Ergotoxine and some other constituents of ergot : by George Barger and H.H. Dale.

  • George Barger
Date:
[1907?]
Catalogue details

Licence: Public Domain Mark

Credit: Ergotoxine and some other constituents of ergot : by George Barger and H.H. Dale. Source: Wellcome Collection.

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    this process a small quantity of an amino-acid was apparently reformed and became suspended in the ether in fine crystals, which were filtered off. On fractionating the mixture of esters at 9 mm. distillation began at 790, and 3*4 c.c. distilled over below 85°. The thermometer then rose rapidly, remaining for a short time at 126° to 1270 ; a few drops of a somewhat viscid and slightly coloured distillate were collected between 120° and 130°. On further heating, the residue in the flask apparently boiled at a still higher temperature, but it was too minute to be distilled over and underwent decomposi¬ tion. The boiling-point of the lower fraction corresponded very closely to that given by Fischer for leucin ester. The boiling-point of the higher fraction in conjunction with its solubility in water (which excludes phenyl-alanin) indicated that it consisted chiefly of aspartic ester, possibly with traces of glutaminic ester. for identification the leucin fraction was hydrolysed by boiling with twenty times its volume of water for five hours ; plates were obtained apparently identical in all respects with a specimen of leucin prepared from casein. On analysis— OU239 gramme gave 0-2494 gramme CO2 and o'llio gramme H,0. Found: C = 54-68 per cent., H = 9-95 per cent. Calculated for C6H1302N : C = 54-96 per cent., H = 9-92 per cent. The copper salt was wholly insoluble in methyl alcohol, thus indicating the absence of iso-leucin.1 A measurement of the optical rotation in 20 per cent, hydrochloric acid gave the following results :— aD = + 0-79° ; c = 5 %; 1 = I dm ; [a]D = + 15-8° The value given by Schulze for /-leucin under these conditions is Md = + 17'5°- The amount of the fraction collected between 120° and 130° was too small to admit of an attempt at hydrolysis, so the impure ester was analysed as such.