COMMUNICATIONS TO THE EDITOR
Dec. 5, 1964
5369
be the 1,2-isomer by reaction with phenyl isocyanate followed by hydrolysis to give hydrazine-N,N'dicarboxylanilide, m.p. 245-248", lit. m . p . 245O.lh T h a t it was free of 1,l-isomer was shown by the n.m.r. spectrum which has a single peak in the Si-C-H region a t r 9.92. I n a typical experiment 4.1 g. (0.023 mole) of 1 , 2 bis(trimethylsily1) hydrazine, prepared by the method of Wannagat and Liehr,'"Zb was treated with 0.048 mole of n-butyllithium in hexane a t 0". After being stirred for about 30 min. to ensure complete reaction, the mixture was chilled to --70°, and 25 ml. of freshly HO OH distilled tetrahydrofuran was added, causing the preC33HaN20io .HX viously white suspension to become light yellow. Methyl iodide (0.48 mole) was then slowly injected. moiety through a glycosidic link, with the pyrrolopyrrole The mixture was then allowed to warm up slowly with nitrogen atoms away from the aromatic nucleus and stirring, filtered in a drybox, and fractionally distilled the furan-pyrrolopyrrole system trans to the sugar. yielding 2.8 g. (60%) of pure colorless product, b.p. The pyrrolopyrrole is planar within *0.04 A. and contains one carbon-carbon double bond. Both 67-71' (17 Torr). Anal. Calcd. for C8H&i2K2: C, 46.99; H , 11.83; K j 13.70. Found: C, 47.33; nitrogen-to-bridge-carbon distances are equal and H, 11.97: N, 13.62. The proton n.m.r. spectrum of the shorter than expected for a carbon-nitrogen single bond (1.33 and 1.31 f 0.03 A,). The two secondary product shows two peaks a t r 9.98 and 9.89, assigned hydroxyl groups of the sugar are hydrogen bonded with to trimethylsilyl protons, and two peaks a t r 7.43 dioxane molecules of solvation. The latter occupy and 7.37, assigned to the methyl protons in the two relatively large cavities in the solid between antiisomers. Relative peak areas are approximately 3 : 3 : biotic molecules and probably assist in maintaining the 1 : 1, respectively, indicating that the two isomers must orientation of the sugar moiety. be present in nearly equal amounts. Partial separation of the mixture could be effected by fractional The details of this structure determination will be distillation. submitted to Acta Crystallographzca. The mixture was solvolyzed with 1-propanol t o STERLING CHEMISTRY LABORATORY A . TULINSKY produce the mixed dimethylhydrazines which were YALEUNIVERSITY SEW HAVE?;,CONNECTICUT treated with p-nitrobenzaldehyde yielding p-nitroRECEIVED OCTOBER15, 1964 benzaldehyde dimethylhydrazone, m.p. 111-1 12, lit.3 m.p. 111') infrared spectrum identical with that of authentic p-nitrobenzaldehyde dimethylhydrazone. A Novel Rearrangement of Isolation of this known hydrazone confirms the pres1,2-Bis(trimethylsily1) hydrazine ence of the rearranged hydrazine in the original reSir: action mixture. I n extending the work of Wannagat and co-workers The rearrangement reported here, though not on organosilylhydrazines,l we have found a novel previously noted, may have occurred in previous rearrangement involving migration of silicon from one reactions of silyl-substituted hydrazines with bases. nitrogen atom to another. If 1,2-bis(trimethylsilyl)- Thus, in the reaction of 1-phenyl-2-trimethylsilylhyhydrazine is treated with 2 equiv. of n-butyllithium in drazine with phenyllithium followed by bromine, a tetrahydrofuran and then with 2 equiv. of methyl large amount of N-trimethylsilylaniline was observed iodide, the reaction mixture is found t o contain both as a b y l p r ~ d u c t perhaps ,~ arising via a 1,2-silicon shift the expected product, 1,2-bis(trimethylsilyl)1,2-diof the type described above. ,Many reactions of lithmethylhydrazine (I), and the rearranged product, ium derivatives of silylhydrazines have been reported l,l-bis(trimethylsilyl)-2,2-dimethylhydrazine (11). in which structures of products are assigned without considering the possibility of rearrangementle,g; some 1 n-CHsLi of these structures may now have to be reconsidered (CHa)rSiNH--NHSi( CH,)r 2 CHDI in the light of our evidence. At present i t is not ( CH3),Si ( CHdSi CHa known whether the rearrangement occurs during or \ / \ N-N after treatment with n-butyllithium, or even conceivN-x / \ / \ ably during the reaction with methyl iodide. InCH, CHI CHI (CH3)aSi vestigations of these possibilities are under way, and I1 I studies of the limits and of the reaction in general are Pure 1,2-bis(trimethylsilyl)hydrazine, b.p. 1 4 7 O , planned for the near future. nz5D 1.4253, d2440.834, was prepared by the method of (2) The material originally supposed by Wannagat a n d Lieht-" t o be Wannagat and Liehr.1a'ba2 This material was shown to 1,2-bis(trimethylsilyl)hydrazinem a y have been a m i x t u r e of t h e 1 . 2 - a n d
7iCHa)s +
(1) (a) U. Wannagat and W. Liehr, Angew. C h e m . , 69, 783 (1957); ( b ) U. Wannagat a n d W . Liehr, 2. anorg. allgem. Chem.. 297, 133 11958); (c) U. Wannagat and H. Niederprum, A n g e w C h e m . , 70, 745 (1988); (d) U. W a n n a g a t a n d W. Liehr, Z . a n o r g . allgem. Chem., 299, 311 (1959), (e) U . Wannagat a n d H . Xiederprum, i b i d . , 310, 32 (19611, (1) H. Niederprum and U. W a n n a g a t , ibrd., 311, 270'(196l); (g) U. W a n n a g a t , C . Krueger, and H. Niederprum. i b i d . , 311, 198 (1963): (h) U. Wannagat a n d C. Krueger, Monalsh. C h e m . , 94, 63 (1963).
1,l-isomers (private communication from Professor U W a n n a g a t ) . T h e proportions of the t w o isomers formed in the reaction of trimethylchlorosilane w i t h h y d r a z i n e d e p e n d s o n t h e reaction conditions i n a w a y n o t yet f u l l y u n d e r s t o o d . When p r e s e n t , t h e l , l - i s o m e r c a n easily be d e t e c t e d h y n.m.r. spectroscopy (Si-C-H resonance at 7 9.99). ( 3 ) 0. L . Btady a n d G P. h I c H u g h , J . Chem. Soc., 121, 1618 11922) (4) U . Wannagat a n d C K r u e g e r , Z . a n o v g . n l i E e m ChPm , 326, 288 ( I 964).
53’70
COMMUKICATIONS TO THE EDITOR
Acknowledgments.-The authors thank Miss P. A. Carney, R . 11. Murch, and F. A. Kramer for assistance in determining n.m.r. spectra, and the Air Force Office of Scientific Research for financial support. DEPARTMENT O F CHEMISTRY OF \$’ISCONSIS UNIVERSITY MADISON, \VISCOSSIX
ROBERTE. BAILEY ROBERTVEST
VOl. 86
molecular proton transfers which lend substantial support to these “conducted tour’’mechanisms. Compound 111,5when treated with various bases in a variety of deuterated solvents, gave IV6 with intramolecularity t h a t varied from 17 to 98y0 (Table
RECEIVED SEPTEMBER 12, 1964
Base-Catalyzed Intramolecular 1,3- and 1,5-Proton Transfers
Sir:
I
Since the report of the first base-catalyzed intramolecular 1,3-proton transfer, enough other examples2 have appeared in the literature to suggest that the phenomena might be rather general. Support for this view is found in a number of examples of enzymecatalyzed intramolecular proton transfers t h a t have been observed. INTRAMOLECULARITY Run no.
IN
COZCHS IV (IV-d)
COzCHs
I11
TABLE I BASE-CATALYZED P R O T O N (DEUTERON) TRANSFERS I N TRIENE111 TO GIVE TRIARYLMETHANE Iv AND DEUTERATED ACETYLENE ( V ) TO GIVE ALLENEVIa
Compd.
I11 I11 I11 I11 111 111 111 111 1V-d* V-de T‘-de
Solventh
Base
T,
O C .
70
IN
intramolecular
(CHZOD)~ DOCHzCHzOK 55 17 2 (CHz)dO-lO% Dz0 DOSa 25 34 3 (CDa)zSO-lO:? CH30D CHaOK 25 40 4 CHaOD CH30Sa 25 47 5 t-BuOD t-BuOK 25 50 75 98 6 (C2Hj)rCOD (C3H7)3N -I 97 ( C2Hj)3CODC ID (C3Hi)3x 8 ( C2H5)3CODd 98 (C3HihX ID 9 t-BuOD t-BuOK 30 22 i 3 10 CHjOH CHjOK 30 19 11 (CH3)zSO-1 .6M t-BuOH N( CHpCHz)3S 30 88 12 (CHa)zSO-3.9 CHaOH N( CHzCHz)3N 30 88 13 V-de (CHa)zSO-3 9 M CH30H’ K( CHzCH2)jN 30 85 14 V-de (CH$),SO-3 9 X CHjOH’ (CH2)jSH 30 58 a .I11 deuterium analyses were made by combustion and falling drop method ( J . S e m e t h ) . Products once formed underwent little if any exchange under conditions of their formation. r, Solvents 97-100Tc deuterated where deuterium is indicated. Solution was Solution was 0.1 -26 in (CzH7)3NDI. e 95% of 1 atom of deuterium. Results were corrected accordingly. 0.1 JI in (C4Hy)aSI. f Solution was 0.14 Jf in S(CH2CHz)zKHI. 1
rr-
A l I
I n studies of the stereochemistry of base-catalyzed hydrogen-deuterium exchange of I and 11, examples of intramolecular racemization (isoracemization) were interpreted as occurring by a series of intramolecular proton transfers (conducted tour mechanism). Some of the steps involved 1,6-proton transfers across an aromatic system ( I ) , others 1,3-proton transfers from carbon (Y to a cyano group to nitrogen and back to
I
I1
carbon. 11-e have now observed examples of intra(1) L). J C r a m and I< T. Uyeda, J . A m . C h e m . S O C .84, , 4358 (1962). ( 2 ) ( a ) S . B a n k , C A Rowe, J r . , and A . Schriesheim, i b i d . , 86, 2115 ( 1 9 6 3 j , ( b j K . B . Bates. R. H . Carnighan, a n d C . E. Staples, i b i d . , 86, 3032 (196B), ( c j 1%‘. von E . Iloering a n d P. P. Gaspar, ibid., 86, 3043 (1963); ( d ) G. Bergsen and A . 51. lveidler, A c i a C ‘ h e m Scand.. 17, 862, 1798 (1963j, (e) G . Bergsen. t b z d . . 17, 2691 (1963j, ( f ) I > . J. C r a m a n d It. T . Uyeda. .I A m / h e ? n . Sor , in p i - ~ s s (~31 (a) F. S K a w a h a r a a n d P Talalay. J . Bioi. (‘hem.. 2 3 6 , P C I (1960j, f b i B. V.‘ i l g r a n o f f . H Eggerer, U Henning. a n d F . Lynen. i b t d . , 236, 326 (19601. (cl H. C Killing and hl. J. Coon, ibid . 236, 3087 (1960). 1 4 1 I ) . J . C r a m and I. Gosser. J . A m ( h e w , S o r . 86, 2950 (1964j.
I). This rearrangement involves proton transfer across the face of a benzene ring. Compound V (deuterated) under similar conditions with base in protonated solvents gave VI with intramolecularity that varied between about 20 and 887G (Table I ) The isomerization of triene I11 to aryl compound IV can be visualized as occurring by one 1,5-rearrangement, or by two successive 1,3-rearrangement.s. Evidence t h a t the latter type of mechanism makes little, if any, contribution is shown by the fact t h a t no deuterium could be detected in the aromatic rings of IV (combination of n.m.r. and combustion techniques) produced in those runs which gave low intramolecularity (1-5). Had intermediates such as VII-d intervened, some deuterium should have been incorporated into the ortho position of the para-substituted ring of IV. These rearrangements are interpreted as occurring largely through ion-pair intermediates whose carbanion is hydrogen bonded to the molecule of oxygen or nitrogen acid generated by proton (deuterium) abstrac( 5 ) R . Heck, P. S. Magee, a n d S. Winstein, r e i v a h e i f v o i i L e l i e r s , 3 0 , 2033 (1964). ( 6 ) All nem compounds used in this investigation gave carbon and hydrogen analysis within 0.37c of theory. All old compounds gave physical properties which corresponded t o literature values.
