Derivatives of glyoxaline-or 4(or 5)-formaldehyde and glyoxaline-4(or 5)-carboxylic acid : a new synthesis of histidine / Frank Lee Pyman.

  • Pyman, Frank Lee.
Date:
[1916?]
Catalogue details

Licence: In copyright

Credit: Derivatives of glyoxaline-or 4(or 5)-formaldehyde and glyoxaline-4(or 5)-carboxylic acid : a new synthesis of histidine / Frank Lee Pyman. Source: Wellcome Collection.

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    residue was mixed with alcohol, filtered from inorganic salts, and evaporated to remove the alcohol. This residue was dissolved in warm concentrated aqueous sodium carbonate and kept, when 3*1 grams of glyoxalineformaldehyde (m. p. 170°) crystallised. The yields of the aldehyde and the acid are 56 and 17 per cent, of the theoretical respectively. (5) Preparation of Glyoxalinecarboxylic Acid.—Seventeen grams of hydroxymethylglyoxaline were dissolved in 100 c.c. of concen¬ trated nitric acid (three times the quantity calculated for its conversion into the nitrate of glyoxalinecarboxylic acid) and warmed on the water-bath in a covered dish until the evolution of brown fumes was almost complete. The liquor was then evaporated to dryness on the water-bath and the crystalline residue dissolved in water. A sufficient quantity (about 45 c.c.) of a cold saturated aqueous solution of sodium carbonate was added until the liquor was only slightly acid to methyl-orange. This caused the separa tion of the bulk of the glyoxalinecarboxylic acid (10*6 grams) as a colourless, crystalline powder which melted and decomposed at 281°. After the removal of this crop, the filtrate and washings were evaporated to a small volume and treated with sodium carbonate until neutral to methyl-orange, a further crop of 3*0 grams of glyoxalinecarboxylic acid (m. p. 275°) being thus obtained. The mother liquor was added to a solution of 12 grams of picric acid in 300 c.c. of boiling water, and after keeping overnight 6*4 grams of glyoxalineformaldehyde picrate (m. p. 191°) separated. The mother liquor was concentrated to half volume and kept, when glyoxalinecarboxylic acid picrate crystallised out mixed with a little picric acid and sodium picrate. It was purified by re¬ crystallisation from water, when 5*0 grams of the pure salt were obtained. The total yields represent 15*3 grams of glyoxalinecarboxylic acid and 1*9 grams of glyoxalineformaldehyde, that is, 82 and 11 per cent, of the theoretical respectively. (c) An oxidation was also carried out with a quantity of nitric acid only slightly greater (using 3*5 instead of 3*0 molecular pro¬ portions) than that calculated for the conversion of hydroxy¬ methylglyoxaline into glyoxalinecarboxylic acid nitrate. In this case the yields of acid and aldehyde were 55 and 29 per cent, of the theoretical respectively.