1
382
Environ. Toxicol. Chem. 20, 2001
C. Tixier et al.
H 5.16, N 13.05, O 14.90), and we found C 50.20, H 5.28, N
1
3.04, O 14.74.
-(4-chloro-3-hydroxyphenyl)-NЈ,NЈ-dimethylurea (com-
N
pound 2) was obtained from 5-amino-2-chlorophenol, previ-
ously synthesized from 2-methoxy-4-nitroaniline.
To synthesize 2-chloro-5-nitroanisole, 4.8 g (36 mmol) of
CuCl and 5.45 ml (36 mmol) of tert-butylnitrite were mixed
2
in 70 ml of acetonitrile. The resulting stirred mixture was
cooled to 0ЊC in an ice bath. A solution of 2-methoxy-4-ni-
troaniline (5 g, 30 mmol) in 50 ml of acetonitrile was slowly
added. After the complete addition of the amine, the reaction
mixture was left at 0ЊC for 2 h and then allowed to reach room
temperature. The reaction solution was then poured into 80 ml
of 20% (v/v) aqueous HCl and extracted with ether. The or-
ganic layer was washed once with 20% (v/v) aqueous HCl and
Fig. 1. General scheme of the photo- and biotransformation of diuron.
dried over MgSO . The ether phase was removed under re-
duced pressure and, after recrystallization in aqueous ethanol,
4
The herbicide diuron (purity, 98%) was obtained from Rh oˆ ne-
Poulenc (Lyon, France).
Chemicals. The 3,4-dichlorophenylisocyanate, methyl-
3
.8 g of an orange solid was obtained.
The yield of 2-chloro-5-nitroanisole was 67%, mp was 80
amine, N-methylformamide, 2-methoxy-4-nitroaniline, tert
-
to 82
ЊC (mp value from the literature [24] was 82–83ЊC): for
butylnitrite, dimethylcarbamylchloride, and 3,4-dichloroani-
line were purchased from Aldrich (Saint-Quentin-Fallavier,
France). The 2-chloro-4-nitrophenol was obtained from Lan-
caster (Bischheim, France).
ϩ.
MS, 187 to 189 (M ), 141 and 143 (M-NO ), 126 and 129
2
1
(M-NO -CH ), 111 and 113 (M
ϩ
1-NO -OCH ); for
H NMR
8.5 Hz),
8.5 Hz
), 56.7 ppm (CH3),
106.8 ppm (C ), 116.3 ppm (C ), 130.0 ppm (C ), 130.5 ppm
2
3
2
3
(CDCl3-
␦
), 4.00 ppm (s, 3H), 7.53 ppm (d, 1H, J
2.5 Hz), 7.90 ppm (dd, 1H, J
2.5 Hz); for 13C NMR (CDCl3-
ϭ
ϭ
7.79 ppm (d, 1H, J
and J
ϭ
Syntheses. For synthesis of N-(3,4-dichlorophenyl)-N
Ј
-for-
ϭ
␦
myl- -methylurea (product 3), an equimolar solution of 3,4-
N
Ј
6
4
2
dichlorophenylisocyanate and N-methylformamide was pre-
pared as a 30% (w/w) acetone solution. The mixture was stirred
under reflux for 24 h. After filtration, the white solid obtained
was purified on silica gel (eluent was ether:cyclohexane:eth-
anol [75:20:5]).
(C ), 147.4 ppm (C ), 155.5 ppm (C ).
3 5 1
To synthesize 2-chloro-5-nitrophenol, 5 g (27 mmol) of 2-
chloro-5-nitroanisole was refluxed in 30 ml of aqueous HBr
(48%, w/v) for 24 h. After cooling to room temperature, the
reaction mixture was extracted with diethyl ether (total volume
For product 3, the yield was 70%, rate of flow (Rf) was
ϭ
200 ml). The organic phase was then washed twice with 50
1
0
.49, melting point (mp) was 145 to 146
methylsulfoxide [DMSO] d6-
dd, 1H, J 2.4 Hz and J
.8 Hz), 7.90 ppm (d, 1H, J
.87 ppm (s, CHO); for 13C NMR (DMSO d6-
Њ
C: for H NMR (di-
ml of distilled water and extracted three times with a Na CO
(10%, w/v) solution. The aqueous yellow phase was then acid-
ified with concentrated HCl to pH 1 and extracted with Et O.
The combined ether extracts were dried over MgSO and the
solvent was evaporated to dryness, with 2.6 g of yellow crys-
tals being obtained.
2
3
␦
ϭ
), 3.45 ppm (s, 3H), 7.54 ppm
8.8 Hz), 7.62 ppm (d, 1H, J
(
8
9
ϭ
ϭ
2
ϭ
2.4 Hz), 9.15 ppm (s, NH),
4
␦
), 27.2 ppm
(
CH ), 120.4 ppm (C ), 121.7 ppm (C ), 125.3 ppm (C ), 130.6
3 6 2 4
ppm (C ), 130.9 ppm (C ), 138.7 ppm (C ), 153.1 ppm (CO),
The yield of 2-chloro-5-nitrophenol was 56%, mp was 110
5
3
1
1
4
1
62.8 ppm (CHO). Analysis was done for C H Cl N O (C
3.75; H 3.26; N 11.33), and we found C 43.55, H 3.23, N
1.44.
to 112ЊC (mp value from the literature [24] was 118–119ЊC):
9
8
2
2
2
ϩ
.
for MS, 173 and 175 (M ), 143 and 145 (M-NO), 127 and
129 (M-NO ), 115 and 117 (M-NO-CO), and 46 (base, NO );
2
2
1
Hydroxylated compounds 1 and 2 were synthesized by re-
for H NMR (CDCl -
␦
), 6.00 ppm (s, OH), 7.51 ppm (d, 1H,
3
action of the appropriate chlorohydroxyaniline (obtained by
J
ϭ
8.8 Hz), 7.79 ppm (dd, 1H, J
ϭ 8.8 Hz and J ϭ 2.6 Hz),
catalytic hydrogenation of the nitro compound on PtO in ab-
7.90 ppm (d, 1H, J 2.6Hz).
ϭ
2
solute ethanol) with an excess of dimethylcarbamylchloride (5
equivalents) under an argon atmosphere in anhydrous tetrah-
ydrofurane. The mixture was stirred overnight at room tem-
perature. The reaction mixture was then diluted with ether and
washed several times with water. The organic layer was dried
2-Chloro-5-aminophenol (compound 8) was obtained after
catalytic hydrogenation (on PtO in absolute ethanol) of the
2
2-chloro-5-nitrophenol. The yield was 90%, Rf was 0.20, mp
was 158 to 160ЊC with the following results: for MS, 143 to
ϩ
.
1
145 (M ), 105, 80, 77, 50; for H NMR (400.13 MHz, CDCl -
3
over MgSO and evaporated to dryness. The residue was pu-
␦
), 3.70 ppm (s, NH ), 5.45 ppm (s, OH), 6.22 ppm (dd, 1H,
2
4
rified on silica gel using the mixture ether:cyclohexane:ethanol
J
ϭ
2.5 Hz and J
ϭ
ϭ
8.7 Hz), 6.36 ppm (d, 1H, J
8.7 Hz).
-(4-chloro-3-hydroxyphenyl)-
(compound 2), the yield was 28%, Rf was 0.25, mp was 220
ϭ 2.5 Hz),
(
75:20:5) as eluent.
-(3-chloro-4-hydroxyphenyl)-
7.06 ppm (d, 1H, J
For
N
N
Ј
,N
Ј
-dimethylurea (com-
N
NЈ,NЈ-dimethylurea
pound 1) was synthesized from 4-amino-2-chlorophenol ob-
tained from the corresponding commercial nitroderivative.
1
to 221
(dd, 1H, J
Hz), 7.32 ppm (d, 1H, J
), 37.0 ppm (2CH ), 109.7 ppm (C ), 114.4 ppm (C ), 115.9
Њ
C: for H NMR(CD OD-
␦
), 3.20 ppm (s, 6H), 6.97 ppm
2.5 Hz and 8.8 Hz), 7.30 ppm (d, 1H, J 2.5
8.8 Hz); for C NMR (CD OD-
3
The yield for compound 1 was 30%, Rf was 0.23, mp was
ϭ
ϭ
1
13
1
19 to 120
Њ
C: for H NMR (CD OD-
␦
), 3.20 ppm (s, 6H), 7.01
2.5 Hz and
2.5 Hz); for C NMR (CD OD-
ϭ
3
3
ppm (d, 1H, J
8
ϭ
8.7 Hz), 7.27 ppm (dd, 1H, J
.7 Hz), 7.54 ppm (d, 1H, J
ϭ
␦
3
2
6
13
ϭ
ppm (C ), 130.6 ppm (C ), 141.2 ppm (C ), 154.4 ppm (C ),
4 5 1 3
3
␦
) 37.0 ppm (2 CH ), 117.5 ppm (C ), 121.4 ppm (C ), 123.3
158.9 pp, (CO). Analysis was done for C H ClN O (C 50.36,
9 11 2 2
3
5
3
ppm (C ), 125.0 ppm (C ), 133.8 ppm (C ), 150.7 ppm (C ),
H 5.16, N 13.05, O 14.90), and we found C 50.57, H 5.23,N
13.13, O 15.11.
6
2
1
4
1
59.4 ppm (CO). Analysis was done for C H ClN O (C 50.36,
9 11 2 2