GUIDOE. HILBERTAND EUGENE F. JANSEN
134
Vol. 30
TABLE I1 TOLANES M. p., ' C .
Substance
Solvent
(con.)
p,p'-Diethyltolane p$'-Di-n-propyltolane p,p'- Di-n-butyltolane 3,3 ',4,4'-Tetramcthyltolane p,p'- Diphenyltolane
71.5-72.5 69 5-70.5 11-42 143-144 243-244
Formula
Methanol Methanol Methanol Acetic acid Benzene
With the low melting tolanes the crude products were oils and were extracted with ether. The ethereal solutions were dried with calcium chloride and the ether evaporated. The residues crystallized upon standing several hours in a vacuum desiccator. Tolane and p,p'-diphenyltolane were prepared by the action of potassium amide on the corresponding dichloroethanes. The yields of crude product were 85 and 9170, respectively. A sample of the p,p'-diphenyltolane was oxidized with ozone by the method used by Harries' for other acetylene derivatives. The acid obtained was shown to be p-phenylbenzoic acid by its melting point and by a mixed melting point with known p-phenylbenzoic acid. In. Table I1 are given the physical properties of the tolanes not previously recorded.
Absorption Spectra.-In studying the absorption spectra a Hilger quartz spectrograph and a Hilger sector photometer were used. A tungsten steel spark was the source of light. The reference line from which the wave lengths were determined was that of iron at 4957 8.units. In Table I11 are given the positions of the absorption bands of tolane aiid substituted tolanes. Chloroethenes show non-selective absorption in the region between 200-280 millimicrons.
Molecular weight Calcd. Found
ClgH18
234
CaoHzz C Z Z H ? ~ 290 ClsHla CzgHts 330
[CONTRIBUTION FROM FIXED NITROGENDIVISIONOF
THE
Rast
270
Freezing benzene
347
Boiling benzene
TABLE I11 POSITIONSOF ABSORPTIONBANDSOF TOLANE AND SUBSTITUTED TOLANES (WAVE LENGTHSIN mfi) Wave length
Tolane Dimethyltolane Diethyltolane Di-n-propyltolane Di-n-butyltolane Tetramethyltolane Dimethoxytolane
298 304 30
CJfaCHBrCOOC2Hs S a , then CHJ ---
CH,CH (COOC,H,), C,II~CHBrCOOC~Hj ---+ C~HK-CHCOOC~HK
which had previously been made.3 Attempts to introduce another methyl group by means of sodium and methyl iodide were unsuccessful. The method which finally gave the desired acid was the reaction between a-bromopropionic ester an.d the sodium derivative of a-phenylpropionitrile, follcwed by hydrolysis. Cl;X.,C(CH,)CN
This triester, which was not known, was identified by analysis, molecular weight determinations, and by hydrolysis to cu-methyl-cr'-phenylsuccinic acid (1) Smith anfi Crawford, T H I S J O U K N A L , 60, 860 (1028). ( 2 ) Hone and Spranklin:, .I. Chem. Soc.. 7 5 , 8X!) (18!39).
CHa
CHI
C&-C-CN
-+
CHa----CHCOOCaHs
C&H6--C --COOH CHa---~CHCOOH
The acid, as first obtained by hydrolysis, melted around 145'. The two racemic forms, when finally separated, melted a t 170-172' and 159160'. The higher melting form is identical with the acid obtained by the oxidation of 2,X,3,(itetramethyl-3-phenplcyclohexene-5-dioneI,&. X o attempt was made to resolve the two acids into optically active forms.
1
CH~-C(COOC~H,)~
+ CH3CI-IBrCOOC&15---+
(sa)
Experimental Mandelic Acid.-This was prepared from benzaldehyde a i i d sodium cyanide hy the, method outlined in "Organic SI-nthrses ' ' I .
Zcliiisky, t k r , 24, 1878 (IS!)]). ( 4 ) "C)rganic S) nllirsci ' ' , I o l i i i Wilry Val. V I . 1' 5s. (:
