Diversity-oriented synthesis of α-aminophosphonates: A new class of potential anticancer agents

Article abstract of DOI:10.1016/j.ejmech.2013.05.036

A small library of structurally diverse α-aminophosphonates has been synthesized by reacting alkyl/aryl aldehydes, alkyl/aryl amines and alkyl/aryl phosphites in one-pot catalyzed by Amberlite-IR 120 resin (acidic). All the synthesized a-aminophosphonates were assayed for their in vitro cytotoxic activities against a panel of five human cancer cell lines including A-549, NCI-H23 (Lung), Colo 320DM (Colon), MG-63 (Bone marrow) and Jurkat (Blood T lymphocytes). Compound 4n having (R)-1-phenylethanamine was found to be the most active amongst all the synthesized a-aminophosphonates against all the five cancer cell lines, most prominent being against Jurkat cell line with an IC ₅₀ value of 4 μM. Surprisingly, compound 4o having (S)-1-phenylethanamine was found to be devoid of any cytotoxicity. Our finding suggests that these chemical entities could further serve as interesting template for the design of potential anticancer agents.

Full text of DOI:10.1016/j.ejmech.2013.05.036

European Journal of Medicinal Chemistry 66 (2013) 146e152
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Diversity-oriented synthesis of
of potential anticancer agents
a-aminophosphonates: A new class
,
a
a
Asish K. Bhattacharya a , Dnyaneshwar S. Raut , Kalpeshkumar C. Rana ,
*
Innaiah K. Polanki a, Mohd Sajid Khan b, Sana Iram b
a Division of Organic Chemistry, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune 411 008, India
b Department of Biotechnology, Integral University, Lucknow 226 026, India
a r t i c l e i n f o
a b s t r a c t
Article history:
A small library of structurally diverse a-aminophosphonates has been synthesized by reacting alkyl/aryl
Received 1 April 2013
Received in revised form
22 May 2013
Accepted 24 May 2013
Available online 5 June 2013
aldehydes, alkyl/aryl amines and alkyl/aryl phosphites in one-pot catalyzed by Amberlite-IR 120 resin
(acidic). All the synthesized -aminophosphonates were assayed for their in vitro cytotoxic activities
a
against a panel of five human cancer cell lines including A-549, NCI-H23 (Lung), Colo 320DM (Colon),
MG-63 (Bone marrow) and Jurkat (Blood T lymphocytes). Compound 4n having (R)-1-phenylethanamine
was found to be the most active amongst all the synthesized
a-aminophosphonates against all the five
Dedicated to Prof. Dr. Richard R. Schmidt on
the occasion of his 78th birthday.
cancer cell lines, most prominent being against Jurkat cell line with an IC50 value of 4
m
M. Surprisingly,
compound 4o having (S)-1-phenylethanamine was found to be devoid of any cytotoxicity. Our finding
suggests that these chemical entities could further serve as interesting template for the design of
potential anticancer agents.
Keywords:
a
-Aminophosphonates
Ó 2013 Elsevier Masson SAS. All rights reserved.
Aldehydes
Amines
Multicomponent reaction
Anticancer activity
1. Introduction
the synthesis of a-aminophosphonates, but the most preferred
methods is the nucleophilic addition reaction of phosphites with
imines, which is generally catalyzed by an alkali metal alkoxide, e.g.,
NaOEt or Lewis acids [8] such as SnCl4, SnCl2, ZnCl2, MgBr2 and
BF3$Et2O [9,10]. During the formation of imine, water is formed
which could either deactivate or decompose the Lewis acid catalyst
thereby limiting the scope of carrying out this reaction in one-pot
[11]. Recently, we found [12] that bismuth nitrate pentahydrate to
Diversity-oriented synthesis (DOS) has garnered much attention
in recent times as a tool to generate structurally diverse and com-
plex set of small molecules. The basic intention of DOS is to furnish
collections of small molecules having diversified scaffolds to
spearhead drug discovery programme [1].
a-Aminophosphonates
are considered to be structural analogs of the corresponding
a
a
-amino acids and transition-state mimics of peptide hydrolysis.
-Aminophosphonates have been reported to exert several phar-
be an efficient Lewis acid to catalyze synthesis of a-amino-
phosphonates in one-pot due to its ability to tolerate the water
generated during the course of the reaction. This result suggests
that there is further scope to develop convenient and general
approach utilizing an environmentally benign and recyclable
macological activities such as peptide mimics [2], haptens of cata-
lytic antibodies [3], antibiotics and pharmacological agents [4] and
herbicides [5]. Additionally, phosphinic acid and phosphinic amino
acid analogs have been reported to be enzyme inhibitors [6]. We
have been intrigued by the biological properties of amino-
phosphonates and have further explored amino-phosphonates as
novel cysteine protease inhibitors [7a,b] and its anti-HIV activities
[7c]. In literature, several synthetic methods have been reported for
catalyst for the synthesis of a-aminophosphonates.
The advantages associated with the use of solid acidic catalysts
in organic synthesis e.g., non-toxicity, low cost, operational
simplicity, reusability, and ease of isolation after completion of the
reaction has rendered them as the most preferred heterogeneous
catalysts. Our search for efficient, cost effective, reusable and
environmentally benign catalyst converged on Amberlite-IR 120
resin. As an efficient heterogeneous catalyst, Amberlite-IR 120
has been reported to catalyze various chemical transformations
* Corresponding author. Tel.: þ91 20 2590 2309; fax: þ91 20 2590 2629.
E-mail address: ak.bhattacharya@ncl.res.in (A.K. Bhattacharya).
0223-5234/$ e see front matter Ó 2013 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2013.05.036

A.K. Bhattacharya et al. / European Journal of Medicinal Chemistry 66 (2013) 146e152
147
[13e15]. The application of microwave irradiation in organic syn-
thesis is nowadays a widely employed procedure allowing fast
product formation circumventing some of the harsh reaction con-
ditions and also reactions could be performed under solvent-free
conditions [16e20].
Cancer, which is a broad group of diverse diseases and charac-
terized by uncontrolled growth of abnormal cells is a major health
problem worldwide. Though, through these years medicinal
chemistry research has afforded a number of new and effective
remedies, the drugs currently being used for treatments have some
limitations. Hence, there is an all out effort in the discovery of new
scaffolds to find potent, safe and selective anticancer drugs. Barring
displayed a concentration-dependent cytotoxic profile in all five
cell lines. The synthesized -aminophosphonates were evaluated
a
against five human cancer cell lines for their cytotoxic profiles and
the results of active compounds are summarized in Table 2. Com-
pound 4c, 4d, 4j, 4l, 4r, 4x, 4y and 4aa were found to be active
against four cell lines A-549, NCI-H23, Colo 320DM and MG-63,
respectively. In general, compounds having piperonal moiety
showed cytotoxicity against studied cell lines. Compounds (4x, 4y
and 4aa) having aniline and diethyl phosphite moieties showed
cytotoxic activities against A-549, NCI-H23, Colo 320DM and MG-
63 cell lines with IC50 values in the range of 31.9e74.1 mM. The
product 4p containing piperonal, 3-fluoroaniline and diphenyl
some preliminary reports [21],
not been explored for its cytotoxic activities. Therefore, we opined
that detailed investigation of -aminophosphonates related to its
cytotoxicity shall be of importance from the view point of medic-
inal chemistry since phosphonates have been known to be stable at
physiological conditions and have good cell permeability [22].
a
-aminophosphonate moiety has
phosphite moiety was found to be selectively active against NCI-
H23 cell line having IC50 value of 48.2 mM. Of all the compounds
synthesized, compound 4n having piperonal, dibutyl phosphite and
(R)-1-phenylethanamine was found to be the most active with IC50
values of 43.4, 28.6, 15.8, 13.6 and 4 mM against all the five cancer
cell lines, A-549, NCI-H23, Colo 320DM and MG-63 and Jurkat,
respectively. However, it is interesting that compound 4o having
piperonal, dibutyl phosphite and (S)-1-phenylethanamine was
devoid of any cytotoxicity against all the cell lines. It could not reach
up to the IC50 at the significant concentration. The change in con-
centration of 4o with change in cell line was adopted with the
relative concentration of other compounds.
a
2. Results and discussion
2.1. Chemistry
In this full Article [preliminary report: Ref. [23]], we report
Amberlite-IR 120 as an heterogeneous acid catalyst for the syn-
3. Conclusions
thesis of a-aminophosphonates in one-pot under solvent-free re-
action conditions using microwave irradiation (Scheme 1). In our
preliminary communication [23], we have reported reaction of
various aromatic/aliphatic aldehyde or ketone, amine and diethyl
In conclusion, Amberlite-IR 120 catalyzed one-pot multicom-
ponent reaction of alkyl/aryl aldehydes, alkyl/aryl amines, and
alkyl/aryl phosphite to afford corresponding a-aminophosphonates
in good to excellent yields has been established. The utilities of the
present developed synthetic protocol are solvent-free reaction
conditions, reusable catalyst and easy reaction work-up procedure.
phosphite in one-pot to furnish
excellent yields (Scheme 1). Taking a clue from this reaction and in
order to generate a small library of diverse -aminophosphonates,
a-aminophosphonates in good to
a
we have selectively reacted diverse alkyl/aryl aldehydes, alkyl/aryl
amines and alkyl/aryl phosphites to generate structurally diverse
The efficacy of all synthesized
a-aminophosphonate derivatives
were assayed for their in vitro cytotoxic activities against a panel of
five human cancer cell lines including A-549, NCI-H23 (Lung), Colo
320DM (Colon), MG-63 (Bone marrow) and Jurkat (Blood T lym-
phocytes). Compound 4n having (R)-1-phenylethanamine, was
a
-aminophosphonates in good to excellent yields (Table 1). The
three-component reaction in one-pot proceeded smoothly in all
cases to furnish the corresponding -aminophosphonates. The re-
a
action of aromatic aldehydes resulted in excellent yields of the
products due to their higher reactivity. But the product was formed
in low yield in case of conjugated aldehyde (Table 1, entry 26). It is
noteworthy to mention that the present method was found to be
tolerant toward various functional groups present in the substrates
i.e. substrates bearing methylenedioxy, methoxy, ethers, halides,
olefinic and hydroxy groups. It is pertinent to mention here that the
catalyst, Amberlite-IR 120 (acidic) can be reused after completion of
reaction by filtration, washing and drying it without affecting the
yield of the desired product and reaction time thereby rendering it
environmentally benign.
amongst all the synthesized
most active against all the five cancer cell lines, most prominent
being against Jurkat cell line with an IC50 value of 4 M whereas
a-aminophosphonates found to be the
m
compound 4o having opposite stereocenter i.e. (S)-1-
phenylethanamine was totally inactive against all the cell lines.
Due to the fact that phosphonates are known to be stable at
physiological conditions and have good cell permeability, it is
presumed that results from these studies will provide an approach
to design and synthesize new a-aminophosphonate derivatives for
further structure optimization and development to obtain new
leads for the treatment of cancer.
2.2. Biological activity
4. Experimental section
All the synthesized compounds were assayed for their in vitro
cytotoxicity [24] against a panel of five human cancer cell lines
including A-549, NCI-H23 (Lung), Colo 320DM (Colon), MG-63
(Bone marrow) and Jurkat (Blood T lymphocytes). IC50 values
were based on doseeresponse curves. The MTT assay for each test
compound was performed thrice in triplicates. Each test compound
4.1. General
Melting points were recorded in open capillaries and are un-
corrected. The FT-IR spectra were recorded on an FT-IR-8300 Shi-
madzu spectrometer and microanalyses were carried out on a
Carlo-Erba instrument. NMR spectra were recorded on Bruker
ACF 200 and AV200 (200 MHz for 1H NMR and 50 MHz for 13C
NMR), AV400 (400 MHz for 1H NMR and 100 MHz for 13C NMR) and
AV500 (500 MHz for 1H NMR and 125 MHz for 13C NMR), using
CDCl3 as solvent. Tetramethylsilane (0.00 ppm) served as an in-
ternal standard in 1H NMR and CDCl3 (77.0 ppm) in 13C NMR,
respectively. Chemical shifts are expressed in parts per million
(ppm). Mass spectra were recorded on LCeMS/MS-TOF API QSTAR
Scheme 1. One-pot synthesis of a-aminophosphonates.

148
A.K. Bhattacharya et al. / European Journal of Medicinal Chemistry 66 (2013) 146e152
Table 1
Amberlite-IR 120 (Hþ) catalyzed one-pot synthesis of
a
-aminophosphonates.
Entry
Aldehyde (1)
Amine (2)
Phosphite (3)
Product (4)
Time (min)
Yielda (%)
1
2
3
4
5
6
7
8
R ¼ R1 ¼ R2 ¼ R3 ¼ H
R4 ¼ Bn
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
4a
4b
4c
4d
4e
4f
4g
4h
4i
1
3
2
3
2
3
3
1
4
2
2
2
3
87
98
79
91
96
88
90
96
91
90
93
92
90
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R4 ¼ 4-OHC6H4
R4 ¼ 2-OHC6H4
R4 ¼ 2,6-diMeC6H3
R4 ¼ 3,4-OCH2CH2OC6H3
R4 ¼ n-C3H7
R4 ¼ 3,4-OCH2OC6H3
R4 ¼ 2-OHC6H4
R4 ¼ 2,6-diMeC6H3
R4 ¼ 3-FC6H4
R5
R5
R5
R5
R5
R5
R5
¼
¼
¼
¼
¼
¼
¼
nBu
nBu
nBu
nBu
nBu
nBu
nBu
9
10
11
12
13
4j
4k
4l
R4 ¼ 2-MeC6H4
R4 ¼ 3-ClC6H4
R4 ¼ Bn
4m
14
15
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R5
¼
nBu
4n
4o
3
3
92
90
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R5
¼
nBu
16
17
18
19
20
21
22
23
24
25
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R,R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R ¼ R1 ¼ R2 ¼ H, R3 ¼ OMe
R ¼ R2 ¼ R3 ¼ H, R1 ¼ F
R4 ¼ 3-FC6H4
R4 ¼ 3-ClC6H4
R4 ¼ Ph
R5 ¼ Ph
R5 ¼ Ph
R5 ¼ Et
4p
4q
4r
4s
4t
4u
4v
4w
4x
4y
3
2
2
2
1
1
1
1
2
2
88
90
92
95
98
94
87
87
90
87
R4 ¼ Ph
R5 ¼ Allyl
R5 ¼ Allyl
R5 ¼ Allyl
R5 ¼ Et
R4 ¼ 3,4-OCH2OC6H3
R4 ¼ Bn
R4 ¼ Ph
R4 ¼ Ph
R5 ¼ Et
R ¼ R3 ¼ H, R1 ¼ R2 ¼ OMe
R ¼ R3 ¼ H,R1 ¼ OMe, R2 ¼ OH
R4 ¼ Ph
R5 ¼ Et
R4 ¼ Ph
R5 ¼ Et
26
R4 ¼ Ph
R5 ¼ Et
4z
1
11
27
28
29
R ¼ R2 ¼ R3 ¼ H, R1 ¼ NO2
R ¼ R1 ¼ R3 ¼ H, R2 ¼ NO2
R ¼ R1 ¼ OCH2O, R2 ¼ R3 ¼ H
R4 ¼ Ph
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
4aa
4ab
4ac
1
2.5
3
95
88
90
R4 ¼ Ph
R4 ¼ 2-MeC6H4
30
R4 ¼ Bn
R5 ¼ Et
4ad
2
84
31
32
33
34
35
36
37
38
R ¼ R2 ¼ R3 ¼ H, R1 ¼ Me
R ¼ R2 ¼ R3 ¼ H, R1 ¼ Me
R ¼ R2 ¼ R3 ¼ H, R1 ¼ Me
R ¼ R2 ¼ R3 ¼ H, R1 ¼ Me
R ¼ R2 ¼ R3 ¼ H, R1 ¼ NO2
R ¼ R1 ¼ R3 ¼ H, R2 ¼ NO2
R ¼ R2 ¼ R3 ¼ H, R1 ¼ NO2
R ¼ R2 ¼ R3 ¼ H, R1 ¼ OMe
R4 ¼ Ph
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
R5 ¼ Et
4ae
4af
4ag
4ah
4ai
4aj
4ak
4al
1
2
1
1
1
2
1
5
89
90
93
91
94
90
93
81
R4 ¼ 2-OMeC6H4
R4 ¼ Bn
R4 ¼ 3-FC6H4
R4 ¼ 2-OMeC6H4
R4 ¼ Bn
R4 ¼ Bn
R4 ¼ Ph
a
Yields refer to those of pure isolated products fully characterized by spectral data (refer to Experimental section and Supporting information).

A.K. Bhattacharya et al. / European Journal of Medicinal Chemistry 66 (2013) 146e152
149
Table 2
IC50 values of synthesized
a
-aminophosphonates against human cancer cell lines of different tissues.
Compound
IC50 (mM)
Lung cancer
A-549
Colon cancer
Colo 320DM
Bone marrow cancer
MG-63
Blood T lymphocytes
NCI-H23
Jurkat
4c
4d
4g
4j
4k
4l
4n
4o
4p
4r
4w
4x
4y
4aa
4al
277.8 (ꢂ1.36)
>500 (ꢂ2.15)
191.9 (ꢂ1.54)
363.8 (ꢂ2.42)
NAa
190.4 (ꢂ0.95)
248.0 (ꢂ1.24)
NAa
79.4 (ꢂ0.79)
105.3 (ꢂ2.01)
66.5 (ꢂ0.79)
80.3 (ꢂ0.81)
NAa
114.8 (ꢂ0.66)
114.3 (ꢂ0.73)
NAa
>500 (ꢂ2.74)
>500 (ꢂ2.16)
80.0 (ꢂ1.47)
>500 (ꢂ1.99)
>500 (ꢂ2.65)
>500 (ꢂ2.54)
4.0 (ꢂ0.08)
NAa
95.8 (ꢂ0.47)
121.7 (ꢂ0.91)
NAa
NAa
263.3 (ꢂ1.87)
43.4 (ꢂ0.39)
NAa
77.2 (ꢂ0.38)
28.6 (ꢂ0.14)
NAa
48.2 (ꢂ0.24)
65.8 (ꢂ0.32)
NAa
39.5 (ꢂ0.19)
39.7 (ꢂ0.23)
37.4 (ꢂ0.18)
53.8 (ꢂ0.26)
NTb
93.0 (ꢂ0.98)
15.8 (ꢂ0.12)
NAa
108.3 (ꢂ0.88)
13.6 (ꢂ0.12)
NAa
NAa
NAa
NAa
490.0 (ꢂ3.01)
>500 (ꢂ3.45)
NAa
134.4 (ꢂ0.94)
92.0 (ꢂ1.37)
160.0 (ꢂ2.01)
36.4 (ꢂ0.98)
47.9 (ꢂ1.31)
42.1 (ꢂ0.87)
NAa
68.8 (ꢂ1.32)
NAa
NAa
74.1 (ꢂ0.51)
62.4 (ꢂ0.49)
57.5 (ꢂ0.40)
NAa
34.0 (ꢂ0.89)
37.5 (ꢂ0.91)
31.9 (ꢂ0.45)
105.8 (ꢂ1.06)
3.17 (ꢂ0.01)
NTb
NAa
57.0 (ꢂ1.14)
NAa
NAa
Doxorubicin
Mytomycin
5-Fluorouracil
Tamoxifen
4.0 (ꢂ0.02)
NTb
NTb
NTb
2.0 (ꢂ0.11)
NTb
NTb
NTb
NTb
2.0 (ꢂ1.98)
NTb
NTb
NTb
NTb
NTb
NTb
8.3 (ꢂ0.16)
(ꢂ) Standard deviation; n ¼ 3.
a
NA: Not active up to significant concentration.
NT: Not tested.
b
PULSAR spectrometer, samples introduced by infusion method
using Electrospray Ionization Technique (ESI). Flash chromatog-
raphy was performed using CombiFlash Companion, Isco Teledyne
Inc., USA. All other chemicals were of analytical grade.
4.4. Diethyl (benzo[d][1,3]dioxol-5-yl((2,3-dihydrobenzo[b][1,4]
dioxin-6-yl)amino)methyl) phosphonate (4e)
Colorless solid; mp 120e21 ꢀC; Rf ¼ 0.60 (EtOAc/PE, 3:2); IR
(Nujol): nmax 3318, 2900, 2830, 1463, 1376, 1169, 1022, 722 cmꢁ1; 1H
NMR (200 MHz, CDCl3, TMS): dH 6.95e6.61 (m, 4H), 6.17e6.10 (m,
2H), 5.93 (s, 2H), 4.56 (d, 1JPH ¼ 24.0 Hz,1H), 4.20e3.74 (m, 8H), 1.29
(t, J ¼ 8.0 Hz, 3H), 1.17 (t, J ¼ 8.0 Hz, 3H); 13C NMR (50 MHz, CDCl3,
TMS): dC 148.0, 147.5, 143.9, 141.2, 140.9, 136.3, 129.8, 121.5, 117.6,
108.4, 107.7, 102.7, 101.1, 63.4 (d, 2JPC ¼ 7.0 Hz, eOCH2CH3), 63.3 (d,
2JPC ¼ 7.0 Hz, eOCH2CH3), 56.4 (d, 1JPC ¼ 150.0 Hz, eCHP), 16.5 (d,
4.2. General experimental procedure for the synthesis of
a-aminophosphonates
The corresponding alkyl/aryl aldehyde (1 mmol), alkyl/aryl
amine (1 mmol), alky/aryl phosphite (1 mmol) and Amberlite-IR
120 (100 mg) were taken in a Pyrex test tube and exposed to mi-
crowave irradiation (Samsung Model No. C103FL; 2450 MHz,
900 W) for the appropriate time (see Table 1). After completion of
the reaction (as assessed by TLC), the reaction mixture was cooled,
and dichloromethane (25 mL) was added. The catalyst was filtered
from the reaction mixture and the filtrate was concentrated under
vacuum. The residue was purified by flash chromatography (Com-
biFlash Companion, RediSepÒ flash silica gel column, 12 g) eluting
with petroleum ether/ethyl acetate (15e30%, gradient) to afford the
3
3JPC ¼ 5.8 Hz, eOCH2CH3), 16.3 (d, JPC ¼ 5.8 Hz, eOCH2CH3); MS
(ESI): m/z 422.0933 [M þ H]þ, 444.0867 [M þ Na]þ; Found: C, 57.05;
H, 5.78; N, 3.24. Calcd for C20H24NO7P: C, 57.01; H, 5.74; N, 3.32%.
4.5. Diethyl (benzo[d][1,3]dioxol-5-yl(propylamino)methyl)
phosphonate (4f)
Semisolid; Rf ¼ 0.66 (EtOAc/PE, 3:2); IR (Neat): nmax 3461, 3316,
corresponding pure
a-aminophosphonates. All the products were
2931, 2875, 1609, 1504, 1487, 1441, 1246, 1032, 965, 808, 752,
characterized from their spectral data. The spectral data of all new
compounds are given.
629 cmꢁ1 1H NMR (200 MHz, CDCl3, TMS): dH 6.97e6.75 (m, 3H),
;
5.95 (s, 2H), 4.17e3.87 (m, 5H), 2.53e2.33 (m, 3H),1.48 (m, 2H),1.30
(t, J ¼ 8.0 Hz, 3H), 1.20 (t, J ¼ 8.0 Hz, 3H), 0.87 (t, J ¼ 8.0 Hz, 3H); 13
C
NMR (50 MHz, CDCl3, TMS): dC 147.8, 147.2, 129.9,122.1, 108.6, 108.0,
4.3. Diethyl (benzo[d][1,3]dioxol-5-yl((2,6-dimethylphenyl)amino)
methyl)phosphonate (4d)
2
2
101.0, 62.9 (d, JPC ¼ 7.0 Hz, eOCH2CH3), 62.8 (d, JPC ¼ 7.0 Hz, e
1
OCH2CH3), 60.7 (d, JPC ¼ 154.1 Hz, eCHP), 49.5, 22.9, 16.5 (d,
3JPC ¼ 5.5 Hz, eOCH2CH3), 16.3 (d, JPC ¼ 5.8 Hz, eOCH2CH3), 11.6;
3
Semisolid; Rf ¼ 0.25 (EtOAc/PE, 3:7); IR (CHCl3): nmax 3351, 2910,
2850, 1463, 1377, 1033, 722; 1H NMR (500 MHz, CDCl3, TMS): dH
7.00e6.73 (m, 6H), 5.94 (s, 2H), 4.44 (d, 1JPH ¼ 25.0 Hz, 1H), 4.15 (m,
3H), 3.96 (m, 1H), 3.69 (m, 1H), 2.25 (s, 6H), 1.30 (t, J ¼ 10.0 Hz, 3H),
1.10 (t, J ¼ 10.0 Hz, 3H); 13C NMR (100 MHz, CDCl3, TMS): dC 147.6,
147.3, 144.1, 130.8, 129.0, 128.7, 121.9, 121.8, 108.7, 108.6, 108.1, 101.1,
63.0 (d, 2JPC ¼ 6.6 Hz, eOCH2CH3), 62.9 (d, 2JPC ¼ 7.3 Hz, eOCH2CH3),
MS (ESI): m/z 330.1139 [M þ H]þ, 352.0248 [M þ Na]þ; Found: C,
54.68; H, 7.30; N, 4.32. Calcd for C15H24NO5P: C, 54.71; H, 7.35; N,
4.25%.
4.6. Dibutyl (benzo[d][1,3]dioxol-5-yl(benzo[d][1,3]dioxol-5-yl-
amino)methyl)phosphonate (4g)
1
3
58.7 (d, JPC ¼ 149.7 Hz, eCHP), 18.9, 16.4 (d, JPC ¼ 6.6 Hz, e
3
OCH2CH3), 16.2 (d, JPC ¼ 5.9 Hz, eOCH2CH3); MS (ESI): m/z 392.
Colorless solid; mp 76e77 ꢀC; Rf ¼ 0.46 (EtOAc/PE, 2:3); IR
(CHCl3): nmax 3325, 2934, 2876, 1466, 1364, 1216, 1040, 931,
2505 [M þ H]þ, 414.2394 [M þ Na]þ, 430.1762 [M þ K]þ; Found: C,
61.40; H, 6.74; N, 3.51. Calcd for C20H26NO5P: C, 61.37; H, 6.70; N,
3.58%.
757 cmꢁ1 1H NMR (200 MHz, CDCl3, TMS): dH 6.94e6.55 (m, 3H),
;
6.21 (d, J ¼ 4.0 Hz, 1H), 6.03e5.98 (m, 2H), 5.93 (s, 2H) 5.81 (s, 2H),

150
A.K. Bhattacharya et al. / European Journal of Medicinal Chemistry 66 (2013) 146e152
4.56 (d, 1JPH ¼ 24.0 Hz, 1H), 4.11e3.70 (m, 4H), 1.69e1.21 (m, 8H),
0.94e0.82 (m, 6H); 13C NMR (50 MHz, CDCl3, TMS): dC 148.2, 148.0,
142.0, 140.3, 129.8, 121.4, 108.5, 105.8, 101.2, 100.7, 97.0, 67.0 (d,
760, 668 cmꢁ1 1H NMR (200 MHz, CDCl3, TMS): dH 7.10e6.38 (m,
;
7H), 5.93 (s, 2H), 4.69 (d, 1JPH ¼ 22.0 Hz,1H), 4.10e3.69 (m, 4H), 2.26
(s, 3H), 1.65e1.22 (m, 8H), 0.93e0.82 (m, 6H); 13C NMR (50 MHz,
CDCl3, TMS): dC 148.0, 147.3, 144.2, 130.2, 129.9, 127.0, 122.9, 121.2,
2
2JPC ¼ 7.0 Hz, eOCH2CH2CH2CH3), 66.9 (d, JPC ¼ 7.0 Hz, e
1
2
OCH2CH2CH2CH3), 56.6 (d, JPC ¼ 152.2 Hz, eCHP), 32.6 (d,
118.1, 111.2, 108.3, 101.1, 67.0 (d, JPC ¼ 7.3 Hz, eOCH2CH2CH2CH3),
3
3JPC ¼ 7.7 Hz, eOCH2CH2CH2CH3), 32.5 (d, JPC ¼ 7.7 Hz, e
66.9 (d, 2JPC ¼ 7.3 Hz, eOCH2CH2CH2CH3), 55.8 (d, 1JPC ¼ 151.5 Hz, e
OCH2CH2CH2CH3), 18.7, 13.6; MS (ESI): m/z 464.3811 [M þ H]þ;
Found: C, 59.55; H, 6.48; N, 3.12. Calcd for C23H30NO7P: C, 59.61; H,
6.52; N, 3.02%.
CHP), 32.6 (d, JPC
¼
6.2 Hz, eOCH2CH2CH2CH3), 32.5 (d,
3
3JPC ¼ 6.2 Hz, eOCH2CH2CH2CH3), 18.7, 17.6, 13.6; MS (ESI): m/z
434.2427 [M þ H]þ, 456.2332 [M þ Na]þ; Found: C, 63.78; H, 7.48;
N, 3.14. Calcd for C23H32NO5P: C, 63.73; H, 7.44; N, 3.23%.
4.7. Dibutyl (benzo[d][1,3]dioxol-5-yl((2-hydroxyphenyl)amino)
methyl)phosphonate (4h)
4.11. Dibutyl (benzo[d][1,3]dioxol-5-yl((3-chlorophenyl) amino)
methyl)phosphonate (4l)
Semisolid; Rf ¼ 0.66 (EtOAc/PE, 3:2); IR (Nujol): nmax 3400, 3305,
2954, 2854, 1611, 1505, 1459, 1376, 1242, 1215, 1037, 762, 736, 627,
540 cmꢁ1; 1H NMR (200 MHz, CDCl3, TMS): dH 6.96e6.46 (m, 7H),
5.87 (s, 2H), 4.79 (d, 1JPH ¼ 26.0 Hz, 1H), 4.23e3.64 (m, 4H), 1.65e
1.22 (m, 8H), 0.89e0.80 (m, 6H); 13C NMR (50 MHz, CDCl3, TMS): dC
147.9, 145.3, 135.0, 129.6, 121.6, 119.8, 118.2, 114.3, 111.8, 108.6, 101.1,
Semisolid; Rf ¼ 0.46 (EtOAc/PE, 2:3); IR (Neat): nmax 3415, 3296,
3018, 2963, 2875, 1598, 1504, 1487, 1250, 1216, 1040, 990, 933, 757,
668 cmꢁ1 1H NMR (200 MHz, CDCl3, TMS): dH 7.05e6.44 (m, 7H),
;
5.94 (s, 2H), 4.61 (d, 1JPH ¼ 22.0 Hz,1H), 4.11e3.63 (m, 4H),1.68e1.17
(m, 8H), 0.93e0.82 (m, 6H); 13C NMR (50 MHz, CDCl3, TMS): dC
2
2
68.0 (d, JPC ¼ 7.3 Hz, eOCH2CH2CH2CH3), 67.2 (d, JPC ¼ 7.3 Hz, e
148.1, 147.7, 134.9, 130.1, 129.3, 121.4, 118.3, 113.7, 112.0, 108.4, 108.2,
1
2
OCH2CH2CH2CH3), 55.6 (d, JPC ¼ 155.9 Hz, eCHP), 32.5 (d,
101.2, 67.1 (d, JPC
¼
8.0 Hz, eOCH2CH2CH2CH3), 67.0 (d,
3
3JPC ¼ 8.4 Hz, eOCH2CH2CH2CH3), 32.4 (d, JPC ¼ 8.4 Hz, e
2JPC ¼ 8.0 Hz, eOCH2CH2CH2CH3), 55.5 (d, 1JPC ¼ 152.0 Hz, eCHP),
OCH2CH2CH2CH3), 18.6, 13.6; MS (ESI): m/z 436.2792 [M þ H]þ,
32.6 (d, JPC ¼ 6.1 Hz, eOCH2CH2CH2CH3), 32.4 (d, JPC ¼ 6.1 Hz, e
OCH2CH2CH2CH3), 18.7, 13.6; MS (ESI): m/z 454.2110 [M þ H]þ,
476.2034 [M þ Na]þ; Found: C, 58.17; H, 6.40; N, 3.17. Calcd for
3
3
458.2665 [M þ Na]þ; Found: C, 60.63; H, 6.88; N, 3.33. Calcd for
C
22H30NO6P: C, 60.68; H, 6.94; N, 3.22%.
C
22H29ClNO5P: C, 58.21; H, 6.44; N, 3.09%.
4.8. Dibutyl (benzo[d][1,3]dioxol-5-yl((2,6-dimethylphenyl)amino)
methyl)phosphonate (4i)
4.12. Dibutyl (benzo[d][1,3]dioxol-5-yl(benzylamino)methyl)
phosphonate (4m)
Colorless solid; mp 70e71 ꢀC; Rf ¼ 0.70 (EtOAc/PE, 3:2); IR
(Neat): nmax 3390, 3018, 2963, 1594, 1504, 1487, 1443, 1250, 1215,
Semisolid; Rf ¼ 0.39 (EtOAc/PE, 2:3); IR (CHCl3): nmax 3452, 3307,
2960, 2873, 2932, 1607, 1504, 1487, 1442, 1361, 1246, 1101, 984, 810,
732, 699, 629, cmꢁ1; 1H NMR (200 MHz, CDCl3, TMS): dH 7.31e7.25
(m, 5H), 6.98e6.76 (m, 3H), 5.97 (s, 2H), 4.08e3.76 (m, 6H), 3.52 (d,
1JPH ¼ 14.0 Hz, 1H), 1.65e1.24 (m, 8H), 0.95e0.82 (m, 6H); 13C NMR
(50 MHz, CDCl3, TMS): dC 147.9, 147.4, 139.3, 129.5, 128.4, 127.1,
122.4, 108.8, 108.2, 101.1, 66.7 (d, 2JPC ¼ 8.8 Hz, eOCH2CH2CH2CH3),
1099, 1040, 989, 934, 756, 668 cmꢁ1 1H NMR (200 MHz, CDCl3,
;
TMS): dH 6.98e6.70 (m, 6H), 5.93 (s, 2H), 4.41 (d, 1JPH ¼ 22.0 Hz,1H),
4.10e3.84 (m, 4H), 3.21 (m, 1H), 2.23 (s, 6H), 1.60e1.21 (m, 8H),
0.93e0.77 (m, 6H); 13C NMR (50 MHz, CDCl3, TMS): dC 147.6, 147.3,
144.2, 131.0, 130.0, 128.6, 121.9, 121.8, 108.8, 108.1, 101.1, 66.6 (d,
2
2JPC ¼ 7.0 Hz, eOCH2CH2CH2CH3), 66.5 (d, JPC ¼ 7.0 Hz, e
1
OCH2CH2CH2CH3), 58.6 (d, JPC ¼ 149.3 Hz, eCHP), 32.5 (d,
66.5 (d, 2JPC ¼ 8.8 Hz, eOCH2CH2CH2CH3), 59.1 (d, 1JPC ¼ 155.2 Hz, e
3
3
3JPC ¼ 9.5 Hz, eOCH2CH2CH2CH3), 32.4 (d, JPC ¼ 9.5 Hz, e
CHP), 32.6 (d, JPC
¼
6.2 Hz, eOCH2CH2CH2CH3), 32.5 (d,
OCH2CH2CH2CH3), 19.0, 18.6, 13.6; MS (ESI): m/z 448.2405
[M þ H]þ, 470.2261 [M þ Na]þ; Found: C, 64.37; H, 7.61; N, 3.22.
Calcd for C24H34NO5P: C, 64.41; H, 7.66; N, 3.13%.
3JPC ¼ 6.2 Hz, eOCH2CH2CH2CH3), 18.6,13.6; MS (ESI): m/z 434.2477
[M þ H]þ, 456.2236 [M þ Na]þ; Found: C, 63.67; H, 7.48; N, 3.25.
Calcd for C23H32NO5P: C, 63.73; H, 7.44; N, 3.23%.
4.9. Dibutyl (benzo[d][1,3]dioxol-5-yl((3-fluorophenyl)amino)
methyl)phosphonate (4j)
4.13. Dibutyl (benzo[d][1,3]dioxol-5-yl(((R)-1-phenylethyl)amino)
methyl)phosphonate (4n)
Colorless solid; mp 69e70 ꢀC; Rf ¼ 0.50 (EtOAc/PE, 3:2); IR
(Neat): nmax 3298, 3018, 2963, 2965, 1619, 1594, 1489, 1443, 1240,
1216, 1040, 758, 668, 628 cmꢁ1; 1H NMR (200 MHz, CDCl3, TMS): dH
7.06e6.75 (m, 4H), 6.42e6.23 (m, 3H), 5.94 (s, 2H), 4.61 (d,
1JPH ¼ 24.0 Hz, 1H), 4.11e3.85 (m, 3H), 3.72e3.63 (m, 1H), 1.69e1.20
(m, 8H), 0.94e0.82 (m, 6H); 13C NMR (50 MHz, CDCl3, TMS): dC
Semisolid; Rf ¼ 0.60 (EtOAc/PE, 3:2); IR (CHCl3): nmax 3448,
3293, 2961, 2874, 1604, 1488, 1442, 1369, 1241, 1064, 984, 759,
630 cmꢁ1 1H NMR (200 MHz, CDCl3, TMS): dH 7.32e7.20 (m, 5H),
;
6.89e6.71 (m, 3H), 5.94 (s, 2H), 4.14e3.59 (m, 6H), 1.70e1.60 (m,
3H), 1.50e1.12 (m, 8H), 0.98e0.78 (m, 6H); 13C NMR (50 MHz,
CDCl3, TMS): dC 147.8, 147.2, 145.3, 144.2, 130.5, 128.5, 126.8, 122.0,
108.7, 108.1, 101.1, 66.7 (d, 2JPC ¼ 7.0 Hz, eOCH2CH2CH2CH3), 66.6 (d,
2JPC ¼ 7.0 Hz, eOCH2CH2CH2CH3), 57.8 (d, 1JPC ¼ 153.0 Hz, eCHP),
32.7 (d, 3JPC ¼ 6.0 Hz, eOCH2CH2CH2CH3), 32.5 (d, 3JPC ¼ 6.0 Hz, e
OCH2CH2CH2CH3), 24.9, 22.4, 18.8, 13.7; MS (ESI): m/z 448.3595
[M þ H]þ, 470.3450 [M þ Na]þ; Found: C, 64.36; H, 7.62; N, 3.22.
Calcd for C24H34NO5P: C, 64.41; H, 7.66; N, 3.13%.
166.3, 161.4, 148.1, 130.4, 129.4, 121.4, 109.7, 108.4, 101.5, 100.9,
2
100.4, 67.1 (d, JPC
¼
7.0 Hz, eOCH2CH2CH2CH3), 67.0 (d,
2JPC ¼ 7.1 Hz, eOCH2CH2CH2CH3), 55.7 (d, 1JPC ¼ 152.6 Hz, eCHP),
32.6 (d, 3JPC ¼ 6.2 Hz, eOCH2CH2CH2CH3), 32.4 (d, 3JPC ¼ 6.2 Hz, e
OCH2CH2CH2CH3), 18.7, 13.6; MS (ESI): m/z 438.4244 [M þ H]þ,
460.3364 [M þ Na]þ, 476.3144 [M þ K]þ; Found: C, 60.44; H, 6.72;
N, 3.12. Calcd for C22H29FNO5P: C, 60.40; H, 6.68; N, 3.20%.
4.14. Dibutyl (benzo[d][1,3]dioxol-5-yl(((S)-1-phenylethyl)amino)
4.10. Dibutyl (benzo[d][1,3]dioxol-5-yl(o-tolylamino)methyl)
methyl)phosphonate (4o)
phosphonate (4k)
Colorless syrup; Rf ¼ 0.66 (EtOAc/PE, 3:2); IR (Neat): nmax 3329,
Semisolid; Rf ¼ 0.70 (EtOAc/PE, 3:2); IR (Neat): nmax 3392, 3016,
3018, 2964, 1608, 1504, 1487, 1443, 1248, 1216, 1063, 989, 934, 668,
2960, 2870, 1590, 1510, 1486, 1430, 1245, 1225, 1102, 1045, 986, 930,
628 cmꢁ1 1H NMR (200 MHz, CDCl3, TMS): dH 7.27e7.19 (m, 5H),
;

A.K. Bhattacharya et al. / European Journal of Medicinal Chemistry 66 (2013) 146e152
151
6.90e6.70 (m, 3H), 5.93 (s, 2H), 4.14e3.59 (m, 6H), 1.71e1.60 (m,
4.19. Diallyl (benzo[d][1,3]dioxol-5-yl(benzo[d][1,3]dioxol-5-
ylamino)methyl)phosphonate (4t)
3H), 1.49e1.14 (m, 8H), 0.98e0.78 (m, 6H); 13C NMR (50 MHz,
CDCl3, TMS): dC 147.9, 147.3, 145.3, 144.2, 130.5, 128.5, 126.7, 122.3,
121.9, 108.7, 108.1, 101.0, 66.6 (d, 2JPC ¼ 7.0 Hz, eOCH2CH2CH2CH3),
Colorless syrup; Rf ¼ 0.56 (EtOAc/PE, 1:1); IR (Neat): nmax 3310,
3019, 2912, 2896, 1720, 1634, 1611, 1504, 1488, 1440, 1366, 1215,
1041, 758, 669 cmꢁ1; 1H NMR (200 MHz, CDCl3, TMS): dH 6.96e6.55
(m, 4H), 6.23e5.76 (m, 6H), 5.37e5.14 (m, 4H), 4.68e4.05 (m, 7H);
13C NMR (50 MHz, CDCl3, TMS): dC 148.2, 147.5, 141.9, 140.4, 132.8,
132.6, 129.4, 121.5, 118.4, 108.5, 108.3, 105.9, 101.2, 100.7, 97.1, 67.5
66.3 (d, 2JPC ¼ 7.0 Hz, eOCH2CH2CH2CH3), 57.8 (d, 1JPC ¼ 152.5 Hz, e
3
CHP), 32.7 (d, JPC
¼
5.5 Hz, eOCH2CH2CH2CH3), 32.4 (d,
3JPC ¼ 5.5 Hz, eOCH2CH2CH2CH3), 24.9, 22.3, 18.8, 13.7; MS (ESI): m/
z 448.7261 [M þ H]þ, 470.7327 [M þ Na]þ; Found: C, 64.45; H, 7.70;
N, 3.05. Calcd for C24H34NO5P: C, 64.41; H, 7.66; N, 3.13%.
2
2
(d, JPC ¼ 7.5 Hz, eOCH2CHCH2), 67.4 (d, JPC ¼ 7.5 Hz, e
1
OCH2CHCH2), 56.9 (d, JPC ¼ 152.0 Hz, eCHP); MS (ESI): m/z
4.15. Diphenyl (benzo[d][1,3]dioxol-5-yl((3-fluorophenyl)amino)
methyl)phosphonate (4p)
432.7462 [M þ H]þ, 454.7790 [M þ Na]þ, 470.7651 [M þ K]þ;
Found: C, 58.41; H, 5.23; N, 3.22. Calcd for C21H22NO7P: C, 58.47; H,
5.14; N, 3.25%.
Semisolid; Rf ¼ 0.56 (EtOAc/PE, 3:2); IR (CHCl3): nmax 3294,
3056, 3018, 2926, 2855, 1730, 1615, 1594, 1537, 1443, 1288, 1193,
1040, 934, 819, 731, 594, cmꢁ1; 1H NMR (200 MHz, CDCl3, TMS): dH
4.20. Diallyl (benzo[d][1,3]dioxol-5-yl(benzylamino)methyl)
phosphonate (4u)
1
7.32e6.39 (m, 17H), 5.92 (s, 2H), 5.01 (d, JPH ¼ 22.0 Hz, 1H); 13C
NMR (50 MHz, CDCl3, TMS): dC 166.3, 161.5, 155.1, 150.3, 150.2,
148.3, 147.9, 147.7, 130.5, 129.8, 128.0, 125.6, 120.7, 120.3, 109.9,
108.6, 108.4, 101.3, 100.7, 55.6 (d, 1JPC ¼ 155.0 Hz, eCHP); MS (ESI):
m/z 500.2444 [M þ Na]þ; Found: C, 65.45; H, 4.35; N, 2.97. Calcd for
Semisolid; Rf ¼ 0.60 (EtOAc/PE,1:1); IR (CHCl3): nmax 3300, 3055,
2955, 2862, 2928, 2910, 1705, 1610, 1509, 1460, 1370, 1242, 1105,
981, 729, 631, 550 cmꢁ1; 1H NMR (400 MHz, CDCl3, TMS): dH 7.34e
7.25 (m, 5H), 7.00 (s, 1H), 6.87e6.81 (m, 2H), 5.99 (s, 2H), 5.94e5.60
(m, 2H), 5.32 (d, 1JPH ¼ 24 Hz, 1H), 5.25e5.15 (m, 3H) 4.58e4.31 (m,
4H), 4.00 (d, J ¼ 20.0 Hz, 1H), 3.83 (d, J ¼ 16.0 Hz, 1H), 3.56 (d,
J ¼ 16.0 Hz, 1H); 13C NMR (50 MHz, CDCl3, TMS): dC 148.0, 147.4,
139.21, 133.1, 132.9, 129.2, 128.4, 127.2, 122.4, 117.8, 108.8, 108.2,
101.1, 67.3 (d, 2JPC ¼ 7.0 Hz, eOCH2CHCH2), 67.1 (d, 2JPC ¼ 6.5 Hz, e
C
26H21FNO5P: C, 65.41; H, 4.43; N, 2.93%.
4.16. Diphenyl (benzo[d][1,3]dioxol-5-yl((3-chlorophenyl)amino)
methyl)phosphonate (4q)
Semisolid; Rf ¼ 0.65 (EtOAc/PE, 3:2); IR (CHCl3): nmax 3350, 2778,
1
OCH2CHCH2), 59.3 (d, JPC ¼ 154.5 Hz, eCHP), 51.2; MS (ESI): m/z
2489, 2243, 1602, 1468, 1398, 1122, 975, 824, 679 cmꢁ1 1H NMR
;
402.3432 [M þ H]þ, 424.2536 [M þ Na]þ; Found: C, 62.76; H, 6.08;
(200 MHz, CDCl3, TMS): dH 7.32e6.50 (m, 17H), 5.92 (s, 2H), 5.01 (d,
1JPH ¼ 22.0 Hz, 1H); 13C NMR (50 MHz, CDCl3, TMS): dC 150.3, 148.3,
147.2, 146.9, 135.0, 130.3, 129.8, 128.0, 125.6, 122.0, 120.7, 120.2,
118.8, 113.9, 112.2, 108.5, 101.3, 55.5 (d, 1JPC ¼ 155.0 Hz, eCHP); MS
(ESI): m/z 516.2692 [M þ Na]þ, 532.2478 [M þ K]þ; Found: C, 63.27;
H, 4.21; N, 2.87. Calcd for C26H21ClNO5P: C, 63.23; H, 4.29; N, 2.84%.
N, 3.53. Calcd for C21H24NO5P: C, 62.84; H, 6.03; N, 3.49%.
4.21. Diethyl (benzo[d][1,3]dioxol-5-yl(o-tolylamino)methyl)
phosphonate (4ac)
Colorless solid; mp 106e07 ꢀC; Rf ¼ 0.22 (EtOAc/PE, 3:7); IR
(CHCl3): nmax 3428, 3007, 2927, 1606, 1587, 1505, 1488, 1241, 1216,
1041, 972, 754, 667, 624 cmꢁ1; 1H NMR (200 MHz, CDCl3, TMS): dH
7.06e6.90 (m, 4H), 6.78e6.62 (m, 2H), 6.41 (d, J ¼ 8.0 Hz, 1H), 5.93
(s, 2H), 4.69 (d, 1JPH ¼ 24.0 Hz, 1H), 4.16e3.95 (m, 3H), 3.82e3.78
(m, 1H), 2.26 (s, 3H), 1.29 (t, J ¼ 8.0 Hz, 3H), 1.19 (t, J ¼ 8.0 Hz, 3H);
13C NMR (50 MHz, CDCl3, TMS): dC 148.0, 147.5, 144.5, 144.2, 130.2,
129.9, 127.0, 123.0, 121.2, 118.1, 111.2, 108.3, 101.1, 67.0, 57.6, 54.3,
4.17. Diethyl (benzo[d][1,3]dioxol-5-yl(phenylamino)methyl)
phosphonate (4r)
Semisolid; Rf ¼ 0.71 (EtOAc/PE, 1:1); IR (CHCl3): nmax 3348, 2905,
2848, 1455, 1365, 1027, 723; 1H NMR (200 MHz, CDCl3, TMS): dH
7.15e6.57 (m. 8H), 5.92 (s, 2H), 4.66 (d, 1JPH ¼ 24 Hz, 1H), 4.18e3.79
(m, 4H),1.33e1.14 (m, 6H); 13C NMR (50 MHz, CDCl3, TMS): dC 148.0,
147.4, 146.4, 129.7, 129.2, 124.5, 118.5, 113.9, 108.4, 108.2, 101.2, 63.3
(d, 2JPC ¼ 7.0 Hz, eOCH2CH3), 63.2 (d, 2JPC ¼ 7.0 Hz, eOCH2CH3), 55.7
(d, 1JPC ¼ 152.2 Hz, eCHP),16.5 (d, 3JPC ¼ 8.1 Hz, eOCH2CH3), 16.4 (d,
3JPC ¼ 8.1 Hz, eOCH2CH3); MS (ESI): m/z 364.7069 [M þ H]þ,
386.7274 [M þ Na]þ, 402.7225 [M þ K]þ; Found: C, 59.56; H, 6.14; N,
3.76. Calcd for C18H22NO5P: C, 59.50; H, 6.10; N, 3.85%.
3
3
18.3, 16.3 (d, JPC ¼ 6.2 Hz, eOCH2CH3), 16.1 (d, JPC ¼ 6.2 Hz, e
OCH2CH3); MS (ESI): m/z 378.1438 [M þ H]þ, 400.2078 [M þ Na]þ,
416.0956 [M þ K]þ; Found: C, 60.44; H, 6.38; N, 3.77. Calcd for
C
19H24NO5P: C, 60.47; H, 6.41; N, 3.71%.
4.22. Biological assays
In vitro cytotoxicity of synthesized compounds against human
cancer cell lines: Cell lines MG-63 (Human osteosarcoma) was
maintained in MEM þ Na pyruvate þ 10% FBS þ 1% ampicillin
whereas NCI-H23 (alveolar adenocarcinoma); Jurkat (T cell human
leukemia) and Colo 320DM (colorectal human adenocarcinoma)
were maintained in RPMI 1640 þ 10% FBS þ 1% ampicillin; and
A549 (alveolar adenocarcinoma) was maintained in 90% Dulbecco’s
MEM þ 10% FBS. Briefly, cell lines were inoculated into a series of
96-well microtiter plates, seeding densities depending on the
growth characteristics of particular cell lines. Following a 24-h
compound-free incubation, test compounds were added routinely
at 2-fold dilutions till sixth concentration with a maximum con-
centration of 50 ꢃ 10ꢁ4 M. After 48 h of treatment MTT [3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] at con-
centration of 10 mg/ml in PBS was added to evaluate the mito-
chondrial function (cell viability) with incubation at 37 ꢀC for 4 h.
4.18. Diallyl (benzo[d][1,3]dioxol-5-yl(phenylamino)methyl)
phosphonate (4s)
Semisolid; Rf ¼ 0.58 (EtOAc/PE, 2:3); IR (Neat): nmax 3307, 3062,
2960, 2873, 2932, 2901, 1718, 1628, 1607, 1504, 1487, 1442, 1361,
1246, 1101, 984, 930, 810, 732, 699, 629, 574 cmꢁ1 1H NMR
;
(200 MHz, CDCl3, TMS): dH 7.15e6.55 (m, 8H), 6.00e5.68 (m, 4H),
5.37e5.13 (m, 4H), 4.72 (d, 1JPH ¼ 22.6 Hz, 1H), 4.60e4.43 (m, 3H),
4.25e4.05 (m, 1H); 13C NMR (50 MHz, CDCl3, TMS): dC 148.3, 147.5,
141.8,141.5, 140.4,132.8,132.6,129.5,121.5,118.4,108.5,105.9,101.2,
2
2
97.1, 67.6 (d, JPC ¼ 7.3 Hz, eOCH2CHCH2), 67.5 (d, JPC ¼ 7.3 Hz, e
1
OCH2CHCH2), 56.9 (d, JPC ¼ 152.6 Hz, eCHP); MS (ESI): m/z
388.3389 [M þ H]þ, 410.3642 [M þ Na]þ, 426.3478 [M þ K]þ;
Found: C, 62.05; H, 5.65; N, 3.65. Calcd for C20H22NO5P: C, 62.01; H,
5.72; N, 3.62%.

152
A.K. Bhattacharya et al. / European Journal of Medicinal Chemistry 66 (2013) 146e152
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mMe500 mM); 4d
(75
(100
(100
(50
(10
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m
M); 4g (10
M); 4l (50
M); 4p (10
M); 4x (10
M) and 4al (10
m
m
m
Me250
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Me500
m
m
m
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m
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Biomol. Chem. 9 (2011) 5407;
Conflict of interest
(b) A.K. Bhattacharya, K.C. Rana, Bioorg. Med. Chem. 19 (2011) 7129;
(c) A.K. Bhattacharya, K.C. Rana, C. Pannecouque, E. De Clercq, ChemMedChem
7 (2012) 1601.
Authors declare no conflict of interest.
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AKB is grateful to the Department of Biotechnology (DBT),
Government of India, New Delhi, India for financial support. KCR
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Research (CSIR), New Delhi, India for the award of their research
fellowship.
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Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.ejmech.2013.05.036.
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