
1950
Catalogue details

Licence: In copyright

Credit: Sir Wyndham Rowland Dunstan 1861-1949 / [Thomas Anderson Henry]. Source: Wellcome Collection.

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    o hon:c ch2-nh -o (Cash and Dunstan, Phil. Trans., 1893, B, 184, 505). A side issue of this work was the observation by Dunstan and Dymond (Proc. Chem. Soc., 1888, 117; J., 1891, 59, 410) that the action of alkali on nitroethane produces acetonitrile, nitrous acid, and 3:4: 5-trimethyksooxazole, the last a type of compound first prepared by Claisen and Lowman (Ber., 1888, 21, 18, 1149). With nitromethane, alkalis produce, not an isooxazole, but methazonic acid, C2H403N2, a substance first obtained by Lecco (Ber., 1876, 9, 705). It was prepared and examined by Dunstan and Goulding (J., 1900, 77, 1262) who, mainly on the ground that on hydrolysis by alkali or acid it produced carbon dioxide, hydroxylamine, and hydrocyanic acid, proposed for it the annexed formula, but shortly afterwards Scholl (Ber., 1901, 34, 862) suggested that it might be regarded as a nitrogen analogue of acetoacetic acid and formulated as CH2!NOCHINO*OH, and later Meister (Ber., 1907, 40, 3435) recorded a number of new reactions for the acid and claimed that it could be represented as H0N!CH*CH2‘N02, or as its conjugated tautomeride HO*NICH*CH!NOOH. About this time the long-continued discussion on the isomerism of aldoximes was beginning and Dunstan and Dymond showed that acetaldoxime, b. p. 114‘5°, was a mixture of two forms, one crystalline, m. p. 46'5°, and the other liquid, of which the latter was not obtained quite free from its isomeride. Both were interconvertible and much less stable than the two benzaldoximes but such experimental evidence as could be obtained indicated that they corresponded to the anti- and syw-aldoximes respectively. Propaldoxime and zsobutaldoxime were also each separated into anti- and syw-forms (/., 1892, 61, 470; Proc. Chem. Soc., 1892, 135; /., 1894, 65, 206; cf. Carveth, J. Physical Chem., 1898, 2, 159). In the period 1896—1901, in collaboration with E. Goulding, Dunstan published six papers dealing with the action of alkyl halides on hydroxylamine and on oximes. With the former, action is most complete with methyl iodide, which produces di- and tri-hydroxylamine hydriodides, and trimethylhydroxylamine hydriodide, (CH3)3NO,HI, later called trimethyloxamine or trimethylamine oxide hydriodide. With ethyl, w-propyl, or isopropyl iodide only the dialkylhydroxylamine is formed at the first stage but the triethyl compound can be got by further action of the alkyl iodide, though this does not happen with the di-w-propyl and diisopropyl compounds. These trialkylated substances were the first examples of aliphatic amine oxides, and it was later found that they could be produced by the action of hydrogen peroxide on trialkylamines and that by like means dialkylaminfes could be converted into the dialkylhydroxylamines (Alk)2N*OH, except in the case of dimethylamine, which instead was oxidised to formaldehyde and formic and nitrous acids (/., 1896, 69, 839; 1899, 75, 792, 1004; 1901, 79, 641). Also, with E. Goulding as collaborator, Dunstan investi¬ gated the action of alkyl iodides on a series of aldoximes and ketoximes alone and in presence of sodium methoxide in methyl alcohol. In the former case A'-alkyl derivatives, then represented r~0_i as alkylisooximes, e.g., the alkylisoaldoximes R*CH—NR', were alone formed, whereas in presence of alkali the isomeric ethers, e.g., the alkylaldoximes, R'CHUNhOR', were also produced, the relative proportions of the two isomerides varying with the nature of the oxime and the alkyl iodide used (/., 1897, 71, 573; 1901, 79, 628). Of the remaining investigations probably the most important is that of the aconite alkaloids, on which eighteen papers were published during 1891—1905, with several collaborators, notably W. H. Ince, J. C. Umney, F. W. Passmore, F. H. Carr, H. A. D. Jowett, E. F. Harrison, T. Tickle, H. M. Read, and A. E. Andrews. The early workers on aconitine, Alder Wright in this country and Jurgens in Germany, adopted for the alkaloid the formula C33H43012N or C33H47012N, and C33H45012N was found by Dunstan and Ince. Up to that time aconitine had been regarded as benzoylaconine, isomeric with the substance variously named picraconitine, isaconitine, or benzaconine. In 1892 Ehrenburg and Purfurst (J. pr. Chem., 1892, 45, 604) showed that, when heated dry, aconitine loses acetic acid, and this was later confirmed by Dunstan and Carr (J., 1894, 65, 176) who isolated and characterised the resulting pyraconitine, C31H41O10N. Mean¬ while Freund and Beck (Ber., 1894, 27, 433, 720) had found that the empirical formula of aconitine should be C34H47011N, which after some discussion was accepted by the English workers, and both protagonists agreed that aconitine was acetylbenzoylaconine. It thus became the prototype of the highly toxic diacylaconines characteristic of many aconites of which pseud?iComt\r\e from Nepaul aconite was shown to be acetylveratroyl/>s£wdaconine (Dunstan and Carr, /., 1897, 71, 350), indac.onitine from A. chasmanthum to be acetylbenzoyl^sewdaconine (Dunstan and Andrews, J., 1905, 87, 1620), bikhaconitine from A. spicatum to be acetylveratroyl- bikhaconine (Dunstan and Andrews, ibid., p. 1636), and japaconitine from'Japanese aconite to be acetylbenzoyljapaconine (Dunstan and Read, J., 1900, 77, 49). All these alkaloids and certain of their derivatives were examined pharmacologically by Professor Cash, and the detailed results