Reaction of seven-membered cyclic orthosilicates with acetonitrile

Full text of DOI:10.1023/A:1012355718734

Russian Journal of Organic Chemistry, Vol. 37, No. 2, 2001, pp. 295 296. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 2, 2001,
pp. 308 309.
Original Russian Text Copyright
2001 by Kuznetsov, Bochkor, Brusilovskii, Mazepa.
SHORT
COMMUNICATIONS
Reaction of Seven-membered Cyclic Orthosilicates
with Acetonitrile
V. V. Kuznetsov1, S. A. Bochkor2, Yu. E. Brusilovskii2, and A. V. Mazepa2
1Ufa State Oil Technical University, Ufa, Bashkortostan, 450162 Russia
2Bogatskii Physico-chemical Institute, Ukrainian Academy of Sciences, Bogatsk, Ukraine
Received April 19, 2000
Reaction of certain heterocycles containing 2 or 3
heteroatoms in 1,2 and 1,2,3 positions respectively
with nitriles may serve as a promising and sufficiently
simple procedure for aminoalcohols preparation [1, 2].
We showed formerly [3,4] that methyl-substituted
1,3,2-dioxasilolanes and -dioxasilinanes reacted with
acetonitrile to yield 1,3-oxazoline and 5,6-dihydro-
4H-1,3-oxazine respectively. The latter in alkaline
medium are readily hydrolyzed to 1,2- and 1,3-amino-
alcohols. Here by examples of 3,3-dimethyl-1,5-di-
hydro-2,4,3-benzodioxasilepine (I) and 1,6,8,13-
tetraoxa-7-siladibenzo[c,j]spiro[6,6]tridecane (II) we
show for the first time the possibility for analogous
transformation of seven-membered cyclic ortho-
silicates yielding 4,7-dihydro-2-methylbenzo[e]-1,3-
oxazepine (III) and its hydrolysis product, 1-amino-
methyl-2-hydroxymethylbenzene (IV).
Benzoxazepine III was isolated in both cases in
10% yield; it is a colorless crystalline compound that
decomposes at heating over 185 C. Its composition
and structure was confirmed by the data of mass
1
spectrometry, and also by IR and H NMR spectra.
In the IR spectrum appear strong bands at 1665
1
[ (C=N)] and 1510 cm [ (C C arom)].
In the mass spectrum is present the molecular ion
peak (m/z 161) of relative intensity 70%, and a signal
with m/z 119 of maximum intensity corresponding to
fragmentation M+ CH3CNH. 1H NMR spectrum
contains the expected signals from all proton groups
( , ppm): 1.91 s (3H), 4.10 s (2H), 4.42 s (2H), 7.19
s (4H). The yield of aminoalcohol IV formed in the
course of benzoxazepine III isolation due to hydro-
lysis of the latter amounts to 44%(with respect to
ether I) and 49% (with respect to ether II). It is a
viscous fluid with a characteristic amine odor. In its
IR spectrum appear absorption bands at 3450
ppm): 3.53 s (3H), 3.75 s (2H), 4.48 s (2H), 7.14 s
(4H).
The reaction under study extends the possibility of
chemical transformations for the seven-membered
cyclic orthosilicates and opens a new approach to the
synthesis of 1,3-benzoxazepines and the correspond-
ing 1,4-aminoalcohols.
1
The H NMR spectra were recorded on Tesla BS
497 spectrometer from 15% solutions of compounds
under study in CDCl3 with respect to TMS as internal
reference. IR spectra were registered on spectro-
photometer Specord 75IR from thin films or mulls in
mineral oil. Mass spectrum was measured on
1
3290 cm [ (OH), (NH)], and also at 1580 and
1
1
1510 cm [ (C C arom)]. H NMR spectrum ( ,
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296
KUZNETSOV et al.
MKh-1321 spectrometer, ionizing irradiation energy
70 eV.
then compound IV was extracted with chloroform
(4...50 ml), and the solvent was distilled off on a
rotary evaporator.
Initial compounds I and II were synthesized
according to [5, 6] in 62 and 40% yield respectively.
Their physical constants and H NMR spectra were
REFERENCES
1
consistent with the published data. To a solution of
0.01 mol of ester I in 30 ml (0.57 mol) of acetonitrile
or to 0.01 mol of ester II in 180 ml (3.44 mol) of
acetonitrile was added dropwise slowly while stirring
10.6 ml (0.2 mol) of concn. H2SO4, and then the
mixture was refluxed at heating on a water bath for
5 h; the excess of acetonitrile was distilled off on
rotary evaporator, and the viscous residue was diluted
with 100 ml of water; the impurities were extracted
into chloroform (2...50 ml). The remaining water
phase was treated at cooling with ice with solid LiOH
till pH 9 10, the separated precipitate of 1,3-benzox-
azepine (III) was filtered off, and the water phase was
extracted with chloroform (4...50 ml). On evaporat-
ing the solvent we obtained a residue containing
aminoalcohol IV and oxazepine III as impurity. To
isolate compound IV the residue was boiled for 3 h
in 5-fold volume of 15% water solution of KOH, and
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Conf. on Organic Chemistry, 1995, Kharkiv, p. 191.
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on Manufacture and Application of Chemical Reactives
and Reagents Reaktiv-99 , Ufa Moskow, 1999.
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tor, E.A., and Syrkin, A.M., 1,3-Dioksa-2-silatsiklo-
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 2 2001