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FEDOROVA et al.
for the catalyst I, 78% for II, 97% for III, and 24% for
IV. The iron phthalocyanine-catalyzed chlorination
proceeded selectively to give one or in some cases two
isomeric monochlorinated derivatives. The only
products of chlorination of 3,4-dimethoxytoluene,
naphthalene, 2-methylnaphthalene and 2-methoxy-
naphthalene were 1-methyl-4,5-dimethoxy-2-chloro-
benzene, 1-chloronaphthalene, 2-methyl-1-chloronaph-
thalene, and 2-methoxy-1-chloronaphthalene respec-
tively. Phenol and anisidine gave a mixture of ortho-
and para-chloroderivatives in the 1:1.2 and 1:3 ratio
respectively. Chlorination of 2,3- and 2,6-dime-
thylnaphthalenes leads initially to the formation of 1-
chloroderivatives. The addition of new portions of iron
phthalocyanine and H2O2 caused further chlorination
to 1,4-dichloro- and 1,6-dichloronaph-thalenes
respectively. At performing the reaction under
analogous conditions conversion (η, %) increased with
the increase in the electron-donating character of
substituent in the AH molecule and the increase in the
amount of such substituents. For example, the
conversion of naphthalene was 32%, of 2-methylnaph-
thalene 71%, and of 2-methoxynaphthalene 100%. 2,3-
Dimethyl and 2,6-dimethylnaphthalenes attained 80%
and 100% conversion respectively. These facts show
that chlorinating agent has the electrophilic character
(Cl+). Interestingly, analogous species formed in H2O2–
Cl– system in the presence of chloroperoxidases [10].
0.05 ml of aqueous H2O2 (1.125×10–4 mol). The
reaction product was identical to 2-methyl-1-chloro-
naphthalene prepared according to the procedure [12].
Yield 94% (HPLC). The product was subjected to
column chromatography on silica gel, elution with
chloroform–hexane mixture. 1H NMR spectrum
(CDCl3), δ, ppm: 2.6 s (3H, CH3), 7.36 d (1H, H3),
7.46–7.63 m (2H, H6, H7), 7.7 d (1H, H5), 7.83 d (1H,
H4), 8.31 d (1H, H8). Mass spectrum. m/z (Irel, %): 176
(100) [M]+, 141 (84). Found, %: C 74.57, H 5.22, Cl
20.07. C11H9Cl. Calculated, %: C 74.80, H 5.14, Cl
20.07.
2-Methoxy-1-chloronaphthalene was prepared
1
from 2-methoxynaphthalene. Yield 99%. H NMR
spectrum, (CDCl3), δ, ppm: 4.06 s (3H, OCH3), 7.31 d
(1H, H3), 7.42 t (1H, H6), 7.59 t (1H, H7), 7.75–7.82 m
(2H, H4, H5), 8.25 d (1H, H8). Mass spectrum, m/z (Irel,
%): 192 (28) [M]+, 177 (7), 149 (100), 126 (12), 114
(31). Found, %: C 68.28, H 4.44, Cl 18.10. C11H9ClO.
Calculated, %: C 68.58, H 4.71, Cl 18.40.
2,3-Dimethyl-1,4-dichloronaphthalene was prepared
from 2,3-dimethylnaphthalene, yield 95%, mp 152–
1
153°C (EtOH). H NMR spectrum, (CDCl3), δ, ppm:
2.6 s (6H, CH3), 7.56, 7.58 d.d (2H, H6, H7), 8.29, 8.31
d.d (2H, H5, H8). Mass spectrum, m/z (Irel, %): 224
(100) [M – 1]+, 189 (98), 152 (55), 139 (4). Found, %:
C 64.26, H 4.25, Cl 31.28. C12H10Cl2. Calculated, %: C
64.03, H 4.48, Cl 31.50.
EXPERIMENTAL
2,6-Dimethyl-1,5-dichloronaphthalene was prepared
Commercial reagents and solvents were used in this
study. Reaction mixture was analyzed by HPLC on a
Hewlett-Packard 1100 device equipped with a UV
detector (λ 254 nm), a Zorbax Eclipse 4.6×150 mm
column with the dimethyl-n-octylsilane stationary
phase, elution with the 6:4 acetonitrile–water mixture,
flow rate 1 ml min–1. Naphthalene was used as in-
ternal reference. Mass spectra were obtained on a
from 2,6-dimethylnaphthalene, yield 95%, mp 133–
1
134°C. H NMR spectrum (CDCl3), δ, ppm: 2.59 s
(6H, CH3), 7.4 d (2H, H3, H7). 8.12 d (2H, H4, H8).
Mass spectrum, m/z (Irel, %): 224 (100) [M – 1]+, 189
(66), 152 (27), 139 (4). Found, %: C 64.25, H 4.29, Cl
31.29. C12H10Cl2. Calculated, %: C 64.03, H 4.48, Cl
31.50.
1
Finnigan MAT INCOS-50 instrument. H NMR spec-
1-Methyl-4,5-dimethoxy-2-chlorobenzene was pre-
pared from 3,4-dimethoxytoluene, yield 99%, mp 33–
34°C (EtOH). 1H NMR spectrum (CDCl3), δ, ppm: 2.3
s (CH3), 3.85 s (6H, OCH3), 6.7 s (H2), 6.83 s (H5).
Mass spectrum, m/z (Irel, %): 186 (100) [M]+, 171 (44),
143 (40), 125 (18), 108 (78), 93 (34), 77 (72). Found,
%: C 58.19, H 5.91, Cl 18.76. C11H9Cl. Calculated, %:
C 57.92, H 5.94, Cl 19.0.
tra were taken on a Bruker AM300 (300 MHz)
spectrometer. The analysis for C,H,and O in the
reaction products was done on a Carlo Erba 1106
analyzer. Chlorine content was evaluated according to
[11].
Oxidative chlorination of 2-methylnaphthalene
(general procedure). To a solution of 2-methylnaph-
thalene (0.037×10–3 mol) in 1.9 ml of ethanol 0.5 ml of
HCl (1.125×10–3 mol) and 0.05 ml of water solution of
iron phthalocyanine I (0.11×10–6 mol) were added.
The mixture obtained was treated while stirring with
o- and p-Chloro derivatives of phenol and anisol as
well as 1-chloronaphthalene according to HPLC data
were identical to the commercial samples.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 8 2008