PINACOL REARRANGEMENT OB SOME ACETYLENIC GLYCOLS
July 5, 1954
[CONTRIBUTION FROM
THE
3477
CHEMISTRY DEPARTMENT, UNIVERSITY OF NOTRE DAME]
The Pinacol Rearrangement of Some a,@-AcetylenicGlycols1 BY R. B. DAVIS~ AND W. F. ERMAN RECEIVEDNOVEMBER 12, 1953 An improved method is offered for the preparation of cu&acetylenic glycols. The pinacol rearrangement of 3,4-dimethylwas accomplished, yielding 3,3-dimethylpentyne-l3,4-dihydroxypentyne-l and 3-methyl-4-ethyl-3,4-dihydroxyhexyne-l respectively. A complete proof of structure of the products is offered. one-4 and 3-methyl-3-ethylhexyne-1-one-4,
Favorskii and Onishchenko3 reported that the istic infrared absorption bands were found in the a,P-acetylenic glycol, 3,4-dimethyl-3,4-dihydroxy-region of 4.73 p , indicating the presence of the termpentyne-1 (I), on treatment with cold concentrated inal triple bond, and in the region of 5.85 p , indicatsulfuric acid underwent a pinacol rearrangement ing the presence of the carbonyl group5 Ultravioaccompanied by a simultaneous hydration of the let absorption spectra showed maximum peaks a t and a t 281 triple bond to produce dimethylacetylacetone (11). 284 mp for 3,3-dimethylpentyne-l-one-4 mp for 3-methyl-3-ethylhexyne-1-one-4, which were OH OH 0 CH3 0 in favorable agreement with values reported for I I HzS04 ll I II similar non-conjugated ketones.& Had the triple CH3-C-C-C=CH CH3-C-C-C-CH3 I I - 10" I bond been conjugated with the carbonyl group in d!H3 CHa eIH3 these ketones, the maximum peaks would have been I I1 expected a t 214 mp.' The final products IV were We have accomplished the pinacol rearrange- oxidized with potassium permanganate to the corment of this same glycol I and also of 3-methyl-4- responding P-ketoacids (V) and characteristic of Pethyl-3,4-dihydroxyhexyne-l without hydration of ketoacidsJ8 these were readily decarboxylated to the triple bond, using dilute sulfuric acid and em- corresponding known ketones. ploying variations of the Hill and Flosdorf method.4 O R OH OH
ll
O R
I I R--C-C-C=CH I I
HzSOI ___f
R CHI 111
I R-C-C-C=CH I
f H20
CHI IV R = CH3 and CHs-CHt
/I
R-C-R
OH HCECNa ___f
3"
I R-C-C=CH I R
I I
CHI IV R = CH3 and CH3-CHz
I
L
I
CHI
v
0
ll
R-C-CH-R
Following this procedure, using 2570 sulfuric acid, 3,4-dimethyl-3 ,4-dihydroxypentyne-1 (I) was in 11% converted to 3,3-dimethylpentyne-l-one-4 yield, a large mass of tarry material also being produced. Best results were obtained by allowing a water solution of the glycol I to drop into a reaction mixture of 4Oy0 sulfuric acid, and simultaneously distilling the mixture a t the rate of addition of the glycol-water solution. By this method, 3,3-dimethylpentyne-1-one-4 was obtained in 28% yield. The pinacol rearrangement of 3-methyl-4-ethyl3,4-dihydroxyhexyne-l proceeded more smoothly and in better yield. Following the method previ0
I
R-C-C-CECH
II
VI
I n this manner, 3,3-dimethylpentyne-l-one-4 gave 3-methyl-2-butanonej and 3-methyl-3-ethylhexyne-1-one-4 gave 4-methyl-3-hexanone. The a,$acetylenic glycols I11 were prepared by the reaction of sodium acetylide in liquid ammonia with acetone and diethyl ketoneYgrespectively, followed by hydration of the triple bond.I0 The hydroxyketones thus formed, reacted with an excess of sodium acetylide in liquid ammonia to give the corresponding acetylenic glycols I11 in excellent yield. OH 0
I II + R-C-C-CHs + Hz0 1
HgS04 HzSO4
I
CHI
R
OH
OH
R
CHI
1 1 + R-C----C-C=CH hTH3 I 1 NaCSCH
R = CHI (66%) R C2Hs (82%)
ously cited,4 using 25y0 sulfuric acid, 3-methyl-3ethylhexyne-1-one-4 was obtained in 54% yield. Employing an alternate m e t h ~ dusing , ~ 42y0 phosphoric acid, the same ketone was obtained in 32Oj, yield. The structure of the products IV was conclusively established, the most salient facts being: character(1) Further work is in progress. (2) Rev. Ralph B. Davis, C.S.C. (3) A. E.Favorskii and A. S. Onishchenko, J. Gcn.Chcm. (U.S.S.R), 11, 1111 (1941). (4) G. A. Hill and E. W. Flosdorf, OIE. Syntheses, 5, 91 (1925).
The reaction of a-hydroxyketones with sodium acetylide in liquid ammonia to produce a,&acetyl(5) N.B. Colthup, J. Opt. SOC.Am., 40,397 (1950). (6) R. A. Day. A. E. Robinson, J . M. Bellis and S. B. Till, THIS JOURNAL, 72, 1379 (1950). (7) K.Bowden, I. M. Heilbron, E. R. H. Jones and B. C. L. Weedon, J. Chem. SOC.,39 (1946). (8) B. E. Hudson and C. R. Hauser, Tnxs JOURNAL, 63, 3163 (1941). (9) K. N. Campbell, B. K. Campbell and L. T.Eby, ibid., 80, 2882 (1938). (10) G.F.Hennion, R. 8 . navis asd D.E.Maloney, ibid., 71, 2813 (1949).
3478
R. B. DAVISAND W. F. ERWAN
voi. 7 6
sulfuric acid, 50 g. of I gave 5.3 g. of 3,3-dimethylpentyne-lo n e 4 (10.6% yield). Pinacol Rearrangement of 3-Methyl-4-ethyl-3,4-dihydroxyhexyne-1.-Following substantially the method of Hill and F l ~ s d o r f ,150 ~ g. of 3-methyI4-ethyl-3,4-dihydroxyhexyne-1 was treated with 25% sulfuric acid to give 71.1 g. (53.6% yield) of 3-methyl-3-ethylhexyne-1-one-4; b.p. 79.5-81" a t 56 mm., l t Z 6 1.4328, ~ d2b 0.8594, MRD calcd. 41.77, obsd. 41.78. Anal. Calcd. for QHlaO: C, 78.26; H , 10.15. Found: C, 78.40; H, 10.54. a,pAcetylenic Glycols.-Acetone and diethyl ketone The 3-methyl-3-ethylhexyne-1-one-4 gave an orange 2,4were treated with sodium acetylide in liquid ammonia ac- dinitrophenylhydrazone, m.p. 108-109". The ketone gave cording to the method of Campbell, Campbell and EbyO to a positive test for terminal acetylene with alcoholic ammonigive dimethylethynylcarbinol in 66.4% yield and diethyl- acal silver nitrate. The ultraviolet absorption spectrum ethynylcarbinol in 81.6% yield. The ethynylcarbinols were showed a maximum peak a t 281 mp, and characteristic infrahydrated according to the procedure of Hennion, Davis and red absotption bands appeared a t 4.73 and 5.85 mp. When 77 g. of the acetylenic glycol was refluxed with Maloneylo to give 3-methyl-3-hydroxy-2-butanone, b.p. 79" a t 90 mm. (64% yield); semicarbazone m.p. 162.5- 400 g. of 42% phosphoric acid for four hours,4 22 g. of 3methyl-3-ethylhexyne-1-one-4 was obtained (32.1% ' yield) 163.5' (lit. Val.* 163'), and 3-ethyl-3-hydroxy-2-pentanone, Potassium Permanganate Oxidation of the Acetylenic b.p. 85-85.5' a t 54 mm. (75.5% yield); semicarbazone Ketones and Subsequent Decarboxylation.* 3,3-Dimethylm.p. 158-160' (lit. val.la 155-156'). pentyne-l-one-4.-To a mixture of 20 g. of the ketone, 200 The hydroxyketones were treated with sodium acetylide g. of water and 1 g. of sodium hydroxide was added portionin liquid ammonia following substantially the procedure of Campbell, Campbell and Eby? with the exception that two wise with stirring over a period of three hours 60 g. of potasmoles plus a slight excess of sodium acetylide was used for sium permanganate. The mixture was then filtered and each mole of hydroxyketone. 3,4-Dimethyl-3,4-dihydroxy- the precipitate washed twice with 25 cc. of water. The pentyne-1 was obtained in 62.5% yield; b.p. 90-91' at filtrate was extracted twice with 50 cc. of ether. The water layer was then acidified with dilute sulfuric acid and ex19 mm., m.p. 17-18', n D b1.4600, ~ and 3-methyl-4-ethyltracted three times with 100 cc. of ether. After adding 2 3,4-dihydroxyhexyne-l was obtained in 85.7% yield; b.p. g. of 50% sulfuric acid and 3 g. of glacial acetic acid, the 99-100' a t 13 mm., m.p. 36-37', +D 1.4691. Pinacol Rearrangement of 3,4-Dimethyl-3,4-dihydroxy- ethereal solution was refluxed until carbon dioxide ceased to be evolved-approximately four hours. After all acids pentyne-1 (I).-A solution of 138 g. of I and 400 g. of water was added dropwise to a boiling solution of 280 g. of concen- were neutralized, the ether was removed and the product trated sulfuric acid and 420 g. of water, distilling the reac- was distilled, giving 4 g. of 3-methyl-2-butanone (25.3% wer-all yield); b.p. 92-93' (lit. vaI.1492-94'); 2,4-dinitrotion rnixtttreat the r&e of addition cf the g!!gcol mixture. phenylhydrazone, m.p. 122-123' (lit. val.'S 117'); pAfter the addition was complete, distillation was continued until no oil appeared in the distillate. The distillate was nitrophenylhydrazone, m .p. 102-103 ' (lit. Val. 103.5"). extracted m ith ether, washed with dilute potassium carbon- The ketone gave a positive iodoform test. 3-MethylJ-ethylhexyne-l-one-4.-1n similar manner, 20 ate and dried- over calcium chloride. Fractional distillation gave 33 3 g. of 3,3-dimethylpentyne-l-one-4(28.1% g. of this acetylenic ketone was oxidized and the ketoacid yield); b p. 117.5', T Z * ~ D1.4180, d2t 0.8514, M R D calcd. produced was decarboxylated to give 6 g. of 4-methyl-3hexanone (36.4% over-all yield), b.p. 134-136" (lit. Val.'' 32.54, obsd. 32 58. A n d . Calcd. for ClHloO: C, 76.37; 13, 9.16. Found: 134-136'); 2,4-dinitrophenylhydrazone,m.p. 76-77" (lit Val.'* 78'). The ketone failed to give an iodoform test. C, 76 45; H , 9 33. The 3,3-dimethylpentyne-l-one-4gave a yellow-orange XOTREDAME,INDIANA 2,4-dinitrophenylhydrazone,m.p. 139'. The ketone gave (14) F.C.Whitmore, W. L. E v e n and H. S. Rothrock, O r g . Synthca positive test for terminal acetylene with alcoholic ammoniacal silver nitrate. The ultraviolet absorption spectrum scs, 13, 68 (1933). (15) C. F. H. Allen, THIS JOURNAL, 62, 2955 (1930). showed a maximum peak a t 284 mp. Characteristic infra(16) H.Burton, C.W. Shoppee and C. L. m7il~0n,J. Chcm. SOC.,720 red absorption bands appeared a t 4.73 and at 5.85 p. (1933). Following the method of Hill and Flosdorf,' using 25%
enic glycols gave much improved yields over former methods, the best yields having been reported by Cologne and Bernard" who obtained 3,4-dimethyl3,4-dihydroxypentyne-l in 11% yield and 3-methyl4-&yL-3,4-dihydraxyhyexyne-L in 6% yi& ky treatment of the sodium derivatives of the corresponding hydroxyketones with acetylene under pressure. Experimental12
(11) J. Cologne and G . Bernard, Compt. rend., 216, 202 (1943). (12) Analyses by Micro-Tech Laboratories. Skokie, Illinois (13) R Locquin and S. Wouseng, Compt. rend., 176, 516 (1923).
(17) M. Hanriot and L. Bouveault, Bull. SOC. chim., [3] 1, 550 (1889). (18) W. A. Mosher and E. 0. Langerak. THISJOURNAL, 71, 28fl (1949).
