s 31 k~CEl,V,\Ih-A S D HARRYCOHEN
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'CONTRIRl.TIOS FHO?4 1Hf 1,4BORATORV O F ORCTANIC CHBMISTRI; OF THE ~ i N I V 8 R S l T SO F \$rlSCOXcIN1
Ketene Acetals. VIII. The Reaction of Ketene Diethylacetal with a,p-Unsaturated Carbonyl Compounds BY S 3f. ?iIcEr,vun' \SI) H~
R
COHEN Y
benzene solution for several days, none of the yellow anhydride [IT) is noticed but in its stead a 5aturated carbonyl compound, C white solid, to which the bicyclooctene structure to produce a positive or cationoid ceuter o f rt' ( 111) is assigned, precipitates. This structure is activity on the 3-carbon atom suggested a stud! the result of a 1,4addition of maleic anhydride to of the reaction of compound> of this type with the conjugate bonds of (IT) and is substantiated ketene diethylacetal, which 15 knowii to have by the fact that (111) is most readily prepared a strong anionoid center. I t seemed of particular when (11) is heated with an equivalent of maleic interest to determine whether a single moleculc anhydride in benzene solution. The reason that of ketene acetal would add to the unsaturated none of (111) is formed in the ether solution may carbonyl structure or whether the reacting unit be due to the fact that (11) is so insoluble in this would consist of two molecules of the acetal in solvent that it precipitates before i t can react some such form as . CH2C(OEt)s-CH2C- further with the maleic anhydride. (OEt)? . . . This latter type of behavior is remiWhen the yellow anhydride (11) is moistened niscent of an ordinary t,4 addition. Indeed, i t with water, i t slowly turns to a white dibasic acid may be considered as a 1,1intermolecular addition the analytical data for which indicate that it has in which the establishment of the % , 3 double bond the structure (VI). This dibasic acid loses carin the ordinary type is replaced by the formation bon dioxide when heated to its melting point, of a single bond that joins the two units of the Y t S . j " , and passes into the keto-acid (VII), The ketene acetal that are involved in the reaction. facile loss of an ethyl group in the hydrolysis of T w o reactions of this latter- type have been ( 11) is undoubtedly associated with the internoted : ( 1 ) the addition of bromine to bromo- mediate structure (V) which, i t may be seen, is a ketene acetal to form the ketal of a tribromo- vinylog of ethyl bicarbonate at the 2 , s positions acetoacetic ester,' I3r?CHC(OEt),CHHrCOOEt, in the ring. The p-keto-acid structure readily exand the addition of a variety of acids across t W J plains the decarboxylation of (VI) to form (1'11). inolecules of keteur: acetal t o form ethyl O-ethyl'The yellow anhydride (11)with absolute alcohol acetoacetattA,- C H,C ( 0 E t ) - -CHCOOEt. 'I'he yields a half-ester to which the structure ( I X ) is aspresent paper reports the results or a study of the signed. The reasons for this structure are the reaction o f ketene diethylacetal with the following ethoxyl conteii t, iieutral equivalent, and failure il,ij-uiisaturatcd carbonyl compouiids . m a k e o i the acid ester to decarboxylate on heating anhydride, acetyleriedicarboxylic ester, dimethyl- L-his latter characteristic definitely excludes the maleic anhydride, quinone, dibenzalacetone, hell- isomcric compound (X) from consideration. 'The zalacetone, benzalacetophenone and phorone. loss of the ethyl group from the :ðoxyl during In an ether solution ketene acetal reacts with the alcoholysis ol the anhydride was unexpected maleic anhydride in a ratio of 4 :1 to give, presuni- and seems quite unusual. The only explanation ably, the ~yclohrxanc.derivative (1) which then that can be oEered for this reaction presumes the passes, by the loss of alcohol, into ;S,;i-diethoxy- intermediate formation of the ketal IVIII) by the I ,ii-dihydrophthalic anhydride !II). This latter addition of two equivalents of alcohol to III), compound precipitates from the ether solution followed by the loss of ether from this ketal til after a few hours as yellow crystals iii a YOr; yield. produce i1X) The alcohol that is lost by I converts an equivalent 'I'he main support for the structure oi (11) IS its amount of ketene acetal uito ethyl orthoacetatc dehydrogenation by palladium t o the known When a mixture of ketene acetal and maleic an- 3,3-diethoxyphthalic anhydride (IV) and the h y hydride in the ratio of 2 1 is allowed t o stand in drolysis of this anhydride to 3,5-diethoxyphthalic acida3 The corresponding N-phenylphthalimide Mag-nani and McElvain TIIIJ J O U K N I L 60, 2210 (1088 The characteristic polarization of an d - u n
,-i
1) '1
McElvain a n d K n n d i ~ e rtbrd
84, 2 7 4
I
IN2
Frirsch
AOJI
296, $58 (1897)
KETENEDIETHYLACETAL WITH UNSATURATED CARBONYL COMPOUNDS
Feb., 1942
J
Benzene solution COEt
/I\
HC'
CHz
HCCO CH? Maleic anhydride
HCCO CH
btUC \'/I
C
I
26 1
/\
EtOC
CH-CO I >O CH C-CO %Et
11
+ in benzene
1
solution
o=c\/c=o 0
I1
+ 2EtOH
,/.
CHz=C(OEt)2 CHaC(OEt),
\
11
CH
\&'
6'/I
ll
0
0 VI
VI1
VI11
could be prepared by heating either the anhydride (IV) or the acid with aniline. It was also possible to obtain 3J-diethoxyphthalic acid in small yield from the reaction of ketene acetal with acetylenedicarboxylic ester. This reaction, as might be expected, was very much more sluggish than that between the acetal and maleic anhydride; in fact, it was necessary to heat the reactants in a sealed tube at 195' for twenty-four hours in order to obtain any appreciable quantity of the phthalic acid from the reaction mixture. Under such conditions most of the ketene acetal was converted to polymers and pyrolysis products. Since the condensation of maleic anhydride with ketene acetal produces a dihydrobenzene derivative, the formation of which requires the loss of one of the a-hydrogens of the anhydride, it seemed advisable to investigate the reaction be-
IV
V
IX
X
tween ketene acetal and dimethylmaleic anhydride which contains no such hydrogens. This anhydride showed no reaction with the acetal in refluxing benzene after twelve hours. At 175-180° in a sealed tube for fifteen hours a reaction occurred, since none of the starting materials was recovered. However, the reaction mixture on fractionation gave no definite fraction that could be characterized. The reaction between benzoquinone and ketene acetal starts a t about 80' and, without a solvent, becomes so violent that it cannot be controlled. In benzene solution, however, the reaction proceeds quite smoothly and two equivalents of the acetal are used up by each equivalent of the quinone. The main reaction product is a white crystalline material, m. p. 9495'. The ethoxyl content of this compound indicates that it has the bicycla-octadiene (XI)which is the result of
262
S. M. MCELVAIN AND HARRYCOHEN
Vol. 64
the addition of a single ketene acetal t o one of the quinone carbon t o carbon double bonds followed by the loss of ethyl alcohol. This alcohol converts the second equivalent of the acetal into ethyl orthoacetate, which was one of the lower boiling reaction products. The structure of the
of ketene acetal and gives 1,l diethoxy-2-cinnamoyl-3-phenylcyclobutane(XV). In this case there is no elimination of alcohol and consequently no formation of ethyl orthoacetate. The product (XV) is converted by hydrolysis with dilute acid into P-phenyl-ylcinnamoylbutyric acid (XVI) which proved to be identical with an 0 authentic specimen prepared by the procedure of Borsche.’ Bromination -CHz + CHsC(0Et)a of (XV) produces ethyl P-phenyl-y+ 2CH*=C(OEt)z + =COEt bromo-y-cinnamoyl-butyrate (XVII) ll ll by brominolysis of the cyclobutane 0 0 XI ring followed by the loss of ethyl broJHzO mide. Further treatment with broOH OH o-co mine produces a tribromo derivative I I (XVIII) by addition of bromine to \ -CH~COOCH~ fCHzNz ~-CH.COOH ()--CH~ the monobromo compound (XVII). No definite product could be obI I I tained from the reaction of ketene aceOH OH OH XI11 XI1 XIV tal and benzalacetone. When these reactants were allowed to reflux for bicyclo-octadiene (XI) is shown by its hydrolysis ten hours, only ethyl acetate, ethyl ortho-acetate to hydroquinone-acetic acid4 (XII) and the con- mixture formed. The main portion of this mixversion of this acid to its methyl ester (XIII) by ture was a non-distillable residue, the ethoxyl diazomethane and t o the corresponding lactone content (8.6%) of which indicated that i t was a (XIV) by heating just above its melting point.5 mixture of ketene acetal polymer and self-conThe fact that XI is colorless is further evi- densed benzalacetone. dence in favor of the 0 0 structure assigned to I/ 1I i t because the elecC~HE.CH-CHCCH=CHC~H~ CBH~CH-CHZCCH=CHC~H~ I I HzO I tronic conjugation of CHr-C (0Et)z + CHz-COOH the ethoxyl group with . xv XVI the lower carbonyl Cd%CH-CHBrCOCH=CHCaH5 CaH5CH--CHBrCOCHBrCHBrCeHs group neutralizes the EtBr I Brz I CHz-COOEt ----f CHz-COOEt + HBr ketonic nature of this XVII XVIII carbonyl. T h a t is t o Benzalacetophenone, which does not have this podion of XI is a say, the O=C--C=C-oEt I l l tendency t o undergo self-condensation, reacts vinylog of an ester and while quinone is vinylogous to the colored 1,2-&ketones, XI is a vinylog with ketene acetal as does dibenzalacetone of the colorless a-keto-esters. and forms l,l-diethoxy-2-benzoyl-3-phenyl-cyThis product On It w;ts not possible to cause a second molecule ‘lobutane of ketene acetal to add to (XI). This failure to yields ~-phenyl-y-benzoylbu~Yric acid8 (XX) form a tricyclic parallels the results which was characterized as its semicarba~one.~ 0 reported by Abuzov and Spekterman6 who found I1 that they could not force quinone to react with CsHaCH-CHCCaHj CeHaCH-CH2 CaH5 more than one equivalent of hexadiene. I I I CHz-C(0Et)z CHz-COOH Dibenzalacetone reacts with only one equivalent XIX xx
6
bl ’
’
0
1
+
P
(4) This acid is generally known as homogehtisic acid which was first obtained from the urine of alcaptonurics (ref. 5). I t has also been prepared by Hahn and Stenner, Z . physiol. Chem., 181, 88 (1929). by the ozonization of 2 allyl-hydroquinone dibenzoate and the hydrolysis of the resulting carboxylic acid. ( 5 ) C f . Wolkow and Baumann, Z . physiol. Chem., 16, 253 (1891). (6) Abuzov and Spekterman, Chem. Abs., S5, 2498 (1941).
Phorone, (CH&L!=CHCOCH=C(CH,)z, . .~ showed no signs of reaction with ketene acetal (7) Borsche, Ann., 376, 174 (1910). (8) Vorlander and KnMzsch, ibid., 194, 392 (1897). (9) Stobbe and Volland, Bw., 84, 655 (1901).
Feb., 1942
KETENEDIETHYLACETAL WITH a,@-UNSATURATED CARBONYL COMPOUNDS
263
even after they were refluxed together for twelve hours. Practically all of the ketene acetal was recovered unchanged. Such behavior would seem to indicate that the methyl groups of phorone, by their inductive effect, sufficiently reduce the cationoid character of each of the carbons in the p-position to the carbonyl group to prevent the reaction of either of them with the anionoid center of ketene acetal.
the yield of material that melted at 148-149" amounted to 2.3 g. (43%). It had a neutral equivalent of 252 (calcd., 256). Anal. Calcd. for C~rHlsOs: C, 56.3; H , 6.3; C,H50, 35.1. Found: C, 56.2; H , 6.2; C2H60, 35.1.
acid could be obtained by further concentration of the mother liquor. After recrystallization from ethyl acetate
(10) "Organic Syntheses," 18, 3 (1938); Ruhemann and Beddow, J . Chcm. Soc., 8'7. 1121 (1900).
(d) Dehydrogenation with Palladium.-In a 500-ml. flask fitted with a stirrer and condenser were placed 5 g. of palladium, 25 g. of 3,5-diethoxy-1,6-dihydrophthalic anhydride and 280 ml. of dry xylene. The mixture was refluxed and stirred for twenty-four hours. After this time the catalyst was removed by centrifuging the warm soluExperimental tion and then on cooling 7.4 g. of 3,5-diethoxyphthalic Reaction of Ketene Diethylacetal with Maleic Anhy- anhydride separated from the solution. Concentration dride.-To a solution of 4.9 g. (0.05 mole) of maleic an- of the mother liquors yielded an additional 2 g. of the anhydride in 75 ml. of dry ether in a 125-ml. flask was added hydride. After recrystallization from a dioxane-cyclo11.6 g. (0.1 mole) of ketene acetal. The solution turned hexane mixture the anhydride melted3 a t 137-138" and yellow and then red, and after one to two minutes the ether contained 37.8% (calcd., 38.1) ethoxyl. Hydrolysis conbegan to boil. The flask was cooled and after a few min- verted this anhydride into the 3,bdiethoxyphthalic acid3 utes the reaction subsided. The stoppered flask was then which, after recrystallization from an alcohol-water mixallowed to stand overnight. The yellow precipitate of ture, melted at 178-180". 3,5-diethoxy-l,6-dihydrophthalic anhydride (11) was fil3,5-Diethoxy-N-phenylphthalimide.-A mixture of 1.5 tered off and washed with dry ether; it could be recrystal- g. of the 3,5-diethoxyphthalic anhydride and 1.5 ml. of lized from xylene but for practically all purposes the ether- aniline was heated in an oil-bath a t 170" for twenty minwashed material was satisfactory. The yield of product utes. On cooling the semi-solid reaction mixture was that melted a t 110-111" amounted to 4.3 g. (71%). treated with 10 ml. of water and 2 ml. of a saturated Anal. Calcd. for C12H140j: C, 60.5; H, 5.9; C2Hs0, sodium bicarbonate solution and filtered. The remaining 37.8. Found: C, 60.5; H, 6.1; C2Hb0, 37.4. solid was washed with 10 ml. of 10% hydrochloric acid Reactions of 3,5-Diethoxy-1,6-dihydrophthalic Anhy- solution and twice with 10 ml. portions of water. The dride: (a) With Maleic Anhydride.-A mixture of 1.2 g. remaining phthalimide was warmed with 5 ml. of alcohol of the anhydride and 1.0 g. of maleic anhydride was heated containing a few drops of acetone and filtered. This treatin 10 ml. of dry benzene for four hours. On cooling, 1.1 g. ment removed most of the yellow color from the imide and (60%) of the dianhydride of 1,5-diethoxy-3,4,7,8-tetra-left 1.8g. (92%) of it as a white solid that melted a t 164carboxy-bicyclo [2,2,2]octene-5(111) settled out of the ben- 166'. Recrystallization from dioxane or ethyl acetate gave a product that melted a t 167-168'. zene solution. After recrystallization from a dioxanecyclohexane mixture it melted at 253-255'. Anal. Calcd. for C18Hl,04N: C, 69.5; H, 5.5; C2H50, Anal. Calcd. for CleHleOs: C, 57.2; H, 4.76; CzH60, 28.9. Found: C, 69.5; H, 5.5; CnHaO, 28.9. 26.8. Found: C, 57.5; H, 5.0; GH60,26.6. Reaction of Ketene Acetal and Acetylenedicarboxylic mixture of 9.8 g. of acetylenedicarboxylic (b) With Water.-To 1.2 g. of the dihydrophthalic an- Ester.-A hydride (11) on a crystallizing dish was added a few drops esterlo and 30 g. of ketene acetal was heated in a sealed of water. After several hours this mixture turned white tube at 195" for twenty-four hours. After the removal and was washed with benzene. The dibasic acid, pre- of material that distilled up t o 180" (1 mm.), a small resisumably (VI), so obtained melted a t 83-85' and contained due was left. Fractionation of the distillate so obtained 19.3% ethoxyl (calcd., 19.7%). It showed a neutral gave no definite fraction. To the residue was added 10 equivalent of 128 (calcd., 114). When this acid was kept ml. of a 30% solution of potassium hydroxide and the mixa t its melting point for fifteen minutes it was decarboxy- ture allowed to stand for four days. After extraction lated to 3-keto-5-ethoxy- A4-cyclohexenecarboxylic acid with ether the aqueous alkaline solution was then acidified (VII). This acid weighed 0.9 g. and, after recrystalliza- and filtered. The 3,5-diethoxyphthalic acid so obtained tion from an ethyl acetate-petroleum ether (60-68") mix- weighed 0.5 g. and melted a t 171-172'. When converted ture, melted a t 124-125" and had a neutral equivalent of t o the anhydride and the phthalimide derivative, products were obtained that produced no lowering in melting point 188 (calcd., 184). when mixed with the corresponding derivatives of the 3,5Anal. Calcd. for CgH1204: C, 58.7; H, 6.5'; CzH60, diethoxyphthalic acid obtained from the palladium dehy24.5. Found: C, 58.8; H, 6.6; GH60, 24.9. drogenation of (11). (c) With Alcohol.-A mixture of 4.9 g. of the dihydroReaction of Ketene Acetal and Dimethylmaleic Anphthalic anhydride (11) and 20 ml. of absolute alcohol was refluxed for four hours. The main portion of the alcohol hydride.-A mixture of 5 g. of dimethylmaleic anhydride was then removed under diminished pressure from the red and 20 g. of ketene acetal showed no sign of reaction when solution, and the separated solid, 2-carbethoxy-3-keto-5- heated a t 80" or in solution in refluxing benzene. If, howethoxy- A4-cyclohexenecarboxylic acid (IX), filtered and ever, the mixture was heated a t 175-180" for fifteen hours washed with dry ether. Additional quantities of this keto- in a sealed tube the following indefinite fractions could be
264
P. SI.MCELVAIN AND HXRKYCOHEN
"01. (i4
distilled after the removal of the ethyl acetate and ethyl (XV), after evaporation of the solvent and recrystallizaorthoacetate: (a) 2.2 g., b. p. 55-119" (1 mm.); (b) 1.3g., tion of the solid residue from petroleum ether, 0.6 g. of ethyl 8-phenyl-y-bromo-y-cinnamoylbutyrate (XVII), m. 1). p., 119-139' ( 1 mm.); (cj 2.1 g., b. p., 139-201" (1 p. 111-112°, was obtained. mm.); (d) 2.1 g., b. p., 201-206' (1 mm.). The Reaction of Ketene Acetal and Benzoquinone.--A Anal. Calcd. for C21H210tBr: Br, 20.0; C~HBO, 11.2. mixture of 27 g. of benzoquinone and 60 g. of ketene acetal Found: Br, 19.9; CLHSO,11.3. in 110 ml. of dry benzene was allowed to reflux for twelve When 1.76 g. of (XV) was treated with 2 equivalents of hours. The benzene was removed by distillation and the bromine in carbon tetrachloride as described above, 1.6 g. remaining material heated a t 100' (12 mm.) to remove the of ethyl p',{-diphenyl-y, e,r-tribromo-$-keto-caproate ethyl orthoacetate. The residue was then distilled a t 2 ~ X V I I I J111. , p . 171-172', was obtained. This product inm. and the fraction (39 9.) boiling a t 110--17Oocollected. way recrystallized from ethyl acetate. On redistillation the fraction that boiled mainly at 136 Anul. Calcd. for CSiHz,OiBrr: Br, 42.8; C?HjO, 8.0. 114' (1 mm.) amounted to 29 g. and solidified on cooling. Found: Br, 43.0; C2Ha0, 8.2. Recrystallization from a benzene-petroleum mixture gavc Reaction of Ketene Acetal with Benza1acetophenone.-A ~-ethoxy-2,5-diketo-bicyclo[4,2,0]octadieuc-~i,fi ( X I ) , 111. niixture of 22 g. of ketene acetal and 15.6 g. of benzalacetop., 91-95", phenonc was refluxed for twelvc hours. After this time Anal. Calcd. for CloHlcOa: C, 67.4; H, 5.t;: C2H:O. the c'xcess of ketene acetal was removed under diminished 25.3. Found: C, 67.0; H, 5.9; CLHSO,25.0. pressure and the remaining reaction product fractionated. Hydrolysis of (XI)to Hydroquinone-acetic Acid (XII) .-The following fractions were collected: (a) 1 g., b. p. A mixture of 5 g. oE (XI) and a solution of 2.5 ml. of con- 162-164" (0.5 nim.); (b) 6.9 g., b. p. 164-168' (0.5 mm.); centrated hydrochloric acid and 25 ml. of water was re- i c ) 15.3 g., b. p . 168-170" (0.5 mm.); (d) 0.8 g., b. p. fluxed for twelve hours. After cooling the solution was above 170" (0.5 mm.). Fraction (c) was pure 1,l-diextracted with six 20-1111, portions of ether. The ether et hoxy-2-benzoyl-3-phenyl-cyclobutane(XIX). solution after evaporation left 4.2 g. of crude hydroquinone A n a / . Calcd. for CrlHgaOa: C, 77.7; H , 7.4; CzHjO, acetic acid which, after recrystallization from an ethyl 27.8. Found: C, 77.3; H, 7.7; C2H50,27.7. acetate-petroleum ether (b. p. 60458") mixture, melted at Fraction (b) was practically pure (XIX) since it gave as 144-146' .'$ high a yield of 8-phenyl-y-benzoylbutyricacid8 (XX) as Methyl Hydroquinone-acetate.--To 0 . 3 g. of hydroquinone-acetic acid was added an ether solution of diazo- did fraction (c) when it was hydrolyzed by the procedure methane until the characteristic yellow color of the diazo described above for the hydrolysis of l,l-diethoxy-2(XV). This acid melted compound persisted. The solution then was filtered, the cinnanioyl-3-phenylcyclobutane that melted a t ether evaporated, and the remaining methyl hydroquinone- a t 155-156' and yielded a ~emicarbazone~ 21 1.."1"". acetate recrystallized from an ethyl acetate-petroleum Summary ether mixture. It melted. a t l16-l17'". Anul. Calcd. for CgHloOd: C, 59.4; H, 6.5; CH&, The reactions between ketene diethylacetal and 17.0. Found: C, 59.8; H, 5.5; CHaO, 17.0. a variety of u ,@-unsaturatedcarbonyl compounds Reaction of Ketene Acetal with Dibenzalacet0ne.--A have been studied and the structures of the reac-. mixture of 5.5 g. of ketene acetal and 7.7 g. of dibenzalacction products determitird. tone was heated a t the refluxing temperature of the acetal With maleic anhydride two equivalents of the for twelve hours after which time the excess acetal was reacetal add in the form, ----CH&(OEt)2--CH&rnoved under diminished pressure. The remaining light colored oil was dissolved in 30 ml. of warm alcohol. On (OEt)s--, to the carbon to carbon double bond of cooling and scratching the sides of the container 10.1 g. of the anhydride to form, presumably, a cyclohex1,l-diethoxy-2-cinnamoyl-3-phenyl-cyclobutane (XV) crysane derivative that loses two equivalents of alt.allized. After filtering, washing with alcohol and drying cohol and passes into 3,5-diethoxy-1,6-dihydroit melted a t 87-88'. Anal. Calcd. for CIaHzeOa: C, 78.8; H, 7.4; CtH,O, phthalic anhydride. This latter coinpound was dehydrogenated over palladium to 3,S-diethoxy35.7. Found: C, 78.7; H, 7.7; C2Hj0, 26.0. A mixture of 1 g. of l,l-diethoxy-2-cinnamoyl-3-phenyl-phthalic anhydride. The acid corresponding to cyclobutane, 2 ml. of concentrated hydroehloric acid, 8 ml. this anhydride also was prepared in small yields of water and 10 ml. of dioxane was refluxed for twelve by the saponification of the non-distillable resihours, and then the main portion of the solvent removed due from the reaction of ketene acetal and acetyunder diminished pressure. From the remaining residue lenedicarboxylic ester. Other reactions of 3,j0.8 g. of @-phenyl-y-cinnamoyl-butyricacid (XVI) sepadiethoxy- 1,6-dihydrophthalic anhydride are disrated. After recrystallization from an alcohol-water mixture it melted a t 157-158' and gave no depression with cussed. a n authentic specimen of this acid prepared by the procedWhen benzoquinone and ketene acetal react a ure of Borsche.? single molecule of the acetal adds to one of the One equivalent of bromine in carbon tetrachloride reacted rapidly with l,l-diethoxy-2-cinnamoyI-3-phenyl-carbon to carbon double bonds of the quinone. This addition product loses alcohol and passes cyclobut.ane (XV)in the same solvent, From 0.57 g. of
Feb., 1942
5- (METHOXYMETHYL) -~-FURALDEHY~E
into a bicyclo-octadiene (XI), which is converted by hydrolysis into hydroquinone-acetic acid (homogentisic acid). Both dibenzalacetone and benzalacetophenone react with one equivalent of ketene acetal to produce 1,1-diethoxy-2-cinnamoyl(orbenzoyl)-3phenyl-cyclobutane. Each of these products may
[CONTRIBUTION FROM THE CHEMICAL
265
be hydrolyzed to the known 8-phenyl-y-cinnamoyl(or benzoy1)butyric acid. Neither dimethylmaleic anhydride nor phorone reacts with ketene acetal under conditions that caused satisfactory reactions with the other a,@unsaturated carbonyl compounds. MADISON, WISCONSIN
LABORATORY OF THEOHIO
RECEIVED OCTOBER27,1941
STATE UNIVERSITY]
The Transformation of Tetramethylglucoseen-1,2 into 5-(Methoxymethy1)-2-furaldehyde BY M.L.WOLFROM, E. G. WALLACE AND E. A. METCALF Raymond1 has made the very reasonable and was afforded by the preparation of three crystalstimulating suggestion that 2,3,4,6-tetramethyl- line derivatives and comparison of two of these d-glucoseen-1,2 (I) may be the intermediate in the with authentic specimens prepared by other methinterconversion of tetramethylglucose and tetra- ods. These derivatives were the oxime (m. p. methylmannose in dilute alkali. This intercon- 97-98’), semicarbazone (m. p. 163.5-164.5’) and version has been investigated by Lewis and his acid (5-(methoxymethyl)-2-furoicacid of m. p. students.2 Tetramethylglucoseen was then syn- 67.5-68.6’). This aldehyde (111) is also the prodthesized in crystalline condition in this Labora- uct obtained on the acid treatment of tetramethyland i t is of interest t o note that I t was found that this substance was not fructofurano~e~ oxidized by Fehling solution and was thus not the methylated pentoses produce furaldehyde alkali-sensitive. Lewis and co-workers2noted that on treatment with mineral acids6 The conversion of tetramethylglucoseen into the equilibrated alkaline solution of tetramethylglucose exhibited an abnormally high hypoiodite 5 - (methoxymet hyl) -2 -furaldehyde by mineral consumption which was brought to a normal acidity is, however, a complex reaction and some value by acid treatment. Tetramethylglucoseen information was obtained regarding its course. was found3 to consume four atoms of iodine per HC=O HC=O I I mole, or a value of 200% “apparent tetramethylCOMe C=O HC-1 aldohexose.” I I II I + CH ---f CH 1 The behavior of tetramethylglucoseen in acid M ~ O C H FH I media was then of interest. It was soon found HCOMe I I that it did not form a mixture of tetramethylH&OH Hemannose and tetramethylglucose and was thus I I I CH20Me CH20Me not an intermediate in the interconversion of I11 these two sugars. I t s behavior in acid media was nevertheless of interest and a report of this study HC=N-NHCsHs HC=N-NHCaHh I I is the subject of the present communication. C=N-NHCEH~ C=N-NHCsHr The final product of the acid treatment of I I CH -+ CH tetramethylglucoseen has been found to be 5/I 11 (methoxymethyl)-2-furaldehyde(111). This was CH CH I I I identified by freezing point (-go), analysis, and HCOHCOAc HCOH by its behavior with Fehling solution and with I CHzOMe I I CHzOMe CH20Me acid resorcinol. Further confirmation of identity
!
1
HLO-J
IV
( 1 ) A L. Raymond in Gilman, “Organic Chemistry,” John Wiley and Sons, New York. N . Y , 1938, Vol. 11, p. 1512. (2) M. L. Wolfroni with W. Lee Lewis, THIS JOURNAL. SO, 837 (1928); R . 13. Greeue with W. Lee Lewis, i b i d . , SO, 2813 (1928). cf J. H. Simons and H . C.Struck, i b i d . , 66, 1947 (1934). (3) M. L Wolfrom and D. R . Husted, i b i d . . 69, 2559 (1837)
V
VI
(4) W. N . Haworth, E. L. Hirst and V. S. Nicholson, J . Chem. S o c . , 1513 (1927). (6) C. E. Gross with W. Lee Lewis,T H r s JOURNAL, 2772 (1931); H . T.Neher with W. Lee Lewis. ibid., 68, 4411 (1931); K. G. Bott and E. L. Hirst, 1.Ckcm. SOL,2821 (1932).
a,
