Facile and catalytic degradation method of DDT using Pd/C-Et3N system under ambient pressure and temperature

Article abstract of DOI:10.1016/j.tet.2006.06.041

The catalytic degradation method of p,p′-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its regioisomer o,p′-DDT [1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane] using the Pd/C-Et₃N system under ambient hydrogen pressure and temperature was established. The presence of Et₃N was necessary for the quick and complete breakdown of DDT. The independent degradation study of two intermediates, p,p′-DDD [2,2-bis(p-chlorophenyl)-1,1-dichloroethane] and p,p′-DDE [2,2-bis(p-chlorophenyl)-1,1-dichloroethylene] using GC-MS let us to speculate the degradation pathway of p,p′-DDT. In the initial phase of the reaction, p,p′-DDT degradation splits into two ways: a dehydrochlorination pathway and a hydrodechlorination pathway. In each pathway, reaction starts from an aliphatic moiety and subsequent hydrodechlorination from the benzene moieties takes place in a stepwise manner. The former pathway leads to the formation of 1,1-diphenylethane and the latter leads to the formation of 1,1-dichloro-2,2-diphenylethane. These diphenylethane analogs, which are less toxic compared with p,p′-DDT, are terminal degradation products in our system. The distinctive features of our catalytic degradation method of DDTs are reliability, simplicity, efficiency, and inexpensiveness.

Full text of DOI:10.1016/j.tet.2006.06.041

Tetrahedron 62 (2006) 8384–8392
Facile and catalytic degradation method of DDT using
Pd/C–Et3N system under ambient pressure and temperature
*
Yasunari Monguchi, Akira Kume and Hironao Sajiki
Laboratory of Medicinal Chemistry, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585, Japan
Received 10 May 2006; accepted 8 June 2006
Available online 30 June 2006
Abstract—The catalytic degradation method of p,p0-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its regioisomer o,p0-DDT
[1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane] using the Pd/C–Et3N system under ambient hydrogen pressure and tempera-
ture was established. The presence of Et3N was necessary for the quick and complete breakdown of DDT. The independent degradation study
of two intermediates, p,p0-DDD [2,2-bis(p-chlorophenyl)-1,1-dichloroethane] and p,p0-DDE [2,2-bis(p-chlorophenyl)-1,1-dichloroethylene]
using GC–MS let us to speculate the degradation pathway of p,p0-DDT. In the initial phase of the reaction, p,p0-DDT degradation splits into
two ways: a dehydrochlorination pathway and a hydrodechlorination pathway. In each pathway, reaction starts from an aliphatic moiety and
subsequent hydrodechlorination from the benzene moieties takes place in a stepwise manner. The former pathway leads to the formation of
1,1-diphenylethane and the latter leads to the formation of 1,1-dichloro-2,2-diphenylethane. These diphenylethane analogs, which are less
toxic compared with p,p0-DDT, are terminal degradation products in our system. The distinctive features of our catalytic degradation method
of DDTs are reliability, simplicity, efficiency, and inexpensiveness.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
efficient degradation methods of DDT.9 Numerous studies
for the development of DDT degradation methods reported
to date include photoremediation,10–16 bioremediation,17–19
mechanochemical remediation,20 hydride reduction,21
hydrodechlorination,22–24 reductive dechlorination using
metals,25,26 electrolysis,27–30 and supercritical water oxida-
tion.31 Most processes require special and/or expensive
equipment and facilities, large amounts of reagents, high
heat, high pressure, radiation, and/or strong base conditions,
and many of them do not complete degradation of DDT. Re-
cently, Blum and co-workers reported a hydrodechlorination
method using a combined Pd–Rh catalyst to achieve the
complete removal of five chlorine atoms and saturation of
aromatic rings of p,p0-DDT.22 Tundo and co-workers also
succeeded in the complete dechlorination of p,p0-DDT by
Pd/C or Raney-Ni-catalyzed hydrodechlorination method.24
These hydrodechlorinations were performed under rela-
tively mild conditions, but still the former method requires
heating (80–100 ꢀC) and high pressure (27 atm) and the
latter requires heating (50 ꢀC) and continuous bubbling of
hydrogen (10 mL/min).
1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane (p,p0-DDT)
used to be employed worldwide as a broad-spectrum pesti-
cide to protect crops from insects and to control insect-borne
diseases such as malaria. But today the use of p,p0-DDT is
banned in many countries because of its hydrophobic nature
and of its persistence based on its chemical stability, leading
to bioaccumulation and biomagnification in food chains.1–3
p,p0-DDT affects the nervous system to cause tremors and
convulsions.4 Both o,p0-DDT [1,1,1-trichloro-2-(o-chloro-
phenyl)-2-(p-chlorophenyl)ethane],
a
regioisomer of
p,p0-DDT and p,p0-DDE [2,2-bis(p-chlorophenyl)-1,1-di-
chloroethylene], a metabolite of p,p0-DDT have been recog-
nized as endocrine disruptors as a result of recent studies on
DDT families.5,6 Despite such risks arising from p,p0-DDT
and its related compounds, DDT (technical grade: a mixture
of p,p0-DDT and its regioisomers) is still in use in some
countries to combat disease-carrying insects because of the
cost-efficiency of DDT. Furthermore, there is a fear of an
accidental leak of a major fraction of DDTs, which was
packed into drums and stored underground in 1970’s espe-
cially in Japan due to the lack of suitable degradation
methods of DDTs based on the high thermodynamic, chem-
ical, and biological stability. As a global environmental
issue, therefore, it is very important to monitor the pollution
caused by the persistent insecticide7,8 and to develop
We have reported that addition of a nitrogen-containing base
such as NH3, pyridine, and ammonium acetate to a Pd/C-
catalyzed hydrogenation system as a weak catalyst poison
chemoselectively inhibited the hydrogenolysis of a benzyl
ether with smooth hydrogenation of other reducible func-
tionalities such as olefin, Cbz, benzyl ester, azide, and so
on.32,33 During the course of our further study on the chemo-
selective hydrogenation using a Pd/C–Et3N system, the
catalytic activity of Pd/C towards the hydrodechlorination
* Corresponding author. Tel.: +81 58 237 3931; fax: +81 58 237 5979;
e-mail: sajiki@gifu-pu.ac.jp
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.06.041

Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
8385
of aromatic chlorides was found to be remarkably and
selectively enhanced by the addition of Et3N34 and this
system efficiently worked for the complete dechlorination
of polychlorinated biphenyls (PCBs).35 This method
required only a catalytic amount of Pd/C and an almost stoi-
chiometric amount of Et3N (1.2 equiv vs chlorine atom) and
did not require heating, high pressure of hydrogen, nor
special equipment. In this paper, we discuss the application
of this mild system to the degradation of p,p0-DDT and
o,p0-DDT and also propose the dechlorination pathways of
p,p0-DDT in our system.
2. Results and discussion
2.1. Degradation of p,p0-DDT
In accordance with our previous work for the hydrodechlori-
nation of PCBs,35 10% Pd/C was used with 10% of the
H2 (balloon)
10% Pd/C (10 wt% of 1)
H
CCI3
H
CH3
H
CHCI2
Et3N (6 equiv)
+
MeOH, rt, >4 h
Cl
Cl
p,p'-DDT (1)
7
8
Cl
Cl
H
CH3
H
CHCI2
Cl
Cl Cl
Cl
Cl
Cl
2
p,p'-DDD (3)
p,p'-DDE (4)
H
CH3
H
CHCI2
Cl
Cl
6
5
100
90
80
70
60
50
40
30
20
10
1
2
3
5
6
7
8
0
0
24 h
30
60
90
120
150
180
210
240
Time (min)
Yield (%)
Time
(min)
1
2
3
4
5
6
7
8
0
2
~100
88
68
36
12
trace
0
0
trace
12
19
28
34
34
25
19
12
trace
0
trace
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
trace
13
36
54
66
59
45
29
7
trace
4
trace
0
6
trace
trace
trace
trace
16
8
trace
10
15
20
30
60
120
240
24 h
0
0
0
0
0
0
0
0
trace
trace
7
0
24
5
8
8
4
0
0
trace
6
0
30
15
39
52
69
69
0
29
17
27
31
31
0
trace
0
17
0
0
trace
0
0
0
0
Figure 1. Pd/C catalyzed degradation of p,p0-DDT (1) under ambient hydrogen pressure and temperature with Et3N (1.2 equiv vs Cl).

8386
Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
substrate weight and 6 equiv of Et3N (1.2 equiv to each
chlorine atom of the substrate) was employed. The hydro-
dechlorination of p,p0-DDT 1 (CAS Registry Number
50-29-3) in MeOH using Pd/C–Et3N system under ambient
temperature and pressure is shown in Figure 1. p,p0-DDT 1
was completely consumed in the first 10 min and
1,1-bis(p-chlorophenyl)ethane 2 (CAS Registry Number
3547-04-4),36 in which structure all aliphatic chlorine atoms
of 1 were replaced with hydrogen atoms, and p,p0-DDD 3
(CAS Registry Number 72-54-8), in which structure an ali-
phatic chlorine atom of 1 was replaced with a hydrogen
atom, were accordingly generated in the ratio of about 2:1.
A trace amount of p,p0-DDE 4 (CAS Registry Number
72-55-9) was also detected during the initial phase (not
shown in Fig. 1). After the formation of 2 and 3, the dechlo-
rination of these compounds took place from their benzene
rings step by step to generate mono-chlorophenyl com-
pounds 5 (CAS Registry Number 60617-89-2)37 and 6
(CAS Registry Number 6952-08-5)38 and after 4 h the reac-
tion was led to the formation of 1,1-diphenylethane 7 (CAS
Registry Number 612-00-0)37,39 and 1,1-dichloro-2,2-di-
phenylethane 8 (CAS Registry Number 2387-16-8)40 in
the ratio of ca. 2:1. The reaction was monitored up to 24 h,
but further reduction was not observed and the material ratio
of 7 and 8 was virtually the same.
On the other hand, the reaction of 1 in the absence of Et3N
did not completely consume 1 even after 72 h of the reaction
(Fig. 2). The chlorine atoms on the benzene rings remained
almost intact. Both the consumption of 1 and the formation
of 2 and 3 were remarkably delayed, suggesting that the
presence of Et3N favorably affects the promotion of the de-
chlorination of alkyl chlorides as well as aromatic chlorides.
Furthermore, methyl bis(p-chlorophenyl)acetate 9 (CAS
Registry Number 5359-38-6),41 which is supposed to be
formed via methanolysis of 1, 3, or 4, was generated as
a by-product, whereas only a trace amount of the ester 9
was detected in the case of the reaction of 1 using Et3N
(not shown in Fig. 1). These results indicate that the presence
of Et3N in the catalytic degradation of p,p0-DDT 1 is crucial
for increasing the efficiency of the reaction.
2.2. Degradation of o,p0-DDT
The application of the hydrodechlorination method using
Pd/C and Et3N was also investigated for the degradation
H2 (balloon)
10% Pd/C (10 wt% of 1)
H
CH3
H
CHCl2
H
CO2CH3
without Et3N
1
+
+
MeOH, rt
Cl
Cl
Cl
Cl
Cl
Cl
2
p,p'-DDD (3)
9
100
90
80
70
60
50
40
30
20
10
1
2
3
6
7
9
0
0
12
24
72
Time (h)
Time
(h)
Yield (%)
1
2
3
6
7
9
0
10min
0.5
1
100
~100
82
0
trace
10
0
trace
8
0
0
0
0
0
trace
trace
trace
5
0
0
0
67
20
13
16
19
22
21
20
0
2
48
31
0
0
trace
2
4
25
44
trace
trace
4
12
12
24
72
11
48
17
12
38
1
18
10
34
3
2
17
Figure 2. Pd/C catalyzed degradation of p,p0-DDT (1) under ambient hydrogen pressure and temperature without Et3N.

Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
8387
H2 (balloon)
Cl
10% Pd/C (10 wt% of 10)
H
CCl3
H
CH3
H
CHCl2
H
CO2CH3
Et3N (6 equiv)
+
+
MeOH, rt
Cl
o,p'-DDT (10)
7
8
15
Cl
Cl
H
Cl
Cl
H
H
CH3
CHCl2
H
CH3
CHCl2
Cl
Cl
11
o,p'-DDD (12)
13
14
100
10
90
80
70
60
50
40
30
20
10
0
11
12
5 + 13
6 + 14
15
7
8
24 h
360
0
60
120
240
Time (min)
Time
Yield (%)
(min)
10
11
12
5 +
13
6 +
14
15
7
8
0
100
7
0
42
37
24
17
8
0
0
11
0
0
0
0
trace
8
0
0
10
25
21
15
10
5
0
30
0
21
3
6
trace
3
trace
3
60
0
22
16
24
37
62
120
240
24 h
0
21
7
7
6
0
17
6
12
16
12
22
0
trace
0
trace
trace
Figure 3. Catalytic degradation of o,p0-DDT (10) using Pd/C–Et3N system under ambient hydrogen pressure and temperature.
of o,p0-DDT 10 (CAS Registry Number 789-02-06)
(Fig. 3). As we expected, 10 was degraded in a similar
way to 1, although the reaction appeared somewhat more
complicated than the reaction of p,p0-DDT 1 because of
the asymmetrical structure of 10: (i) 10 completely
disappeared within 30 min; (ii) the dechlorination started
from aliphatic chlorides to generate 1-(o-chlorophenyl)-
1-(p-chlorophenyl)ethane 11 (CAS Registry Number
77008-62-9)38,42 and 1-(o-chlorophenyl)-1-(p-chloro-
phenyl)-2,2-dichloroethane 12 (CAS Registry Number
53-19-0)38 as the first detectable intermediates; (iii) then
mono-hydrodechlorination from the benzene rings pro-
ceeded to afford each regioisomeric mixture of monochlo-
rides [5 and 13 (CAS Registry Number 76690-79-4)43] and
trichlorides [6 and 14 (CAS Registry Number 61693-
87-6)38]; (iv) finally the reaction resulted in the genera-
tion of 7 and 8, which are the same products from
p,p0-DDT 1, with methyl diphenylacetate 15 (CAS Registry
Number 3469-00-9),44 which was structurally dechlori-
nated from 9.
2.3. Degradation of p,p0-DDD
As we mentioned above, in the early stage of the degradation
of p,p0-DDT 1, a trace of p,p0-DDE 4 was detected with 2 and
p,p0-DDD 3. We anticipated that both 3 and 4 were the first
intermediates of the dechlorination of 1. To investigate the
degradation pathway of p,p0-DDT by the hydrodechlorina-
tion using the Pd/C–Et3N system, the reactions of p,p0-DDD
3 and p,p0-DDE 4 were independently monitored. As shown
in Figure 4, 3 disappeared within 15 min and the chlorine
atoms attached on the benzene rings were completely
replaced with hydrogen atoms to generate 8 within 30 min.
The reaction showed that the aliphatic chlorines of 3 were
quite stable, but further dechlorination of 8 slowly proceeded
to give 7 in about 30% yield after 24 h.
2.4. Degradation of p,p0-DDE
p,p0-DDE 4 was dechlorinated easily from both the aliphatic
and aromatic portions (Fig. 5): 4 was completely consumed

8388
Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
H2 (balloon)
10% Pd/C (10 wt% of 3)
H
CHCl2
H
CHCl2
H
CH3
Et3N (4.8 equiv)
+
MeOH, rt, >1 h
Cl
Cl
p,p'-DDD (3)
8
7
100
90
80
70
60
50
40
30
20
10
3
6
7
8
0
0
10
20
30
40
Time (min)
50
60
24 h
Time
(min)
Yield (%)
3
6
7
8
0
5
100
26
7
0
21
11
4
0
0
0
0
0
0
0
53
10
15
20
30
60
24 h
82
trace
0
96
trace
0
~100
100
~100
73
0
0
0
trace
27
0
0
Figure 4. Catalytic degradation of p,p0-DDD (3) using Pd/C–Et3N system under ambient hydrogen pressure and temperature.
in 10 min; 2 and 5 were detected as intermediates; 7 was
obtained as sole product after 30 min of the reaction; further
reaction did not occur afterwards. If 4 had undergone the
hydrogenation of its double bond before the dechlorination
of its aliphatic chlorides, p,p0-DDD 3 would have been
generated as an intermediate, leading to the formation of 8
as a final product as was expected from Figure 4. However,
neither 3 nor 8 was detected at all, i.e., 4 was not a precursor
of 3. It is, therefore, reasonable to think that the aliphatic
chlorine atoms of 4 underwent the hydrodechlorination first
to afford 1,1-di-p-chlorophenylethylene 16 (CAS Registry
Number 2642-81-1),36 subsequent quick hydrogenation of
the ethylene moiety gave 2, and stepwise dechlorination
from the benzene rings of 2 produced 7.
ratio of about 2:1, respectively. Two chlorine atoms attached
with the alkene moiety of 4 were dechlorinated to generate
16 and subsequent hydrogenation of the alkene afforded 2.
Intermediates 2 and 3 underwent the successive dechlorina-
tion of their aromatic moieties to produce 7 and 8, respec-
tively. As we discussed above, 4 was not transformed to 3.
The dechlorination from the aliphatic moiety of 3 and 6
was so sluggish that no conversion from 3 to 2 nor from 6
to 5 was observed. After the complete dechlorination of
the aromatic moieties of 3 and 6, however, the resulting 8
could be transformed to 7 as shown in Figure 4, while the
transformation of 8 to 7 were hardly observed in the reaction
mixture starting from p,p0-DDT 1 (Fig. 1).
2.6. Dechlorination mechanism of trichloromethyl
group of p,p0-DDT using Pd/C–Et3N–H2 system
2.5. Reductive degradation pathway of p,p0-DDT
using Pd/C–Et3N–H2 system
The hydrogenolysis of p,p0-DDT 1 over Pd/C without Et3N
(Fig. 2) gave 2 and 3 in the ratio of about 2:1, respectively,
in which the ratio of 2 and 3 was almost same as the one
in the reaction of 1 with Et3N (Fig. 1). These results indicate
that p,p0-DDE 4, which is a precursor of 2, was not formed
via a simple base (Et3N) promoted dehydrochlorination of
1.45,46 The dechlorination of the trichloromethyl group of
Considering the degradation reactions of p,p0-DDD 3 and
p,p0-DDE 4, the degradation pathway of p,p0-DDT 1 was
proposed in Figure 6. In the initial stage of the reaction,
the aliphatic moiety of 1 was subjected, in two different
manners, to a dehydrochlorination to afford p,p0-DDE 4
and to a hydrodechlorination to afford p,p0-DDD 3 in the

Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
8389
H2 (balloon)
Cl
Cl
10% Pd/C (10 wt% of 4)
H
CH3
Et3N (4.8 equiv)
MeOH, rt, >0.5 h
Cl
Cl
p,p'-DDE (4)
7
H
H
Cl
Cl
16
100
90
80
70
60
50
40
30
20
10
0
4
2
5
7
0
10
20
30
40 50
Time (min)
60
24 h
Time
(min)
Yield (%)
4
2
5
7
0
5
100
57
trace
0
0
15
23
trace
0
0
22
33
10
trace
0
0
6
10
15
20
30
60
24 h
44
90
0
~100
100
100
100
0
0
0
0
0
0
0
0
Figure 5. Catalytic degradation of p,p0-DDE (4) using Pd/C–Et3N system under ambient hydrogen pressure and temperature.
1 in our system would involve a single electron transfer
(SET) process (Fig. 7), as we previously proposed in the
hydrodechlorination of aromatic chlorides using Pd/C–
Et3N system, where Et3N worked as an electron donor as
well as an HCl scavenger.
In a polarographic study reported by Rosenthal et al., the
half-wave potential (E1/2) on the first reduction wave of 1
(for the reaction from 1 to 3) and the potential E1/2 on the first
reduction wave of 3 [for the reaction from 3 to 2,2-bis(p-
chlorophenyl)-1-chloroethane] were ꢁ0.93 V and ꢁ2.31 V
(vs a saturated calomel electrode), respectively.49 This study
suggests that 3 cannot readily accept an electron compared
with 1 and it is rationale to think that in our system the
SET initiated dechlorination of aliphatic moiety of 3 did
not take place until the dechlorinations of aromatic moiety
completed.
According to the reported molecular orbital (CNDO/2)
study, 98% of the electron density in the LUMO of p,p0-
DDT is localized in aliphatic carbon–chlorine s antibonding
orbital.47 Initial single electron transfer from Pd(0) to this
orbital of 1 affords a chloride anion and an alkyl radical A
since the reductive cleavage of aliphatic halides does not
afford anion radicals as discrete intermediates.48 In the
hydrodechlorination pathway, A abstracts hydrogen to form
p,p0-DDD 3, whereas in the dehydrodechlorination pathway,
A undergoes an abstraction of the hydrogen at the benzylic
position by the chloride radical to form p,p0-DDE 4, which
undergoes successive hydrodechlorinations and subsequent
hydrogenation of the double bond to afford 2.
3. Conclusion
In summary, the hydrodechlorination method using the
Pd/C–Et3N system accomplished the complete degradation
of DDTs with the use of a catalytic amount of Pd/C under
ambient pressure and temperature, generating much less

8390
Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
H
CCl3
toxic 1,1-diphenylethane, 1,1-dichloro-2,2-diphenylethane,
and triethylammonium chloride. The addition of Et3N ac-
celerated the dechlorination from the alkyl moiety as well
as the phenyl moiety. All reagents and solvents used for
the degradation reaction are commercially available and
could be recovered and reused. The method is very simple,
efficient, and does not require any expensive facilities. Fur-
ther study to achieve the complete dechlorination of DDT
under mild conditions is now ongoing in our laboratory.
Dehydrochlorination
Hydrodechlorination
Cl
Cl
p,p'-DDT (1)
Cl
Cl
H
CHCl2
Cl
Cl
Cl
Cl
p,p'-DDE (4)
p,p'-DDD (3)
4. Experimental
4.1. Chemicals
H
H
H
H
H
CHCl2
CHCl2
CH3
p,p0-DDT, p,p0-DDD [2,2-bis(p-chlorophenyl)-1,1-dichloro-
ethane], p,p0-DDE, and o,p0-DDT were purchased from
Kanto Chemical Co. Inc. (Tokyo, Japan) and used without
any purification prior to use. Pd/C (10%) and Et3N were
purchased from Sigma–Aldrich (St. Louis, MO) and Wako
Pure Chemical Industries, Ltd. (Osaka, Japan), respectively.
MeOH (analytical grade) was purchased from Kanto Chem-
ical Co. Inc. and used without any purification prior to use.
Cl
Cl
Cl
Cl
Cl
16
6
H
CH3
2
8
4.2. General procedure
After two vaccum/H2 cycles to remove air from a round-
suspension of p,p0-DDT (50 mg,
H
CH3
bottom flask,
a
0.14 mmol), 10% Pd/C (5.0 mg), and Et3N (86 mg,
0.85 mmol) in MeOH (10 mL) was vigorously stirred using
a stir bar under hydrogen atmosphere (balloon) at ambient
temperature (ca. 20 ꢀC). At a given time point, the reaction
mixture (1 mL) was sampled using a syringe, filtered
through a 0.2 mL Millipore membrane filter (Millipore,
Billerica, MA), and concentrated in vacuo. The residue
Cl
7
5
Figure 6. Proposed degradation pathway of p,p0-DDT under H2 atmosphere
using Pd/C–Et3N system.
Dehydrochlorination
Cl
Cl
Cl
Pathway
Cl
Cl
Cl
Cl
H
Cl
Cl
e–
Cl
Cl
Cl
Cl
p,p'-DDT (1)
A
p,p'-DDE (4)
Et3N
Cl–
Et3N·HCl
HCl
HCl
Cl
Pd(0) or Et3N
Pd(I) or Et3N+
e–
Et3N
Et3N·HCl
Hydrodechlorination
Pathway
H2/Pd
H
Cl
Cl
Cl
Cl
H
Cl
Cl
Cl
Cl
A
p,p'-DDD (3)
Figure 7. Tentative dechlorination mechanism of aliphatic moiety of p,p0-DDT.

Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
8391
10. Sherman, W. V.; Evans, R.; Nesyto, E.; Radlowski, C. Nature
1971, 232, 118–119.
11. Van Beek, H. C. A.; van der Stoep, H. J.; van Oort, H.;
van Leenen, J. Ind. Eng. Chem. Prod. Res. Dev. 1982, 21,
123–125.
was partitioned between Et2O (10 mL) and H2O (10 mL)
and the organic layer was washed with brine (10 mL), dried
(MgSO4), and filtered. An aliquot (2 mL) was taken from the
filtrate, diluted with Et2O (18 mL), and analyzed by a
Hewlett Packard 5891 series II gas chromatograph equipped
with a Hewlett Packard 5972 mass-selective detector
(Hewlett Packard, Palo Alto, CA) and a Neutrabond-5 capi-
llary column (30 mꢂ0.25 m, 0.4 mm film thickness; GL
Science, Tokyo, Japan). Helium was employed as carrier
gas with a flow rate of 1.0 mL/min. Injector and detector
temperatures were 230 and 250 ꢀC, respectively. The col-
umn temperature was programed to ramp from 150 ꢀC
(5 min hold) to 250 ꢀC (3 min hold) at a rate of 5 ꢀC/min.
Retention time and molecular ion peak and/or fragment
peak of each compound are as follows: 1, 24.08 min, m/z
352 (M+, 0.6%), 235 (MꢁCCl3, 100%); 2, 16.10 min,
m/z 250 (M+, 35%), 235 (MꢁCH3, 100%); 3, 22.75 min,
m/z 318 (M+, 1.4%), 235 (MꢁCHCl2, 100%); 4,
21.19 min, m/z 316 (M+, 57%), 246 (MꢁCl2, 100%); 5,
11.39 min, m/z 216 (M+, 39%), 201 (MꢁCH3, 100%); 6,
18.86 min, m/z 201 (MꢁCHCl2, 100%); 7, 6.88 min, m/z
182 (M+, 35%), 167 (MꢁCH3, 100%); 8, 14.68 min, m/z
178 (MꢁH2Cl2, 11%), 167 (MꢁCH2Cl2, 100%); 9,
20.40 min, m/z 294 (M+, 12%), 235 (MꢁCO2CH3, 100%);
10, 22.81 min, m/z 352 (M+, 0.9%), 235 (MꢁCCl3,
100%); 11, 14.98 min, m/z 250 (M+, 40%), 235 (MꢁCH3,
100%); 12, 21.45 min, m/z 318 (M+, 0.8%), 235
(MꢁCHCl2, 100%); 13, 10.45 min, m/z 216 (M+, 42%),
201 (MꢁCH3, 100%); 14, 17.62 min, m/z 201 (MꢁCH2Cl2,
100%); 15 12.49 min, m/z 226 (M+, 11%), 167
(MꢁCO2CH3, 100%).
12. Galadi, A.; Bitar, H.; Chanon, M.; Julliard, M. Chemosphere
1995, 30, 1655–1669.
13. Chu, W. Environ. Sci. Technol. 1999, 33, 421–425.
14. Zaleska, A.; Hupka, J.; Wiergowski, M.; Biziuk, M.
J. Photochem. Photobiol., A 2000, 135, 213–220.
15. Shimakoshi, H.; Tokunaga, M.; Baba, T.; Hisaeda, Y. Chem.
Commun. 2004, 1806–1807.
16. Quan, X.; Zhao, X.; Chen, S.; Zhao, H.; Chen, J.; Zhao, Y.
Chemosphere 2005, 60, 266–273.
17. Garrison, A. W.; Nzengung, V. A.; Avants, J. K.; Ellington, J. J.;
Jones, W. J.; Rennels, D.; Wolfe, N. L. Environ. Sci. Technol.
2000, 34, 1663–1670.
18. Kamanavalli, C. M.; Ninnekar, H. Z. Curr. Microbiol. 2004, 48,
10–13.
19. Suresh, B.; Sherkhane, P. D.; Kale, S.; Eapen, S.; Ravishankar,
G. A. Chemosphere 2005, 61, 1288–1292.
20. Hall, A. K.; Harrowfield, J. M.; Hart, R. J.; McCormick, P. G.
Environ. Sci. Technol. 1996, 30, 3401–3407.
21. Tabaei, S. M. H.; Satarinezhad, E.; Seradj, S. H.; Ebrahimian,
G. R. Synth. Commun. 2000, 30, 43–51.
22. Ghattas, A.; Abu-Reziq, R.; Avnir, D.; Blum, J. Green Chem.
2003, 5, 40–43.
23. Murena, F.; Gioia, F. J. Hazard Mater. 2004, B112, 151–154.
24. Zinovyev, S. S.; Shinkova, N. A.; Perosa, A.; Tundo, P. Appl.
Catal., B 2005, 55, 39–48.
25. Sayles, G. D.; You, G.; Wang, M.; Kupferle, M. J. Environ. Sci.
Technol. 1997, 31, 3448–3454.
26. Engelmann, M. D.; Doyle, J. G.; Cheng, I. F. Chemosphere
2001, 43, 195–198.
Acknowledgements
27. Schweizer, S.; Rusling, J. F.; Huang, Q. Chemosphere 1994, 28,
961–970.
28. Merica, S. G.; Jxdral, W.; Lait, S.; Keech, P.; Bunce, N. J.
Can. J. Chem. 1999, 77, 1281–1287.
29. Matsunaga, A.; Yasuhara, A. Chemosphere 2005, 59, 1487–
1496.
30. Shimakoshi, H.; Tokunaga, M.; Hisaeda, Y. Dalton Trans.
2004, 878–882.
This work was supported by a Grant-in Aid for Scientific
Research from the Ministry of Education, Science, Sports,
and Culture, of the Japanese Government (No. 13672222),
the Research Foundation for Pharmaceutical Sciences and
the Research Foundation for the Electrotechnology of
Chubu.
31. Modell, M. U.S. Patent 4,338,199, 1982.
32. Sajiki, H. Tetrahedron Lett. 1995, 36, 3465–3468.
33. Sajiki, H.; Hirota, K. Tetrahedron 1998, 54, 13981–13996.
34. Sajiki, H.; Kume, A.; Hattori, K.; Hirota, K. Tetrahedron Lett.
2002, 43, 7247–7250.
35. Sajiki, H.; Kume, A.; Hattori, K.; Nagase, H.; Hirota, K.
Tetrahedron Lett. 2002, 43, 7251–7254.
36. Laranjeira, M. C. M.; Armstrong, D. W.; Nome, F. Bioorg.
Chem. 1980, 9, 313–317.
37. Miyai, T.; Onishi, Y.; Baba, A. Tetrahedron Lett. 1998, 39,
6291–6294.
38. Inoi, T.; Gericke, P.; Horton, W. J. J. Org. Chem. 1962, 27,
4597–4601.
39. Yakabe, S.; Hirano, M.; Morimoto, T. Tetrahedron Lett. 2000,
41, 6795–6798.
40. Nome, F.; Rezende, M. C.; de Souza, N. S. J. Org. Chem. 1983,
48, 5357–5359.
References and notes
1. U.S. Department of Health and Human Services, Public Health
Service, Agency for Toxic Substances and Disease Registry.
Toxicological Profile for DDT, DDE, and DDD. http://www.
atsdr.cdc.gov/toxprofiles/tp35.pdf; accepted September 2002.
2. Boul, H. L. N. Z. J. Agric. Res. 1994, 38, 257–277.
3. Turusov, V.; Rakitsky, V.; Tomatis, L. Environ. Health
Perspect. 2002, 110, 125–128.
4. Hsieh, H. C. Am. Med. Assoc. Arch. Ind. Health 1954, 10,
344–346.
5. Nelson, J. A. Biochem. Pharmacol. 1974, 23, 447–451.
6. Kelce, W. R.; Stone, C. R.; Laws, S. C.; Gray, L. E.;
Kemppainen, J. A.; Wilson, E. M. Nature 1995, 375, 581–585.
7. Iwata, H.; Tanabe, S.; Sakai, N.; Tatsukawa, R. Environ. Sci.
Technol. 1993, 27, 1080–1098.
8. Tanabe, S.; Iwata, H.; Tatsukawa, R. Sci. Total Environ. 1994,
154, 163–177.
41. Gold, B.; Leuschen, T.; Brunk, G.; Gingell, R. Chem. Biol.
Interact. 1981, 35, 159–176.
9. Hitchman, M. L.; Spackman, R. A.; Ross, N. C.; Agra, C.
Chem. Soc. Rev. 1995, 423–430.
42. Zee-Cheng, K. Y.; Cheng, C. C. J. Med. Chem. 1962, 5, 1008–
1015.

8392
Y. Monguchi et al. / Tetrahedron 62 (2006) 8384–8392
43. Berliner, E. J. Am. Chem. Soc. 1944, 66, 533–535.
44. Kim, S.; Lee, J. I.; Kim, Y. C. J. Org. Chem. 1985, 50, 560–565.
45. McLennan, D. J.; Wong, R. J. J. Chem. Soc., Perkin Trans. 2
1974, 526–532.
46. McLennan, D. J.; Wong, R. J. J. Chem. Soc., Perkin Trans. 2
1974, 1373–1377.
47. Beland, F. A.; Farwell, S. O.; Callis, P. R.; Geer, R. D.
J. Electroanal. Chem. 1977, 78, 145–159.
ꢀ
48. Andrieux, C. P.; Saveant, J. M.; Su, K. B. J. Phys. Chem. 1986,
90, 3815–3823.
49. Rosenthal, I.; Lacoste, R. J. J. Am. Chem. Soc. 1959, 81, 3268–
3270.