Reaction with aqueous alkali of diammonium salts with a 1,1-dimethylbut-2-yne-1,4-diyl common group

Article abstract of DOI:10.1023/A:1023419530311

Quaternary ammonium salts with a 1,1-dimethylbut-2-yne-1,4-diyl common group react with aqueous alkali with intermediate formation of 1,2- rather than 1,4-cleavage products. When both nitrogen atoms bear allylic groups, rearrangement-cleavage-substitution

Full text of DOI:10.1023/A:1023419530311

Russian Journal of General Chemistry, Vol. 72, No. 12, 2002, pp. 1938 1941. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 12, 2002,
pp. 2046 2049.
Original Russian Text Copyright
2002 by Ovakimyan, Barsegyan, Indzhikyan.
Reaction with Aqueous Alkali of Diammonium Salts
with a 1,1-Dimethylbut-2-yne-1,4-diyl Common Group
M. Zh. Ovakimyan, S. K. Barsegyan, and M. G. Indzhikyan
Institute of Organic Chemistry, National Academy of Sciences of Armenia, Erevan, Armenia
Research Center of Molecular Structure, Erevan, Armenia
Received February 2, 2001
Abstract Quaternary ammonium salts with a 1,1-dimethylbut-2-yne-1,4-diyl common group react with
aqueous alkali with intermediate formation of 1,2- rather than 1,4-cleavage products. When both nitrogen
atoms bear allylic groups, rearrangement cleavage substitution occurs to give methyl isopropyl ketones. Salts
with two 3-methylbut-2-en-1-yl groups cleave isoprene.
We earlier found that 1,4-diammonium salts with
a but-2-yne-1,4-diyl common radical and allylic side
The initial ammonium salts were obtained by reac-
tion of 1,4-bis(dimethylamino)-1,1-dimethylbut-2-yne
groups are cleaved by aqueous alkali to form nitrogen- with alkyl or allyl halides at a 1:2 molar ratio.
free allylacetones as major products and lactones
derived from 1-allylbut-3-enoic acids as by-products
[1].
1,4-Bis(dimethylamino)-1,1-dimethylbut-2-yne reacts
with equimolar amount of methyl bromide to give a
monoammonium salt by the nitrogen atom attached
to the methylene group, which then transforms into
a diammonium salt under the action of the second
methyl bromide molecule.
In the present work we studied transformations
under the action of aqueous alkali of 1,4-diammonium
salts I III having two methyl substituents in a but-2-
yne-1,4-diyl common group.
It was found that bis(trimethylammonium) salt I
fails to react with equimolar amount of aqueous
potassium hydroxide at room temperature. The reac-
tion under reflux yields, after 0.5 h, a 1,2-cleavage
product, a monoammonium salt with a 3-isopropenyl-
prop-2-yn-1-yl group, of the possible 1,2- and 1,4-
cleavage products.
CH3
R
R
+
+
(CH3)2N CH2 C C C N(CH3)2
X
X
CH3
I III
R = CH3 (I), CH2 CH=CH2 (II), CH2 CH=C(CH3)2 (III).
(CH3)2N CH2 C C C(CH3)2 N(CH3)2
2CH3Br
CH3Br
Br
Br
+
+
CH3Br
+
(CH3)3N CH2 C CC(CH3)2 N(CH3)2
(CH3)3NCH2C CC(CH3)2N(CH3)3
Br
OH
CH3
+
(CH3)3NCH2C C C=CH2
Br
Cleavage of the same salt under the action of thrice
the molar amount of 25% aqueous sodium hydroxide
was accompanied by strong tarring. The only isolable
reaction products were acetone (9%) and trimethyl-
amine (76%). Acetone is most likely formed by a
scheme involving nucleophilic attack by the -carbon
atom of the pentatriene system.
1070-3632/02/7212-1938$27.00 2002 MAIK Nauka/Interperiodica

REACTION WITH AQUEOUS ALKALI OF DIAMMONIUM SALTS
CH3
1939
+ Br
Br
Br
+
+
+
OH
(CH3)3N CH=C=C=C(CH3)2
(CH3)3NCH2C C C=CH2
(CH3)3NCH2C C C(CH3)2N(CH3)3
Br
+
+
(CH3)3N CH2 C C=C(CH3)2
(CH3)3N CH2 C CH + CH3CCH3
<
O
OH
O
H
(CH3)3N + tar
Among the products of alkaline cleavage of salt II
we found dimethylamine (mole per mole of the initial
salt), 32% of isopropyl 3-buten-1-yl ketone, dimethyl-
amine, formic acid, and a high-boiling product. Ac-
cording to GLC and TLC, the latter is a mixture of
several amines.
The substituted methyl isopropyl ketone is most
likely formed by a scheme we proposed earlier for
cleavage of salts containing no substituents in the
butatriene system.
A substituted methyl isopropyl ketone, while in a
much smaller amount (19%), was also obtained by
cleavage of salt III. Simultaneously, a great amount
of a mixture of high-boiling amines was obtained,
which we failed to separate by chromatography. From
this mixture, 1,1-dimethyl-1,4-(dimethylamino)but-2-
yne (6%) was isolated. This compound is formed by
cleavage of both 3-methylbut-2-en-1-yl groups from
the ammonium complex. Among the reaction products
we also found isoprene.
CH2CH=C(CH3)2
+
CH2CH=C(CH3)2
N(CH3)2
+
(CH3)2N
2CH2=C(CH3)CH=CH2 + (CH3)2NCH2C C C(CH3)2N(CH3)2
CH2 C C C(CH3)2
OH
EXPERIMENTAL
amino)prop-2-yne [2], 4.7 g of dimethylamine in
50 ml of dioxane, 4 g of Paraform, and 0.15 g of
The IR spectra were measured on a UR-20 spec-
trometer in thin films. The H NMR spectra were ob-
tained on Perkin Elmer R-12B (60 MHz, external
reference TMS) and Varian Mercury-300 instruments.
copper acetate was heated for 50 h on a boiling water
bath in a germetically sealed steel balloon. The reac-
tion mixture was treated with 15 ml of 36% hydro-
chloric acid and thoroughly extracted with ether. After
reamoval of ca. 20 ml of the solvent in a vacuum, the
residue was made alkaline and extracted with ether.
Usual workup and vacuum distillation of the ethereal
1
1,4-Bis(dimethylamino)-1,1-dimethylbut-2-yne.
A mixture of 10.8 g of 1,1-dimethyl-1-(dimethyl-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 12 2002

1940
OVAKIMYAN et al.
extracts gave 10.6 g (66%) of 1,4-bis(dimethylamino)-
CH2, JHH 7.3 Hz, 4.85 s (2H, CH2C ), 5.6 6.0 m (4H,
1,1-dimethylbut-2-yne, bp 102 C (36 mm), d240 0.8385, =CH2), 6.05 6.3 m (2H, CH=). Found Br , %: 38.21.
n2D0 1.4570. mp 231 232 C (pycrate). H NMR spec-
trum, , ppm: 1.3 s [6H, C(CH3)2], 2.1 s [12H,
(CH3)2N], 3.1 s (2N, CH2N). Found N, %: 16.72.
C10H20N2. Calculated N, %: 16.66.
C16H30BrN2. Calculated Br , %: 39.02.
1
1,4-Bis[dimethyl(3-methylbut-2-en-1-yl)am-
monio]-1,1-dimethylbut-2-yne dichloride (III) was
obtained in a similar way from 5.3 g of 1,4-bis(di-
methylamino)-1,1-dimethylbut-2-yne and 6.3 g of
3-methyl-but-2-en-1-yl chloride. Yield 10.2 g (93%).
Found Cl , %: 18.13. C20H38Cl2N2. Calculated Cl ,
%: 18.83.
Trimethyl[(4,4-dimethyl-4-dimethylamino)but-
2-yl]ammonium bromide. Methyl bromide, 2 ml,
was barboted through an ice-cooled ethereal solution
of 3.4 g of 1,4-bis(dimethylamino)-1,1-dimethylbut-
2-yne. A day after, a precipitate formed and washed
filtered off, thoroughly was with dry ether, and dried
Alkaline cleavage of 1,4-bis(allyldimethyl-
ammonio)-1,1-dimethylbut-2-yne bromide was per-
formed similarly to salt I with a difference that the
residue in the reaction flask was treated with ether,
the ethereal extract was added to the receiver contents,
the ethereal layer was separated, dried, and distilled to
obtain 2.1 g (32%) of 6-methylhept-1-en-5-one, bp
44 C (9 mm), d240 0.8301, n2D0 1.4300. IR spectrum, ,
1
to obtain 5.2 g (99%) of the monoammonium salt. H
NMR spectrum, , ppm: 1.4 s [6H, C(CH3)2], 2.4 s
+
[6H, N(CH3)2], 3.3 s [9H, N(CH3)3], 4.7 s (2H, N
CH2). Found Br , %: 30.11. C11H23BrN2. Calculated
Br , %: 30.42.
1,4-Bis(trimethylammonio)-1,1-dimethylbut-2-
yne dibromide (I). A slight molar excess of methyl
bromide was barboted through an ice-cooled metha-
nolic solution of 4 g of trimethyl[4,4-dimethyl-4-(di-
methylamino)]but-2-yl]ammonium bromide. A day
after, the quaternary ammonium salt was precipitated
with dry ether, filtered off, and dried to obtain 5 g
1
1
cm : 925, 1640, 3080 (vinyl group), 1710 (CO). H
NMR spectrum, , ppm: 5.1 5.7 m (1H, CH=), 4.6
4.9 m (2H, =CH2), 1.5 2.5 m (5H, CH CO CH2CH2),
0.6 d [6H, CH(CH3)2, JHH 6.7 Hz]. Found, %: C
76.31; N 11.70. C8H14O. Calculated, %: C 76.19;
H 11.11.
1
(93%) of salt I. H NMR spectrum (CDCl3), , ppm:
Back titration of the combined hydrochloric solu-
tions in the receiver and Tishchenko flask gave
0.10 mol of an amine. The reaction mixture was made
alkaline, cooled, and, after addition of ether and
double the molar amount of acrylonitrile, left to stand
for 3 days. (2-Cyanoethyl)dimethylamine, 1.2 g (23%),
was added, bp 165 170 C (680 mm), mp 155 C
(pycrate). The ethereal distillate was titrated to found
0.05 mol (94%) of allyldimethylamine, mp 100 C
(pycrate).
+
1.9 s [6H, C(CH3)2], 3.2 s [18H, N(CH3)3], 4.7 s (2H,
N CH2). Found Br , %: 44.30. C12H26BrN2. Cal-
culated Br , %: 44.69.
Alkaline cleavage of salt I. A mixture of 17.5 g
of salt I and 0.144 mol of 25% aqueous sodium hydr-
oxide was heated on a sand bath in a flask with a
Liebig condenser connected to a receiver, a Tishchen-
ko flask filled with a titrated hydrochloric acid solu-
tion, and a gasometer. The reaction was performed at
105 115 C. The aqueous solution distilled off from
the combined solutions in the receiver and Tishchenko
flask was treated with a solution of 2,4-dinitrophenyl-
hydrazine to obtain 1.04 g (9%) of acetone 2,4-dinitro-
phenylhydrazone, mp 122 C. The hydrochloric acid
solutions were made alkaline and treated with ether to
obtain 0.071 mol (74%) of trimethylamine, mp 217 C
(pycrate). The reaction flask contained much tar
(1.4 g). Found, %: C 54.44; H 7.00; N 5.44.
An amine product, 1.6 g, was also obtained, bp
107 108 C (18 mm), containing, according to TLC
and GLC, five compound. Found, %: C 73.07; H
10.01; N 8.66.
The residue in the reaction flask was made acidic
to isolate 0.0056 mol (11%) of formic acid which
gave with a mercuric chloride solution a characteristic
white precilitate.
1,4-Bis(dimethylammonio)-1,1-dimethylbut-2-
yne dibromide (II). Allyl bromide, 7.4 g, was added
dropwise to a methanolic solution of 5.3 g of 1,4-bis-
(dimethylamino)-1,1-dimethylbut-2-yne. The mixture
was stirred for 5 h, the methanol was distilled off, and
the residue was washed with ether and dried in a
vacuum to obtain 11 g (90%) of salt II. H NMR
spectrum (DMSO), , ppm: 1.9 s [6H, C(CH3)2], 3.1 s
and 3.3 s [12H, N(CH3)2], 4.2 d and 4.3 d (4H, N
Alkaline cleavage of 1,4-bis[dimethyl(3-methyl-
but-2-en-1-yl)ammonio)-1,1-dimethylbut-2-yne di-
chloride was performed like the above with a dif-
ference that we first isolated isoprene, and then per-
formed usual workup. From 88 g of the salt we ob-
tained 1,1 g (68%) of isoprene, bp 38 40 C (680 mm),
n2D0 1.4170, and 6.8 g (19%) 3,3,6-trimethylhept-1-en-
5-one, bp 68 71 C (18 mm), n2D0 1.4348. IR spectrum,
1
1
, cm : 1640, 3080 (vinyl group), 1710 (CO). Found,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 12 2002

REACTION WITH AQUEOUS ALKALI OF DIAMMONIUM SALTS
1941
%: C 77.63; H 12.22. C10H18O. Calculated, %: C
77.92; H 11.68.
amino)-1,1-dimetthylbut-2-yne, 2.4 g (6%), bp 74 C
(7 mm), mp 230 231 C (pycrate).
The aqueous solution distilled from the combined
hydrochloric acid solutions was treated with 2,4-di-
nitrophenylhydrazine to obtain 0.86 g (1.5%) of
acetone 2,4-dinitrophenylhydrazone, mp 122 C. From
the hydrochloric acid solutions we isolated
0.0677 mol (29%) of dimethylamine, mp 157 C
(pycrate), 10.8 g (44%) of 1-(dimethylamino)-3-me-
thylbut-2-ene, bp 113 115 C (680 mm), mp 102
103 C (pycrate), and 6.4 g (21%) of 1-(dimethyl-
amino)-3-methylbutan-3-ol [3], bp 71 C (30 mm), mp
134 136 C (pycrate). From the fraction with bp 68
130 C (18 mm) we also isolated 13.5 g of amine
compounds which could be separated neither by di-
stillation, nor by chromatography. The only com-
pound isolated from this mixture was 1,4-bis(dimethyl-
From the residue in the reaction flask we obtained
1.2 g (11%) of formic acid which gave with a
mercuric acid solution a characteristic white pre-
cipitate.
REFERENCES
1. Babayan, A.T., Indzhikyan, M.G., Grigoryan, A.A.,
Minasyan, R.B., and Ovakimyan, M.Zh., Izv. Akad.
Nauk Arm. SSR, Ser. Khim. Nauk, 1965, vol. 18, p. 166.
2. Hennion, G.F. and Nelson, K.W., J. Am. Chem. Soc.,
1957, vol. 79, p. 2142.
3. Nazarov, I.N. and Kruglikova, R.I., Zh. Obshch. Khim.,
1957, vol. 27, p. 346.
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