6640
VOl. 77
NOTES
material melting at 154-156 O . 1 P J 6 After neutralization of the free carboxyls, a neutral equivalent of 177 was obtained, calculated 174.1. Potentiometric Titrations.-Fifty to 100 mg. of a particular lactone was dissolved in 10 ml. of water and titrated at 28" under nitrogen with standard 0.1 N base, using a model G Beckman pH-meter and external electrodes.
5.00
4.00
% 3.00
acetal of an a-haloaldehyde with ammonia or amines usually has been employed.2 No ketone acetals appear to have been used in this reaction. The reaction also has been carried out with alkali metal derivatives of aniline and alkylanilines. One disadvantage of the synthesis from ammonia and chloroacetal is the considerable amount of corrosion which may accompany the reaction unless the vessel is constructed of the proper material. It may also be difficult to obtain a pure product, since chloroacetal, aminoacetal and hydroxyacetal cannot be separated very well by distillation. There are two less important methods of preparing a-amino acetals. One is the reduction of glycine esters with sodium amalgam and subsequent conversion of the aminoacetaldehyde so formed into its acetals4 The other is the reduction of acetals of nitroacetaldehyde with sodium and alcoh01.~ We have found that hydrogenation of 2,2-dialkoxyalkanenitriles gives a-amino acetals (I) in good yields. Since the nitrile group is converted
2.00
(R0)tCCN I
I
I
0.7
0.3
I
I
I
I
I
1.1 1.5 n. Fig. 1.-Potentiometric titration of 59.1 mg. of DLalloisocitric lactone (neut. equiv. 88.2, theory 87.1) and of 64.8 mg. of DL-isocitric lactone (neut. equiv. 86.3, theory 87.1). -
I
R'
Hz + H~XCH~C(OR)Z
I
R' I, R = alkyl R' = H, alkyl or aryl
to an aminomethyl group, this method can give acetals of aminoacetaldehyde and a wide variety of a-aminomethyl ketones. We used it to prepare acetals of aminoacetaldehyde, aminoacetone and a~ K values A were obtained from a plot (Fig. 1) of pH 28s. aminoacetophenone. By hydrogenation in the ii, ii being defined as16 presence of primary and secondary amines, Nsubstituted a-amino acetals could be prepared. 2(TA) - (SaOH) - ( H + ) +-(OH-) n = This phase has not been studied thoroughly. I It has been shown6 that the cyano group in dialkoxyalkanenitriles is more reactive toward diI+&++< ( H + ) ( H + I 2 cyandiamide than i t is in most other nitriles. where This appears to be true in hydrogenations also. The hydrogenation reaction takes place readily = concentration of added lactone (TA) (IiaOH) = concentration of added base under moderate conditions, giving, in general, = hydrogen ion concentration as calculated (H+) good yields of amino acetals-from 65 to 90%. from the p H measurement (OH-) = hydroxyl ion concentration as calculated from No unreacted nitrile survives to complicate the purification of the amino acetal. When no amKW and the hydrogen ion concentration At ii equal to 1.5, the p H is equal to pK1 and a t ii equal to monia is added to the reaction mixture, the usual I T * \
0..5, PH is equal to pK2. (14) Senearls reports 157-158.5'. report 153'. (15) Greenstein, et d.,] (16) Using t h e Bjerrum treatment and considering H as t h e ligand. For details of this treatment see A. E. Martell and h l . Calvin, "Chemist r y of t h e Metal Chelate Compounds," Prentice-Hall, I n c . , New York, hT. Y., 1952, p . 78.
DEPARTMEST OF CHEMISTRY UNIVERSITY DUQUESNE PITTSBURGH 19, PENNA.
Dialkoxyalkanenitriles. 111. Hydrogenation to aAmino Acetals BY JOHNG. E R I C K S O NW. , ~ H. MOKTGOMERY AND OLE RORSO RECEIVEDACGUST11, 1955
Of the several methods described for the preparation of acetals, the one involving reaction of an (1) Research Department, General Mills, Inc., Minneapolis, Minn.
(2) (a) A. Wohl, B e y . , 21, 616 (1888); 39, 1951 (1906); (b) L. Wolff, ibid., 21, 1481 (1888); (c) W. Marckwald, ibid., 26, 2354 (1892); (d) R . Burtles, F. L. P y m a n and J. Roylance, J . Chem. Soc.. 127,581 (1925); (e) F. A. Mason, ibid., 127, 1032 (1925); (f)W. H. Hartung and H . Adkins, THIS JOURNAL,49, 2517 (1927); (9) J. Boeseken and B. B. C. Felix, Bey., 62, 1311 (1929); (h) J. S. Buck and S.N. Wrenn, THISJOURNAL. 61, 3612 (1929); (i) A. Kirrmann, M. Goudard and hl. Chahidzadeh, Bull. soc. chim., 2, 2143 (1935); (j) H . Albers, R . Kallischnigg and A. Schmidt, Bev., 7 7 , 617 (1944); (k) R. B. Woodward and W. E. Doering, THIS JOURNAL,67, 860 (1945); (1) J. P. Fourneau and S. Chantalou, BzdZ. soc. chim., 12, 845 (1945); (m) H. H. Richmond and G. F. Wright, Can. J . Reseavch. 23D, 158 (1945); (n) E . F. J. Janetzky, P. E . Verkade and W. Meerburg, Rec. t v a v . chim., 66, 312 (1947); i o ) C. F. H. Allen and J . H. Clark, Org. Synfheses, 24, 3 (1944); (p) I. A. Kaye and I . Minsk?, THISJOURNAL, 71, 2272 (1949); (9)R . S. Sweet, U. S. Patent 2,190,385 (Dec. 6, 1949); (r) R . G . Jones, E. C. Kornfeld, K. C . McLaughlin and R . C . Anderson, THISJOURNAL, 71, 400 (1949); (SI S.Senda, J. Pharm. Soc. J a p a n , 71, 601 (1951). (3) E . F. J . Janetzky, P . E. Verkade and W. Meerburg, Rec.Irau. chim., 66,317 (1917). (4) E. Fischer, Bey., 41, 1019 (1908). ( 5 ) M , S. Losanitsch, ibid., 42, 4044 (1909). (6) V. P. Wystrach and J. G. Erickson, THIS JOURNAL,76, 6345 (1953).
-NitrileStructure
TABLE I HYDROGESATION OF 2,2-DIALKOXYALKANENITRILES
-
Temp. of OC.
"S,
Moles
Solvent
MI.
moles
1 .o
I:eacn.,
(CH3O)zCHCN (CH30)zCHCN (CH30)2CHCN (CzH50)XHCX (CzH50)zCHCN (CzHb0)zCHCX (CzH50)zCHCS
0.50 .50 .50 .39 .39 1.16 1.16
Dioxane Methylal" Cyclohexane Ethanol Methylalb Cyclohexane Cyclohexane
80 80 80 80 75 240 275
1.0 1.0 0.7 .8 2.3 0
75-90 75-80 80-90 75-125 75-80 75-90 75-80
(CaHeO)&HCN (CH30)zCCN
0.27 -83
Cyclohexane Cyclohexane
85 300
0.5 3.0
75-80 75-115
,35
Cyclohexane
40
1.5
100-150
I
CH3 (CzH60)ZCCN
I
a
6641
NOTES
Dec. 20, 1955
Max. press., atm.
130 135 87 197 197 100 100 an d 87 122 163
r
ProductStructure
HzNCHzCH( OCH3)z HzXCH?CH(OCH3)z HzNCHzCH( OCH3)z HzNCHzCH(OC2H5)2 HzXCHzCH(OCzHj)2 HzKCHzCH(OC?Hj)z HzSCHzCH( OCzHj)2 HN(CHzCH(0Et)z)z HzNCHzCH(OC4Hg)z H*NCHzC(OCH3)z I, CHI HzNCHzC(OCzH6)z
I
7
Yield, yo
38 56 67 10
85 87 67 13 67 88 71
C6Hs
CEHS Unpurified. Purified.
TABLE I1 PROPERTIES OF AMINOACETALS Structure
B.P., Mm.
'C.
H2XCHzCH(OCHa)z 139.5 768 HZNCHzCH(OCzH5)i 163 769 1 HN(CHzCH(OEt)z)? 86 H~NCH~CH(OC~HQ 118 )Z 17 78 2 HzKCH2C(OCH3)2 146 751
I
89 CH3 HZKCHZC(OCZHS)Z 68
I
105 0.5
F.P., OC.
