THE PREPARATION OF 4 B. CARBOXY ETHENYL 1 CHLORO MERCURI METHYL 1, 2, DIHYDRO BENZO FURAN FROM P. HYDROXY BENZALDEHYDE By HORACE BALDWIN HUDDLE B. S. Georgetown College, 1919 THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN CHEMISTRY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS, 1922 URBANA, ILLINOIS Digitized by the Internet Archive in 2016 https://archive.org/details/preparationof4bc00hudd ff ^(o UNIVERSITY OF ILLINOIS THE GRADUATE SCHOOL - M a y — 25— -192 2 - I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY Hor.ac.e_. Baldwin Huddle ENTITLED The Pr epar ation of- ivl 1 Chi or - q Mere up i Methyl X, 2 Dihydr o Be nzo Fur an from E, Hydroxy Benzaldehyde BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE . V . s- j of Science In Charge of Thesis Head of Department Recommendation concurred in* Committee on Final Examination* •Required for doctor’s degree but not for master’s 4S9068 ACKNOWLEDGMENT The author wishes to acknowledge that this re- search was undertaken at the suggestion of and was carried out under the kind and helpful direction of Dr. Roger Adams. TABLE OP CONTENTS Page I Introduction --------------------- 1 II Historical and Theoretical -------------- 2 1. (a) Preparation of Para Cumaric Acid ------ 2 (h) Properties of Para Cumaric Acid ------ 4 2. Preparation and Properties of the Methyl - - Ester of Para Cumaric Acid --------- 5 3. Preparation of Phenyl Allyl Ethers ----- 5 4. Preparation of Allyl Phenols -------- 7 5. The Reaction with Mercury - - ------- 7 III Experimental --------------------- 9 1. Preparation of Para Cumaric Acid ------ 9 2. Preparation of the Methyl Ester of Para Cumaric Acid ---------------- ll 3. Preparation of the Allyl Ether of Para Hydroxy Methyl Cinnamate ----------12 4. Preparation of Para Hydroxy, Meta Allyl Methyl Cinnamate --------------13 5. Preparation of Para Hydroxy Meta Allyl Cinnamic Acid --------------- 14 6. The Reaction with HgCl 2 ---------- 15 IV Summary ----------------------- 16 V Bibliography -------------------- 17 1 INTRODUCTION It was found in this laboratory that mercuric chloride v/ould re- act with ortho allyl phenols to give chloro mercuri dihydro benzo Curanes. The purpose of this research was to prepare such a deriva- tive which would be alkali soluble in hope that it might be a useful drug. The particular carboxyl bearing group introduced was the acry- lic acid radical. The order of procedure was first to prepare para hydroxy cinnamic acid from para hydroxy benzaldehyde • The acid was then esterified with methyl alcohol giving para hydroxy methyl cinna- mate. Next in order the allyl ether was prepared and rearranged into the allyl phenol according to Claisen* . Lastly the mercury was in- troduced into the molecule. P. Hydroxy Benzaldehyde )CH 2 CH=CH 2 OH 0 0 CH=CHCOGH ch=chcooch 3 Hydroxy Cinnamic P. Hydroxy Methyl Acid Cinnamate ch 2 ch=ch 2 CH 2 CH=CH 2 ch=chcooch b si™ Hydroxy Allyl P. Hydroxy Allyl Methyl Cinnamate Cinnamic Acid ;h=chcooch 3 r 1 Ether of P. Hydr< Methyl Cinnamate HgCl 4 Carboxy Ethenyl 1 Chloro Mercuri Methyl 1, 2, Dihydro Benzo Fur an ' ■ - ■ f ■ ■ r 1 ;x ■ . V Y. • • .• -i ■ " . 1 V' V r . i 2 II HISTORICAL AMD THEORETICAL 1. (a) Preparation of Para Cumaric Acid . Preparation of para hydroxy cinnamic acid according to Posner 1 . Para hydroxy cinnamic acid can be easily obtained from 100 grams para hydroxy benzaldehyde, 160 grams sodium acetate, fused, and 200 grams acetic anhydride. The mixture was boiled with a re- flux for eight hours in an oil bath. The yield was 83 grams. Tiemann and Herzfeld 2 describe the following method; eight parts of the sodium salt of para hydroxy benzaldehyde, five parts of pul- verized anhydrous sodium acetate and twenty parts of acetic anhy- dride are gently boiled with an air condenser for an hour. When cool almost the whole mass solidifies in radiating crystals. By treatment v/ith water the sodium acetate and the excess of acetic an- hydride are dissolved and there is left behind a yellow crystalline substance. This dissolves in alcohol, ether, acetic acid and boiling water. It is almost insoluble in cold water, benzene and chloroform. It sublimes undecomposed before it melts, and can so by sublimation as well as recrystallization from hot water be obtained in pure form. The crystals are fine white needles which melt at 195 uncorrected. The melting point is hard to observe for the acetyl para hydroxy cin- namic acid seems to contract and begin to sublime at about twenty degrees. Boiling with potassium hydroxide changes the substance into acetic acid and para cumaric acid. CH = CH - COOH GH = CH - COOH 3 The alkaline solution is then cooled and acidified with HCl f /hen the para cumaric acid separates as an almost red colored needle } The para cumaric acid is soluble in alcohol, ether, and hot water and slightly soluble in cold water# An article by Zinche and Leisse 3 states that a description of this acid ( para cumaric) was given by Tieraann and Herzfeld but that the authors had tried the method described and obtained only very poor yields. By making slight changes in the quantities used the yield o was increased to 80 /o of the theoretical. In detail the method was a 3 follows: 50 grams of para hydroxy benzaldehyde, 80 grams fused so- dium acetate and 150 grams acetic anhydride were intimately mixed in a round bottom flask with an air reflux and maintained at a gentle boil on a sand bath for four or five hours# The now fluid contents of the flask were poured in water and the acetyl para hydroxy cinna- mic acid allowed to separate. When the separation was complete the material was filtered on a suction filter and washed with water# Then the acetyl para hydroxy cinnamic acid was saponified by boiling in dilute NaOH. Care is necessary to prevent too long heating. After the alkaline so lution has cooled it is poured, drop by drop into an excess of somewhat dilute HC1. The solid obtained is then dissolved after washing, v/ith water, in very dilute sodium hydroxide solution and boiled for a longer time with animal charcoal. The acid is again separated from the cooled alkaline solution v/ith HC1 as above. The o acid is recrystallized from hot water and melts at 206 C. S. Gabriel in his article "Zur Kenntiss der Hydrozimmt- und der Zimmts&ure 4 describes the preparation of para cumaric acid from para 4 diazo cinnamic acid. The diazo cinnamic acid was dissolved in fifty carts of water and warmed on a water hath. The solution became yel- low and black flakes separated. After boiling a half hour the solu- tion was filtered and a light violet filtrate obtained from which, when cooled, crystals were obtained that on recrystallization from o hot water melted at 200 . Although the melting point was low and o the analysis showed a deficit of 1-1.5 / carbon Gabriel was sure o the substance was pure cumaric acid because of the identity of the copper salt obtained from this acid with that prepared by Halswetz 5 . Halswetz boiled a hot water solution of alo£ with dilute sulfuric acid for an hour. He then extracted with ether and after distilla- tion of the ether recrystallized the residue from weak alcohol. Five pounds of alod gave 24 grams of raw product. The para cumaric acid is colorless and crystallizes in shining white needles from, water. From alcohol the needles are somewhat longer. Halswetz prepared the ammonium, calcium, copper, and silver salts. (b) Properties of Para Cumaric Acid . The melting point of para cumaric acid is given at 206-207, and o 208 C. It is non volatile with steam and decomposes on distilling giving C0 2 and phenol. Dissolves slightly in cold water better than in alcohol. It is insoluble in CHC1 3 and CS s , only slightly soluble o in pure ether and mixes or dissolves in 10 / 0 H 2 S0 4 with heating. Para cumaric acid is soluble in dilute ammonia and in strong alkali giving a yellow fluid which is green in reflected light. In the presence of CS 2 and in the cold bromine unites with the acid. The acid can be separated from an aldehyde by shaking with a water solu- 5 tion of sodium bisulfite* 2. The Preparation and Properties of the Methyl Ester of Para Cumaric Acid , In Posner* s 1 article there is a statement that the methyl ester of OH para cumaric acid 0 has not hitherto been described CH=CH C-OCH 3 but that it is obtained from alkali solution with carbonic acid and is crystallized from methyl alcohol giving a bright sandlike powder o which melts at 139-140 • ^ 3 The article by Zinche and Leisse states that the methyl ester can be obtained in the usual manner with HC1 and can be recrystallizec o from hot water. The ester forms beautiful white needles m.p. 137 easily soluble in ether, acetic acid, alcohol and slightly soluble in benzene . Emil Fischer and Osman Nouri prepared the methyl ester by heating in a pressure flask 20 grams of para hydroxy cinnamic acid, 50 grams methyl alcohol and 5 grams concentrated sulfuric acid for four hours at a temperature of 75-80 degrees. After dilution with 150 cc. of o water the solution was cooled to 0 and the ester allowed to separate. The unchanged acid was removed by washing with sodium carbonate solu- tion. The ester was then recrystallized from hot water giving 18 o grams or 83 / Q of theory of white needlelike crystals m.p. 139-140 corrected. The ester was readily soluble in alcohol, ether, chloro- form, and ethyl acetate; very soluble in acetone and difficultly solu- ble in petroleum ether. 3. The Preparation of Phenyl Allyl Ethers . In an article by Claisen and Eiselb? can be found the following . • . . . : . . . 6 statements as to the formation of phenyl allyl ethers. The phenol under consideration is hoiled in a suitable solvent, usually acetone, with finely pulverized K 2 C0 3 and allyl bromide on a water bath till the reaction is complete. One uses a little more than the theoretical, amount of K 2 C0 3 and CH 2 = CH - CH 2 Br indicated in the equation: ROH + 0 3 H 5 Br + K 2 C0 3 ROC 3 H s + KBr + KHC0 3 An amount of acetone equal in weight to that of the phenol is used or just enough to make a thick porridge with the potassium salt of the phenol. Too much acetone is to be avoided since it gives a solu- tion too thick. The higher boiling methyl ethyl ketone is a better solvent in many cases. Acetone is not practical for benzaldehyde since it condemns with it. Alcohol can be used instead. To judge of the progress and the end of the reaction a sample is removed occa- sionally. This sample is dissolved in petroleum ether and extracted with sodium hydroxide solution. After separation the alkaline solu- tion is neutralized with HG1 to see whether any phenol separates. When none separates the reaction is complete. The time needed varies from four to eight hours. After the reaction is complete water and petroleum ether are added to the flask. The ether and water are separated and the ether extracted well with NaOH solution. The ether is washed with water and dried with potash. The ether is volatilized from a water bath. The allyl ether remaining as an oil or solid is sufficiently pure for use. Further purification ma.y sometimes be ac- complished by vacuum distillation. To prepare the allyl ether of para hydroxy ethyl benzoate o c 3 h 5 0 which is analagous to the allyl ether of para C - 0C 2 H 5 . . •> . . - • . . ■ *• • . * ♦ 7 hydroxy methylcinnamate C a H 3 iJ -5 which was a necessary inter- ;h=cH-c-och 3 mediate compound in this synthesis and is not described in the liter- para hydroxy allyl ben- U ature Claisen used 250 grams of ■'cooc H 5 zoate with 210 grams of K 2 C0 3 and 185 grams allyl bromide in 300 grams of acetone. The mixture was boiled six hours and treated as O . described above. The yield was 95 / • 4. Preparation of the Allyl Phenols from the Allyl Phenyl ethers . Claisen found that by heating alkali insoluble allyl phenylethers were transformed to the alkali soluble allyl phenols; the allyl group shifting to the position ortho to the phenolic hydroxyl group. 296 grams of the allyl ether of para hydroxy ethyl benzoate described o above were heated in an oil bath at 220-250 for one half hour. Free boiling did not occur, however, the change was complete. The change o of boiling point was some 30 C. from that of the ether. 5. The Reaction with Mercury . The problem of bringing about the reaction the ortho hydroxy meta allyl cinnamic acid was not difficult. The acid was prepared from the corresponding methyl ester by simple hydrolysis in dilute NaOH. Whitmore states that common cinnamic acid gives no compound with mercuric salts from which all of the mercury cannot be precipi- tated by acids. No reaction was expected with the acrylic acid radical. It has been discovered in this laboratory that o allyl phenols v/ill react with mercuric salts to give chloro mercuric, 1,2 dihydro benzo furanes. It was purposed to bring about such a re- action between mercuric chloride and the o, hydroxy meta allyl cinna- mic acid. - •• ■ . . * • • . . . . S’ r . . r ■ c. Ill EXPERIMENTAL 9 1. The Preparation of Para Hydr oxy Cinnamic Acid from Para Hydroxy Benz aldehyde . The first attempt to prepare para hydroxy cumaric acid gave very poor yields. Upon investigation it was found that the acetic anhy- o dride used contained more than 50 /© of the low boiling anhydride. After distillation of the acetic anhydride and refusion of the sodium acetate several 10 gram samples of the para hydroxy benzaldehyde were tried according to the following directions which were formulated by , :0H experimentation: 10 gram of y/ 16 gram of sodium acetate o fused and 30 gram acetic anhydride which boiled at or above 137 v/ere placed in a 200 cc. flask, with an air reflux and maintained at a gentle boil for five hours. The liquid contents of the flask v/ere then poured with stirring into 800 cc. water. It is best to let the precipitate stand, over night in order to collect. If this is not done it is sometimes very difficult to filter 1 . The precipitate af- ter having been washed successively with small amounts of water to o remove any acetic acid is dissolved in 250 cc. of 10 / D NaOH and boiled from one to two hours. The alkaline solution is filtered and cooled. The s olution is then poured drop by drop with stirring into o 300 cc. 10 / 0 HC1 ice cold. Again it is best to allow the precipi- tate to stand over night. After washing as before with small amounts of water filter and dissolve by boiling in 500 cc. water. Let the filtered yellow solution cool slowly and stand- over night. There is 1. The filtrate is diluted v/ith water to precipitate any acetyl para hydroxy cinnamic acid present in case the concentration of acetic acid is too strong. - . . . . ) . . . . . . 10 o a loss of as much as 37 / of the crude acid upon crystallization from hot water. The crystalline acid seems mixed with a brownish red gum and long boiling seems to convert some of this gum by solu- tion and crystallization into the crystalline form. Better results are obtained if the sodium acetate, finely pulverized, is dissolved in the acetic anhydride, as far as possible and just brought to a boil. If the mixture is allowed to stop boiling and the flame is removed when the para hydroxy benzaldehyde is added, the boiling recommences from the heat of reaction and will continue for fifteen minutes without the flame. It was suggested that I 2 might act as a catalyst for this reaction. This work failed to verify such a con- elusion • No. Grams Diluted with Recrystallized Catalyst Yield M.P. CH c c « H 2 0 from cc . H a 0 c=o H o 1. 25 52 /„ 206 2. 10 800 500 la 52°/ 0 206 3. 10 800 500 -- 52°/ 0 206 4. 10 800 500 la 67°/o 206 5. 10 800 500 -- o . 68 /o 206 6 • 10 800 500 Is 68°/ 0 205 7. 10 800 500 -- o , 76 /<> 205 8. 100 8000 3000 -- o . 50 /„ 206 9. 100 8000 3000 -- O , 80 / 0 206 10. 200 13000 13000 -- ° . 43 / o 206 11. 100 8000 3000 -- 52 / 0 206 11 Samples (2, 3) (4, 5) and (6, 7) were duplicates and in all details were given the same treatment. Too long boiling of the alkaline solu- tion during saponification is probably the cause of some of the low yields. Overheating or too long boiling of the original mixture seems to increase the amount of reddish brown gum. Upon three recrystalli- zations from hot water a pure white short needle was obtained which o nelted slightly above 206 G. 2. Preparation of the Methyl Ester of Para Hydroxy Cinnamic Acid . The first method used in preparation of the ester was: 5.6 grams o Df puce acid were dissolved in 100 cc. of CH 3 0H containing 4 / 0 dry IC1. This cherry red solution was refluxed on a water bath for ten lours. The solution was poured in water and the ester filtered. The field was insignificant. The method of Fischer and Nouri gave the best results. After several trials the following method was determined. 20 grams of the icid, 50 grams of absolute methyl alcohol and 5 grams concentrated :i 2 S0 4 were put in a pressure flask and maintained at a temperature of o 75-85 for eight hours. The liquid, after filtration of any crystals which may separate, is poured, into a liter of ice water. The precipi- tate is filtered and washed and finally dissolved in 1 liter of hot water. On standing over night white needles sometimes more than an Lnch long separate. It was thought that possibly by evaporation of bhe alcohol water filtrate under diminished pressure the yield could De increased. This process seemed only to increase the amount of red- lish brown gum. . . . . : • . . 12 In the literature mention of only one form of crystal was found. Upon recrystallization from alcohol hexagonal plates separated. These plates were apparently perfect in form and symmetry and when recrystallized from hot water assumed the familar needle like form. o The melting points of both forms were the same, namely 137 C. An- other interesting detail was noticed. When a pressure flask contain- ing the charge described, above is allowed to stand without heating a weight of crystals equal to one half the usual total yield separates from the solution. There is also usually present a small amount of unchanged acid. No. G • Ac id used h 2 so 4 G Alco hoi Time of heating Temper- ature M.P. Yield o . Alcohol Recrystal- diluted lized from with cc. cc. water water 1 . 20 5.g 50 g 6 hrs 75-80 137 25 /„ 500 cc . 1500 cc. 2. 18 5.g 45 g 6 hrs 75-80 137 34 / 0 500 cc. 1000 cc. 3. 20 1 10. g 50 g 8 hrs 75-83 137 43 /o 500 c c • 4. 20 1 5.g 50 g 8 hrs 83 137 39 /„ 500 cc . 1000 cc . 5. 60 15. g 150 g 4 hrs 75-80 137 34°/ o 1500 cc. 3000 cc. 6 • 116 30. g 400 cc5 hrs 75-80 137 34°/ 0 4000 cc. 4000 cc. 3. Preparation of the Allyl Ether of Para Hydroxy Methyl Cinnamate. 25.3 grams of methyl ester of para hydroxy cinnamic acid, 18. grams allyl bromide 2 , 21. grams K 2 C0 3 finely pulverized and 30 grams acetone were heated on a water bath for thirty minutes over a low 1. 3,4 were run to test effect of acid. From these the filtrates were evaporated under diminished pressure yielding only small amounts • 2. The allyl bromide used was prepared according to the directions p.76. University of Illinois Bulletin. Organic Chemical Re- agents, I. 13 flame. The temperature was then allowed to rise till the mixture boiled. A forty one inch condenser was necessary. When the sodium hydroxide extract of an ether solution of a sample gave no phenol upon neutralization the reaction was complete. The solid (K s C0 3 + KBR) was filtered and washed with acetone. The washings were added to the filtrate. The acetone was then distilled off and the yellow- ish red oil poured with stirring in 400 cc ♦ of water. A creamy white solid separated which was filtered and washed with water. This mater. O , ial is insoluble in 10 / 0 NaOH, and in water. It is soluble in al- cohol, very soluble in ether, less soluble in petroleum ether and o soluble in CHC1 3 . The crude product melted 64 uncorrected, 66.9 corrected. This product can be crystallized from an alcohol water solution in the following manner; dissolve the material in just a sufficient amount of hot alcohol. Add enough hot water to almost precipitate and let cool slowly. Snow white glistening flakes separate w hich melt at 64.5 uncorrected or 71.3 corrected. o . The yield on sample 1. was 85 / . Sample 2 consisting of 50.6 g. o gave 92 / yield. 4. The Preparation of Para Hydroxy, Meta Allyl Methyl Cinnamate . The crude ester described above was placed in a round bottomed flask and with an air reflux and heated in an oil bath. When cooled the reddish bro wn oil was dissolved in ether and extracted succes- sively with small amounts of 10 / 0 NaOH. The alkaline solution was o then poured into an excess of 10 / 0 HC1 ice cold. After filtering and washing the dry brown powder was dissolved in d.ry ether and dried for fifteen minutes with CaCl 3 . When poured off the ether was evapo- rated the last portion being volatilized in a vacuum desiccator. A 14 o brown powder resulted which, was soluble 10 / 0 NaOH, soluble in ace- o tone, alcohol and ether. Insoluble in water, benzene, HC1 10 / 0 » o 10 /o NaHC0 5 and chloroform. This product was not obtained in crys- talline form but was used to prepare the next product which was ob- tained in crystalline form. Allyl ether used Time of heating Temperature Yield /N 18 1 hour 235-245 yJ 89 / 0 25 2 hours 220-240 O / 64 / o 25 2 hours 230 80°/ o 5. Preparation of Para Hydroxy Meta Allyl Cinnamic Acid . This reaction was a simple hydrolysis in 10 / 0 NaOH of the pro- duct obtained above. The alkaline solution was poured in an excess o of 10 / HC1 ice cold and the precipitate allowed to collect. When washed and dried it is dissolved in ether and extracted with NaHC0 3 o solution 10 / D . This solution is again poured into an acid solution as above. The washed and dried precipitate is dissolved in alcohol and almost precipitated with hot water. The solution is then boiled till a film of crystals begin to cover the surface. On cooling the acid comes down as short white needles. An oil begins to collect in the bottom of the beaker. Pour off the supernatant liquid with the crystals and redissolve the oil in alcohol repeating the process. The crystals melt at 165 uncorrected and 168 corrected. They are soluble in alcohol, ether and slightly soluble in CHC1 S . * / 15 . of CII CH ~ CH = CK 2 Time of hydrolysis Yield CH = CHC 00CH 3 5. g 1 hour 95°/ 20. g 4 hours o 77 / 7. g 3 hours 54 / 6# The Reaction with HgCl?. . .5 grains of the para hydroxy meta allyl cinnamic acid described above were dissolved in the last possible amount of ethyl alcohol, • 66 grains of HgCl 3 were likewise dissolved, and the two solutions poured together and evaporated nearly to dryness, A solid separated leaving a green stain on the sides of the beaker. The solid was washed with water to remove the excess HgCl a and with alcohol to re- move the unchanged acid. The remaining brown homogenous powder was soluble in 10 / 0 NaOH but insoluble in water or alcohol and only slightly if at all soluble in ether, no melting point was obtained. . . . IV 16 SUMMARY In the preparation of 4 car "boxy ethenyl, 1 chloromercuri methyl, 1, 2 dihydro benzo furan from para hydroxy benzaldehyde it was necessary to prepare para hydroxy cinnamic acid and its methyl ester, both of which were described in the literature, and also the new compounds the allyl ether of para hydroxy methyl cinnamate, the para hydroxy meta allyl me thy J cinnamate, and para hydro xy meta allyl cinnamic acid. Of the four new compounds two were obtained in crystalline form. Although the para hydroxy meta allyl methyl cinnamate was not obtained in crystalline form the acid prepared from it was. The mercury compound differed from the acid from which it was prepared in not being soluble in alcohol. A hitherto undescribed crystalline form of the methyl ester of para hydroxy cinnamic acid was noted, and detailed directions formu- lated for the preparation of para cumaric acid and its methyl ester. It was also noted that heat was unnecessary to produce esterfication of the para hydroxy meta allyl cinnamic acid. . . .. ! ' ' •' V 17 BIBLIOGRAPHY 1. Posner. Zur Darstellung substituierter ZimmtsMuren. Journal fur Pracktische Chemie • Vol.82 (New Series), p.428, 1910. 2. Perd. Tiemann and Herm. Eerzfeld. Ueber Abkdramlinge des Para- oxybenzaldehyde . Berichte der Deutschen Chemischen Gesellschaf t. Vol.10, p.65, 1877. 3. Th. Zinche and Fr. Leisse. Ueber die Einwirkung von Brom auf p-oxyzimrntsMure . Tetrabrom p-oxyzimmtsMure, p-vinyl- und p- aethylphenolbromide . Annalen der Chemie. Vol.322, p.223, 1902. 4. S. Gabriel. Zur Kenntiss der Hydrosimmt- und der ZimmtsMure. Berichter der Deutschen Chemischen Gesellschaf t . Vol.15, p.2301, 1882. 5. Haziwetz. Ueber eine neue de CumarsMure isomere sMure. Annalen der Chemie. Vol.136, p.31, 1865. 6. Emil Pischer and Osman Nouri. Synthese des Phloretins und Dar- stellung der nitrile von Phe no 1 carbons Mure . Berichter, Vol.50, p.611, 1917. 7. L. Claisen and 0. Eiselb. Uber die Umlagerung von Phenolallyl- Sthern in die isomeren Allylphenole . Annalen der Chemie. Vol. 401, p.29, 1913. 8. Whitmore. Organic Compounds of Mercury, p.309.