1-Acyloxygermatranes

Article abstract of DOI:10.1134/S1070363213080045

A one-step method for the synthesis of 1-acyloxygermatranes RC(O)OGe(OCH₂CH₂)₃N in the reaction of germanium dioxide with triethanolamine and a carboxylic acid was developed. 1-Acyloxygermatranes, including those containing biologically active acyloxy groups (R = 2-MeC₆H₄CH₂OCH₂, C ₆H₅, 2-HOC₆H₄), were obtained with a 82-96.5% yield.

Full text of DOI:10.1134/S1070363213080045

ISSN 1070-3632, Russian Journal of General Chemistry, 2013, Vol. 83, No. 8, pp. 1501–1502. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © V.P. Baryshok, L.N. Thuy Zang, M. G.Voronkov, 2013, published in Zhurnal Obshchei Khimii, 2013, Vol. 83, No. 8, pp. 1267–1269.
1-Acyloxygermatranes
V. P. Baryshoka, L. N. Thuy Zanga, and M. G. Voronkovb
a Irkutsk State Technical University, ul. Lermontova, 83, Irkutsk, 664074 Russia
b Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
e-mail: baryshok@istu.edu
Received September 24, 2012
Abstract—A one-step method for the synthesis of 1-acyloxygermatranes RC(O)OGe(OCH2CH2)3N in the
reaction of germanium dioxide with triethanolamine and a carboxylic acid was developed. 1- Acyloxygermatranes,
including those containing biologically active acyloxy groups (R = 2-MeC6H4CH2OCH2, C6H5, 2-HOC6H4), were
obtained with a 82–96.5% yield.
DOI: 10.1134/S1070363213080045
Continuing interest in the 1-substituted germatranes
is due to their specific biological activity [1, 2] unlike
that of the corresponding silatranes [3]. Markedly
greater stability of the germatrane ring to hydrolytic
cleavage compared to silatrane allows using germa-
tranes for transporting the biologically active fragments
to the living cells [4–6].
acetoxygermatrane CH3C(O)OGe(OCH2CH2)3N was
obtained in 91% yield by the reaction of 1-meth-
oxygermatrane with 98% acetic acid or acetic an-
hydride in o-dichlorobenzene at 100°C [7].
We have developed a simple and convenient
method for the synthesis of 1-acyloxygermatranes from
germanium dioxide, triethanolamine, and a carboxylic
acid in xylene or isoamyl alcohol.
The first specimen of 1-acyloxygermatranes, the 1-
+ RC(O)OH
GeO2 + (HOCH2CH2)3N
H2O HOGe(OCH2CH2)3N
RC(O)OGe(OCH2CH2)3N
−2H2O
I−IV
R = CH3 (I), 2-CH3C6H4OCH2 (II), C6H5 (III), 2-HOC6H4 (IV).
The reaction is performed by successive addition of
water and a solution of a carboxylic acid in xylene or
isoamyl alcohol to a mixture of stoichiometric amounts
of germanium dioxide and triethanolamine.
not the 1-isoamyloxygermatrane, and the reaction time
is significantly reduced judging from the rate of release
of the theoretical amount of water (Table 1).
The composition and structure of the synthesized 1-
acyloxygermatranes was established by elemental
The 1-germatranol hydrate [8, 9] formed in the first
stage in the presence of water undergoes esterification
with the carboxylic acid while the theoretical amount
of hydration and formed water is distilled off, to afford
the corresponding 1-acyloxygermatrane. The yield of
compounds I–IV is 82–96.5%.
1
analysis (Table 1), H NMR (Table 2), and IR spec-
troscopy. The IR spectra of compounds I–IV contain
the following absorption bands, cm–1: νGeOC, νCOC
(1000–1010, 1020–1060, 1080–1110), and νC=O
(1640–1680). The band of the stretching vibrations of
OH group in IV appears at 3240 cm–1.
We have previously reported that the germatranol
1-hydrate when heated with an excess aliphatic alcohol
is converted almost quantitatively to the corresponding
1-alkoxygermatrane [10]. It is noteworthy that in
isoamyl alcohol (instead of xylene) the reaction with
benzoic acid leads to 1-benzyloxygermatrane (III), but
EXPERIMENTAL
The melting points, yields, solvents, reaction time,
and the elemental analyses data of the 1-acyloxy-
germatranes are given in Table 1. The 1H NMR spectra
1501

1502
BARYSHOK et al.
Table 1. Yields, melting points, and elemental analysis data of 1-acyloxygermatranes
Found, %
Calculated, %
Ge
Comp. Reaction time, Yield,
mp, °С
(solvent)
Formula
no.
h
%
С
Н
Ge
N
С
Н
N
3
4
94.2
94.3
210–216 (xylene)
183–184 (xylene)
34.95 5.35 25.83 4.86 C8H15GeNO5 34.59 5.44 26.13 5.04
47.11 5.78 19.16 3.65 C15Н21GeNО6 46.93 5.51 18.91 3.65
46.04 5.19 20.56 4.80 C13H17GeNO5 45.94 5.04 21.36 4.12
I
II
8
1
96.5
82.0
258–262 (xylene)
257–262 (isoamyl alcohol)
III
3
94.7
225–226 (xylene)
44.57 4.65 20.53 4.06 C13H17GeNО6 43.88 4.82 20.40 3.94
IV
Table 2. 1H NMR spectra of 1-acyloxygermatranes RC(O)OGe(OCH2CH2)3N
δ, ppm (J, Hz)
Comp. no.
R
Solvent
OCH2
NCH2
R
CH3
CDCl3
3.95 t (3JHH 5.4) 2.99 t (3JHH 5.6) 2.06 s
3.62 t (3JHH 5.6) 2.82 t (3JHH 5.4) 1.90 s
3.87 t (3JHH 5.6) 3.02 t (3JHH 5.4) 2.29 (s, CH3), 4.71 (s, CH2), 6.86–7.18 m (C6H4)
3.85 t (3JHH 5.6) 3.01 t (3JHH 5.6) 7.57–8.00 m (C6H5)
I
(CD3)2SO
CD3OD
CD3OD
CD3OD
CH3C6H4OCH2
C6H5
II
III
IV
2-HOC6H4
3.86 t (3JHH 5.5) 3.00 t (3JHH 5.6) 4.50 (s, ОН), 6.91–6.99 m (C6H4)
were recorded on Bruker-400 spectrometer with an
operating frequency 400 MHz in solutions of deuterated
solvents (Table 2), internal reference HMDS. The IR
spectra were obtained on a Bruker VERTEX 70 instru-
ment from the tablets with KBr.
REFERENCES
1. Ignatenko, M.A., Khim. Farm. Zh., 1987, no. 4, p. 402.
2. Lukevits, E., Ignatovich, L., Khokhlova, L., and
Belyakov, S., Khim. Geterotsikl. Soed., 1997, no. 2,
p. 275.
Triethanolamine pure quality was additionally
distilled in a vacuum, bp 162–163°C (2 mm Hg).
3. Voronkov, M.G., Levit, T.Kh., Kirillov, A.F., Bary-
shok, V.P., Koz’mik, R.A., Skurtul, A.M., Grozova, V.M.,
and Ovchinnikova, Z.A., Dokl. Akad. Nauk SSSR, 1988,
vol. 299, no. 2, p. 509.
Glacial acetic acid pure quality was distilled at
atmospheric pressure. Germanium dioxide, benzoic
acid, o-methylphenoxyacetic and salicylic acids of
pure grade were used without additional purification.
4. Voronkov, M.G. and Baryshok, V.P., Vestnik Ross.
Akad. Nauk, 2010, vol. 80, no. 11, p. 985.
5. Voronkov, M.G. and Baryshok, V.P., Silatranes v
meditsine i sel'skom khozyaistve (Silatranes in Medicine
and Agriculture), Novosibirsk: Sib. Otd. Ross. Akad.
Nauk, 2005.
General procedure for the synthesis of 1-
acyloxygermatranes I–IV. A mixture of 0.01 mol of
germanium dioxide, 0.01 mol of triethanolamine, and
1 ml of water was stirred for 5 min until 1-germatranol
hydrate formed (solidification of the reaction mixture),
and then a solution of 0.01 mol of a carboxylic acid in
200 ml of xylene or isoamyl alcohol was poured and
the mixture was heated with a Dean–Stark trap until
the theoretical amount of water was released. The hot
solution was filtered, the small colorless crystals of 1-
acyloxygermatrane precipitated at cooling to 20°C
were filtered off, washed with diethyl ether, and dried
in a desiccator in a vacuum of 15–20 mm Hg. The
mother liquor was evaporated to two-thirds of volume
and cooled to 20°C. The crystalline precipitate of 1-
acyloxygermatrane was treated similarly to that
precipitated of the solution directly after synthesis.
6. Bashkirova, S.A., Doskoch, Ya.E., Bessonov, A.E.,
Berezovskaya, I.V., and Kalmykova, E.A., Spravochnik
vracha obshchei praktiki (Handbook of General Prac-
titioner), 2009, no. 9, p. 61
7. Gar, T.K., Khromova, N.Yu., Sonina, N.V., Nikitin, V.P.,
Polyakova, M.V., and Mironov, V.F., Zh. Obsch. Khim.,
1979, vol. 49, no. 7, p. 1516.
8. Voronkov, M.G., Ovchinnikova, Z.A., and Baryshok, V.P.,
Izv. Akad. Nauk SSSR, Ser. Khim., 1987, no. 4, p. 880.
9. Gar, T.K. and Mironov, V.F., Metalloorgan. Khim.,
1988, vol. 1, no. 2, p. 260.
10. Voronkov, M.G., Ovchinnikova, Z.A., Romanenko, L.P.,
and Baryshok, V.P., Metalloorgan. Khim., 1989, vol. 2,
no. 6, p. 1308.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 8 2013