738
ORGANIC AND BIOLOGICAL.
It was slightly resinified by boiling with potassium hydroxide solution, but i t failed t o reduce Fehling's solution even upon continued boiling. The quantity was not large enough to determin satisfactorily whether a sulfite compound was formed or not, and the attempt to prepare a small quantity of the semicarbazone was unsuccessful. It is dextrorotatory. An aldehyde with the formula C,,H,,O, with two ethylene linkages, would be a n olefin, homologous with geraniol. The name cy@raZ will be given to this compound, as a t present no such homolog of the olefinic camphors is known. As circumstances have made necessary the postponement of this work for several months, the details so far gathered have been given in this paper for the interest of those engaged in terpene-investigations.
Summary. The s u m m a 6 of the physical properties of the two new compounds described is as follows: Cypressme, CllH2(, a yellowish-green, viscous, and almost odorless oil, b. p. 218-22ooS5and 2 9 5 - 3 ~ 0 ~ ~Sp. ~ ~ .gr. 0.9647~~1~. ng 1.5240. [a]'," = 6.53'. Cyfiral, C,,H,,O, a light yellow, mobil, and very fragrant oil of b. p. 182-185'~. Sp. gr. 0.9469~O/,. 7a2p 1.5040. Dextrorotatxy. t O U I S I A N A STATK UNIVERbITY,
BATON ROUGE,LA.
[CONTRIBUTIONS FROM TH& fh3"IELD
LABORATORY OF
YALE UNIVERSITY.]
RESEARCHES ON PYRIMIDINES: SYNTHESIS OF CYTOSINE-5ACETIC ACID.
[FIFTY-FIRST PAPER.] BY
TREATB . JOHNSON (Experimental work by HARLEYT. PECK and JOSEPH A . A M R L E R ) . Received March 21, 1911.
If one considers only the carbon-substitution products of uracil (I), there are two possible uracilcarboxylic and two uracilacetic acids. They are represented by the structural formulas, 11, 111, IV, and V. NH-CO
I
CO
I
kCOOH.H,O
II
NH-CH 11.
NH-CO
r+
+q
I
L-
NH-CO
I
I
CO NH-CO
I
CO
I
/ CCH,COOH II
r-
I
+J
I --1
I
CO
I
CH.H,O
I I1 NH-C . COOH 111.
CH
I
IJ
NH-CH
I.
-1
I L+
NH-CO LO
I
J H .H,O
II
NH-C . CH,COOH NH-CH IV. V. A list of "Papers on Pyrimidines," previously published from this laboratory, is appended to this paper.
759
RESEARCHES ON PYRIMIDINES.
Three of these have been synthesized in this laboratory, viz. :uracil-g-carboxylic acid' (11), uracil-5-acetic acid2 (IV) and uracil-4-acetic acidS (V). The last member of the series, or uracil-4-carboxylic acid (111), was prepared by Muller' and its constitution later definitly established by Wheeler.5 Of the four correspcnding acids of cytosine (VI), only one has previously been described, viz. :cytosine-5-carboxylic acid (VII) , which was synthesized by Wheeler and Johns.6 A description of the synthesis and properties of cytosine-5-acetic acid (IX) will be given in this paper. N = CNH,
I CO I
1 C.COOH I/
N = CNH, C
L-
I
-j
I
I
CCH,COOH
N = CNH,
I
N = CNH, CO
r+
1
I
NH-CH VII.
I
-
+A
1
--
CO
CH.H,O
I
/I
NH--CH VI.
I
1 I
CO
1
CH /I
NH-C.COOH VIII. N = C.NH,
-7
I
L+
I/
NH-CH IX.
I
CO
I
I
CH
'
NH--CCH,COOH.
X. Johnson and Speh7 have shown that the sodium salt of diethyl formylsuccinate (XI) condenses smoothly with pseudoethylthiourea, in aqueous solution, giving ethyl ~-ethylmercapto-6-oxypyrimidine-g-acetate (XV). We now find that this mercaptopyrimidine (XV) reacts with phosphorus oxychloride under proper conditions, without destruction of the ester grouping, giving a n excellent yield of ethyl 2-ethylmercapto-6-chlorpyrimidine-5-acetate (XVI) . Especially interesting was the behavior of this chloride towards ammonia. The corresponding aminopyrimidine (XIX) was not obtained as expected, but it underwent an inner condensation giving smoothly the r-lactam of a-ethylmercapto-6-amino-pyrimidine-5-acetic acid (XVIII), with formation of a molecule of alcohol. This cyclic compound underwent hydrolysis easily, by heating with concentrated hydrochloric acid, giving practically a quantitative yield of the hydrochloride of cytosine-5-acetic acid (XX) . The free acid was then obtained by treatment of this salt with one molecular proportion of alkali, in aqueous solution. Thiourea and diethyl formylsuccinate condensed smoothly, in the presence of sodium ethylate, giving a good yield of ethyl 2-thio-6-oxypyrimiWheeler, Johnson and Johns, A m . Chem. J., 37, 392. Johnson and Speh, Ib
