Iso amygdalin and the resolution of its hepta-acetyl derivative / by Frank Tutin.
- Tutin, Frank.
- Date:
- [1909?]
Licence: In copyright
Credit: Iso amygdalin and the resolution of its hepta-acetyl derivative / by Frank Tutin. Source: Wellcome Collection.
5/10 page 665
![racemised, and when the acetyl groups are removed by mineral acids dextrose is also liberated. Experimental. The amygdalin employed was obtained from Kahlbaum. After drying for a short time at 120°, it melted at about 220°, when heated semewhat rapidly. The temperature at which fusion occurs, however, depends entirely on the rate of heating: 0*4054, made up to 20 c.c. with water, gave aD - 1°32' in a 2-dcm. tube, whence [a]D -37 ’8°. The material was twice recrystallised from dilute alcohol, and then dried for two hours at 120°, when the weight was constant, no appreciable change in colour occurring : 0*4247, made up to 20 c.c. with water, gave aD - 1°37' in a 2-dcm. tube, whence [a]D - 38*0°. The rotation of isoamygdalin was determined by dissolving 0*4597 of anhydrous amygdalin in 20 c.c. of water containing a little ammonia. After standing overnight this solution gave aD - 2°25' in a 2-dcm. tube, whence [a]D -52*6°. These values for the specific rotations of amygdalin and fsoamygdalin, -38*0° and -52*6° respectively, are somewhat higher than those given by Caldwell and Courtauld (loc. cit.) for these substances ( - 35*5° and -47*6° respectively), but the latter figures probably refer to the hydrated material. Before conducting experiments with hepta-acetyhsoamygdalin, a quantity of amygdalin was acetylated for the purpose of comparison. It is stated by the above-mentioned authors that hydrated amygdalin may be completely acetylated by boiling it for two hours with ten times its weight of acetic anhydride. The following method of prepar¬ ing hepta-acetylamygdalin is, however, much more rapid and convenient. Amygdalin was heated with an excess of acetic anhydride, and a trace of d-camphorsulphonic acid added (A. Reychler, Bull. Soc. chim. Belg., 1907, 21, 428). A vigorous reaction then takes place and the mixture boils spontaneously, acetylation being complete in about one minute. The greater part of the anhydride was then removed by dis¬ tillation, and the residue diluted with about five times its volume of ether. Pure hepta-acetylamygdalin separates immediately, and the yield is almost quantitative. The product thus obtained melted at 166—167°, and, when recrystallised from alcohol, formed long, glistening needles : 0 4074, make up to 20 c.c. with chloroform, gave aD - 1°32' in a 2-dcm. tube, whence [a]D -37*6°. 0*4065, made up to 20 c.c. with ethyl acetate, gave aD — 1°23' in a 2*dcm. tube, whence [a]D -34*0°.](https://iiif.wellcomecollection.org/image/b30614405_0005.jp2/full/800%2C/0/default.jpg)
