Reactions of 2-alkoxy-7,7-dichlorobicyclo[4.1.0]heptanes with phosphorus trichloride

Full text of DOI:10.1134/S1070363207120201

ISSN 1070-3632, Russian Journal of General Chemistry, 2007, Vol. 77, No. 12, pp. 2203 2204.
Pleiades Publishing, Ltd., 2007.
Original Russian Text
Yu.N. Mitrasov, E.A. Simakova, O.V. Kondrat’eva, I.N. Smolina, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77,
No. 12, pp. 2058 2059.
LETTERS
TO THE EDITOR
Reactions of 2-Alkoxy-7,7-dichlorobicyclo[4.1.0]heptanes
with Phosphorus Trichloride
Yu. N. Mitrasova, E. A. Simakovab, O. V. Kondrat’evaa, and I. N. Smolinaa
a Yakovlev Chuvash State Pedagogical University,
ul. K. Marksa 38, Cheboksary, Chuvashia, 428000 Russia
b Il’ya Ul’yanov Chuvash State University, Cheboksary, Chuvashia, Russia
Received May 15, 2007
DOI: 10.1134/S1070363207120201
Bicyclic terpene hydrocarbons of the carane, carene,
thujane, thujene series, etc., widely occur in plants in
the form of such functional derivatives as alcohols,
ketones, carboxylic acids, or esters which exhibit a
broad spectrum of biological activity [1]. These
properties may be enhanced by introducing phos-
phorus-containing groups into their structure. In this
connection, we have studied the reactions of some
derivatives of these hydrocarbons with phosphorus
trichloride. Readily accessible 2-alkoxy-7,7-dichloro-
bicyclo[4.1.0]heptanes Ia Id were used as starting
compounds. We found that they react with phosphorus
trichloride in the presence of Lewis acids, e.g., of
anhydrous aluminum trichloride, with the opening of
the small ring and formation of 2-dichloromethylene-
cyclohexylphosphonic acid dichloride (pathway 1).
CCl2
CCl2
1
(1) PCl3
(2) H2O
Cl
Cl
[ROAlCl3]
+
P(O)Cl2
+
AlCl3
Cl
Cl
i1
i2
II
CHCl
CHCl
[AlCl4]
RO
+
2
Cl
Ia Id
RCl,
AlCl3
[AlCl4]
+
_
^
>
O
:
RO
O
III
R
i3
i4
R = CH3 (a), C2H5 (b), C3H7 (c), i-C3H7 (d).
However, the yield of phosphonic dichloride II
does not exceed 30%, which is apparently caused by
the possibility of stabilization of carbocation i2 by
deprotonation leading to 3-dichloromethylenecyclo-
hexene, which readily polymerizes. The reaction may
also occur at the three-membered ring (pathway 2) to
form 3-chloromethylenecyclohexanone III.
chloride in 5 g of phosphorus trichloride, 6.8 g of 7,7-
dichloro-2-ethoxybicyclo[4.1.0]heptane was added
dropwise with stirring. The dark brown liquid com-
plex thus formed was dissolved in 50 ml of dichloro-
methane and treated with 4.5 g of water at 0 C. The
white precipitate obtained was filtered off and washed
with 20 ml of dichloromethane. Distillation of the
filtrate gave 1.5 g (20%) of acid dichloride II, bp
128 130 C (5 mm Hg), d240 1.4863, nD20 1.5341.
2-Dichloromethylenecyclohexylphosphonic di-
chloride. To a suspension of 5.5 g of aluminum tri-
1
IR spectrum, , cm : 1600 (C=C), 1275 (P=O), 730
2203

2204
MITRASOV et al.
1
(C Cl), 575, 536 (P Cl). H NMR spectrum, , ppm:
1 3 m (9H, C6H9). 31P NMR spectrum, P, ppm: 52.
Found, %: C 29.71; H 3.18; Cl 50.14; P 10.80.
C7H9Cl4OP. Calculated, %: C 29.82; H 3.22; Cl 50.30;
P 10.99. Distillation of the low-boiling fraction gave
3-chloromethylenecyclohexanone III in 27% yield, bp
105 107 C (13 mm Hg), d240 1.2479, nD20 1.5082.
The IR spectra were recorded on a UR-20 spec-
trometer, KBr prism, thin film. The H NMR spectra
were taken on a Bruker WM-250 (250 MHz) device in
DMSO-d6 against its residual protons. The 31P NMR
spectra were obtained on a Bruker WP-80 spectrometer
(32.44 MHz) against external 85% phosphoric acid.
1
1
IR spectrum, , cm : 1710 (C=O), 1590 (C=C).
REFERENCES
Found, %: Cl 39.51. C7H9ClO. Calculated, %: Cl
39.60. 2,4-Dinitriphenylhydrazone, mp 159 C. Found,
%: C 47.92; H 4.14; Cl 10.79; N 17.30. C13H13Cl
N4O4. Calculated, %: C 48.08; H 4.03; Cl 10.92;
N 17.25.
1. Yanovskaya, L.A., Dombrovskii, V.A., and Khu-
sid, A.Kh., Tsiklopropany s funktsional’nymi gruppami.
Sintez i primenenie (Cyclopropanes with Functional
Groups. Synthesis and Use), Moscow: Nauka, 1980.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 12 2007