Alkylation of adamantane with alkyl halides catalyzed by ruthenium complexes

Article abstract of DOI:10.1134/S0965544106030030

The feasibility of catalytic alkylation of adamantane and 1-bromoadamantane with alkyl halides in the presence of ruthenium-containing catalysts was revealed. The optimum molar ratios between the catalyst components and the reactants, as well as the reaction conditions for the selective synthesis of mono-and dialkylsubstituted adamantane derivatives with a 70-98% yield, were determined. Nauka/Interperiodica 2006.

Full text of DOI:10.1134/S0965544106030030

ISSN 0965-5441, Petroleum Chemistry, 2006, Vol. 46, No. 3, pp. 159–163. © Pleiades Publishing, Inc., 2006.
Original Russian Text © R.I. Khusnutdinov, N.A. Shchadneva, A.I. Malikov, U.M. Dzhemilev, 2006, published in Neftekhimiya, 2006, Vol. 46, No. 3, pp. 181–185.
Alkylation of Adamantane with Alkyl Halides Catalyzed
by Ruthenium Complexes
R. I. Khusnutdinov, N. A. Shchadneva, A. I. Malikov, and U. M. Dzhemilev
Institute of Petroleum Chemistry and Catalysis, Russian Academy of Sciences, Ufa, Bashkortostan, Russia
Received August 30, 2005
Abstract—The feasibility of catalytic alkylation of adamantane and 1-bromoadamantane with alkyl halides in
the presence of ruthenium-containing catalysts was revealed. The optimum molar ratios between the catalyst
components and the reactants, as well as the reaction conditions for the selective synthesis of mono- and
dialkylsubstituted adamantane derivatives with a 70–98% yield, were determined.
DOI: 10.1134/S0965544106030030
Preparation of alkyl-substituted adamantanes is of mercially available chemicals. The catalysts were puri-
great interest due to the fact that these compounds, pos- fied by standard procedures; for example, Ru(PPh3)3Cl2
sessing high thermal stability, satisfactory viscosity
characteristics, and bactericidal properties, are widely
used as valuable components of lubricating oils, gear
and hydraulic fluids, effective heat-transfer media, etc.
Alkyladamantanes are usually obtained via adaman-
tane alkylation with olefins, alcohols, and alkanes in the
presence of acid catalysts. At the same time, published
data concerning the alkylation of adamantane and some
of its functional derivatives (containing Cl, Br, and OH
groups) with olefins, alcohols, or paraffins indicate that
the reaction is difficult to initiate and the product yield
is low [1]. In the presence of strong acid catalysts
(H2SO4, HF, CF3COOH, AlCl3, AlBr3), which are nec-
essary for adamantane activation, olefins rapidly
isomerize and polymerize and alcohols form the prod-
ucts of dehydration, oxidation, and polycondensation
[2]. Alkyl halides are less effective as alkylating agents;
the alkylation of adamantane and its derivatives with
RX (X = Cl, Br) catalyzed by AlCl3 proceeds non-
selectively and is often accompanied by halogenation
[3]. There is the example of catalytic alkylation of ada-
mantane with n-butyl bromide in the presence of the
zeolitic catalyst Zeokar-2, which was used in a 1 : 1
ratio relative to the hydrocarbon, at 310°C for 3 h [4].
In spite of the stringent reaction conditions, the conver-
sion of adamantane was less than 100% and the total
yield of 1-n-butyladamantane was 40%.
was prepared according to a known procedure [5].
The reaction was carried out in sealed glass ampules
(V = 20 ml) or in stainless steel microautoclaves (V =
17 ml) (the results of parallel experiments were practi-
cally the same). Methylene chloride, alkyl halides
(methyl iodide, ethyl bromide, n-propyl bromide, n-
propyl chloride, iso-propyl bromide, n-butyl bromide,
n-butyl chloride, n-butyl iodide, iso-butyl chloride,
tert-butyl chloride), and bromobenzene used in the
work were preliminarily purified and dried [6]. The
reactants adamantane (1), 1-chloroadamantane (2), and
1-bromoadamantane (3) were of reagent grade and
were used without additional purification.
Product Analysis
The purity of the synthesized compounds and the
product composition were monitored by GLC on a
Chrome-5 chromatograph with a column of 1.2 m ×
3 mm packed with 5% SE-30-coated Chromaton
N-AW-HMDS at a temperature programmed from 50 to
280°ë at a rate of 8°C/min and helium as a carrier gas,
using n-tridecane as an internal standard.
Infrared spectra were recorded on an IR-75 spec-
trometer (in a thin layer or nujol mull) in the range 550–
3600 cm–1.
The aim of this work was to develop an effective
process for the alkylation of adamantane and its deriv-
atives with alkyl halides in the presence of metal-com-
plex catalysts based on ruthenium compounds.
1H and 13C NMR spectra were recorded on a JEOL
FX 90Q instrument operating at 90 and 25.5 MHz,
respectively, in CDCl3 as a solvent; chemical shifts (δ)
are given in ppm relative to TMS.
EXPERIMENTAL
Mass spectra were recorded with a Finnigan MAT-
112S gas chromatograph–mass spectrometer in the
electron ionization mode at an ionization energy of
70 eV and a source temperature of 22°C.
Alkylation of adamantane and its derivatives was
carried out in the presence of the ruthenium catalysts
RuCl3, Ru(OH)Cl3, and Ru(PPh3)3Cl2, which are com-
159

160
KHUSNUTDINOV et al.
trum, m/z, (Jrel, %): 178 [M]+ (14), 135 (100), 79 (17),
93 (15), 136 (14), 67 (13), 81 (7), 55 (7), 91 (6), 107 (5).
Found (%): C, 87.32; H, 12.68; C13H22. Calculated for
C13H22: C, 87.56; H, 12.44.
1-n-Butyladamantane (8). Yield 94%, bp 117–
118°C/6 torr. nD20 = 1.4912. 13C NMR (CDCl3, δ, ppm):
General Procedure for Adamantane Alkylation
with Alkyl Halides
A stainless-steel microautoclave (V = 17 ml) or a
glass ampoule (V = 20 ml) was charged with 0.25 mmol
of
a
ruthenium catalyst (RuCl3, Ru(OH)Cl3,
Ru(PPh3)3Cl2), 25 mmol of adamantane (1) (or 1-chlo-
roadamantane (2), or 1-bromoadamantane (3)), and 25–
50 mmol of an alkyl halide in 5 ml of CH2Cl2 under
argon, and the autoclave was tightly closed (the
ampoule was sealed). The reaction was conducted
under continuous agitation for 3–5 h at 150°C. Then,
the autoclave was cooled to room temperature, the reac-
tion mixture was passed through a silica gel column
32.41 (C1), 42.80 (C2, C8, C9), 29.15 (ë3, ë5, ë7), 37.64
(ë4, ë6, ë10), 44.81 (C11), 25.02 (C12), 23.97 (C13),
14.30 (C14). Mass spectrum, m/z, (Jrel, %): 192 [M]+ (2),
135 (100), 79 (14), 93 (12), 67 (7), 55 (7), 107 (6), 91
(6), 77 (5). Found (%): C, 86.88; H, 13.12; C14H24. Cal-
culated for C14H24: C, 87.56; H, 12.44. Published data:
(l = 20 cm, d = 30 mm, 1 : 1 hexane–ether solvent bp 254°C [10].
blend), the solvent was evaporated, and the residue was
1-iso-Butyladamantane (9). Yield 82%, bp 114–
115°C/6 torr. nD20 = 1.4884. 13C NMR (CDCl3, δ, ppm):
distilled in vacuum.
The isolated products had the following characteris-
tics:
33.34 (C1), 43.30 (C2, C8, C9), 29.03 (ë3, ë5, ë7), 37.55
(ë4, ë6, ë10), 54.48 (C11), 22.81 (C12), 16.02 (C13, C14).
Mass spectrum, m/z, (Jrel, %): 192 [M]+ (2), 135 (100),
79 (12), 93 (12), 136 (11), 67 (6), 107 (6), 91 (5), 77 (5),
81 (4), 55 (4). Found (%): C, 86.92; H, 13.08; C14H24.
Calculated for C14H24: C, 87.43; H, 12.57. Published
data: bp 248°C [10].
1-Methyladamantane (4).Yield 97%, bp 83°C/10 torr.
1ç NMR (CDCl3, δ, ppm): 1.48 (6H, 3CH2), 1.92 (3H,
3CH), 1.68 (6H, 3CH2), 0.82 (CH3). 13C NMR (CDCl3,
δ, ppm): 29.72 (C1), 44.65 (C2, C8, C9), 28.90 (C3, C5,
C7), 36.94 (C4, C6, C10), 31.28 (C11). Mass spectrum,
m/z, (Jrel, %): 150 [M]+ (3), 135 (100). Found (%): C,
87.91; H, 12.09; C11H18. Calculated for C11H18: C,
87.92; H, 12.08. Published data: bp 98–101°C [7].
1-tert-Butyladamantane (10).Yield 98%, mp 112–
112.5°C (in a sealed capillary). 13C NMR (CDCl3, δ,
ppm): 32.40 (C1), 42.85 (C2, C8, C9), 29.15 (ë3, ë5, ë7),
37.62 (ë4, ë6, ë10), 44.86 (C11), 34.40 (C12, C13, C14).
Mass spectrum, m/z, (Jrel, %): 192 [M]+ (abs), 135
(100), 79 (11), 136 (11), 93 (10), 67 (5), 107 (6), 91 (4),
55 (4), 77 (4), 81 (4). Found (%): C, 87.31; H, 12.69;
C14H24. Calculated for C14H24: C, 87.42; H, 12.58. Pub-
lished data: mp 111.7–113.0°C [9].
1-Ethyladamantane (5). Yield 95%, bp 95°C/10 torr,
nD20 = 1.4950. H NMR (CDCl3, δ, ppm): 1.50 (6H,
1
3CH2), 2.00 (3H, 3CH), 1.74 (6H, 3CH2), 0.81 (3H,
CH3), 1.12 (2H, CH2). 13C NMR (CDCl3, δ, ppm):
32.41 (C1), 42.30 (C2, C8, C9), 28.95 (C3, C5, C7), 37.63
(C4, C6, C10), 36.94 (C11), 14.52 (C12). Mass spectrum,
m/z, (Jrel, %): 164 [M]+ (4), 135 (100), 79 (21), 93 (15),
136 (11), 67 (9), 107 (7), 77 (6), 55 (6), 91 (5), 81 (5).
Found (%): C, 87.69; H, 12.31; C12H20. Calculated for
C12H20: C, 87.73; H, 12.27. Published data: bp
228°C/752 torr [8].
1-Phenyladamantane (11). Yield 85%, mp 79–
80°C. 1H NMR (CDCl3, δ, ppm): 1.90 (6H, 3CH2), 2.04
(3H, 3CH), 1.75 (6H, 3CH2), 7.11 (aromatic protons).
13C NMR (CDCl3, δ, ppm): 36.11 (C1), 43.18 (C2, C8,
C9), 29.05 (ë3, ë5, ë7), 36.82 (ë4, ë6, ë10), 151.12
(C11), 125.28 (C12, C12'), 128.16 (C13, C13'), 125.17
(C14). Found (%): C, 89.84; H, 10.16; C16H20. Calcu-
1-n-Propyladamantane (6). Yield 94%, bp 110–
111°C/6 torr. nD20 = 1.4908. 13C NMR (CDCl3, δ, ppm): lated for C16H20: C, 90.50; H, 9.50. Published data: mp
32.49 (C1), 43.20 (C2, C8, C9), 29.14 (ë3, ë5, ë7), 37.68
(ë4, ë6, ë10), 47.65 (C11), 16.05 (C12), 15.48 (C13).
Mass spectrum, m/z, (Jrel, %): 178 [M]+ (3), 135 (100),
79 (14), 93 (12), 67 (6), 91 (6), 107 (6), 77 (5), 55 (4),
81 (4). Found (%): C, 87.02; H, 12.98; C13H22. Calcu-
lated for C13H22: C, 87.56; H, 12.44. Published data: bp
234°C [9].
80°C [11].
1,3-Dimethyladamantane (12). Yield 79%, bp
84°C/6 torr. 13C NMR (CDCl3, δ, ppm): 30.64 (C1, C3),
51.80 (C2), 44.15 (C4, C8, C9, C10), 29.56 (C5, C7),
36.41 (C6), 31.02 (C11, C12). Found (%): C, 87.12; H,
12.88; C12H20. Calculated for C12H20: C, 87.73; H,
12.27. Published data: bp 100–105°C/25 torr [12].
1,3-Diethyladamantane (13). Yield 75%, bp 113–
1-iso-Propyladamantane (7). Yield 86%, bp 108–
114°C/6 torr. nD20 = 1.4855. 13C NMR (CDCl3, δ, ppm):
109°C/6 torr. nD20 = 1.4884. 1H NMR (CDCl3, δ, ppm):
1.52 (6H, 3CH2), 2.00 (3H, 3CH), 1.69 (6H, 3CH2), 33.29 (C1, C3), 48.92 (C2), 43.50 (C4, C8, C9, C10),
29.52 (C5, C7), 36.41 (C6), 31.92 (C11, C13), 14.50 (C12,
C14). Mass spectrum, m/z, (Jrel, %): 192 [M]+ (abs), 163
[M-C2H5]+ (100), 93 (28), 107 (13), 79 (9), 55 (7), 81
0.80 (CH3), 1.10 (CH). 13C NMR (CDCl3, δ, ppm):
34.62 (C1), 39.64 (C2, C8, C9), 29.20 (ë3, ë5, ë7), 37.67
(ë4, ë6, ë10), 38.02 (C11), 16.50 (C12, C13). Mass spec-
PETROLEUM CHEMISTRY Vol. 46 No. 3 2006

ALKYLATION OF ADAMANTANE WITH ALKYL HALIDES
161
Influence of the reaction conditions and alkyl halide structure on the alkylation of adamantane
Reaction conditions
Yield
[cat] : [AdH] : [RX] mole
Catalyst
RuCl3
RX
Product
ratio
T, °C
time, h
Ad-R
Ad-R2
MeI
1 : 100 : 100
100
150
100
″
150
150
150
″
5
3
5
″
3
3
3
″
″
5
″
″
3
″
″
″
″
″
″
″
4
30
42
63
97
95
21
87
95
25
68
72
89
94
27
86
94
82
98
85
80
–
–
″
″
″
″
″
″
″
″
″
″
″
″
″
Ru(OH)Cl3
–
Ru(PPh3)3Cl
–
–
1 : 100 : 200
4; 12
79
–
Ru(OH)C3
EtBr
1 : 100 : 100
5
Ru(PPh3)3Cl
″
″
″
″
5; 13
6
–
1 : 100 : 200
″
100
75
–
n-PrI
1 : 100 : 100
n-PrBr
n-PrCl
″
″
″
″
″
″
150
″
″
″
–
–
–
″
1 : 100 : 200
″
″
″
″
″
″
″
6; 14
73
–
iso-PrCl
BuCl
iso-BuCl
tert-BuCl
PhCl
1 : 100 : 100
7
″
″
″
″
″
8
–
9
–
10
11
15
–
–
AdBr
–
(7), 121 (5), 77 (5), 53 (4). Found (%): C, 87.35; H,
12.65; C14H24. Calculated for C14H24: C, 87.42; H,
12.58.
RESULTS AND DISCUSSION
Searching for convenient preparative methods of
selective introduction of alkyl substituents into the ada-
mantane (1) molecule, we studied its reaction with
alkyl halides in the presence of metal-complex catalysts
based on platinum, rhodium, palladium, and ruthenium
compounds, which are known to activate C–H and
C−Hal bonds.
1,3-Di-n-propyladamantane (14). Yield 73%, bp
139–140°C/6 torr. nD20 = 1.4880. 13C NMR (CDCl3, δ,
ppm): 33.31 (C1, C3), 47.95 (C2), 42.56 (C4, C8, C9,
C10), 29.48 (C5, C7), 37.30 (C6), 47.32 (C11, C14), 16.02
(C12, C15), 15.34 (C13, C16). Mass spectrum, m/z, (Jrel,
It was found that, of the variety of examined cata-
lysts, the ruthenium complexes exhibit noticeable
activity in the alkylation of adamantane 1 with alkyl
halides.
%): 220 [M]+ (2), 177 (100), 93 (15), 178 (12), 79 (11),
121 (10), 135 (10), 81 (7), 55 (7), 91 (7), 107 (6). Found
(%): C, 87.11; H, 12.89; C16H28. Calculated for C16H28:
C, 87.19; H, 12.81. Published data: bp 275°C [10].
For example, the reaction of adamantane with
chloro-, bromo-, and iodoalkanes in the presence of
1,1-Diadamantyl (15). Yield 80%, subp 72°C/10 torr.
13C NMR (CDCl3, δ, ppm): 36.12 (C1, C1'), 35.20 (C2,
ruthenium
compounds
([RuCl3,
Ru(OH)Cl3,
C8, C10, C2', C8', C10'), 28.83 (ë3, ë5, ë7, C3', C5', C7'),
37.46 (C4, C6, C9, C4', C6', C9'). Found (%): C, 88.74; H,
11.26; C20H30. Calculated for C20H30: C, 88.82; H,
Ru(PPh3)3Cl2) taken in a molar ratio of [Ru] : [AdH] :
[RX] = 1 : 100 : 100 in a CH2Cl2 medium resulted in the
formation of alkyladamantanes with a total yield of
70−98%.
11.18. Mass spectrum, m/z: 270 [M]+.
The process is highly regioselective: alkylation pro-
ceeds exclusively at the bridgehead (tertiary) carbon
atom of adamantane, with the yields of 1-alkyl- (4–11)
and 1,3-dialkyladamantanes (12–14) depending on the
length and branching of the alkyl radical in a halogenal-
kane and on the reaction time.
1-But-2-enyladamantane (16). Yield 25%, mp 35–
36°C (bp 70–71°C/2 torr). 13C NMR (CDCl3, δ, ppm):
33.20 (C1), 42.24 (C2, C8, C9), 28.33 (ë3, ë5, ë7), 37.60
(ë4, ë6, ë10), 37.74 (C11), 42.51 (C12), 138.04 (C13),
114.89 (C14).
PETROLEUM CHEMISTRY Vol. 46 No. 3 2006

162
KHUSNUTDINOV et al.
The activity of ë1–ë3 alkyl halides in this reaction mass compounds. A GC–MS analysis and titration of
the reaction mixture with a NaOH solution showed that
the reaction mixture contained hydrogen halides (HCl,
HBr, HI) along with alkylated adamantanes, thus indi-
cating that alkylation proceeds via the substitution of
alkyl for the bridgehead hydrogen of adamantane.
An increase in alkyl halide concentration increases
the degree of adamantane alkylation. For example, a
two-fold excess of RX ([AdH] : [RX] = 1 : 2) results in
replacement of two bridgehead hydrogen atoms in the
adamantane molecule and the formation of 1,3- dialkyl-
adamantanes.
is practically the same; they alkylate adamantane
within 3 h at 150°ë giving monoalkyladamantanes 4–6
with quantitative yields. An increase in the length of the
alkyl radical in RX gradually decreases the activity of
alkyl halide. The reaction of adamantane with n-butyl
chloride over 3 h at 150°ë afforded 1-n-butyladaman-
tane (8) in a yield of 72%; an increase of the reaction
time to 5 h increased the yield of 8 to 94%. The reaction
of adamantane with tert-butyl chloride proceeds twice
as slowly: the yields of 10 in 3, 5, and 10 h were 54, 71,
and 98%, respectively.
The alkylation of adamantane 1 with 1-chloroada-
mantane 2 is difficult and results in low yields of the
product (3 h, 30%) even with an increase in the reaction
time (5 h, 44%). However, the use of 1-bromoadaman-
tane 3 instead of 1-chloroadamantane 2 resulted in an
80% yield of 1,1'-diadamantyl (15) in the reaction at
150°C for 5 h in a CH2Cl2 solution at a reactant molar
ratio of [Ru] : [AdH] : [RX] = 1 : 100 : 100.
RX
85–90%
–HX
R
(4–11)
[Ru] – CH2Cl2
150°C, 3–5 h
R
2RX
70–80%
–HX
R
[Ru] – CH2Cl2
+
Br
150°C, 5
–HBr
R = Me (4, 12); Et (5, 13); n-Pr (6, 14); iso-Pr (7);
n-Bu (8); iso-Bu (9); tret-Bu (10); Pb (11).
X = Cl, Br, I
~80%
(1)
(3)
(15)
In turn, 1-bromoadamantane 3 is also alkylated with
Adamantane alkylation with alkyl bromides and alkyl halides, in particular, n-butyl bromide, but the
alkyl iodides proceeds more rapidly and more readily; product contains 1-but-2-enyladamantane (16) along
however, the yields of alkyladamantanes are consider- with 1-n-butyladamantane 8, where 16 is presumably
ably lower because of the formation of high-molecular- formed via HBr elimination from the side chain.
[Ru] – CH2Cl2
+
Br + BuBr
150°C, 5 ˜
–HBr
~100%
(3)
(16)
(17)
3 : 1
An attempt to involve 1,3-dibromoadamantane in
The proposed method for the synthesis of alkylada-
the reaction in question was unsuccessful. In this case, mantanes in the presence of ruthenium-containing cat-
we observed the formation of a mixture of isomeric alysts is simple and ensures a high yield of the desired
monobromodichloro- and monobromotrichloroada- products and high selectivity.
mantanes, which were obviously due to the direct par-
ticipation of CH2Cl2 in the chlorination of the adaman-
tane ring and the replacement of bromine by chlorine in
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PETROLEUM CHEMISTRY Vol. 46 No. 3 2006

ALKYLATION OF ADAMANTANE WITH ALKYL HALIDES
163
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