Hydrolysis of excelsin / by Thomas B. Osborne and S.H. Clapp.

  • Osborne, Thomas B. (Thomas Burr), 1859-1929.
Date:
[1907]
Catalogue details

Licence: In copyright

Credit: Hydrolysis of excelsin / by Thomas B. Osborne and S.H. Clapp. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    The oil-free meal of the Brazil-nut was extracted with 3 per cent ammonium sulphate solution, heated to 50°, and the perfectly clear extract dialyzed until the greater part of the dissolved excelsin was deposited as crystals. These were then washed thoroughly with dilute sodium chloride solution and then with dilute alcohol which was gradually increased in strength up to absolute alcohol. The preparation was then dried over sulphuric acid. Of the perfectly crystallized excelsin thus prepared 500 gm., equal to 450 gm. water and ash-free, were suspended in a mixture of 500 c.c. of water and 500 c.c. of hydrochloric acid of specific gravity 1.19, and warmed in a bath of boiling water for two and one-half hours. The heating was then continued in a bath of oil and the hydrolysis solution boiled for eighteen hours. The esterification of the hydrochlorides of the amino acids and the liberation and extraction of the free esters were then executed in the manner often described. The dark-colored ether extracts were dried in the usual manner with potassium carbonate and anhydrous sodium sulphate. The aqueous layer was freed from inorganic salts in the usual way, and the esterification repeated. As the yield of ester was consider- able, the whole process was again repeated, but this last treatment yielded very little of ether-soluble ester. After distilling off the ether on the water-bath the esters were fractioned under diminished pressure as follows : Temp, of bath Fraction up to Pressure Weight I 5*° 10 mm. 43-55 gm. II 90° 10 “ 32.77 “ III 105° 0.47 “ 9x-65 “ IV 130° 0.40 “ 59-57 “ V 1 70° 0.38 “ 56.83 “ 4'otal The undistilled residue weighed.132 gm. Fraction I. — This fraction consisted largely of alcohol and ether. It yielded, after esterification with alcohol and hydrochloric acid, 2.98 gm. of glycocoll ester hydrochloride, equivalent to 1.33 gm. of glyco- coll. The melting-point was 1440. Nitrogen, 0.4044 gm. subst., required 4.19 c.c. 5/7 N HC1. Chlorine, 0.4158 gm. subst., gave 0.4265 gm. AgCl. Calculated for C4H10O2NCl = N 10.04 ; Cl 25.45 per cent. Found =N 10.36; Cl 25.34