Hydrophosphonylation of benzoylhydrazones using iodine as a catalyst: A facile synthesis of α-(N′-acylhydrazino)-substituted phosphonates

Article abstract of DOI:10.1055/s-0030-1258179

A simple and efficient method for the synthesis of α-(N′- acylhydrazino)-substituted phosphonates has been developed using the hydrophosphonylation of benzoylhydrazones with triethyl phosphite in the presence of iodine as a catalyst at room temperature. The products are formed in excellent yields (89-95%) within two to three hours. Georg Thieme Verlag Stuttgart - New York.

Full text of DOI:10.1055/s-0030-1258179

PAPER
3113
Hydrophosphonylation of Benzoylhydrazones Using Iodine as a Catalyst:
A Facile Synthesis of a-(N¢-Acylhydrazino)-Substituted Phosphonates1
a
-(
N
¢
-Acylhydraz
i
ino)-Su
s
bstituted
wPhosphonates anath Das,* Jayprakash Narayan Kumar, Avula Satya Kumar, Boddu Shashi Kanth
Organic Chemistry Division-1, Indian Institute of Chemical Technology, Hyderabad 500 007, India
Fax +91(40)27193198; E-mail: biswanathdas@yahoo.com
Received 5 May 2010; revised 17 May 2010
odologies, we have observed that benzoylhydrazones 1,
when treated with triethyl phosphite (2) in the presence of
iodine as a catalyst at room temperature, afford the corre-
sponding a-(N¢-acylhydrazino)-substituted phosphonates
Abstract: A simple and efficient method for the synthesis of a-(N¢-
acylhydrazino)-substituted phosphonates has been developed using
the hydrophosphonylation of benzoylhydrazones with triethyl phos-
phite in the presence of iodine as a catalyst at room temperature.
The products are formed in excellent yields (89–95%) within two to 3 (Scheme 1).
three hours.
O
N
Ar
Key words: hydrophosphonylation, benzoylhydrazones, triethyl
phosphite, a-(N¢-acylhydrazino)-substituted phosphonates, iodine
O
Ar
NH
O
NH
H
I2 (20 mol%)
HN
P(OEt)3
+
OEt
MeCN, r.t., 2–3 h
R
P
R
a-Amino-substituted phosphonic acids and their deriva-
tives possess various important biological activities.2
They are employed as anticancer,3a anti-HIV,3b and anti-
thrombotic agents.3c They are also used as enzyme
inhibitors4a,b and peptide mimics.4c In addition, some a-
amino-substituted phosphonates are used as antibiotics,5a
herbicides,5b fungicides,5c and insecticides.5d The general
method for the preparation of a-amino-substituted phos-
phonates is the hydrophosphonylation of imines with di-
alkyl and trialkyl phosphites, and several procedures have
been developed for this purpose.6 However, methods for
the hydrophosphonylation of hydrazones (directly or gen-
erated in situ from carbonyl compounds and hydrazines)
are limited. The reaction of tosylhydrazones with dialkyl
phosphites requires a strong Brønsted acid or a large ex-
cess of the phosphonylating agent.7 In some cases, long
reaction times and poor yields are also problems. Hydro-
phosphonylation of dialkylhydrazones, generated in situ
from carbonyl compounds and N,N-dialkylhydrazines,
has been carried out using different catalysts, but in some
methods the hydrazones derived from aromatic aldehydes
were inert.8 Surprisingly, the reaction of acylhydrazones,
which are versatile electrophiles,9 with trialkyl phosphites
has been reported.10 The hydrazones were derived from
cyclic ketones and the reaction was conducted with trifluo-
romethanesulfonic acid. The disadvantage of this proce-
dure is that it required long reaction times (18–24 h) and
achieved poor yields in some cases. Recently, another
method for the reaction of acylhydrazones with diphenyl
phosphite has been disclosed.11 However, the reaction did
not proceed with dialkyl phosphites, the hydrazones were
derived from aliphatic aldehydes only, the reaction times
were long, and the yields were variable. In continuation of
our work12 on the development of useful synthetic meth-
1
2
3
OEt
89–95%
R = alkyl, aryl
Scheme 1 Synthesis of a-(N¢-acylhydrazino)-substituted phosphon-
ates from benzoylhydrazones
Initially, we carried out the reaction of benzaldehyde ben-
zoylhydrazone with triethyl phosphite (2) using various
catalysts (Table 1).
Considering the reaction times required and yields
achieved (Table 1), iodine was the preferred catalyst, and
it was subsequently used to prepare a series of a-(N¢-acyl-
hydrazino)-substituted phosphonates from different ben-
zoylhydrazones (Scheme 1 and Table 2). Iodine is
inexpensive and nontoxic, and it can efficiently polarize
the carbon–nitrogen double bond of the hydrazones to
conduct the hydrophosphonylation. Yterrbium(III) trifluo-
romethanesulfonate is also an effective catalyst for the
reaction (Table 1, entry 8), but it is costly.
Several benzoylhydrazones underwent facile phosphony-
lation in the presence of a catalytic amount of iodine with-
in 2–3 hours, and the products were formed in excellent
yields (89–95%) (Table 2). In the absence of this catalyst,
the reaction did not proceed within the above-mentioned
time. The hydrazones were derived from aromatic, het-
eroaromatic, and aliphatic aldehydes. The aromatic alde-
hydes contained both electron-donating and electron-
withdrawing groups. Several functional groups, such as
ether, halide, nitrile, and nitro moieties, remained intact.
A benzoylhydrazone derived from a long chain aliphatic
aldehyde also underwent the conversion smoothly (entry
2). The structures of the products were established from
their spectral data (IR, 1H and 13C NMR, and MS). a-(N¢-
Acylhydrazino)-substituted phosphonates can easily be
converted9 into a-hydrazino- and a-amino-substituted
SYNTHESIS 2010, No. 18, pp 3113–3116
x
x.
x
x
.
2
0
1
0
Advanced online publication: 16.07.2010
DOI: 10.1055/s-0030-1258179; Art ID: Z11610SS
© Georg Thieme Verlag Stuttgart · New York

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B. Das et al.
PAPER
Table 2 Iodine-Catalyzed Synthesis of a-(N¢-Acylhydrazino)-Sub-
stituted Phosphonates from Benzoylhydrazones and Triethyl Phos-
phitea
Table 1 Synthesis of an a-(N¢-Benzoylhydrazino)-Substituted
Phosphonate from Benzaldehyde Benzoylhydrazone and Triethyl
Phosphite Using Different Lewis Acids at Room Temperaturea
O
Ph
O
Ph
Entry
R
Ar
Product Time
(h)
Yieldb
(%)
NH
NH
Lewis acid (X mol%)
MeCN, r.t.
HN
N
P(OEt)3
+
O
P
1
2
i-Pr
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
3a
3b
3c
3d
3e
3f
2.75
3.00
2.50
2.50
2.75
2.50
2.25
2.00
2.50
3.00
2.50
2.25
2.75
2.50
93
94
93
91
89
90
92
95
94
89
91
95
90
92
OEt
Ph
Ph
H
CH2(CH2)3Me
Ph
OEt
3c
1c
2
3
Entry
Lewis acid
Amount of Lewis Time
Yieldb
4
4-Tol
acid (mol%)
(h)
2.0
4.0
10
12
5.0
(%)
24
33
–
5
4-i-PrC6H4
4-BrC6H4
4-NCC6H4
3-O2NC6H4
4-FC6H4
1
2
In(OTf)3
In(OTf)3
BF3·OEt2
NbCl5
InCl3
FeCl3
NiCl2
Yb(OTf)3
I2
20
20
20
20
20
20
20
20
10
10
20
20
6
7
3g
3h
3i
3
8
4
–
9
5
41
–
10
11
12
13
14
3,4,5-(MeO)3C6H2 Ph
3j
6
10
14
4-ClC6H4
2-furyl
Ph
Ph
Ph
3k
3l
7
–
8
4.0
82
76
79
93
93
3,4-(MeO)2C6H3
Ph
3m
9
3.0
4.0
2.5
3.5
4-O2NC6H4 3n
10
11
12
I2
a See Scheme 1; reaction conditions: benzoylhydrazone 1 (1 mmol),
P(OEt)3 (2) (1.3 mmol), I2 (20 mol%), MeCN (4 mL), r.t.
I2
b Yield of pure isolated compound after column chromatography.
I2
a Reaction conditions: benzaldehyde benzoylhydrazone (1 mmol),
P(OEt)3 (1.3 mmol), MeCN (4 mL).
corresponding benzoylhydrazone which was used in the synthesis
of 3 without further purification.
b Yield of isolated pure compound after column chromatography.
a-(N¢-Acylhydrazino)-Substituted Phosphonates 3; General
Procedure
phosphonates, which can be used to synthesize their ana-
logues and also to explore their biological properties.
To a solution of a benzoylhydrazone 1 (1.0 mmol) in MeCN (4 mL)
was added I2 (20 mol%) at r.t. Then, P(OEt)3 (2) (1.3 mmol) was
added and the mixture was stirred. The reaction was monitored by
TLC. After completion, the mixture was washed with sat. Na2S2O3
(10 mL) and extracted with EtOAc (3 × 10 mL). The solvent was
evaporated under reduced pressure and the residue was subjected to
column chromatography (silica gel, hexane–EtOAc, 7:3) to obtain
the pure a-(N¢-acylhydrazino)-substituted phosphonate.
In conclusion, we have developed an efficient synthesis of
a-(N¢-acylhydrazino)-substituted phosphonates from ben-
zoylhydrazones and triethyl phosphite using iodine as a
catalyst. The operational simplicity, mild reaction condi-
tions, application of an easily available catalyst, short re-
action times, and excellent yields are the advantages of
this method. The method is general for the hydrophospho-
nylation of benzoylhydrazones derived from both aromat-
ic and aliphatic aldehydes.
Diethyl 1-(N¢-Benzoylhydrazino)-2-methylpropylphosphonate
(3a)
IR (neat): 3272, 1652, 1462, 1226 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.99 (br s, 1 H), 7.81 (d, J = 8.0
Hz, 2 H), 7.50–7.32 (m, 3 H), 4.30–4.02 (m, 4 H), 2.93 (t, J = 6.2
Hz, 1 H), 2.17–2.05 (m, 2 H), 1.39–1.22 (m, 6 H), 1.12 (d, J = 7.0
Hz, 6 H).
13C NMR (50 MHz, CDCl3): d = 165.9, 133.0, 131.7, 128.6, 127.1,
64.2 (d, J = 155.0 Hz), 62.8 (d, J = 7.0 Hz), 61.9 (d, J = 7.0 Hz),
28.0, 20.2 (d, J = 6.0 Hz), 18.8 (d, J = 6.0 Hz), 16.4 (d, J = 6.0 Hz).
The IR spectra were recorded on a Perkin-Elmer RX FT-IR spectro-
1
photometer and the H and 13C NMR spectra on a Varian Gemini
spectrometer at 200 and 50 MHz, respectively. The ESI-MS was
conducted on a VG-Autospec micromass (70 eV) instrument. Col-
umn chromatography was performed on silica gel (BDH, 100–200
mesh) and TLC with Merck silica gel F254 plates.
ESI-MS: m/z = 329 [M + H]+.
HRMS (ESI): m/z [M + Na]+ calcd for C15H25N2O4P: 351.1449;
Benzoylhydrazones 1; General Procedure
To a solution of an aldehyde (20 mmol) in MeOH (5 mL) was added
a mixture of benzoylhydrazine (20 mmol) in MeOH (7 mL) and
AcOH (1.5 mL) at r.t. The mixture was stirred overnight. The result-
ing precipitate was collected by filtration and dried to obtain the
found: 351.1447.
Diethyl 1-(N¢-Benzoylhydrazino)hexylphosphonate (3b)
IR (neat): 3271, 1654, 1463, 1256 cm–1.
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PAPER
a-(N¢-Acylhydrazino)-Substituted Phosphonates
3115
1H NMR (200 MHz, CDCl3): d = 8.97 (br s, 1 H), 8.00–7.72 (m, 2
H), 7.58–7.31 (m, 3 H), 4.28–4.03 (m, 4 H), 3.32 (t, J = 6.8 Hz, 1
H), 2.09–1.83 (m, 3 H), 1.72–1.41 (m, 4 H), 1.38–1.12 (m, 8 H),
0.82 (t, J = 7.0 Hz, 3 H).
13C NMR (50 MHz, CDCl3): d = 165.9, 132.6, 131.2, 128.4, 126.7,
63.1 (d, J = 7.0 Hz), 62.4 (d, J = 7.0 Hz), 58.5 (d, J = 152.0 Hz),
31.1, 27.4, 25.5 (d, J = 6.0 Hz), 21.6, 16.0 (d, J = 6.0 Hz), 13.2.
J = 7.0 Hz), 63.0 (d, J = 7.0 Hz), 62.1 (d, J = 155.0 Hz), 16.1 (d,
J = 6.0 Hz).
ESI-MS: m/z = 441 [M + H]+.
HRMS (ESI): m/z [M + H]+ calcd for C18H22BrN2O4P: 441.0578;
found: 441.0590.
Diethyl (N¢-Benzoylhydrazino)(4-cyanophenyl)methylphospho-
nate (3g)
ESI-MS: m/z = 357 [M + H]+.
HRMS (ESI): m/z [M + H]+ calcd for C17H29N2O4P: 357.1943;
IR (neat): 3275, 2229, 1655, 1464, 1251 cm–1.
found: 357.1954.
1H NMR (200 MHz, CDCl3): d = 8.38 (br s, 1 H), 7.72–7.34 (m, 9
H), 4.73 (d, J = 15.0 Hz, 1 H), 4.19–4.01 (m, 4 H), 2.17 (br s, 1 H),
1.42–1.14 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.5, 139.9 (d, J = 6.5 Hz), 132.8,
132.4, 131.0, 130.0 (d, J = 6.0 Hz), 128.8, 126.8, 123.8, 112.2, 63.9
(d, J = 7.0 Hz), 63.4 (d, J = 7.0 Hz), 62.2 (d, J = 152.0 Hz), 16.2 (d,
J = 6.0 Hz).
Diethyl (N¢-Benzoylhydrazino)(phenyl)methylphosphonate (3c)
IR (neat): 3271, 1651, 1455, 1247 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.39 (br s, 1 H), 7.70 (d, J = 8.0
Hz, 2 H), 7.53–7.28 (m, 8 H), 4.61 (d, J = 14.0 Hz, 1 H), 4.04–3.91
(m, 4 H), 2.00 (br s, 1 H), 1.36–1.18 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.0, 134.1 (d, J = 6.5 Hz), 132.3,
131.5, 128.7 (d, J = 6.0 Hz), 128.1, 127.2, 63.1 (d, J = 7.0 Hz), 62.8
(d, J = 7.0 Hz), 62.5 (d, J = 155.0 Hz), 16.0 (d, J = 5.5 Hz).
ESI-MS: m/z = 388 [M + H]+.
HRMS (ESI): m/z [M + H]+ calcd for C19H22N3O4P: 388.1426;
found: 388.1439.
ESI-MS: m/z = 363 [M + H]+.
Diethyl (N¢-Benzoylhydrazino)(3-nitrophenyl)methylphospho-
nate (3h)
HRMS (ESI): m/z [M + H]+ calcd for C18H23N2O4P: 363.1473;
found: 363.1488.
IR (neat): 3270, 1655, 1470, 1249 cm–1.
Diethyl (N¢-Benzoylhydrazino)(4-tolyl)methylphosphonate (3d)
1H NMR (200 MHz, CDCl3): d = 8.80 (br s, 1 H), 8.42 (d, J = 2.0
Hz, 1 H), 8.18 (d, J = 8.0 Hz, 1 H), 7.84–7.65 (m, 3 H), 7.58–7.30
(m, 4 H), 4.80 (d, J = 14.0 Hz, 1 H), 4.21–4.00 (m, 4 H), 2.02 (br s,
1 H), 1.41–1.20 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 168.0, 148.2, 136.9 (d, J = 6.0 Hz),
135.1 (d, J = 6.0 Hz), 132.2, 129.1, 128.5, 127.0, 123.8 (d, J = 6.0
Hz), 123.1, 63.2 (d, J = 7.0 Hz), 62.8 (d, J = 150.0 Hz), 61.6 (d, J =
7.0 Hz), 16.2 (d, J = 8.0 Hz).
IR (neat): 3271, 1652, 1459, 1244 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.61 (br s, 1 H), 7.69 (d, J = 8.0
Hz, 2 H), 7.51–7.25 (m, 5 H), 7.10 (d, J = 8.0 Hz, 2 H), 4.52 (d, J =
14.0 Hz, 1 H), 4.09–3.90 (m, 4 H), 2.31 (s, 3 H), 2.02 (br s, 1 H),
1.41–1.13 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.0, 138.1, 132.8, 131.2, 130.5
(d, J = 6.5 Hz), 129.0, 128.9 (d, J = 6.0 Hz), 128.0, 126.4, 63.1 (d,
J = 7.0 Hz), 62.2 (d, J = 7.0 Hz), 61.8 (d, J = 154.0 Hz), 21.0, 16.2
(d, J = 6.0 Hz).
ESI-MS: m/z = 408 [M + H]+.
HRMS (ESI): m/z [M + H]+ calcd for C18H22N3O6P: 408.1324;
ESI-MS: m/z = 377 [M + H]+.
found: 408.1322.
HRMS (ESI): m/z [M + H]+ calcd for C19H25N2O4P: 377.1630;
found: 377.1633.
Diethyl (N¢-Benzoylhydrazino)(4-fluorophenyl)methylphos-
phonate (3i)
IR (neat): 3279, 1654, 1509, 1226 cm–1.
Diethyl (N¢-Benzoylhydrazino)(4-isopropylphenyl)methylphos-
phonate (3e)
1H NMR (200 MHz, CDCl3): d = 8.62 (br s, 1 H), 7.71 (d, J = 8.0
Hz, 2 H), 7.53–7.33 (m, 4 H), 7.08–6.95 (m, 3 H), 4.52 (d, J = 14.0
Hz, 1 H), 4.13–3.92 (m, 4 H), 2.02 (br s, 1 H), 1.40–1.12 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.2, 162.4 (d, J = 180 Hz), 132.2
(d, J = 6.5 Hz), 130.4, 129.7, 128.9, 127.0, 116.0 (d, J = 10.0 Hz),
63.1 (d, J = 6.5 Hz), 62.8 (d, J = 6.5 Hz), 61.5 (d, J = 152.0 Hz), 16.8
(d, J = 6.0 Hz).
IR (neat): 3274, 1650, 1455, 1248 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.62 (br s, 1 H), 7.66 (d, J = 8.0
Hz, 2 H), 7.49–7.30 (m, 5 H), 7.18 (d, J = 8.0 Hz, 2 H), 4.61 (d, J =
14.0 Hz, 1 H), 4.11–3.91 (m, 4 H), 2.92–2.88 (m, 1 H), 2.12 (br s, 1
H), 1.40–1.16 (m, 12 H).
13C NMR (50 MHz, CDCl3): d = 166.9, 148.8, 132.2, 131.1, 130.2
(d, J = 6.5 Hz), 128.8 (d, J = 6.0 Hz), 128.2, 127.0, 126.4, 63.7 (d,
J = 7.0 Hz), 62.8 (d, J = 7.0 Hz), 62.2 (d, J = 154.0 Hz), 34.0, 23.2,
16.2 (d, J = 6.0 Hz).
ESI-MS: m/z = 381 [M + H]+.
HRMS (ESI): m/z [M + H]+ calcd for C18H22FN2O4P: 381.1379;
found: 381.1397.
ESI-MS: m/z = 405 [M + H]+.
Diethyl (N¢-Benzoylhydrazino)(3,4,5-trimethoxyphenyl)meth-
ylphosphonate (3j)
HRMS (ESI): m/z [M + H]+ calcd for C21H29N2O4P: 405.1943;
found: 405.1930.
IR (neat): 3273, 1655, 1456, 1248 cm–1.
Diethyl (N¢-Benzoylhydrazino)(4-bromophenyl)methylphos-
phonate (3f)
1H NMR (200 MHz, CDCl3): d = 8.41 (br s, 1 H), 7.71–7.61 (m, 2
H), 7.53–7.32 (m, 3 H), 6.71 (d, J = 8.0 Hz, 2 H), 4.50 (d, J = 15.0
Hz, 1 H), 4.11–3.90 (m, 4 H), 3.88–3.76 (m, 9 H), 2.01 (br s, 1 H),
1.35–1.16 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.4, 153.2, 132.7 (d, J = 6.5 Hz),
132.0, 131.1, 129.0, 128.5, 128.2, 127.1, 104.1 (d, J = 6.0 Hz), 64.0
(d, J = 7.0 Hz), 63.8 (d, J = 7.0 Hz), 63.2 (d, J = 150.0 Hz), 61.1,
56.5, 16.1 (d, J = 6.0 Hz).
IR (neat): 3275, 1656, 1484, 1244 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.35 (br s, 1 H), 7.70 (d, J = 8.0
Hz, 2 H), 7.52–7.31 (m, 7 H), 4.54 (d, J = 14.0 Hz, 1 H), 4.16–3.99
(m, 4 H), 2.16 (br s, 1 H), 1.40–1.20 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.1, 133.0 (d, J = 6.5 Hz), 131.7
(d, J = 6.0 Hz), 131.2, 130.9, 129.1, 129.0, 127.1, 122.3, 63.3 (d,
ESI-MS: m/z = 453 [M + H]+.
Synthesis 2010, No. 18, 3113–3116 © Thieme Stuttgart · New York

3116
B. Das et al.
PAPER
HRMS (ESI): m/z [M + Na]+ calcd for C21H29N2O7P: 475.1610;
found: 475.1627.
Acknowledgment
The authors thank CSIR and UGC, New Delhi, for financial assis-
tance. They are also thankful to the NMR, Mass, and IR Divisions
of the IICT for recording spectra.
Diethyl (N¢-Benzoylhydrazino)(4-chlorophenyl)methylphos-
phonate (3k)
IR (neat): 3274, 1652, 1470, 1249 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.40 (br s, 1 H), 7.69 (d, J = 8.0
Hz, 2 H), 7.52–7.27 (m, 7 H), 4.61 (d, J = 15.0 Hz, 1 H), 4.12–3.90
(m, 4 H), 2.03 (br s, 1 H), 1.42–1.27 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.4, 134.2 (d, J = 7.0 Hz), 132.4
132.0, 130.2 (d, J = 6.5 Hz), 128.7, 128.5, 128.2, 126.7, 63.2 (d, J =
7.0 Hz), 62.8 (d, J = 7.0 Hz), 61.8 (d, J = 155.0 Hz), 16.4 (d, J = 6.0
Hz).
References
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ESI-MS: m/z = 397 [M + H]+.
HRMS (ESI): m/z [M + Na]+ calcd for C18H22ClN2O4P: 419.0903;
found: 419.0904.
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Diethyl (N¢-Benzoylhydrazino)(2-furyl)methylphosphonate (3l)
IR (neat): 3275, 1654, 1472, 1248 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.32 (br s, 1 H), 7.71 (d, J = 8.0
Hz, 2 H), 7.40–7.37 (m, 4 H), 6.52 (br s, 1 H), 6.40 (br s, 1 H), 4.62
(d, J = 14.0 Hz, 1 H), 4.28–4.10 (m, 4 H), 2.02 (br s, 1 H), 1.40–1.19
(m, 6 H).
13C NMR (50 MHz, CDCl3): d = 167.2, 147.2 (d, J = 6.5 Hz), 143.2,
132.5, 131.7, 128.2, 126.5, 110.8, 110.6 (d, J = 6.0 Hz), 64.0 (d, J =
6.5 Hz), 63.5 (d, J = 150.0 Hz), 63.0 (d, J = 6.5 Hz), 16.1 (d, J = 6.0
Hz).
(6) (a) Changtao, Q.; Taishing, H. J. Org. Chem. 1998, 63,
4125. (b) Ranu, B.; Hjra, A.; Jana, H. Org. Lett. 1999, 1,
1141. (c) Manabe, K.; Kobayashi, S. Chem. Commun. 2000,
669. (d) Yadav, J. S.; Reddy, B. V. S.; Sreedhar, P. Green
Chem. 2002, 4, 436. (e) Saidi, M. R.; Azizi, N. Synlett 2002,
1347. (f) Joly, G. D.; Jacobsen, E. N. J. Am. Chem. Soc.
2004, 126, 4102. (g) Pawar, V. D.; Bettigeri, S.; Weng, S.-
S.; Kao, J.-Q.; Chen, C.-T. J. Am. Chem. Soc. 2006, 128,
6308. (h) Saito, B.; Egami, H.; Katsuki, T. J. Am. Chem. Soc.
2007, 129, 1978. (i) Bhagat, S.; Chakraborthi, A. K. J. Org.
Chem. 2007, 72, 1263. (j) Merino, P.; Marques-Lopez, E.;
Herrera, R. P. Adv. Synth. Catal. 2008, 350, 1195.
(7) (a) Inokawa, S.; Nakatsukasa, Y.; Horisaki, M.; Yamashita,
M.; Yoshida, H.; Ogata, T. Synthesis 1977, 179.
(b) Yamashita, M.; Takeuchi, J.; Nakatani, K.; Oshikawa, T.
Bull. Chem. Soc. Jpn. 1985, 58, 377. (c) Yamamoto, H.;
Hanaya, T.; Kawamoto, H.; Inokawa, S. Chem. Lett. 1989,
121.
ESI-MS: m/z = 375 [M + Na]+.
HRMS (ESI): m/z [M + Na]+ calcd for C16H21N2O5P: 375.1085;
found: 375.1073.
Diethyl (N¢-Benzoylhydrazino)(3,4-dimethoxyphenyl)methyl-
phosphonate (3m)
IR (neat): 3272, 1655, 1460, 1245 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.43 (br s, 1 H), 7.72 (d, J = 8.0
Hz, 1 H), 7.58–7.23 (m, 3 H), 7.09–6.90 (m, 3 H), 6.80–6.76 (m, 1
H), 4.91 (d, J = 14.0 Hz, 1 H), 4.12–4.01 (m, 4 H), 3.85 (s, 6 H),
2.02 (br s, 1 H), 1.39–0.97 (m, 6 H).
13C NMR (50 MHz, CDCl3): d = 169.4, 150.5, 149.1, 132.7, 130.4,
129.8 (d, J = 6.5 Hz), 129.6, 128.2 (d, J = 6.0 Hz), 120.0, 114.7,
112.2, 62.8 (d, J = 7.0 Hz), 62.3 (d, J = 7.0 Hz), 61.7 (d, J = 152.0
Hz), 55.6, 16.8 (d, J = 6.0 Hz).
HRMS (ESI): m/z [M – H]+ calcd for C20H27N2O6P: 421.1528;
(8) (a) Heydari, A.; Javidan, A.; Schaffie, M. Tetrahedron Lett.
2001, 42, 8071. (b) Heydari, A.; Mehrdad, M.; Schaffie, M.;
Abdolrezaie, M. S.; Hajinassirei, R. Chem. Lett. 2002, 1146.
(c) Heydari, A.; Arafi, A. Catal. Commun. 2007, 8, 1023.
(9) Sugiura, M.; Kobayashi, S. Angew. Chem. Int. Ed. 2005, 44,
5176.
(10) Rabasso, N.; Fadel, A. Synthesis 2008, 2353.
(11) Herrera, R. P.; Roca-Lopez, D.; Navarro-Moros, G. Eur. J.
Org. Chem. 2010, 1450.
(12) (a) Das, B.; Damodar, K.; Bhunia, N.; Kanth, B. S.
Tetrahedron Lett. 2009, 50, 2072. (b) Das, B.; Damodar, K.;
Bhunia, N. J. Org. Chem. 2009, 74, 5607. (c) Das, B.;
Balasubramanyam, P.; Veeranjaneyulu, B.; Reddy, C. R.
J. Org. Chem. 2009, 74, 9505. (d) Das, B.; Satyalakshmi,
G.; Suneel, K. Tetrahedron Lett. 2009, 50, 2770.
found: 421.1529.
Diethyl [N¢-(4-Nitrobenzoyl)hydrazino](phenyl)methylphos-
phonate (3n)
IR (neat): 3275, 1653, 1462, 1243 cm–1.
1H NMR (200 MHz, CDCl3): d = 9.02 (br s, 1 H), 8.25 (d, J = 8.0
Hz, 2 H), 7.92 (d, J = 8.0 Hz, 2 H), 7.57–7.30 (m, 5 H), 4.59 (d, J =
14.0 Hz, 1 H), 4.14–3.90 (m, 4 H), 1.96 (br s, 1 H), 1.40–1.02 (m, 6
H).
13C NMR (50 MHz, CDCl3): d = 165.3, 149.9, 142.4, 133.2 (d, J =
6.5 Hz), 129.1, 128.7 (d, J = 6.5 Hz), 128.0, 125.1, 123.8, 63.2 (d,
J = 7.0 Hz), 62.5 (d, J = 150.0 Hz), 62.0 (d, J = 7.0 Hz), 16.2 (d,
J = 6.0 Hz).
HRMS (ESI): m/z [M + H]+ calcd for C18H22N3O6P: 408.1324;
found: 408.1330.
Synthesis 2010, No. 18, 3113–3116 © Thieme Stuttgart · New York