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,
M. L. WOLFROM, E. G. WALLACE AND E. A. METCALF
266
Vol. 64
tetramethylaldohexose") . The reaction between an aldehyde and hypoiodite, under the conditions C=O of the Cajorie procedure employed, is represented by the equation &H &H c=o I IICH RCHO + IZ + NazC03 RCOZH + 2NaI Cog CH CHZ The reaction of tetramethylglucoseen with I CHOH I CHO CHO--I 3 iV hydrochloric acid a t 25' was interrupted t I I a t the sixty-five minute stage, which was the CH~OH CH~OH CH~OH VI1 VI11 point of minimum in the polarimetric curve. A low yield of final product, 5-(methoxymethyl)-2furaldehyde, was obtained a t this point by isolaCOH c=o tion as the semicarbazone. A crystalline phenylI c=o osazone, nbt isolable a t the completion of the I reaction, was obtained. This substance (rn. p. CH CH It 120.5-121.5') was optically active (spec. rot. C - - - - J -go, D line, CHC13) and analyzed for a monoI I CHzOH CHzOH methyl phenylosazone of the parent structure IX C6Hs04. Bergmann and Zervas' had obtained It was found that a 5% solution of tetramethyl- a phenylosazone of the same parent structure glucoseen in 3 N hydrochloric acid a t 25' were by the direct treatment of glucoseen-1,2 tetrafavorable conditions for following the course of acetate (oxyglucal tetraacetate) with phenylthis reaction. Polarimetrically (curve A of Fig. 1) hydrazine and subsequent deacetylation, a monothe reaction was found to consist of a very rapid acetate (very probably on carbon six, being reaction producing a levorotatory substance fol- obtained initially. The same substance was prolowed by a slower reaction reaching optical in- duced by these workers from galactoseen-1,2 activity in about eight hours. A minimum in the tetraacetate. For the parent structure, C6H804, polarimetric curve was reached a t about sixty-five Bergrnann and Zervas - proposed two formulas minutes. The copper reduction curve (curve B (VI1 and VIII), favoring the latter (VIII), of Fig. 1) followed the initial faster reaction mainly on the basis that their monoacetate was whereas the hypoiodite consumption curve (curve recovered unchanged on further mild acetylation. C of Fig. 1) paralleled the slower reaction. The Formula VI11 is a dihydro derivative of kojic acid (TX) and some additional, but not definitive, support for this structure has been obtained .-g % 50 +15" Ig5 5 in studies of the phenylosazones of certain B 100 170 racemic reduction products of kojic acid.8 g$ gi f u 0 These two fundamental structures (VI1 and ug 82 a 120 s a VIII, but with a methoxyl group on the tera.z 25 0 $8 2 2 minal primary carbon atom) also come into uM $ " consideration in allocating a structure to the a E 0 -loo 70 parent substance of the phenyloszone isolated F9 in our work. Of these, we favor the acyclic 0 2 4 6 8 10 tautomer of (VII) for the parent body of our Time, hours. isolated monomethyl phenylosazone (V) beFig. l.-Rate of change of 2,3,4,6-tetramethyl-d-glucoseen-l,2 cause this osazone could be further acetylated (5%) in 3.00 N hydrochloric acid at 25' as followed by polarimeand the acetate introduced was o-acetyl try (A), copper reduction (B) and hypoiodite consumption (C). as judged by the fact that i t could be saponilatter began with an iodine consumption of four fied by the Kunz p r o c e d ~ r e . ~The experience of atoms of iodine per mole of starting tetramethyl- this Laboratory has been that the N-acetyl derivaOf about "% glucoSeen and dropped to a (6) F. A. Cajori, J . Biol. Chcm., 64, 617 (1922). Of that required for an iodine ConSUmption of two (7) M. Bergmann and L. Zervas, Ber., B ~ B1434 , (1931). atoms per mole of tetramethylglucoseen monoal~ ; e ~ ~ o ~ " ;(1931); ~ ~ J.~ W. ; Armit g ~ and ~ ~T.~J. dehydic conversion product (70% "apparent (9) A. Kunz and c. s. Hudson, T ~ JOURNAL, ~ S 48,1982 (1926). HC=O
I
1
' A
4-A
2
1
+
!
+
*
Ni:n3.
5-(hqETHOXYMETHYL)-2-FURALDEHYDE
Feb., 1942
tives of sugar nitrogen carbonyl condensation products are not saponified by this procedure.1° Our osazone could not be obtained directly from che tetramethylglucoseen but this observation cannot be correlated with the circumstance that glucoseen tetraacetate formed an osazone directly, since the acetate groups are undoubtedly more labile under these conditions than are the corresponding methoxyl groups. As Bergmann and Zervas7 have noted, these transformations of the very sensitive glucoseens can be considered as intramolecular dismutation reactions involving the elimination of water or, in our case, of methanol. This can be represented schematically as follows.
Te tramethylglucopyranose
was treated with a n excess of barium carbonate, and filtered. To the filtrate was added a filtered solution (5 cc.) containing phenylhydrazine hydrochloride (0.5 9.) and potassium acetate (0.8 g.). The oily solid that separated was removed by decantation, washed with water by decantation and crystallized from ethanol (decolorizing charcoal) by the addition of water; m. p. 118-119.5'. Pure material was obtained on crystallization from acetonewater or ethanol-water; m. p. 120.5-121.5", spec. rot. -9" (21°, c 2.9, U. S. P.I3 CHCla). The substance crystallized in the form of long, yellow needles. Anal. Calcd. for ClaHIQ0N4-OCHa: C, 67.43; H , 6.55; N, 16.56; OCH3, 9.17. Found: C, 67.43; H, 6.55; N, 16.29; OC&, 8.89. No reaction was noted when tetramethylglucoseen was treated with phenylhydrazine acetate under the above conditions (or a t 98" for twenty minutes) but with omission of the 3 iV acid treatment. This phenylosazone could
I
I n the course of this work, the preparation of the tetramethylglucoseen was improved, although the previously recorded constants were verified. We also record the crystalline 1-acetate of tetramethylmannopyranose.
Experimental Preparation of 2,3,4,6-Tetramethyl-d-glucoseen-1,2.The procedure of Wolfrom and Husted3 was modified. In the preparation of the 1-bromo derivative from the 1acetate of tetramethylglucopyranose, the chloroform was replaced by toluene and the final solvent removal was effected at room temperature or lower, a t a pressure of 3-4 mm. After the ether-dioxane solution of the crude tetramethylglucoseen had been filtered from inorganic salts, the sirup obtained on solvent removal under reduced pressure was dissolved in six parts of water, filtered and extracted repeatedly (eight times) with ether. The extracted material was then distilled in a Hickman pot still" at mm.; m. p. 13" (by cooling curve method), spec. rot. +15" (32', c 3.8,Hz0).12 The constants previously recorded3 for this substance were: m. p. 12', spec. rot. +15' ( 3 0 " , c 2, H20). The compound is best stored a t the temperature of solid carbon dioxide-acetone, coloration being noted in four to five days a t 0". Isolation of the Phenylosazone of the Intermediate Product.-2,3,4,6-Tetramethyl-d-glucoseen-l,2 (0.25 g.) was dissolved in 5 cc. of 3 N hydrochloric acid at 25" and maintained a t that temperature for sixty-five minutes. These conditions of acidity and temperature were selected after preliminary experimentation, which showed that the reaction rate increased with temperature and with acid concentration. At the end of this period, the solution (10) hI. L. Wolfrom, hl. Konigsberg and S. Soltzherg, THIS 68, 490 (1936). (11) K. C. D. Hickman and C. R. Sanford, J . P h y s . Chem., 34,637
JOURNAL,
(1930). (12) All rotations are recorded to the D line of sodium light, 32' is the temperature c is the concentration in grams per 100 cc. soh.
267
I1
111
not be isolated, even on nucleation, from the oily phenylhydrazine reaction product obtained from the neutralized solution after the completion of the reaction (eight hours a t 25") between tetramethylglucoseen and 3 iV hydrochloric acid. Phenylosazone Monoacetate of the Intermediate Product.-The above-described phenylosazone (100 mg.) of the intermediate product was acetylated overnight a t 15" with pyridine (2 cc.) and acetic anhydride (0.5 cc.). The crude solid (100 mg.) obtained on pouring the reaction mixture into ice and water was purified from 60% ethanol; m. p. 131-132'. The substance formed flaky, golden crystals and was dextrorotatory in chloroform solution but the amount of material available was insufficient for an evaluation of this constant. Anal. Calcd. for C I ~ H ~ ~ O N ~ - O C H ~ - C C, O C66.30; H~: H, 6.36; N, 14.73; CH,CO, 2.43 cc. 0.1 N NaOH per 100 mg. Found: C, 66.23; H, 6.33; N, 14.68; O-Ac,lO 2.61 cc. S-(Methoxymethyl)-2-furaldehyde from 2,3,4,6-Tetramethyl d glucoseen 1,2.-2,3,4,6 - Tetramethylglucoseen-1,2 (5.45 9,) was brought to a volume of 100 cc. in 3 N hydrochloric acid at 25' and maintained a t that temperature for eight hours. At the end of this period the solution was neutralized with barium carbonate, filtered and extracted with chloroform. The sirup obtained on solvent removal from the dried chloroform (decolorizing charcoal) extract was distilled in the Hickman pot still a t 10-3 mm.; yield 2.82 g. (81%). The distillate was not pure for it was slightly optically active. I t was purified through the semicarbazone. The above distillate (2.82 8 . ) was dissolved in the least amount of hot water, Semicarbazide hydrochloride (2.82 g., 1.25 moles) and sodium acetate (2.5 g., 1.5 moles) were dissolved in a small amount of hot water and added to the above hot solution. The product crystallized on cooling; yield 3.00 g. (76%), m. p. 153.5-154.5".
-
-
-
(13) United States Pharmacopoeia
&I. L.
208
WOLFROM,
E. G. WALLACE
This material was of sufficient purity for the succeeding step but for identification purposes a portion was purified to constant melting point from absolute ethanol; in. p, 163.5-164.5" (uncor.), unchanged on admixture with il specimen of 5-(methoxymethyl)-2-furaldehydesemicarbazone (ni. p. 163.,5-164.5°) prepared from tetramethylfructofuranose according to the procedure of Haworth, Hirst and Nicholson." Haworth and co-workers record the nielting point of 166-lfj7' for this substance and Mid170'. We were unable to verify these d e n d ~ r p records '~ higher melting points. When the semicarbazone was recrystallized from ethyl acetate-hcptane, the maximum melting point was found to be 156--157"but when such a preparation was ground in a mortar the melting point of lt3.5-1t34.5* was obtained.
A n d . Calcd. for C7H8O2N3-0CH3:C , 48.72; H, 5 6 2 ; N, 21.31; OCIlr, 15.74. Found: C, 48.i8; H, 5.45; N,
AND
E. .A.
METCALF
Vol. 64
workers4 record the melting point of 103-104" for this substance. For further confirmation of the identity of 5-(methoxymethyl)-2-furaldehyde, the distilled liquid (1.00 9.) was oxidized to the corresponding acid with alkaline permanganate according to the procedure of Franklin and Aston16 for the preparation of furoic acid from furaldehyde except that the reaction product was isolated in a different manner. The filtrate from the manganese dioxide separation was concentrated to dryness under reduced pressure at 45"' dissolved in a small amount of dilute hydrochloric acid, concentrated under reduced pressure to one-third its volume, acetone added and concentration continued. The crystalline product so obtained was purified from petroleum ether-ether; yield 0.43 g., m. p. 67.5-68.5' (uncor.). Haworth and co-workers4record a melting point of 72-73', with softening a t 69', for 5-(methoxymethyl)-2-furoicacid and Cooper and N ~ t t a l l record '~ 67.5-68.5". Tetramethyl-d-mannopyranose-I(a)-acetate.-Crystalline tetrarnethylmannopyranose (100 9.) was acetylated a t the temperature of the boiling water-bath for three hours (mechanical stirring) with acetic anhydride (500 cc.) and twice-fused sodium acetate (15 g.). The cooled solution was filtered from undissolved sodium acetate, which was washed with toluene. To the filtrate was added toluene (200 cc.) and anhydrous ether (200 cc.) and the acetic anhydride removed under reduced pressure ai 40--5Oo, more of the toluene and ether being added to the rcsidue and again distilled, to effect complete removal of the acetic anhydride. The resultant sirup was dissolved in anhydrous ether and filtered (decolorizing charcoal) from the sodium acetate. The sirup obtained on ether removal under reduced pressure was crystallized by cooling in a solid carbon dioxide-acetone bath, warming in an icebath and stirring with anhydrous ether; yield 52 g. Pure material was obtained on further crystallization from anhydrous ether; 111. p. 48.5-49.5", spec. rot. +ti3" (2lC, c 4.t:. absolute chloroform), +56' ( a i " , c 3.1, water). The substance was soluble in the common organic solvents and was appreciably soluble in water. Anal. Calcd. for Cl~H~gOe(COCHs): CHaCO, 3.59 cc. 0.1 N NaOH per 100 mg. Found: CH,CO, 3.62 cc.
21.64; OCHa, 16.13. This semicarbazone also was isolated, but in low yield, from the neutralized solution obtained after a sixty-five minute reaction period between tetramethylglucoseen and 3 IV hydrochloric acid a t 25.. The aldehyde was regenerated from the semicarbazone according to the general procedure of Wolfrom, Georges and Soltzberg.ls The above semicarhazone (3.00 9.) was dissolved in 225 cc. of water a t 60" in a flask fitted with an aspirator (nitrogen dioxide fumes) and a mechanical stirrer. A solution of 18 g. of sodium nitrite in 90 cc. of water was added. Then 50 cc. of hydrochloric acid ( 1 :I) was added dropwise. After a three-minute interval, 14.4g. of sodium nitrite was added slowly, followed after two minutes by the dropwise addition of 28.8 ce. of hydrochloric acid ( 1 : 1 ) . After a three-minute interval a likeamount of sodium nitrite was added slowly, followed, after a twoininutc interval, by a like amount of the acid. After a threc-minute intwval an equal amount of sodium nitrite was added and stirring (decolorizing charcoal) continued until the cvolut.ion of osidrs of nitrogen ceased. The filtered solution was extracted with chloroform and the sirup obtained on solveiit removal from the dried (decolorizing rharcoal) extract was twicv distilled froti] a Hickman pot i l i l l at i ~ rniii.; ~ - yield ~ 1.77 g. (XU%), optically inactive, We are indebted to Mr. E. Grilly (NYA Proi n . p. -8" ~ l j ycooling curve). Middendorp14 records a iiielting poirii of --9 ' for ~-(methoxymethvl~-2-furalde- ject 0 . S. V.) and to Mr. Arthur D. Evans, Jr., hydt. for assistance in the experimental work. A n d . Calcd. for C7HiOa: C , Ml,MJ: Ii. 5.71. Found: c', 59.34: H, 3.tX. Summary The substance had a pleasant, coumarin-like odor, re1. 2,3,4,6 - Tetramethyl - d - glucoseen - 1,2 is duced hot Fehling solution and gave a brick-red precipitransformed into 3-(methoxymethyl)-2-furaldetate on heating a solution made from a drop of the mahyde by hydrochloric acid. ierial, 3 ce. of hydrochloric acid (1 : 2 ) and a few drops of a 2 . The rates of change in optical rotation, 5% resorcinol solution. The substance formed an oxime which was purified from copper reduction and alkaline iodine consumption low boiling petroleum ether-ether ; ni. p. 97-98" (uncor.) have been followed throughout the course of the tinchanged on admixture with a specimen of 5-(methoxyreaction. methyl)-2-furaldehyde oxime (ni. p. 9 7 9 8 ") prepared from 3 . An intermediate product has been isolated tetramethylfructofuranose according to the procedure of Haworth, Hirs;t and Yicholson.' Haworth and co- as a phenyloszmne, further characterized as a (14)
J . A. Middendorp. Ksc. Iran. chim., 38, 25 (1919).
{Is) M.
1,. Wolfrom. I s . ~ , ~ h i i66, . , 17Q1 f$!4.JJi
L. W. Georncs and S. Soltzhrrg, ' 1 " ~
tnonoacetate, and a structure (11) proposed for it. (16) P. F. Franklin and P.W. Aston. .I. CkPm. Soc.. 19, 515 (1901 (17) W t;. < ' u w r r a n d U' t 1 N u t t i i l l . i h i d , 99, L I W (1911).
INTERMOLECULAR CONDENSATIONS IN POLYMERS
Feb., 1942
4. 2,3,4,6-Tetramethyl-d-glucoseen-1,2 is not a probable intermediate in the epimerization of tetramethylglucopyranose. 5 . An improved preparation of 2,3,4,6-tetra-
[CONTRIBUTION FROM
THE
269
methyl-d-glucoseen-1,2 is recorded. 6. Tetramethyl - d - mannopyranose - 1(a)-acetate has been synthesized in crystalline condition. COLUMBUS, OHIO
RECBIVEDOCTOBER3, 1941
NOYESCHEMICAL LABORATORY, UNIVERSITY OF ILLINOIS ]
Intramolecular Condensations in Polymers* BY FREDERICK T. WALL Recent experimental investigations by Marvel and co-workers1 have shown that polymers of the type formed from methyl vinyl ketone can undergo intramolecular aldol condensations upon heating. The reaction which takes place can be illustrated for a portion of the polymers as follows :
not enter into condensation reactions, they must remain in the polymer. Assuming that the condensations take place in a perfectly random way, the amount of oxygen that can be expected t o remain in a polymer is simply a matter of probability and statistics. -CHz-CH-CH~-CH-HzO -CHz-CH-CHz-CHThe statistical problem involved -+ I i i I here is similar to but not identical c=o c=o (I1) with one considered by Flory and I I CHI CH3 CH3 others2 Flory was concerned with H (1) the removal of pairs of substitu-CHz-CH-CH~-CHI I ents from vinyl polymers. The difference between that problem Or CHa and the present one is that in the 0/‘\e/‘\ H former a given substituent could If the condensations were to continue down the react (be removed) only once, whereas in the entire length of the polymer chain according to present instance a given acetyl group might only one of the patterns, I1 or 111, then all of the react twice, once through its carbonyl and once oxygen save one end atom would be eliminated. through its methyl group. Three cases of the Experimentally1 it was found that the elimination problem will be considered. First it will be asof oxygen was far from complete so the question sumed that all of the acetyl groups are situated 1-3 with respect to their nearest neighbors. This naturally arose as to the reason. The failure t o eliminate nearly all of the oxygen is the so-called “head t o tail” polymer. Next the upon heating can be explained qualitatively in problem will be treated on the assumption that the following way. Supposing that the conden- the vinyl units are oriented at random, giving sations take place in accordance with either of rise t o 1-2, 1-3 and 1 4 linkages. Finally there the patterns I1 or 111, i t is seen that pairs of will be considered the case for which the vinyl carbonyls will ultimately face each other at vari- units are linked up alternately “head t o head” ous places along the chain and “tail to tail,” giving rise to alternating 1-2 and 1 4 linkages. For each of the prob-CH~-CH-CHZ-CH-CH~-CH-CH~-CH1 I i I lems i t will be assumed that an intra(Iv) molecular condensation can occur only beCH3/‘\C/’‘\(-J O//c\C/c\CH3 tween two acetyl groups which are reH H moved from each other by not more than Since the oxygens of such pairs of carbonyls can- three carbon atoms, and that not more than * Since the preparation of this manuscript, a note by P. J. Flory one condensation can occur between a given pair [THIS JOURNAL, 64, 177 (1942)l has come to the author’s attention. It further be supposed that Of In this note, Flory treats one of the problems considered in the present paper. but by a different method. The present treatment percondensations compatible with the above asmits immediate extension to random polymers and to copolymers sumptions can take place with equal probability. which could not be done by Flory’s method.
ACAO
(1) (a) C. S. Marvel and C. S. Levesque, THISJ U W R N A L , 60, 280 E. H. Riddle and J. 0. Corner, ibid., 64,
(1988): (b) C . S. Marvel, 92 (1942).
(2) (a) P. J. Flory, ibid., 61, 1818 (1939); (h) F. T.Wall, i b i d . , 64, 803 (1940); (c) F. 1’. Wall, ibid.. 68, 8’21 (1941); ((1) K. Simha. i b i d . . 68, 1479 (1941).
