Resolution of the alpha-beta-dihydroxy-alpha-methyl-beta-isopropyladipic acids / by T.A. Henry and H. Paget.

  • Thomas Anderson Henry
Date:
[1923.]
Catalogue details

Licence: Public Domain Mark

Credit: Resolution of the alpha-beta-dihydroxy-alpha-methyl-beta-isopropyladipic acids / by T.A. Henry and H. Paget. Source: Wellcome Collection.

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    prisms which melted sharply with effervescence at 198°, and after cooling re-melted at 72—74°, being reconverted into the dilactone. The oily product did not dissolve completely in 2M-sodium hydroxide solution even after standing several days, or on heating on the water- bath. The liquid was therefore extracted with ether, and the clear alkaline solution on acidification yielded the same acid melting at 198°. Seven grams of the pure acid were dissolved in 250 c.c. of boiling water (forming a supersaturated solution, which only began to crystallise after some days), and crystallised in six fractions, all of which melted at 198° (Found: 0 = 51-08; H = 7-67. Calc, for dihydroxymethylfsopropyladipic acid, C10H18O6, C = 51-27; H = 7-69 per cent.). Mixed with the acid of m. p. 203—204°, the melting point is depressed to 187—189°, whilst a mixture with the acid of m. p. 189° begins to melt at 189°. The oily neutral product extracted, with some of the dilactone, from the distillate by ether, after purification with sodium hydrogen sulphite, distilled at 105—130°/10 mm. or 205—215°/760 mm., and on treatment with semicarbazide yielded two substances melting at 189—190° and 174° respectively. These were separated by crystallisation from alcohol; the former, which is the less soluble, crystallised in pearly plates and was identified as the semicarbazone of tanacetophorone (Found : C = 59-29; H = 8-54; N = 22-59, Calc, for C9H15ON3, C = 59-67; H = 8-29; N = 23-2 per cent.), this being formed, no doubt, from dimethylacetonylacetone by the loss of a molecule of water thus : CJT ‘CJJ, CHMe2-CO-CH2-CH2-CO-CH3 -> CHMe2-C<CHL(i;02- The second semicarbazone, m. p. 174°, crystallised in colourless needles. It was obtainable only in small amount, showed no depression in melting point when mixed with tanacetophorone- semicarbazone, and is possibly the latter with some persistently adherent impurity (Found : C = 58-61; H = 8-48 per cent.). Separation of the Acid of m. p. 189° into the Acid of m. p. 198° and the Acid of m. p. 203—204°.—One gram of the acid of m. p. 189°, obtained by the oxidation of a-terpinene, was boiled for forty-five minutes with 20 c.c. of concentrated hydrochloric acid, and the solution diluted with water and steam distilled, yielding 0-44 gram of crystalline dilactone, m. p. 72—74°. From the residual liquor in the flask, 0-53 gram of acid was isolated, which on recrys¬ tallisation melted at 204°. The dilactone on hydrolysis by alkali yielded the calculated amount of the acid of m.p. 198°. In a second experiment, from 3-5 grams of the acid of m. p. 189°, 1-6 grams of dilactone, m.p. 72—74°, were obtained. Conversion of the Acid of m. p. 203—204° into the Supposed Liiactone, m.p. 62°.—Wallach stated that this acid was readily
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