GRIGNARD RFACTZON ON PHTHALIC ACID DERIVATIVES. [CONTRIBUTION
FROM T H E C I l E M I C A L LABORATORY OF
2333
THE RICEINSTITUTE.]
HE REACTION BETWEEN PHENYL-MAGEJESIUM BROMIDE AND THE ESTERS OR ANHYDRIDE OF PHTHALIC ACID. BY LLOYD B. KOWBLL Received July 26, 1920.
It is the commonly accepted fact that the so-called Grignard reagents, R-Mg-X, react with esters to give tertiary alcohols. But an examination of the literature concerning the condensation between the Grignard reagents and certain derivatives of phthalic acid, viz.,the methyl and ethyl esters and the anhyclride, shows some discrepancies. All workers agree that the product of the reaction of 2 moles of a magnesium alkyl, or aryl, halide and phthalic anhydride, or phthalic esters, is a mixture' of a R
VR phthalide (general formula,
/c\ 0
) and an orlko diketone (general
\c/
I1
0
0
I1
/I
formula,
-C-R -C-R
>. The reaction of Grignard reagents in yet higher
/I 0
molecular quantities, however, has been variously reported. In I go5 and I:906, Guyot and CatelZ showed that phenyl-magnesium bromide in excess (over 3 moles) acted normally upon dimethyl phthalate, or phthalic anhydride, to give the tertiary alcohol triphenyl-hydroxy-a, a'-benzoCtHs CsHs
\/ -
p,fl '-dihydro-furfurane,
0
.
But in 1909 Shibata4 reported
OH
that excess of the same Grignard reagent, reacting with diethyl phthalate, CIHB CsHr
v
produced a phthalan derivative of the structure,
/c\
Shibata
\c/o. %H4 Ber., 38, 240 (rgog). 3 Guyot and Catel, Compt. rend., 140,254(1905); Bull. SOG. chim., 131 35,554 (1906). 1
8
Shibata. J. Chem. Soc., 95, 1449 (1909).
2.334
E,I,OYD B.
aow-ar.,.
h a some reason failed to give any re(-ognitinn 1 o the previous work of Cr.uynl
and Catel and made the statemeait that no tertiary alcohol was Iurpwd, but instead, the dehydration product shown shove. Both the and Japanese moorkers clainred that a large exccss of plienyl n ~ a ~ n ~ bromide must be employed, arid the latter daimcd that it was this e’xcess which brought about the ddrycli ation of the expected product. It has been fouod that the differences in the lr~sultsobtained mere due to the varioils m e t h n d ~of isolatiorr cmp’q-ed Chyot and Catel, after making the condensation between dimelhyi phLhalale and phenyl-mag nesiurn brom-ide a d hydrolyzing the product in the usual manner, crystaEzed their poduct from tne ctkier or benzene 59htion. The solid obtaintd melted a t 11%’. SLibnta nrade the condematiun with the diethyl ester in practically the same manner, btrt foiin.d it necessary to isolate t!ie product by distillation under diminished pressure after impurities Ji,ad been expelled by distillatiorr with steam. Eis product had a meltiiig poillt Qf 19.1.’. The preparation of triphenyl hydroxy-a,a‘-benLo B,P’-dihydao-furfurane from either dimethyl or diethyl phthalate has been found. poqsible. It can be made also from phthalic anhydride, although with more difEcu1t.y Furthermore, it has been shown that the c ~ ~ l l p ~ uofn d Shibaia can bc prepared from either the dimethyl or the diethyl ester. Moreo~ed-,it is found that if the tertlary alcohol obtained by Guyot and Catel be heated to a temperature required for distillation under diminished pressure (280’ to 300’) it is dehydrated axid yidds the compound which was obtained by Shibata. In the isolation of the t r i p h e n i . I - h y ~ o x y - a , c r ’ - b e n z o - P , P ’ - d i b u- ~ furane much difficulty is comnionly experienced Gvea if ~ ~ ~ s t a ~ ~ ~ z ‘ ~ is attempted after driving off such volatile impurities as benzene, bromobenzene or diphenyl, an clmorphous jelly or a glass like inass i s apt to be the only result. ’I‘kis was found to be true in many trials. In one case crystal.; failed to form in the viscous mother l i ~ p until ~ r it bad stood for over 2 years, notwithstanding the use of all ordinary mews of starting such processes. When a kew crystals have been obtained acd purified, the process of ““seding out” i s very advantageous. It was no doubt because of s ~ c hdiscouraging results, not mentioned by Guyot a i d Catel, that Shibata had recourse t o destiliati~n,~ ~X~~~~~~~~~~~~ Part* ration of Triphe~yY-hyd~axy-a,cx’-benzo-P,P1-dibquc9Po-f~~~~~~ Diethyl ~ ~-In a 1000 t cc. iovnd-bottom ~ ~ flask pro~ ~ vided with ail efficient, reflux condenser, 19.2 g. (I! nioles) of efpy magnesium turnings, covered by a large excess of anhydrous and alcohol-free ether, W ~ Slowly Created with rzj 6 g. (8 xlaolr,~) of dry r;reonobromoPreksasar Roger Adatlgs, os the Un;vessity af Sllinprs ha? called the attentaw a i
GRIGNARD RBAC’L’ION
ON PNTHALXC ACID DERIVATIVES.
2335
benzene. After the resulting “Grignard” solution had been refluxed for ‘ / z hour it was cooled and 23 g. (one mole) of freshly prepared diethyl phthalate in 50 cc. of anhydrous and alcohol-free ether was added very slowly from a separatory funnel (total time, one hour) while the mixture was shaken constantly and the Bask was cooled by ice-water. Each addition caused a yellow solid to form, but this dissolved instantly in the ether. The solution gradually darkened from yellow to brown. When the condensation was complete, the magnesium-ether complex was hydrolyzed as usual, by pouring it into slightly more than the calculated amount of hydrochloric acid dissolved in a large volume of well iced water while the sohtion was stirred. The ether was then removed, dried over anhydrous sodium sulfate for a few hours, then decanted and allowed to evaporate spontaneously in a loosely covered dish. The ether solution thus obtained passed through a remarkable series of color changes. -4.t first i t was light orange in color and fluorescent. Then it changed in 1 2 hours to a deep purple hue and finally, after 24 hours, the color faded to reddish-purple with a remarkable green fluorescence. When practically all of the ether had evaporated, the iesulting viscous yellow oil was d o w e d to stand for several weeks. After about a month, slow crystallization commenced. From time to time the crude crystals were separated from the semi-fluid, jelly-like mass, washed with a trace os’ ether an a porous plate and allowed to stand overnight in a thin layer. ’When, subsequently, they were recrystallized twice from a mixture of equal volumes of toluene and chloroform, they gave a sharp melting point of 118”(c0rr.). From nearly all other common solvents, such as ether, alcohol, acetone and benzene, the material failed to emerge in crystalline condition but reverted t o the original jell or amorphous glassy mass. eparation of a Compound (C& 180 m. p. rg2-3”) from Dimethyl htksalate.-The Grignard reagent (slightly more than 5 moles) was
the writer to the fact that the structure,
0 , assumed Tor the product by
Shibata, involves the peculiarity of a 3-membered ring and a &membered (aromatic) ring with one side in common Such a structure is entirely unprecedented elsewhere in the literature, atid work undertaken at both the University of Illinois and The Rice Institute, indicates the possibility of an entirely different structure for the dehydration product of triphenyl-hydroxy-a, ai’-benzo. P,@’-dihydro-furfurane.
preprered as described above mitL 12.8 g. of magxesitim ittrnirigs a m 83 j g. of monobromo-berr~e~~e. This product was C C J ~ ~ ~with. W Xil KI g. (0.6: nmfe) of freshly prepared diimthyl phlhalate ill a rmnner siniiiar t u that used with the diethyl ester. T o isolate the product after hydrolysis, the oil obtained from the ether WBS transferred a t once to a large fiaslr and distilled in a slow current GE steam until about 5 liters of dirtillate (vvater, some bromo-beiizerte, hcnzene and diphenyl) had passed over. The deep ycllow oil, after it coolt-d, set to a dark and brittle cake. it was broken up arid subjected t o dttillattion under. 26 inm. pressure in a 50-cc. Claisen flask. The dark oil "bumped" badly, and distilled, with violelit foaming, between zgo" and 3ooo. The distillate showed little tendency to crystallize when cold, b u t it was found that the addilior, OS a little eiker was very efIectivc in carising crystallization to start. After the crude light-brown product was crushed and ''worked" with a little ether ora a porous plate, it was recrystallized 3 times from tduenc. The crystals were nearly white (slightly grayish) and melted sharply at 192-1 93 O (stem immersed). This compound was identified as that p p a r e d by Shiibata, b y a mixed an. p. deterniinal ion with analyzed material made from diethyl phtllakile according to his procedure. ation of ~ ~ ~ p ~ e ~ y ~ - ~ ~ sting.-A iew g. of crystallized triphenyl-hydroxy-a,aibenzo-8,Pf-dihydro-iur~urarae was slowly heated under reduced presswe (26 mm.) in a Wood's metal bath. The crystals melted ti) yield a colorless oil a t 119'. This oil slovrly darkened t o a yellow color a t 16o*, to deep yellow with a green fluoresceiice at about I yoo, t o red-brown at 2 0 0 " and t o dark amber, with fluorescence persisting, above 3j o o (temperature of bath). The bath was then heated slowly to nearty 4o0°, while the behavior of the oil was closely watched. When the temperature ol the vapor had reached z 80 O (uiicorr.) a very noticeable condensation o€ moisttlrc occurred in zlre cool parts oi the apparatus. Y o moisture had previously been evident in the apparatus. Ad. z g s O , distillation of a. pale greenish-yellow fluorescent Xicluid began. At this stage, the heating vas discontinued, the residue in the flask wa5 cooled and removed as a coarse dark-brown crystalline powder It was dissolved in toluene and crysl allized. The crude product thus obtained was freed from oily impurities by pressing it on a clay p?ate and then recrystallized twice from toherre and dried a t 1310' for a hours. 'The crystals were nearly pure white, and melted a t 192--193'. Stlbs., o 1618 C02, o 5 3 0 5 , €120, o 0781 Calc for C2eH18Q:C , 90 1 7 , If, 5 24 Found: C , 89 36; K, 5.36.
ADDITION REACTIONS OF PHOSPHORUS HALIDES. I.
2337
Summary. The reaction of an excess of phenyl-magnesium bromide upon the methyl or ethyl ester of phthalic acid gives a mono-hydric tertiary alcohol which is a derivative of furfurane. 2 . I€ the product of the reaction of an excess of phenyl-magnesium bromide upon the esters of phthalic acid is heated to about 300°, it loses a molecule of water and.gives+thecompound C&l80 of m. p. 19z-rg3' which Shibatal claimed to be a derivativelof phthalan and the direct product of the original condensation. I.
EIOUSTON,TEX.
[CONTRIBUTIONFRON THE CHEMICAL LABORATORY OF HARVARD UNIVERSITY ]
ADDITPON REACTIONS OF PHOSPHORUS HALIDES. I. THE MECHANISM OF THE REACTION OF THE TRHCHLORIDE WITH BENZALDEHYDE. BY JAMSS
B CONANT
AND
ALEXANDER D
iMACI1ONAI.D.
Received August 11, 1920.
I. Introduction. It has been shown in a previous paper2 that phosphorus trichloride adds to the ends of the conjugated system of certain unsaturated ketones. This addition takes place with an increase in valence of the phosphorus atom from 3 to 5 . The chlorine atoms in the addition product are very active and are readily replaced by hydroxyl or oxygeii when the reaction mixture is treated with acetic acid or acetic anhydride. The product thus formed is a phosphonic acid or an intermediate cyclic compound. An exactly similar reaction takes place when simple aldehydes or ketones are treated with phosphorus trichloride. In this case, however, the primary addition product is formed by the r,z-addition of the phosphorus atom. RCHO
+ PCl, $ RCHO V
PCla (1)
Benzaldehyde was chosen as a suitade aldehyde for studying the mechanism of this reaction and only the results obtained with this substance are presented here. The reaction, however, takes place readily with most aldehydes and ketones and the limits of the reaction mill be discussed in a subsequent paper. The Primary Reversible Reaction. %hen benzaldehyde and phosphorus trichloride are brought together considerable heat is evolved and the additjon reaction (Equation I) proceeds t o a definite equilibrium. If equirnolecular amounts of the z sub1 2
I*oc. Cit. Tars JOURNAL, 42, 830 (1920)
