NOTES
304
has been found very satisfactory. By this method three new phenolic esters have been prepared on a one to threemole scale. my14-Phenylphenyl C a r h t e . - T o
-
a solution of 510
g. (3 moles) of 4-phenylphenol in 720 rnl. of pyridine (dried over potassium hydroxide pellets) in a 2-liter reaction flastE, Csnyinea d u x condenser, dropping funnel and mer-
cury-seakd "Hershberg" Stirrer, .there added, with stirriug at 0 ",over a period of 30mutes, 38S.g. (3.4 moles) of ethyl chlorocarbomte. A bulky precipitate formed. Stirring was continued for thirty minutes after addition was complete. The reaction mixture was stirred to a paste with 500 ml. of water and filtered under suction; the precipitate was washed with three 200-ml. portions of icewaterprior to fusion in m n o . The fused material was from 800 ml. of 95% ethanol. There was r o c g . (60%) of ethyl 4-phenylphenyl carbonate, m. p. 73.2-74.3O. A sample, recrystallized repeatedly from methanol, melted at 73.9-75.0". A d . ' Calcd. for CUH~~OS: e,74.36; H, 5.82. Found: C, 73.90: H, 5.88. + ~ ~ & y l p i m y~~ m t e . - ~ h acylation e of 255 g. (1.5 moles) of Pphenylphenol in 860 ml. of pyridine by means of 180 g. (1.7 moles) of isobutyryl chloride as de4cribed for ethyl 4-phenylphenyl carbonate gave 294 g. (82%) of 4-phenylphenyl isobutyrate, m. p. 73.2-74.8". A sample, r repeatedly from methanol, melted at 74.2-74.8? A d . * Calcd. for Ctdf&: C, 79.97; H, 6.71. Found: C. 80.53: H. 6.80. phenyl 180butyrate.-~ solution of 94 g. (1 mole) of phenol in 240 ml. of pyridine was acylated by means of 128g. (1.2 moles) of isoburpryl chloride essentially described above. After &on was complete, the mutture was diluted with water and ether to produce two clear phases. The aqueous phase was extracted with ether and the combined ether phases were dried over anhydrous sodium sulfate followed by "Drierite." After removal of the solvent at atmospheric pressure, the residue was distilled through an eight-inch Vigreux column. Fractions boiling at 60-110' (55 g.) and 110-112' J131g.) were obtained. The lower boiling fraction was d~st~lled up to 105' at 25 mm. and the residue combined with the fraction boiling at 110-112'. Distillation of the mixture gave 4 g. of a forerun, b. p. 105-111" at 25.5 mm., and 144 g. (87%).of phenyl isobutyrate, b. p 111-112.2' at 25.5 mm. A mdfraction (b. p. 112' at 25.5 mm., const.) was analyzed. ilna1.a Calcd. for CIPHI~O~: C , 73.15; H, 7.37. Found: C , 72.84; H, 7.32.
VOl. 66
shells was sixteen inches in diameter and three inches high at the point at which the pipe was attached. Two iron pipes, onehch in diameter, were screwed into the shells as shown in the diagram. The upper, outlet pipe was attached by rubber tubing to a Pprex glass tube (combustion type) about six feet long which served as a condenser. A t the beginning of the process it was found necessary to cool the condenser with wet cloths, but during the end of the operation it was essential, in some instances, to warm the glass tube with a flame to prevent the condensed material from clogging the tube.
Fig. 1. The mucic acid salt was placed in a shallow galvanized iron tray. A short, metal tube had been inserted through the center of the tray in order that a stream of nitrogen could be passed through the apparatus. The apparatus was supported on a tripod, and heated from below with eight Meker burners. Since it was found that rubber tubing attached to the burners melted in a short time, due to the intense heat, it was necessary to unscrew the side arms from the burners and replace them with threaded iron pipes about eighteen inches long. The upper shell of the apparatus was covered with several removable layers of heavy asbestos, and the whole apparatus was surrounded with a large sheet of the same material. 1-Phenylpyrrole.-In order to prepare the required aniline salt of mucic acid, an intimate mixture of 1116 g. of aniline and 1260 g. of mucic acid was placed in a large evaporating dish, 60 cc. of water added, and the mixture stirred and heated on a steam-bath until it became solid. The material was then pulverized and airdried The salt (396 g.) was placed in the apparatus and the distillate was collected in a 2-liter, round-bottomed b k which contained 110 cc. of concd. hydrochloric acid and 400 cc. of water. The aniline dissolved and the insoluble pyrrole was obtained as a brown, crystalline material. After one-half hour the reaction was complete. The crude material was subjected to steam distillation. The phenylpyrrole separated in the distillate in the form of colosless crystals while a tarry residue remained in the distillation flask. The average yield was 60 g. (42%). The product ( 6 ) Analysis by T.S. Ma, University of Chicago, Chicago. Illinois. melted at 58',( and boiled at 230-234". DSPARTXENT OF CHEMISTRY 2-Phenylppole.-A five-foot length of Pyrex combusRECEIVED DECEMBER 6 , 1943 tion DUKEUNIVERSITY tubing was bent, twenty inches from one end, at a DURHAM,NORTHCAROLINA 75" angle, and placed in a combustion furnace. To facilitate the flow of the product through the tube, one end of the furnace was raised about two inches above the level The Preparation of 1- and 2-Phenylpynole of the laboratory table. Fifty grams of 1-phenylpyrrole were put into a 125-1~. distillation flask in which the usual R Y F. F. BLICKEA N D J. L POWERS side ann had been replaced by another 10 cm.long and 9 in thickness, sealed close to the bulb and fitted to the Recently we have been able to synthesize rela- mm. tube by a cork. The tube was heated to a dull red heat, tively large quantities of 1- and 2-phenylpyrrole and the pyrrole was distilled though the tube at such a rate that about thirty minutes were required to empty the by means of the procedures reported bel0w.l The apparatus used for the preparation of l-phenyl- distillation &ask. Sice the rearrangement was not compyrrole consisted of two round, cast-iron shells with plete, the product was distilled through the hot tube two flanges which were clamped together by means of eight more times. The material was fractionated, and the recovered 1short bolts fitted with Wing nuts (only two bolts are shown in the drawing) ; several "cranite" asbestos gaskets phenylpyrrole was subjected to the rearrangement process. placed between the shells prevented leakage.: Each of the From 200 g. of 1-phenylpyrrole there was produced 127 g. (63%) of Z-phenylpyrrole; b. p. 272-278".' A com(1) 0th- methods described during the lpst few yearn are those of pletely colorless product could be obtained only by disAllen,Gilbert and Young (J. Org. Ckcm., t, 280 (1937)) and of Adkins tillation under reduced pressure; b. p. 151-154' (6 mm.).
as
and coonrpdt (THISJOWRIUAL, 85,1588 (1941)). (2) W h e n new gaskets are used, the bolts must be tightened again after the apparatus has become hot.
(3) Kattnitz ( J . @I&. Chsm., (21 6, 148 (1878)) found 62O. (4) Pictet and CrCpieux (Bcr., 98, 1905 (1886)) found 271-272°.
NOTES
Feb., 1944 But even this material soon turned pink when expwed to a=. However, after several recrystsllmtions of the vacuumdistilled product from 70% alcohol the pyrrole was obtained in a form which remained colorless; m. p. 128-129O.5 (5) The melting point has been reported to be 129” (ref. 4).
COLLEGE OF PHARMACY UNIVERSITY OF MICHIGAN ANN ARBOR, MICHIGAN RECEIVED &3PTEMBER 30,1943
Reactions of &Butyl Cinnamate and &Butyl Benzoate with Phenylmagnesium Bromide’ BY FREDFROSTICK, ERWINBAUMGARTEN AND CHARLES R. HAWSER
305
in 160 ml. of eth?), contaiqed in a reaction h k equipped with a U-tube Lmmefsed m a dry ice-bath, was added during one-halfhour 0.3 mole of t-butyl benzoate’ in 100 ml. of ether. After standing overnight the reaction mixture was duxed for five hours. The liquid condensed in the U-tubedid not absorb an appreciable amount of bromine in carbon tetrachloride solution, indicating that no signidcant amount of isobutene was farmed. After daxnnposition of the n&ctloIl mixture with ammonium &laride, the ether solution was Wen with bicarbollpte (fromwhich was isolated a 10% yield of benzoic acid), dried and the solvent distilled. The residue was subjected to steam distillation until oily material (containing diphenyl but apparently no tbutylbenzene) ceased to pass over, and then re-crystaUized from alcohol, yielding triphenykarbinol (41%), m. p. 169-162”. In a similsr experiment, carried out with &butylbenzoate and methylmagnesium iodide, no isobutene appeared to be formed.
Kohler and Heritage’ showed that methyl (6) Nodm and Rigby. THIS JOURMAL, 64, 2097 (1932). cinnamate undergoes both 1,2- and 1,4ddition with phenylmagnesium bromide yielding a mix- DEPARTMENTOF CHEMISTRY 6.1943 ture of products. We have found that t-butyl D r w r U ~ ~ v ~ ~ s m RECEIVED DECEMBER cinnamate (in which the carbonyl group is rela- DURBAY.NORTHCAROLINA tively hindered) undergoes apparently only 1,4addition yielding t-butyl @,@-diphenylpropionate. Nature of Carotenes in Alfalfa -6MgBr BY A. R. KEXKERERAND G. S. Fruw G”CH=CHCOOC(CHs), (OH~)SCHCHICOOC(C&)~ According to Beadle and Zscheile,’ spinach and To a stirred solution of phenylmagnesium bromide, pre- some other plants contain appreciable amounts pared from 6.6 g. (0.23 mole) of magnesium and 46.1 g. of “neo-@-carotene,”stereoisomer of 8-carotene, (0.23 mole) of bromobenzene in 100 ml. of dry ether, was which can be produced by heating @-carotenein added during twenty minutes 23.5 g. (0.116 mole) of t petroleum ether. This pigment is the same as butyl cinnamate.’ The reaction mixture d u x e d gently and a precipitate formed. After duxing for three hours, that termed pseudo-a-carotene by Gillam and El and neo-p-carotene B, by Polg6r and Zechthe muture was poured into an icecold saturated ammonium chloride solution. The ether layer was shaken with meister.8 Kemmerer and Fraps,‘ by chromacold 10% sulfuric acid, and then with cold 6% po-um hydroxide solution. After drying with anhydrous wxhum tographic analysis with calcium hydroxide, found, sulfate followed by “Drierite,” the solvent was distilled, besides @-caroteneand this “neo-@-carotene”in finally using the water aspirator. The solid residue plants, another pigment which they termed “caro(29.6p) was recrystallized from petroleum ether (b. p. tenoid X.” “Carotenoid X” did not possess 30-60 ), yielding. 16 g. (44%) of essent+lly pure.t-buty1 vitamin A potency, while “neo-@-carotene”had &&diphenylpropionate. Four recrystalhattons w e da one-half the potency of &carotene. PolgC and product meltiug at 65.5-55.6”. by various treatments of @-carotene, Anal.‘ Calcd. for CI&~&: C, 80.86; H, 7.86. Found: Zechmei~ter,~ secured about twelve neo-@-carotenes including C. 80.93;H,7.60. The product was further identified by hydrolysis in the neo-@carotenesB and U. Since the identificapresence of concentrated hydrochloric acid to fl,@-diphe-nyl- tion of the carotenes in plants is of both practical propionic acid, which, after recrystallizationfrom acetone- and scientiiic importance,both the “neo-0-carowater mixture, melted at 152-154’ (reported, 166O)f tene” and “carotenoid X”in alfalfa were studied. Analogous to methyl or ethyl benzoate, &butyl Neo-B-carotene B was prepared by d d n g a solution benzoate has been found to undergo the “normal” of 20 mg. of crystalline carotene in 100 ml. of hexane for carbonyl addition reaction with phenylmagnesium one hour.‘ The solution was chromatographed on calcium bromide, yielding triphenylcarbinol. Some ben- hydroxide and the neo-&carotene B was separated and Then it was purified by another chromatozoic acid (which might have resulted from hydroly- extracted. graphic treatment. This pigment is just below the fl-carosis of the ester) was also isolated. Neither iso- tene band in the chromatogram. Neo-&carotene U was butene nor t-butylbenzene was found; these prod- prepared by dissolving about 10 mg. of crystalline car* tene in petroleum naphtha (Skellysolve P). adding a small ucts would have resulted had the elimination or crystal of iodine, and allowing the solution to stand an substitution reaction occurred. hour.’ The neo-&carotene U was separated and purified To a stirred solution of phenylmagnesium bromide (prepared from 0.5 mole each of magnesium and bromobeazene
by absorption on calcium hydroxide. The neo-&carotene U is just above the ,%arotene in the chromatogram. “Carotenoid X” and “neo-~carotene”were prepared from alfalfa leaf meal by extraction with alcholic potassium hydroxide and petroleum naphtha (Skdyso!ve,F) and chromatographic ScpSration on calcium hydroxide.
(1) This work was muppfnted by a grant from the Duke UniverCounal. aity R-ch (2) Kohlu and Heritage, A m C h . J., 88, 21 (IW5); see atro Allen and Blatt in ‘‘Organic Chemhry,” Gilman, Editar-in-Chid, John Wiley and So=, Inc., New York, N. Y.,1843, p. 681. (1) B. W. &uikandP. P.Zchdle,J. Bid. C h . ,144,21(1842). (8) Abramovitch, Shivers, Hudson and H a w , TEIS JOURNAL, (9 h E. Gilhm a d M.9. El RW,Biocksn. J., 80, 1735 (1986). 06, 986 (1943). (8) A. Pol& and L. ZLehrndSter, TEIS JOURNAL. 64,1856 (1942). (4) Analysis by T. S. Ma. Univemity of Chicago, Chicago,IUioOir (4) h R. Kemmaer and G. S. Fram I d . En#. C h . , Anal. Ed., (6) Baun~,Am. Chem. J . , 88, 84 (1905). 11,714 (1948).
