REACTIONS OF ARENEDIAZONIUM TETRAFLUOROBORATES
135
be assigned to e- and b-transitions in the benzene ring.
Compounds I IX displayed a strong IR band in the
region 720 735 cm , which belongs to stretching
was added over a period of 60 min to a mixture of
0.12 mol of 3-chloro-2-methylpropene, 0.015 mol of
copper(I) bromide, and 0.125 mol of potassium bro-
mide in 160 ml of aqueous acetone (1:4). The mix-
ture was stirred until nitrogen no longer evolved (4 h
at 15 20 C) and treated with 200 ml of diethyl ether.
The extract was washed with water and dried over
CaCl2, the solvent was removed, and the residue was
distilled under reduced pressure. Yield 17.1 g (69%).
Compounds V and VI were synthesized in a similar
way.
1
vibrations of C Cl bond, while the IR spectra of VII
1
IX contained a narrow peak at 2140 2160 cm
due to stretching vibrations of the thiocyanato group.
Protons in the aromatic ring of compounds I IX
gave rise to multiplet signals at 7.13 7.37 and 6.73
1
7.26 ppm in the H NMR spectra. Protons in the
2-methyl group resonated as a singlet at 1.59
1.85 ppm, and methylene proton signals appeared as
doublets at 3.54 3.74 (ClCH2) and 3.04 3.16 ppm
(ArCH2).
b. Benzenediazonium bromide, 0.1 mol, was added
over a period of 30 min to a mixture of 0.12 mol of
3-chloro-2-methylpropene and 0.01 mol of copper(I)
bromide in 90 ml of aqueous acetone (1:2). The mix-
ture was stirred until nitrogen no longer evolved (3 h
at 15 20 C) and treated as described above in a. Yield
6.2 g (25%). Compounds V and VI were synthesized
in a similar way.
Thus, in keeping with our previous data [1, 4],
introduction of a methyl group to C2 in 3-chloropro-
pene molecule does not change the regioselectivity of
its reactions with arenediazonium salts and anionic
nucleophiles.
EXPERIMENTAL
3-Chloro-2-methyl-1-phenyl-2-thiocyanatopro-
pane (VII). A mixture of 0.12 mol of 3-chloro-2-
methylpropene, 0.015 mol of Cu(BF4)2 6H2O, and
0.125 mol of potassium thiocyanate in 160 ml of
aqueous acetone (1:4) was cooled to 10 C, 0.1 mol
of benzenediazonium tetrafluoroborate was added over
a period of 40 min, and the mixture was stirred for
3 h at 15 to 5 C until nitrogen no longer evolved.
The mixture was treated with 200 ml of diethyl ether,
the extract was washed with water, dried over CaCl2,
and evaporated, and the residue was distilled under
reduced pressure. Yield 15.34 g (68%). Compounds
VIII and IX were synthesized in a similar way.
The IR spectra were recorded from thin films (neat)
on an IKS-29 spectrometer (Russia). The H NMR
1
spectra were measured from solutions in DMSO-d6
on a Varian Mercury spectrometer operating at
400 MHz; hexamethyldisiloxane was used as external
reference. The UV spectra were recorded from solu-
tions in ethanol on an SF-20 spectrophotometer
(Russia). The purity of the products was checked by
TLC on Silufol UV-254 plates using ethanol acetone
(4:1) as eluent.
2,3-Dichloro-2-methyl-1-phenylpropane (I).
a. Benzenediazonium tetrafluoroborate, 0.1 mol, was
added over a period of 40 min to a mixture of
0.12 mol of 3-chloro-2-methylpropene, 0.015 mol of
copper(II) chloride, and 0.125 mol of potassium chlo-
ride in 160 ml of aqueous acetone (1:4). The mixture
was stirred until nitrogen no longer evolved (6 h at
15 25 C) and treated with 200 ml of diethyl ether.
The extract was washed with water and dried over
CaCl2, the solvent was removed, and the residue was
distilled under reduced pressure. Yield 15.2 g (75%).
Compounds II and III were synthesized in a similar
way.
REFERENCES
1. Grishchuk, B.D., Gorbovoi, P.M., Ganushchak, N.I.,
Kudrik, E.Ya., and Brush, D.M., Russ. J. Gen. Chem.,
1993, vol. 63, no. 7, p. 1156.
2. Grishchuk, B.D., Gorbovii, P.M., Baranovs’kii, V.S.,
and Ganushchak, M.I., Abstract of Papers, Tezi do-
pov’dei XX Ukrains’koi konferentsii z organ’chnoi
khimii (XXth Ukrainian Conf. on Organic Chemistry),
Odessa, 2004, part 1, p. 42.
3. Gorbovoi, P.M., Baranovskii, V.S., and Grishchuk, B.D.,
Materialy mezhdunarodnoi konferentsii po organiches-
koi khimii Organicheskaya khimiya ot Butlerova i
Beil’shteina do sovremennosti (Proc. Int. Conf. on
Organic Chemistry Organic Chemistry from Butlerov
and Beilstein to Present ), St. Petersburg, 2006, p. 424.
b. Benzenediazonium chloride, 0.1 mol, was added
over a period of 30 min to a mixture of 0.12 mol of
3-chloro-2-methylpropene and 0.012 mol of copper(II)
chloride in 90 ml of aqueous acetone (1:2). The mix-
ture was stirred until nitrogen no longer evolved (4 h
at 20 25 C) and treated as described above in a. Yield
7.1 g (35%).
4. Grishchuk, B.D., Gorbovoi, P.M., Zagrichuk, G.Ya.,
Ganushchak, N.I., and Kudrik, E.Ya., Russ. J. Gen.
Chem., 1999, vol. 69, no. 6, p. 1299.
2-Bromo-3-chloro-2-methyl-1-phenylpropane
(IV). a. Benzenediazonium tetrafluoroborate, 0.1 mol,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 1 2008
Gorbovoi
