Feb. 20, 1953
COMMUNICATIONS TO.THE EDITOR
1013
CHEMICAL INTERACTIONS OF AMINO COMPOUNDS AND SUGARS. VI.' THE REPEATING UNIT IN BROWNING POLYMERS2
100%) of the carbon dioxide formed originated in the glycine carboxyl group. The ratio of sugar number-one carbon :glycine methylene carbon : Sir: nitrogen was established as 1:1: 1in all of OUT polyIndividual browning reactions were effected mers. The empirical formulas, relative to the between glycine and each of the radioactive sugars glycine methylene group, were calculated and ~-arabinose-l-C'~,~-xylose-l-C'~, and D-glucose- found to be C6.0Hs.402.oNl.o(CH2) (C02H)o.~for the l-Cl4, as well as between each of these sugars in glycine reaction product from D-glucose and (25.0their inactive forms and glycine-l-C14and glycine- H4.701.~N~.8(CH2) (C02H)o.sfor each of the products 2-C14, respectively. The aqueous solutions, 0.125 from the two pentoses. The pentose-glycine M in sugar and 1.25 M in glycine, were heated polymers were essentially identical. All three under a nitrogen stream a t 95' (short of reflux) polymer fractions appeared to have arisen from an for 90 hr. and the evolved carbon dioxide was col- equimolar reaction between the reducing sugar and lected a s barium carbonate. The polymer selected the amino acid effected without apparent carbon for study was the water-soluble, non-dialyzable, chain scission of the sugar, with partial decarbrown solid fraction' obtained in 20-45% yields boxylation of the amino acid, and with nearly comby dialysis, using a cellulose membrane, followed plete trimolar dehydration of the sugar. The by concentration, precipitation with dioxane and repeating unit for the D-glucose-glycine polymer drying under reduced pressure (0.5 mm.) at 56' very closely approximates C6H602N(CH2)(C02H)o.~ for 20 hr. Elementary analyses were carried while that for the pentose-glycine polymers apout on the polymers. The observable specific proximates CSH~ON(H~O)O.S(CH~) (COZH)~.~. activities3 of the polymers and of the radioactive Illustrative of the method used in deriving these reactants were used to calculate the relative number formulas, the reaction of ~-glucose-l-C'~(630 of each type of labeled carbon atom in the polymers counts/min./mg.) and glycine yielded a polymer and also the percentage recovery of the sugar (610 counts/min./mg.) of analysis: C, 56.17; number-one carbons in the polymers. The amount H, 5.60; N, 8.87. The dilution factor (D. F.) of barium carbonate arising from the glycine car- was then: D. F. = (count on polymer) (%C of bons was calculated from the activities of "in- reactant in labeled position)/(count on active finitely-thick" plates, employing an experimentally sugar) (%C in polymer) = 0.115. Two more D. F. determined factor relating these activities to the values, 0.060 and 0.127, were obtained from the glycine activities. The amounts of carbon dioxide reaction of D-glucose with g 1 y ~ i n e - l - Cand ~ ~glycinearising from the sugar number-one carbons were 2-C14, respectively. Combination of these values NOZ.~O calculated from the maximum specific activities of with the empirical formula C ~ . ~ O H ~ . ~ ~and adjustment to unit glycine methylene carbon gave: the barium carbonate and of the sugar samples. In agreement with Mackinney and co-w~rkers,~CHz, 1; C02H, 0.47; C from C1 of D-glucose, who employed uniformly labeled D-glucose and 0.91; total C from D-glucose, 6.00; total polymer C, glycine-l-C14, we find that essentially all (90- 7.47; N, 1.01; H,8.86; 0, 2.93; and thus C C . ~ ~ Hs.3902.oiNi.oi(CH2)(C02H)o.47. (1) Previous communication in this series: T.-L. Tan, M. L. WolThese repeating units approach the sugar defrom and A. W. Langer, Jr., THISJOURNAL, 71, 5090 (1950). hydration stage represented by a 2-furaldehyde(2) This paper reports research undertaken in co8peration with the Quartermaster Institute for the Armed Forces under Contract Nos. glycine condensation product, for the pentose DAll-009-qm-326 and DAll-009-qm-13294 with The Ohio State system, and by a 5-(hydroxymethyl)-2-furaldeUniversity Research Foundation, and has been assigned number 397 hyde-glycine condensation product for that from in the series of papers approved for publication. The views or conthe hexose, but do not require that the furan rings clusions contained in this report are those of the authors. They are not to be construed as necessarily reflecting the views or indorsement of are necessarily present in their intact cyclized the Department of Defense. forms. We are indebted to Prof. J . E. Varner of the Department of (3) Agricultural Biochemistry of this University for assistance in the radiotracer counting techniques. (4) F. H. Stadtman, C. 0. Chichester and G. Mackinney, THIS JOURNAL, 74, 3194 (1952); C. 0. Chichester, F. H. Stadtman and G. Mackinney, ibid., 74, 3418 (1952).
M. L. WOLFROM R. C. SCHLICHT DEPARTMENT OF CHEMISTRY UNIVERSITY A. W. LANGER, JR. THEOHIOSTATE C. S. ROONEY COLUMBUS 10, OHIO RECEIVED OCTOBER 29, 1952
