July, 19.16
ALKOXY-AND ARYLOXYSTYRENES [CONTRIBUTION FROM THE
NOYESCHEMrCAL LABORATORY, UNIVERSITY
1365 OF ILLINOIS]
Alkoxy- and Aryloxystyrenesl BY ROBERT1;. FRANK, CLARKE. ADAXS,ROBERTE. ALLEN,ROBERTGANDER AND PAUL V. SMITH
The present paper discusses the methods of preparation of a number of substituted styrenes containing methyl and phenyl ether groups. The chloroethylation reaction discovered by Quelet and Ducasse, followed by dehydrohalogenation of the resulting 1-chloroethyl derivative, is a feasible method for a limited number of styrenes, although yields are reduced by a secondary reaction during chloroethylation, represented as follows in the case of anisole
9-bromoanisole, dimethylaniline, N-methylacetanilide and 1,4-dimethoxybenzene were unsuccessful. The preparation of 3,Q-dimethoxystyrene, attempted by chloroethylation of veratrole, gave yields of only 6%, and a more suitable synthesis was sought in the addition of methylmagnesium iodide to veratraldehyde, followed by dehydration of the resulting 1-(3,4-dimethoxyphenyl)ethanol. The latter compound was best dehydrated by slow distillation under reduced pressure, CHaOC6Hj + CH~OC6H~CHClCH~ 4 which gave much better results than heating in ( C H J O C ~ H ~ ) ~ C H C HCl H~ the presence of iodine, activated alumina, poI t seemed that an optimum period of reaction tassium acid sulfate, sulfuric acid or phosphorus might niininiize the formation of this by-product, trichloride. and experiments with anisole (Table I) have 3-Methoxystyrene, an isomer not obtainable by shown this to be true. Extending the reaction chloroethylation of anisole, was prepared in 37time past one hour under the conditions used 41y0 yield by reaction of the Grignard reagent of greatly increased the yield of ltl-di-(4-methoxy- 3-bromoanisole with ethylene oxide and subseph.eny1)-ethane, although the yield in grams of 4- quent catalytic dehydration by means of potasinethoxystyrene was substantially the same in all sium hydroxide of the resulting 2-(3-methoxyruns of greater than one hour duration. phenyl)-ethanol. An additional styrene, the 4-phenoxy derivaTABLE I tive, was prepared by two routes
+
I, p. 105-106' ( 4 m m . ) , n ? " ~ 1.5400; 3,4-tlitnethosystyreilc: 0-10'. ti";, b. p. 116' (8 IIIiii.), n z " D
1.5693. u- and p-nicthylanisoles and methyl thytnyl ether were prepared hy tncthylatioii of the corresponding phenols accorilirig t o tlie method of Hicrs aiid Hagcr.' Thi: yiclils a i i t l physical cotistai~tsof t h e w itlicrs w r c as folllJ\f'S: u-niethylaiiisolc, s;;,' b . p. 7:' (29 iiliil.), ?Z'"I) 1.51iO; p-inrthyiaiiisolc, %Ic+, ti. p. (35 i n n i . ) , IZ% 1.5122; methyl thymyl ether, 78(,';.) b. p. 99-101" (14 m m . ) , n z " 1~5062. 3,4-Dimethoxystyrene (from Veratraldehyde).-In a 5liter. thrce-necked, round-bottomed flask fitted with a stirrer, a condenser and a dropping funriel were placed 58.5 g. (3.41 gram atoms) of magnesium turnings a!id 400 nil. of d r y ether. T o this !vas added with stirring :tiskc-type cnlunin gavc 3 1 g . (1 1 lis7 iFrotiiiii~ha.; repnrtetl t i t j 1 1 L i 9 ) ; .1JK c:tlcd : 4i,l.8t (takiiig itito accoiiiit a i l e ~ l t a t i o nof 2 2 I d u e t o the i v - atid p-iriethosyl groups i i i coiijuiictioii with th(. styrt'~ic~ i i i c l t ~ u s.\if< ~ : f o u i i t l : 4(J tis. k t w / . ' Calctl. for C,,,HI?(>?.C , 7;:.15; 13, 7.37. I.'O;III~: C , 53.09; H, 7 17. A higher fraction (450 g.), judged t o be a mixture
and two inches in diameter, fitted with a dropping fu;inel attached t o a copper tulle leading to the bottom of &he cylinder anti ail outlct tube attached t o a condenser and recciver. Thc receiver was coiinected t o a water pump so that the whole system could be evacuated. The reactor \vas one-.lialf filled with potassium hydroxide pellets (ca. 250 9,) arid heated in an clectrically controlled oil-bath a t l W O , The pressure was reduced to 15-16 mni. and 2-(3inetliosyphriiyl~-etlia~iol was addcd through the dropping funnel a t such a rate that approximately tttn drops of crude product were collected per minute. From 45 g. (0.30 mole) of the alcohol was obtairicd 36.5 g. of crude 3-methosystyrene. This was dissolved i n chloroform, dried over calcium chloride, and fractionally rlistillcd through a sixinch, Fcnskc-typr coluinn t o yirld 27.4 g. (692>;5;,') of pure product, b. p. SO" (14 nim.), ?z% 1.5310 (rcportedCb nzn 1.554). A 1-nil. sample of 3-rnethosystyrene was brominated by the slow addition of a diiute solution of bromine in glacial acetic acid until a perinanent color of excess bromine was obtained. The product was isolated b y the addition of water and twice recrystallized from ethanol t o give shiny white platelets, m. p. I%-ti7". . 4 n d Calcd. for CgHloOBrz: C, 36.77; H, 3.43. Found: C, 37.07; H, 3.44. 4-Phenoxyacetophenone (II).-The general directions of Soller and Adams," used also b y Ingersoll, Brown, Kim, Beauchamp aiid J e i i n i ~ i g s ,were ~ ~ folloived. From 170 g. (1.00 mole) of phenyl ether, 295 g. (2.21 moles) of alirmiiium chloride and 100 nil. (108 g., 1.06 moles) of acetic anhydride in 400 ml. of dry carboii disulfide was obtained 1 i 3 g. (78.
