M. DellaGreca et al. / Chemosphere 63 (2006) 1087–1093
1089
0
0
0
A (16 mg), a red fraction (15%), benzimidazole 4a (5%)
148.7 (C-6 ), 122.6 (C-3 ), 120.0 (CF
3
), 108.3 (C-5 ),
and benzimidazolone 3a (5%) at decreasing R s. Frac-
tion A (16 mg) was purified on preparative TLC
67.2 (OCH ), 64.5 (CH OH), 10.3 (CH ).
2 2 3
f
+
Compound 2b: EIMS m/z 329 [M] ; IR (CHCl
3
):
ꢀ
1
[
CH
Cl
2 2
/CH
3
OH (97:3)] giving dianiline 5a (11%), pyri-
mmax 3100 (NH), 1591 (C@N), cm ; UV kmax 214,
1
0
dine 6a (5%), lansoprazole (24%) at decreasing R s.
300 nm; H NMR: d (CD OD) 8.13 (1H, s, H-6 ), 7.38
f
3
A suspension of omeprazole (80 ppm) in water milliQ
was exposed to the solar simulator for 43 h. After eva-
poration of water, the residue (25 mg) was chroma-
tographed on TLC [CH Cl /CH OH (95:5)] leading, at
(1H, d, J = 8.8, H-7), 7.00 (1H, d, J = 2.4, H-4), 6.81
(1H, dd, J = 8.8, 2.4 Hz, H-6), 4.54 (2H, s, CH
3.79 (3H, s, OCH ), 3.74 (3H, s, OCH ), 2.24 (3H, s,
CH ), 2.22 (3H, s, CH ). C NMR: d (CD OD) 166.4
2
S),
3
3
1
3
2
2
3
3
3
3
0
0
0
decreasing R
f
s, to dianiline 5b (10%), sulfide 2b (16%),
(C-4 ), 158.1 (C-5), 155.6 (C-2 ), 149.8 (C-6 ), 150.3 (C-
0
0
benzimidazolone 3b (20%), pyridine 6b (traces, <1%)
benzimidazolone 4b (traces, <1%) and a red fraction
2), 140.8 (C-9), 135.0 (C-8), 127.7 (C-3 ), 127.3 (C-5 ),
116.1 (C-4), 113.1 (C-6), 97.8 (C-7), 60.6 (OCH ), 56.2
3
(
20%).
(OCH
3 2 3 3
), 37.8 (CH S), 13.4 (CH ), 11.3 (CH ).
+
Compound 3b: EIMS m/z 164 [M] ; IR (CHCl
3
):
H NMR: d
OD) 6.92 (1H, d, J = 8.0, H-7), 6.66 (1H, d,
J = 2.5, H-4), 6.63 (1H, dd, J = 8.5, 2.5 Hz, H-6), 3.77
ꢀ1
1
mmax 3140 (NH), 1720 (C=O) cm
CD
;
2
.4. Photostability of derivatives 2, 3, and 4
(
3
Suspensions of benzimidazoles 3a, 4a, 3b and 4b
13
(
3H, s, OCH3). C NMR: d (CD OD) 158.4 (C-2),
3
(
10 ppm) in MilliQ water were exposed to the solar sim-
1
57.0 (C-5), 131.6 (C-9), 124.7 (C-8), 110.7 (C-7), 108.6
ulator for 72 or 43 h. Each experiment was performed in
duplicate, with one set of dark controls. Each reaction
mixture was evaporated in vacuum and each residue
was analysed by H NMR and TLC showing only the
starting material.
When sulfides 2a and 2b were treated in the same
way, analysis of dark samples showed only starting
materials, while by irradiation they led to a mixture of
products. The mixture from 2a (8 mg) was subjected to
preparative TLC [CH Cl /CH OH (93:7)] affording
dianiline 5a (30%) and benzimidazole 4a (38%). The
mixture (7 mg) deriving from irradiation of 2b was sub-
jected to preparative TLC [CH
(
C-6), 96.9 (C-4), 56.2 (OCH ).
3
+
1
Compound 4b: EIMS m/z 148 [M] ; H NMR: d
(
CD OD) 8.04 (1H, s, H-2), 7.47 (1H, d, J = 9.0, H-7),
1
3
7
.09 (1H, br s, H-4), 6.90 (1H, dd, J = 9.0, 2.5 Hz,
H-6), 3.83 (3H, s, OCH ).
Compound 5b: EIMS m/z 138 [M] ; IR (CHCl ):
3
+
3
m
max 3290 and 3195 (NH
2
stretching), 1626 (NH
ing) cm ; H NMR: d (CD OD) 7.08 (1H, d, J = 9.4,
H-6), 6.78 (2H, m, H-2, H-5), 3.79 (3H, s, OCH3).
NMR: d (CD OD) 157.1 (C-1), 133.4 (C-3), 126.7
C-4), 110.5 (C-6), 110.2 (C-5), 94.7 (C-2), 55.1 (OCH ).
2
bend-
ꢀ1
1
3
13
C
2
2
3
3
(
3
+
1
Compound 6b: EIMS m/z 167 [M] ; H NMR: d
2 2 3
Cl /CH OH (93:7)] giv-
(
(
CD OD) 8.14 (1H, s, H-6), 4.66 (2H, s, CH O), 3.80
3H, s, OCH
3
2
ing dianiline 5b (43%) and benzimidazole 4b (28%).
3
), 2.29 (3H, s, CH
3
3
), 2.26 (3H, s, CH ).
2
.5. Products characterization
2.6. Synthesis of 2-((4-(2,2,2-trifluoroethoxy)-
-methylpyridin-2-yl)methylsulfonyl)-1H-
benzo[d]imidazole (7a) (Fig. 2)
3
Compounds 3a and 4a were identified by comparing
spectral data with those of commercial samples (from
1
Aldrich). Compounds 4b and 6b were identified by H
To a solution of compound 1a (18 mg) in anhydrous
dichloromethane (0.02 M), m-chloroperbenzoic acid (1
equiv.) was added and the resulting mixture kept at
room temperature under magnetic stirring. After two
hours, TLC showed that compound 1a disappeared.
Then, the mixture was washed with water and anhydri-
fied with Na SO . After filtration and evaporation of
NMR and LC-MS due to their low amounts.
+
Compound 2a: EIMS m/z 353 [M] ; IR (CHCl
3
):
ꢀ1
mmax3100 (NH), 1581 (C@N), 1168 (CF ) cm ; UV kmax
08, 292 nm; H NMR: d (CD OD) 8.27 (1H, d,
J = 5.6 Hz, H-6 ), 7.50 (2H, br s, H-4, H-7), 7.22 (2H,
m, H-5, H-6), 7.02 (1H, d, J = 5.6 Hz, H-5 ), 4.70 (2H,
3
1
2
3
0
0
2
4
q, J = 8.4, CH CF ), 4.59 (2H, s, CH S), 2.29 (3H, s,
dichloromethane, the sulfone 7a was purified by TLC
2
3
2
1
3
0
CH
3
). C NMR: d (CD
3
OD) 163.0 (C-4 ), 155.5 (C-
0
0
2
), 149.4 (C-6 ), 147.5 (C-2), 139.8 (C-8, C-9), 122.1
0
(
C-5, C-6), 123.0 (C-3 ), 122.0 (CF ), 113.0 (C-4, C-7),
CF3
3
0
1
06.4 (C-5 ), 64.8 (CH
2
CF
3
), 36.1 (CH
2
S), 9.3 (CH
3
).
4
+
5
6
N 3 O H3C
O
Compound 6a: EIMS m/z 221 [M] ; IR (CHCl
mmax 3357 (OH), 1592 (C@N), 1170 (CF ) cm
NMR: d (CD
3
):
; H
ꢀ
0
1
1
S
N1 O
H
3
5'
3
OD) 8.33 (1H, d, J = 5.5 Hz, H-6 ), 7.06
7
1'N
0
6'
(
1H, d, J = 5.5 Hz, H-5 ), 4.82 (2H, q, J = 8.4,
7a
CH
2
CF
3
), 4.62 (2H, s, CH
2
OH), 2.13 (3H, s, CH
3
0
).
1
3
0
C NMR: d (CD OD) 164.2 (C-4 ), 160.3 (C-2 ),
Fig. 2. Sulfone 7a structure.
3