Resolution of the alpha-beta-dihydroxy-alpha-methyl-beta-isopropyladipic acids / by T.A. Henry and H. Paget.
- Thomas Anderson Henry
- Date:
- [1923.]
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.
12/16 page 1887
![condition, for the reason already stated, but after many crystal¬ lisations (1) 8-6 grams of well-crystallised salt, m. p. 207°, [a]D —129*4° in alcohol (a — 4*99°, c = 2*035, l = 1*894), and (2) 6*5 grams of ultimate residue, partly crystalline, were obtained. Fraction 1 proved to be only partly resolved, since the sodium salt of the acid regenerated from it had [a]D — 1*69°. Fraction 2 yielded an acid which melted at 206° and after cooling re-melted at 74°. On conversion into the sodium salt, the latter gave [a]D — 3*95°, —4*11° in water (a — 0*46°, 0*48°; c = 6*3, 2 = 1*894), and the acid regenerated from this still melted at 206°, and showed specific rotation [a]D -j- 9*03 -j- 9*94° in water (a -f-0*20°, 0*22°, c = 1*107), and [a]D + 9-12° in alcohol (a -f- 0*72°, c = 4*17, l = 1*894). The quinine salt made from the pure acid and recrystallised from dilute alcohol melted at 207° and had [a]D — 134*5° in alcohol (a — 7*60°, c = 2*9 8,2 = 1*894). Acid, m. p. 189°.—This acid on conversion into the quinine salt and fractional crystallisation of the latter yielded (i) a small fraction which after purification had m. p. 228° and [a]D — 130*5°, (ii) a large middle fraction which showed varying melting points on recrystallisation, and (iii) a small ultimate fraction, which could not be obtained well crystallised. The acid regenerated from fraction (i), on recrystallisation from water, proved to give a dextrorotatory sodium salt, and on fractional crystallisation from boiling water was separated into the acid of m. p. 205° and the acid of m. p. 187° in about equal proportions. The acid regenerated from fraction (ii) was largely unchanged acid of melting point 189°, whilst that recovered from fraction (iii) gave a laevorotatory sodium salt, and appeared to consist in part of the dextro-form of the acid m. p. 198°. As shown already (p. 1883), results obtained in other ways proved that the acid melting at 189° is a combination of the anti- and para-acids, into which it can be separated. The authors desire to express their thanks to Mr. F. Walton and Mr. S. E. Pusey for much help with the experimental work. Wellcome Chemical Research Laboratories. [Received, June 11923.] Printed in Great Britain by Richard Clay & Sons, Limited, BUNGAY, SUFFOLK.](https://iiif.wellcomecollection.org/image/b30624058_0012.jp2/full/800%2C/0/default.jpg)
