a method for the determination of uronic acids 775 by the direct action of hydriodic acid and phosphorus upon the following: 2-quinolone-4-carboxylic acid; hydantoin-( 5|3')-oxindole; hydantoin-(A5,3,)-5',7'-dibromoxindole and 2,5-diketopiperazine-(A3,6,3,,3')-di-(oxindole). The ethyl ester of the acid is formed by the action of tin and alcoholic hydrogen chloride on 2-quinolone-4-carboxylic acid.4. 5-Bromo-isatin, and 5,7-dibromo-isatin will condense with hydantoin and also with diketopiperazine.
EXAMINATION OF STARCH AND HEMICELLULOSE EXTRACTS FROM APPLE WOOD' This brief statement is presented in the hope that it may prove of service to those having occasion to determine starch and hemicellulose in woody tissues. Omitting citation of specific cases, mention may be made of prevalent dissatisfaction with the current method of expressing these fractions in terms of reducing power of their extracts. The observations were made on apple branches of one year's growth, with bark attached. Samples were ground to pass a 100-mesh sieve. After the usual extractions by ether and hot alcohol, the starch fraction was removed by use of salivary amylase. The hemicellulose fraction was extracted subsequently by boiling in 2.0 per cent. H2SO4 for one hour. Based upon the nearly equal reducing power of the common hexoses and pentoses, and the similarity of their anhydride factors, the reducing power of these extracts has been expressed as hexosan. In a preliminary series of samples the percentage of glucosan in the material extracted varied as follows: Sugar fraction 23.5 to 42.7, av. 30.3; starch fraction 41.9 to 88.5, av. 67.6; hemicellulose fraction 16.1 to 35.6, av. 26.9. In another series of samples the starch and hemicellulose extracts were analyzed for contents of pentosan, uronic acid anhydride, crude protein, and ash, in addition to the usual determination of reducing power. Using the CO2 yield in distilling with 12 per cent. HC1 as a measure of uronic anhydride, it has been assumed2 that the latter would yield 16.7 per cent.
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