July 20, 1!25.i
NOTES
consequently, the results must be treated with some reserve. It may be noted that the analysis for the basic amino acids by Corfield, Howitt and Robson (Table I, footnote z ) used the chromatographic technique on 15-cm. columns which we have employed; the results are in good agreement. The work of Roche, Michel and Bozzi-Tichadou (Table I , footnote nl) suggests that the composition of the silk fibroin of Boinbyx mori may depend upon the exact geographical source of the silk; perhaps some variations in the results of the literature may be attributed to this cause. Literature references to amino acid analyses of T S F are fragmentary but would indicate a difference between BSF and TSF.
mitted, a translation of the paper by Tsintsevich and Botvinik (Table I, footnote a o ) has been obtained. They comment also upon the reversal in the ratio of glycine t o alanine in the two fibroins. Attention should be called t o a recent paper of F. Lucas, J. T. B. Shaw and S. G. Smith (Shirley Institzde Memoirs, 28, 77 (1955)), which lists partial analyses of fibroins from Bombyx mori silk, from several Tiissah silks, and from three Anaphe silks.
SOTE ADDED
IS PROOF
--Since
this manuscript u as sub-
3913
Acknowledgments.--\\-e wish to express our thanks to Professor S. Mizushiiiia for supplying the sample of Tussah silk and to Dr. C. 13. IT.Hirs for the details of the separation of tyrosine on Dowex 2 prior to publication. This investigation was supported in part by a contract between the Quartermaster Corps, U. S. Army and the Cilifornia Institute of Technology. PASADENA 4,CALIFORNIA
Studies on Chrysenoxazoles
chrysenequinone under pressure. The products obtained were even under these conditions the corBY WILLIAMIBRAHIM AWAD AXD ABDEL REHIMABDEL responding oxazoles (11) and not the imidazole^.^ RAOUF 2-Methylchrysenoxazole also has been preRECEIVED MARCH1, 1955 pared by the action of diazoethane on chryseneIt was found recently' that chrysenequinone (I) quinonimine in a similar manner t o the action of reacts with aldehydes and ammonium acetate in diazomethane on chrysenequinonimine. acetic acid to give chrysenoxazoles and not imidaAnother attempt to prepare chrysenimidazoles zoles as expected from the general procedure for through the interaction of the diimine acetate and the preparation of phenanthrimidazoles2 and have aldehydes was unsuccessful since chrysenequinone concluded that, in contrast to phenanthraquinone, when allowed to react with ammonium acetate in one carbonyl group of chrysenequinone is more acetic acid did not yield the diimine acetate4 as exactive than the other. pected. A pale yellow compound was obtained which we believe to be chrysenequinonimine anhyb dride (111),since it proved to be identical with the a
n
4
11, a
I, a and d = H 11 and c = carbonyl group
-,
LA-
=
H
b, c = carbonyl group d = methyl group bond distances; ------- van der Waals radii.
I n continuing this investigation, we have allowed amines (R-CH~-NH*) to react with ( 1 ) W. I. Awad and A. R. A. Raouf, THISJ O U R N A L , 77, 1013 (1955). ( 2 ) E. A . Steck end A . R . Day, ibid., 86, 452 (1943).
(3) Compare the reactions of phenanthraquinone and retenequinone with amines under pressure by G. M. Jaffe and A. R D a y , J . Ora. Chcm., 8,43 (1943). (4) For the preparation of phenanthraquinone diimine acetate and its interaction with aldehydes to give phenanthrimidazoles, compare ref. 2.
XOTES
3914
compound obtained by the dehydration of chrysenequinonenionoiniine with acetic a n h y ~ l r i d e . ~ XLI
4- NHdOOCCHs 2 (1) + 2 chrysenequinonimine anhydride (111) c--
- H10
This compound was obtained also, according to a German Patents by allowing ammonia to react with chrysenequinone in boiling nitrobenzene, but no constitution was assigned to it. It is clear from the above reactions that in contrast to phenantliraquinone, chrysenequinone has one carbonyl group more active than the other. 0 x 1 drawing the chrysenequinone nlolecule (I) using the known bond distances and van der LYaals radii,' one can conclude t h a t the carbonyl group (c) near the naphthalene nucleus is hindered more sterically than the other carbonyl group (b). Thus it would appear that chrysenequinoniniine is represented best as IVa rather than IVb, since it could be prepared by the action of alcoholic arninonin on the quinone a t room temperature. " 11
0 I1
The oxazole is most probably derived from this structure.' Similarly, retenequinone (1-methyl-7-isopropylphenanthraquinone (11)) has one carbonyl group (c) more sterically hindered by the proximity of the methyl group (d), than the other carbonyl group (b). Schonberg and A ~ a dhave ~ ~dis~ cussed the uncertainty of the structure of retenequinoniniine, but in our opinion it is the carbonyl group (b) t h a t is converted to -C=NH grouping, especially it is obtained by the action of alcoholic ammonia on retenequinone at room temperature. lo Retenoxazoles most probably have the corresponding structure and not that mentioned in a previous paper.g As an experimental proof for the difference in activity of the two carbonyl groups of retenequinone, Jaffe and Day3 have found that this quinone when allowed to react with amines (RCH2.NHy) under pressure yielded only oxazoles and not imidazoles. Steck and Day2 found that retenequinone when heated with ammonium acetate in glacial acetic acid, yielded a compound which was not the diiniine but in their opinion may be aminoretenol. However, by carrying out this reaction in the pres( 5 ) For the preparation of phenanthraquinonimine anhydride by t h e dehydration of the corresponding imine compare A . Schonberg and B. Kosenthal, Bcr., 64, 1789 (1921). (6) German Patent 659,593; Cent. Blolt., 11, 1491 (1938). (7) Linus Pauline, "The N a t u r e of t h e Chemical Bond," 2nd. Ed. (19501, Geoffrey Cumberlege, Oxford University Press, London. (8) A. Schonberg and W. I. Awad, J . Cham. SOL.. 651 (1947). (9) I b i d . , 72 (1950). (IO) von Eugen Bamberger and S. C. Hooker, d n n . , $29, 121 (1885).
1701.
77
ence of aldehydes they obtained reteniinidazoles (mixed with retenoxazoles), although they havc intermediatc. failed to isolate the diirnine as In our opinion, their compound (the amitiorctc1101) is more likely to be retenequinonimine anhydride in analogy with the corresponding compound obtained from chrysenequinone. However, this problem is still under investigation. Experimental" Preparation of 2-Alkyl- and 2-Arylchrysenoxazoles from Chrysenequinone and the Corresponding Amine, under Pressure. ( a ) 2-Methylchrysenoxazo1e.-Five-tenths grani of chrysenequinone and 10 mi. of 25% aqueous ethylamine, in 15 nil. of ethyl alcohol, was heated a t 100" in a sealed tube for 6 hours. The product obtained by cooling was recrystallized from ethyl alcohol as pale >-ellow needles, m.~>. 167", undepressed on admixture \r-ith the product of diazoethane on chr)-senequinonitnine; yield 0.2 g. I t gave no color with concentrated sulfuric acid. Anal. Calcd. for C?&IL80N:C, 84.8; 11, 4.6; S , 4.9. Found: C , 83.9; H , 4.64; S, 4.7. ( b ) 2-Ethylchrysenoxazole.-Five-tenths grani of clirysenequinone, and few drops of n-propylamine, in 20 ml. of benzene were heated a t 100" in a sealed tube for 6 hours. The product came down after concentration and cooling, and was recrystallized from methyl alcohol-benzene mixture to give pale yellow crystals, m.p. 156", yield 0.3 g. I t gave no color with concentrated sulfuric acid. The product ivas proved to be 2-etl1~-lchrysenoxazoleby m . p . and mixed in.11. determinations.l Anal. Cnlcd. for C?1Hli04: C, 84.5; H , 5.1; S ,4.7'. Found: C , 84.9; H,5 . 3 ; S,4.8. (c) 2-n-Propykhrysenoxazole.-Five-tentlis grain of chrysenequinone and a few drops n-butylamine in 20 rnl. of benzene were heated a t 100' in a sealed tube for 6 hours. The benzene was evaporated and the residue was recrystallized from methyl alcohol to give pale yellow needles, m.1). 116-117" brown melt, 1-ield 0.4 g. I t gave blue-green color with concentrated sulfuric acid, then the color faded. The product was proved to be 2-n-prop~lclirysenosazole b>. m.p. and mixed m.p. determinations.1 Anal. Calctl. for C ~ ~ H I ~ OCN, :84.9; H , 5 . 5 ; N,4.5. Found: C, 88.2; H, 5.6; N. 4.6. ( d ) 2-Phenylchrysenoxazole.-Five-tenths gram of clirysencquinone, and few drops of henz?.Ianiine, in 10 nil. of benzene were heated a t 120' in a sealed tube for 8 hours. The product obtained on cooling as recrystallized from sylenc to give colorless fluffy crystals, m.p. 208-269", yield 0.3 g. I t gavc a yellow color with concentrated sulfuric acid. The product \vas proved to he 2-pIien\.lcliryser10~~zole by 1n.p. and mixed m.p.determinations.' Preparation of Chrysenequinonimine Anhydride (111). ~One gram of ciirysenequirionir~lineand 15 mi. of acetic anhydride was heated for 20 minutes on a steam-bath and the product filtered while hot. I t was recrystallized from nitrobenzene to give yellow crystals, m.p. 320°, yield 50%. The m . p . was undepressed on admixture with the product of the action of ammonia on quinone in boiling nitrobenzene.& It gave no color with concentrated sulfuric acid. A n a l . Calcd. for C3eI-€?nOSr: S , 5.7. Found: N, 5.8. Action of Ammonium Acetate and Glacial Acetic Acid on Chrysenequin0ne.-Il'hen 2 g . of chrysenequinone, 16 g. of ammonium acetate and 25 ml. of glacial acetic acid were refluxed for 1 hour, a deposit began to separate in 10 minute.;. The product was filtered, recrystallized from benzene, toluene or xylene to give yellow crystals, m . p . 320°, utidepressed on admixture I\ it11 the product from acetic anhydride ami chryscnequinoiiitnille; >-ield 1 .s g. I t gave no color ivitli concentrated sulfuric acid. .-lnal. Calcd. for CIsHnoOS:: C , 87.1; 1 1 , 4 . 0 ; s , 5.7. Found: C, 87.4; I$, 1.2; S,5.8. Action of Diazoethane'Q on Chrysenequin0nimine.-Twotenths gram of the imine was suspended in ether, cooled in an ice-bath, treated with an excess of ethereal diazoethane (11) Microanalyses were carried out by Alfred Bernhardt, Germanv SIelting points are not corrected (12) E. A. Werner, J. Ckern. S O C ,116, 1093 (1919).
3915
NOTES
July 20, 1955 solution and left for 6 hours. The ether then was evaporated and the residue recrystallized from methyl alcohol to give pale yellow needles, m.p. 167", yield 0.1 g. It gave no color with concentrated sulfuric acid. This product was proved to be 2-methylchrysenoxazole by m.p. and mixed m.p. determinations.l3 Anal. Calcd. for C2oHIION: C, 84.8; H , 4.6; 3,4.9. Found: C, 84.8; H , 4 . 5 ; N, 4.7.
Its structure follows from ring-opening with hydrobromic acid to give (tri-'O-acetyl-a-D-glucopyranosyl bromide)-uronic acid (IIIa) identical with the compound obtained from both CY- and p-forms of tetra-O-aCetyl-D-glUCOpyranUrOniC acid (Ia). Esterification with diazomethane gave methyl (tri-0acetyl-a-D-glucopyranosyl bromide) -uronate (IIIb), isolated in two crystalline modifications, one of (13) In ref. 9 the m.p. of 2-methylchrysenoxazole is stated as 223'. which has been described.2b When the bromide DEPARTMENT OF CHEMISTRY IIIa was heated in pyridine it was reconverted in A'IN SHAMS UNIVERSITY ABBASSIA,CAIRO,EGYPT small yield to the lactone. The p-configuration a t carbon-1 is the only one structurally possible in a lactone derived from a D-glucopyranuronic acid and Tri-O-acetyl-p-~-glucopyranurono-6, l-laCtOne its formation is consistent with previous experience in related reaciions.la BY E. A t . FRY The lactone reacts normally with excess nietliaRECEIVED FEBRUARY 9, 1953 no1 in the presence of catalysts such as pyridine, py'The synthesis of tri-0-acetyl-6-D-glucopyranii-ridine-p-toluenesulfonic acid salt, and silver carbon rono-6,1-lactone (11) was undertaken in order to ate to give oily methyl 2,3,4-tri-O-acetylglucopyransee whether or not this compound is a suitable in- uronate, identified by conversion to methyl tetratermediate for the preparation of alkyl p-D-glUCO- O-acetyl-~-D-glucopyranuronate(Ib). pyranosiduronic acids. The approach was made It was expected that both the lactone I1 arid the p-form of the methyl ester Ib, -.would react with methanol in benCHOA~ p-form 76% HBr-HOAc I zene in the presence of stannic HbOAc ' HCOAc HCOAc chloride to Eive methvl tri-0acetyl - p - D - ghopyrandsiduronic AcOCH I 0 a-form 0I AcOCH 1 0 AcO,!H I , -/+ 1 acidand its methyl ester, respecHCOAc HcOAc hot pyridine H~OAC tively, but in no case could any of I I I the desired material be isolated H C p J from the oily product. That the carbonyl group is favorably situCOOK J L C=O ' COOR I 1, MeOH-cat. ated for interaction with carhoti-l 2, Ac2O-pyridine is demonstrated by the ease with cy- aiid p-forms 11 which i t displaces an acetoxv HBr-HOAr group in this position, and it is In, K = I1 + IIIa, R = H b, = ~ € 1 possible ~ that the failure of these b, K = CHa cornpounds to react iii thc c x attractive by the work of Letnieux who showed that pected way with methanol is in some way re1,ttetl the carbon-1 p-acetoxy group of an acetylated glu- to the influence of the carbonyl group. cose is subject to displacement by an alkoxy1 group Acknowledgment.-The author is grateful for in the presence of stannic chloride. Thus, 1,2,3,4- the interest and help of Dr. Erich Mosettig and tetra-0-acetyl-P-D-glucopyranose was converted Dr. Robert K. Ness. Microanalyses were made tri-O-acetyl-1,6-anhydro-~-~-glucopyranose into by the Institutes service laboratory under the diin 36y0yieldllb and penta-0-acetyl-P-D-glucopyran- rection of Dr. William C. Alford. ose into methyl tetra-0-acetyl-P-D-glucopyranoside Experimental in 50-60% yield.Ic The configuration of the aa- and @ - h o m e r s of Tetra-0-acetyl-D-glucopyranuronic anomers makes them unsuitable for this type of Acids (Ia).-Fifty grams of glucuronolactone was dissolved displacement and an adequate discussion and re- in 175 ml. of water and 25 g. of sodium bicarbonate added a t room temperature. Carbon dioxide was evolved and in 5 view is to be found in Lemieux' paper.la The acetylation of sodium glucuronate in the hours the solid dissolved completely. After standing overwater was removed under reduced pressure at 40". presence of p-toluenesulfonic acid gave two ano- night The residual oil was triturated with ethanol in which it is meric tetraacetylglucuronic acids Ia, which were not soluble. After removing the alcohol under reduced presidentified by conversion into the known methyl es- sure the yellow sodium salt was obtained crystalline. I t ters Ib.7a As expected, the a-form in benzene solu- weighed 66.8 g.3 Sixty-five grams of p-toluenesulfonic acid hydrate was dissolved in 230 ml. of acetic anhydride and tion in the presence of stannic chloride was recov- the solution chilled in a c e t o n e D r y Ice to 0" and held a t this ered for the most part unchanged, whereas the p- temperature. T h e powdered sodium salt was added fairly acid yielded a crystalline compound insoluble in rapidly with mechanical stirring. I t dissolved for the most in 30 minutes a t which time sodium p-toluenesulfonate sodium carbonate. The elemental analysis is t h a t part began to separate. After a time (not recorded but approxirequired by tri-0-acetyl-/3-~-glucopyranurono-6,1mately one hour) the cold mixture was diluted with two lactone (11) and the yield on this basis was 76%. volumes of ether and shaken with an aqueous solution of I
I
--
rtH
'
HCK~
1
~
~
(1) (a) K. U . J>emieux, Cnn. J. Chenz., 29, 1079 ( 1 9 5 1 ) ; R. U. 1-emieux. Advances in Cavbohyrfvate C h e m . , 9 , 1 (19.54); (b) R . U. Lemieux a n d C. Brice, C U I ZJ. . Cheiit., 30,293 (1932) ; ( c ) R. U. Lemieux a n d 1%'. P. S h y l u k , i b i d . , 31, 328 (19.3). 121 (:L) 1V. F. G u c i A a n d E'. 11. B a l m s , J . H i d . rh~i~., 106, G3 l l ~ ! l 3 1 ) , ( 1 , l 1 1 1 , 347 (l!l;l:,)
g. of sodium acetate t o remove excess p-toluenesulfonic acid
(separation into two phases occurs only with relatively large amount of water). The aqueous phase was extracted with chloroform and the organic solutions joined and the solvent5 (3) An improved method for mnking this salt has been published hy W. I1ar.h nud I ) . G . Benjamin, THISJ U U R N X I , , 76, 917 (1954).
