Norm
m.1
VOl. 64
The Alkylation of Linseed Oil
dation. The analytical data are given in the tabulation. With an average of 1.1 active CH2-- groups, The structures of linoleic and linolenic acids condensation with 1.1ethyl groups should be exwhich are present in linseed oil, have been indi- pected, forming an ethylated methyl ester of the cated as having the =CHCH2CH= g r o ~ p i n g . ' ~mixed ~ ~ ~ acids. The fair agreement of the deterit occurred to the authors that the CH2- portion mined iodine number with the calculated value of the grouping might be active enough to show (an approximation) is evidence of reaction. The the reactions of active methylene groups, as lower values for refractive index are also evidence shown by such compounds as cyclopentadiene, of reaction. Furthermore, it was believed that malonic ester and others. if alkylation had occurred, the alkylated esters The first evidence of reaction which it is de- should give a negative fulvene reaction whereas sired to report a t this time is a reaction analogous unalkylated ester should be positive. This acto that of malonic ester. For this purpose an tually was the case. Again, confirmation of the alkali-refined neutral linseed oil was converted fulvene test was obtained by oxidation tests, where to the mixed methyl esters directly by alcohol a dark red color was produced in the original interchange. An excess of absolute methanol, methyl ester but no appreciable darkening in the containing hydrogen chloride was added to dry alkylated methyl ester. The oxidation presumes linseed oil and refluxed until the reaction was com- the formation of a --CO- group, according to plete. The mixed methyl esters after purification S ~ h e i b e r . ~The oxidized portion should in turn were distilled at 200' under 6 mm. pressure. condense with unoxidized oil to give the fulvene Approximately 0.1 mole of these mixed methyl color reaction. esters was treated with 0.1. mole of sodium eth'This study is being continued on pure methyl oxide dissolved in excess absolute ethanol, and linoleate and pure methyl linolenate. refluxed a t 60" for about ten minutes. To the ( 4 ) J Scheiber, Farbe ZL L a c k , 477 (1929), 585 (1929) cooled mixture in the flask, 0.13 mole of ethyl LEHIGH UNIVERSITY iodide was added gradually, with thorough shak- BETHLEHEM,PA RECEIVED SEPTEMBER 3, 1942 ing. This reaction mixture after heating at 90" - _______on the water-bath for forty minutes, was alThe Oxidation of Amino Acids by Hydrogen lowed to stand overnight. The excess ethanol Peroxide in Formic Acid and ethyl iodide were distilled and the remaining BY GERRITTOENNIES AND RICHARD P HOMILLER solution filtered. The filtrate was dissolved in ether, washed with brine, then water, and dried. It has been shown' that the action of hydrogen After removal of the ether, the major portion dis- peroxide on casein dissolved in formic acid cause? tilled at 2 0 3 O and 14 mm. pressure, as a very pale, a selective oxidation of its tryptophan, methiohighly mobile liquid. This procedure was fol- nine and (partly) cystine units. As regards the lowed closely on two other runs. A11 of the effect of other acid oxidizing agents on the natusamples were kept under nitrogen to prevent oxi- ral amino acids Williams and Woods2 stated that of 16 samples tested only cystine, tyrosine Iodine No. (Wijs) Refractive Determined l'heoreticala index and tryptophan were oxidized by iodic acid (at Linseed oil 192.0 ... 1,4811 loo"), and Xicolet and Shinn3 showed that Mixed methyl esters 186.0 .. 1,4&32 periodic acid selectively attacks tryptophan, Alkylated esters A 170.9 167.0 I . 4616 methionine and cystine, as well as the a-hydroxy 1.4619 Samples B 1.78.1 amino acids. Since, however, according to the 1.4613 ;e 183.1 same authors the latter type of compound seemed 1.4616 Av. 177.1 to be protected against the oxidation by acylation " The theoretical iodine number was calculated on the or by peptide formation through the amino group, assumption that linseed oil contains 60% linoleic acid, with one active CHz- group and 2570 linolenic acid, with and since our own observations1 on the action of performic acid (the product of interaction of hytwo active CH2- groups. drogen peroxide and formic acid), which showed ( 1 ) Erdmanri, Bedford and Raspe, Bcr., 43, 1334 (1909). BY JUDSON G. SMULL AND
JOHN
S. SAYLOR
( 2 ) Goldsobet, Chem. Zfg., SO, 826 (1906). (:I) Hilditch arid X'idyarthi, Pvoc. R o y . S o c . (1.ondon). A143, 563 [ 19291.
(1) Toennies, J . B i d . Chem , 146, 667 (1942) (2) Wiiliams and WOOdS, THISJ O G R h A L , 69,1408 (1937) (4) Nicolet and Shrnn, r b d , 61, I b l J (14.24)
