Synthesis of (m-carborane-9,10-diyl)diacetic acids and their derivatives

Article abstract of DOI:10.1023/A:1026336331113

(m-Carborane-9,10-diyl)diacetic acids were obtained by oxidation of 9,10-diallyl-m-carborane which, in its turn, was synthesized by palladium-catalyzed cross coupling of 9,10-diiodo-m-carborane with allylmagnesium bromide.

Full text of DOI:10.1023/A:1026336331113

Russian Journal of General Chemistry, Vol. 73, No. 6, 2003, pp. 868 870. Translated from Zhurnal Obshchei Khimii, Vol. 73, No. 6, 2003,
pp. 918 920.
Original Russian Text Copyright
2003 by Zakharkin, Guseva, Petrovskii.
Synthesis of (m-Carborane-9,10-diyl)diacetic Acids
and Their Derivatives
L. I. Zakharkin, V. V. Guseva, and P. V. Petrovskii
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia
Received May 23, 2001
Abstract (m-Carborane-9,10-diyl)diacetic acids were obtained by oxidation of 9,10-diallyl-m-carborane
which, in its turn, was synthesized by palladium-catalyzed cross coupling of 9,10-diiodo-m-carborane with
allylmagnesium bromide.
(m-Carborane-9,10-diyl)di(alkanecarboxylic acids)
in which the alkyl chain is bound by a C B bond
have not yet been reported. Such acids may offer
interest for synthesis of previously unknown poly-
meric compounds containing m-carboranyl groups in
the polymeric chain. To this end, we have prepared
(m-caborane-9,10-diyl)diacetic acids I as first re-
presentatives of (m-carborane-9,10-diyl)di(alkane-
carboxylic acids). Diacid I was synthesized by the
following scheme from 9,10-diiodo-m-carborane (II).
I + 2SOCl2
9,10-(CH2COCl)2-m-C2B10H10.
IV
Dichloride IV was reacted with aniline to obtain
dianilide V, and its Fridel Crafts reaction with ben-
zene gave 9,10-bis(bezoylmethyl)-m-carborane (VI).
NH2C6H5
IV
9,10-(CH2CO NHC6H5)2-m-C2B10H10,
V
C6H6
IV
9,10-(CH2CO C6H5)2-m-C2B10H10.
AlCl3
VI
9,10-I2-m-C2B10H10 + 2CH2=CH CH2MgBr
II
Pd-cat.
Reduction of diacid I with lithium aluminum
hydride provided 9,10-bis(2-hydroxyethyl)-m-car-
borane (VII).
9,10-(CcH2 CaH=CbH2)2-m-C2B10H10
III
KMnO4, CH3COOH
9,10-(CH2COOH)2-m-C2B10H10
LiAlH4
H2SO4, cat.
I
9,10-(CH2CH2OH)2-m-C2B10H10.
I
ether
VII
Compound II [1] was brought into cross coupling
with allylmagnesium bromide in a mixture of ether
and tetrahydrofuran under (Ph3P)2PdCl2 catalysis in
the presence of copper iodide [2]. 9,10-Diallyl-m-
carborane (III) was obtained in a high yield. Its struc-
We found that (m-carborane-9,10-diyl)diacetic
acids are stable compounds and can be used in the
syntheses of other carboranyl-containing compounds,
involving the B C bond.
1
ture was proved by H and 11B NMR spectroscopy.
EXPERIMENTAL
The 11B {1H} spectra were assigned by comparing
1
with a spectrum measured without 11B H decoupling,
The IR spectra were obtained in KBr on a Specord-
1
as well as using by analysis of off-diagonal crosspeaks
82 instrument. The H and 11B NMR spectra were
in the 11B 11B COSY spectrum (see figure).
measured on a Bruker AMX-400 spectrometer in
CDCl3, internal references TMS and (C2H5)2O BF3,
respectively.
Compound III was oxidized with potassium per-
manganate in acid medium to diacid I. Treatment of
the latter with SOCl2 results in quantitative formation
of dichloride IV.
9,10-Diiodo-m-carborane was prepared by the
procedure in [2]. 9,10-Diallyl-m-carborane was
oxidized by the procedure in [3].
9,10-Diallyl-m-carborane (III). To a stirred solu-
tion of 240 mmol of allylmagnesium bromide in ether,
Deceased.
1070-3632/03/7306-0868$25.00 2003 MAIK Nauka/Interperiodica

SYNTHESIS OF (m-CARBORANE-9,10-DIYL)DIACETIC ACIDS
869
B6,8,11,12
B4,5
B9,10
B2,3
3
2
1
B2,3
B6,8,11,12
B4,5
B9,10
0
1
0
10
B, ppm
20
30
11 11
B
B COSY spectrum of 9,10-(CH CH=CH ) -m-C B H .
2 2 2 2 10 10
1
cooled with ice water, we gradually added under
argon 16 g of 9,10-diiodo-m-carborane in 300 ml of
tetrahydrofuran. After 30-min stirring, 1.12 g of
(Ph3P)2PdCl2 and 304 mg of CuI were added simul-
taneously. The mixture was left to stand for 12 h at
room temperature and then stirred under reflux for 6
h until 9,10-diiodo-m-carborane was consumed com-
pletely (control by TLC on Silufol). The solvent was
removed, the residue was treated with 300 ml of ether,
and excess Grignard reagent was decomposed with
5% HCl with cooling. The organic layer was se-
parated, and the aqueous layer was extracted with
ether (2 40 ml). The organic extracts were combined,
washed with water (2 150 ml), and dried with
MgSO4. The solvent was removed in a vacuum, and
the residue was subjected to column chromatography
on silica gel (eluent hexane) to obtain 8.1 g (89%) of
B
9,10), 6.51 d [2B, B4,5, 1J(11B H) 159 Hz],
13.84 d [4B, B6,8,11,12, J(11B H) 163 Hz], 20.61 d
1
1
1
[2B, B2,3, 1J(11B H) 181 Hz].
(m-Carborane-9,10-diyl)diacetic acids I. To a
stirred mixture of 6 g of compound III, 200 ml of
CH2Cl2, 200 ml of water, 30 ml of 50% H2SO4, 4 ml
of acetic acid, and 2.4 g of PhCH2(C2H5)3NBr,
cooled to 0 C, we gradually added 25 g of KMnO4.
The resulting mixture was kept for 40 min at that
temperature and then allowed to warm to 20 C. The
residue was filtered off and washed with 100 ml of
CH2Cl2 and 100 ml of water, transferred into a flask,
and shaken twice with 100 ml of 10% KOH. The
alkaline extracts were combined, acidified with dilute
HCl, the white precipitate that formed was filtered off,
washed with water to neutral, and dried in a water-jet-
pump vacuum at 60 C to obtain 4.5 g (65%) of
compound I, mp 200 201 C (toluene). IR spectrum,
1
compound III. H NMR spectrum (CDCl3), , ppm:
3
3
3
5.88 d.d.t [1Ha, Jac 17.8, Jab 9.8, J(CaH2) 7.8 Hz],
1
, cm : 1683 (C=O), 3060 2881 (COOH). Found,
%: C 28.43; H 6.34; B 41.35. C6H16B10O4. Cal-
culated, %: C 27.69; H 6.15; B 41.53.
4.89 d.d.t [2H, Hc, Jac 17.8, Jbc 2.2, 4J(CcH2)
1.5 Hz], 4.83 d.d.t (2H, Hb, 3Jab 9.8, 2Jbc 2.2, 4J(CbH2)
1.0 Hz], 2.82 s (2H, carb. CH), 1.76 m (4H, CH2).
11B NMR spectrum (CDCl3), B, ppm: 0.41 s (2B,
3
2
(m-Carboranyl-9,10-diyl)di(acetyl chlorides)
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 6 2003

870
ZAKHARKIN et al.
IV. To a solution of 2.5 g of diacid I in 25 ml of
dry benzene we added 2.9 g of SOCl2 at 20 C. The
reaction mixture was heated for 2 h until HCl and SO2
no longer evolved, cooled, and the solvent and excess
SOCl2 were removed in a vacuum to obtain 2.77 g
(98%) of a solid dichloride.
residue, and treated with hexane to precipitate 0.8 g
(50%) of compound VI, mp 97 98 C. Found, %:
C 56.92; H 6.99. C18H24B10O2. Calculated, %: C
56.84; H 6.31. 2,4-Dinitrophenylhydrazone, mp 270
271 C (benzene hexane). Found N, %: 14.55.
C30H32B10N8O8. Calculated N, %: 15.13.
9,10-Bis(2-hydroxyethyl)-m-carborane (VII). To
1 g of diacid I in 30 ml of dry ether we added 1.2 g
of LiAlH4 in 25 ml of dry ether. The suspension was
heated under reflux for 10 h. After cooling, the reac-
tion mixture was decomposed with caution with 10%
H2SO4, the organic layer was separated, and the
aqueous layer was extracted with ether. The ether
extracts were washed with water, dried with Na2SO4,
and the ether was removed to obtain 0.75 g (85%) of
diol VII, mp 113 114 C (ethanol benzene). IR spec-
(m-Carborane-9,10-diyl)diacetanilides V. Di-
chloride IV (3 g) in 10 ml of dry dioxane was slowly
added to a solution of 0.56 g of freshly distilled
aniline in 4 ml of dry dioxane. The precipitate that
formed was transferred together with the solvent to a
dropping funnel, treated with 10% HCl, and extracted
twice with ether. The ether solution was washed with
water, and the ether was removed in a vacuum to
obtain 0.3 g (73%) of compound V, mp 225 226 C
1
(toluene hexane). IR spectrum, , cm : 1658 (CO),
1
trum, , cm : 3276 (OH). Found,%: C 31.24; H 8.20;
3191, 3132 (NH). Found N, %: 7.04. C18H26B10N2O2.
Calculated N, %: 6.82.
B 46.94. C6H20B10O2. Calculated,%: C 31.03; H 8.62;
B 46.55.
9,10-Bis(benzoylmethyl)-m-carborane (VI). To
1 g of AlCl3 in 10 ml of dry benzene at 20 C we
added 1 g of dichloride IV in 10 ml of dry benzene,
and the mixture was stirred for 5 h at room tempera-
ture. The reaction mixture was poured into 5% HCl,
the benzene layer was separated, and the aqueous
layer was extracted with benzene. The organic extracts
were combined, washed with 2% NaOH and water,
and dried with K2CO3. The benzene was removed, the
residue was dissolved in a little benzene, the solution
was refluxed, the benzene was decanted from the oily
REFERENCES
1. Zakharkin, L.I., Kovredov, A.I., Ol’shevskaya, V.A.,
and Shaugumbekova, Zh.S., J. Org. Chem., 1982,
vol. 226, no. 3, p. 217.
2. Zheng, Zh., Jiang, W., Zinn, A.A., Knobler, C.B., and
Hawthorne, M.F., Inorg. Chem., 1995, vol. 34, no. 8,
p. 2095.
3. Zakharkin, L.I. and Petrushkina, E.A., Izv. Akad. Nauk
SSSR, Ser. Khim., 1985, no. 1, p. 205.
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