Synthesis and characterization of novel benzoxazine-based arylidinyl succinimide derivatives

Article abstract of DOI:10.1080/00397911.2017.1354027

1,4-Benzoxazine skeleton holds substantial promise for further exploration owing to its immense pharmacological potential. In this pursuit, a series of 20 novel benzoxazine-based arylidinyl succinimide derivatives (23–42) were synthesized in moderate to g

Full text of DOI:10.1080/00397911.2017.1354027

Synthetic Communications
An International Journal for Rapid Communication of Synthetic Organic
Chemistry
ISSN: 0039-7911 (Print) 1532-2432 (Online) Journal homepage: http://www.tandfonline.com/loi/lsyc20
Synthesis and Characterization of Novel
Benzoxazine based Arylidinyl Succinimide
Derivatives
Atul K. Sharma, Suchita Prasad & Sunil K. Sharma
To cite this article: Atul K. Sharma, Suchita Prasad & Sunil K. Sharma (2017): Synthesis and
Characterization of Novel Benzoxazine based Arylidinyl Succinimide Derivatives, Synthetic
Communications, DOI: 10.1080/00397911.2017.1354027
To link to this article: http://dx.doi.org/10.1080/00397911.2017.1354027
View supplementary material
Accepted author version posted online: 20
Jul 2017.
Submit your article to this journal
Article views: 1
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=lsyc20
Download by: [Tufts University]
Date: 22 July 2017, At: 09:59

Synthesis and characterization of novel benzoxazine based
arylidinyl succinimide derivatives
Atul K. Sharma
Department of Chemistry, University of Delhi, Delhi, India
Suchita Prasad
Department of Chemistry, University of Delhi, Delhi, India
Sunil K. Sharma*
Department of Chemistry, University of Delhi, Delhi, India
Address correspondence to Sunil K. Sharma, Department of Chemistry, University of Delhi,
*
Delhi 110 007, India. Tele: + 91-11-27666646 Ext. 191. E-mail: sksharma@chemistry.du.ac.in
ABSTRACT
1
,4-Benzoxazine skeleton holds substantial promise for further exploration owing to its
immense pharmacological potential. In this pursuit, a series of twenty novel benzoxazine based
arylidinyl succinimide derivatives (23-42) were synthesized in moderate to good yields by the
reaction of ethyl 2-(7-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3-oxo-2H-benzo[b][1,4]oxazin-
4
(3H)-yl)acetate (22) with various aromatic aldehydes under Wittig reaction conditions in the
presence of triphenylphosphine and ethanol. All these synthesized compounds were fully
1
13
2
characterized from their spectral data ( H, Cꢀ & Dꢀ NMR, IR, UV, HRMS) and further confirmed
1

by X-ray crystallographic analysis of a representative compound (32). Antibacterial activity of
obtained arylidinyl succinimide derivatives were evaluated against both Gram-positive and Gram-
negative bacterial strains and were found to exhibit insignificant activity as compared to the
reference.
GRAPHICAL ABSTRACT
KEYWORDS: antibacterial activity, aromatic aldehyde, arylidinyl succinimide, benzoxazine
1
. Introduction
Heterocycles, innate with the ability to incarnate substituents around a core scaffold in
defined three-dimensional representations, form by far the largest of classical divisions of organic
chemistry.[1] Inevitably woven into life processes, these constitute one of the largest areas of
research as more than 90% of new drugs contain heterocycles and among the approximately 20
million chemical compounds identified by the end of the second millennium, half are
heterocyclic.[1] Heterocyclic compounds, being at the interface of chemistry and biology, have
spurred new scientific insights, discoveries and applications. They have paved the way towards
the biological and industrial development of society, leading to the improvement in the quality of
life. However, with the advent of globalization, newer diseases are coming into the picture and
2

hence, finding newer scaffolds remain a challenging task. Modification of the structure of existing
active pharmacophore can be regarded as a more practical approach to meet such challenges.
Among them, nitrogen- and oxygen-containing heterocycles hold substantial interest of
researchers.[2,3] 1,4-Benzoxazines, a bicyclic system having an oxazine ring annulated to a benzene
ring, appears an ideal subject for further exploration as a result of its exciting pharmacological
potential. Considered as ‘natural plant toxin’, they act as defense chemical against a wide variety
of organisms such as fungi, bacteria, insects and weeds.[4,5] This scaffold has been successfully
exploited by agrochemical industries and drug-discovery programs to bring forth drug like
libraries. Myriad benzoxazine derivatives have been screened for their biological efficacy, such as
[
6]
[7]
[8]
anti-thrombotic (1), non-steroidal mineralocorticoid inhibition (2), antidepressant (3), anti-
platelet aggregation (4), protein-kinase inhibition (5) and antimicrobial (6) (Figure 1).[11]
[
9]
[10]
Furthermore, cyclic imides, a class of naturally occurring N-substituted scaffold such as
maleimides, glutarimides, naphthalimides, phthalimides etc. exhibit broad pharmacological
activity, e.g. androgen receptor antagonist,[12] anti-diabetic agent,[13] anti-HIV,[14] protein kinase
inhibition,[15] anticancer,[16] anti-inflammatory,[17] and anti-stress agent.[18] Apart from various
biological properties attributed to succinimides, another class of cyclic imide, isolated from natural
sources, the medicinal importance of synthetic succinimides (7–11) has also been well documented
in literature (Figure 2).[19–22]
The inclusion of two distinct, biologically active pharmacophores in the same structure,
known as ‘medicinal chemistry hybridization’, can modulate the activity profile of individual
components leading to improved or newer properties. The synthesis of benzoxazine fused cyclic
imides (12–15) has been successfully attempted and has led to the development of useful
pharmacologically active pharmacophores (Figure 3).[5,23–25]
3

The wealth of information obtained from literature and taking the cognizance of the
biological activities of the two scaffolds, the present work was undertaken wherein novel
benzoxazine based arylidinyl succinimides have been synthesized. Benzoxazine based alkylidinyl
succinimides are known in literature, however, there are no reports for benzoxazine based
arylidinyl succinimides and hence, it is for the first time that such hybrid molecules have been
synthesized. Furthermore, to attain their biological insights, antibacterial screening has also been
carried out against Bacillus cereus, Bacillus subtilis and Pseudomonas aeruginosa.
2
. Results and Discussion
2
.1. Chemistry
A series of twenty novel benzoxazine based arylidinyl succinimide derivatives (23-42)
were synthesized by the reaction of ethyl 2-(7-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3-oxo-2H-
benzo[b][1,4]oxazin-4(3H)-yl)acetate (22) with various aromatic aldehydes as outlined in
Schemes 1 and 2.
2
-Amino-5-nitrophenol (16) was used as a key starting material, which was condensed with
2
-chloroacetyl chloride in the presence of potassium carbonate and anhydrous acetonitrile as
solvent to yield 2-chloro-N-(2-hydroxy-4-nitrophenyl)acetamide (17).[26] The intermediate 17
underwent intramolecular cyclization to afford the corresponding 7-nitro-2H-benzo[b][1,4]oxazin-
3
(4H)-one (18) in quantitative yield, using potassium carbonate as base and DMF as a solvent.[26]
The ester derivative of nitrobenzoxazine (19) was obtained as a result of reaction between
compound 18 and ethyl 2-bromoacetate (with some modifications in the literature procedure[27]),
which was subsequently treated with 10% Pd/charcoal and ammonium formate in methanol in
order to obtain the nitro group reduced product 20.[28] On treatment of the intermediate 20 with
4

furan-2,5-dione in THF, formation of compound 21 was observed, which was further cyclized
intra-molecularly in the presence of sodium acetate and acetic anhydride to give ethyl 2-(7-(2,5-
dioxocyclopent-3-en-1-yl)-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl)acetate 22, the desired
maleimide precursor. Condensation of compound 22 with various aromatic aldehydes under Wittig
reaction conditions in the presence of triphenylphosphine and ethanol afforded the desired
benzoxazine based arylidinyl succinimide derivatives 23-36 (Scheme 1).
Furthermore, compounds 23 and 31 were subjected to de-esterification using the lithium
hydroxide solution to yield the corresponding acids 37 and 42 (Scheme 2). The corresponding
amides (38–41) of the acid 37 were obtained by coupling reaction with various aliphatic amines in
the presence of EDC.HCl and HOBt using N-methylmorpholine as a base (Scheme 2).
All the synthesized benzoxazine based arylidinyl succinimide derivatives (23–42) are new
and reported for the first time. Various spectroscopic techniques were employed to achieve the
structural characterization of all the synthesized compounds. The structure of known intermediate
compounds was confirmed by comparing their melting point and spectral data with those reported
in the literature.
The constitution of key intermediate (Z)-4-((4-(2-ethoxy-2-oxoethyl)-3-oxo-3,4-dihydro-
1
2
H-benzo[b][1,4]oxazin-7-yl)amino)-4-oxobut-2-enoic acid (21) was confirmed from the H and
1
3
1
Cꢀ NMR spectral data. In the H NMR spectrum (Figure S1, SI), the two olefinic protons H-2
and H-3 appeared as doublets at δ 6.29 (J = 12.2 Hz) and 6.42 (J = 12.2 Hz) ppm, respectively.
The coupling constant value indicated the cis geometry across the double bond. The corresponding
13
carbons C-2 and C-3 appeared at δ 131.48 and δ 134.73 ppm in the Cꢀ NMR spectrum (Figure
1
S1, SI). In the H NMR spectrum, the aromatic proton H-8'' appeared as a doublet at δ 7.39 (J =
2
.2 Hz) ppm due to meta coupling with H-6'', which in turn appeared as a doublet of doublet at δ
5

7
.21 (J = 2.2 & 8.3 Hz) ppm. H-5'' appeared as an ortho-coupled doublet at δ 7.02 (J = 8.3 Hz)
ppm. Furthermore, the formation of the symmetrical cyclic maleimide in compound 22 from
1
compound 21 was confirmed by the observance of a characteristic singlet at δ 6.84 ppm in the H
NMR spectrum (Figure S2, SI) that corresponded to the olefinic protons H-3'' and H-4'', with the
1
3
appearance of their corresponding carbons C-3'' and C-4'' at δ 134.51 ppm in the Cꢀ NMR
spectrum (Figure S2, SI). The quaternary aromatic carbons C-9 and C-10 appeared at δ 145.11 and
1
27.05 ppm, respectively. The conversion of compound 22 to arylidinyl succinimides (23–42) led
1
to the appearance of a new characteristic peak (δ 3.69–3.86 ppm) for H-4'' in the H NMR spectra
(SI), along with the disappearance of the characteristic olefinic protons’ singlet at δ 6.84ppmꢀ
1
3
observed in the precursor. This was further supported by the Cꢀ NMR spectra (SI) and single X-
ray crystallographic data of the compound (E)-ethyl 2-(7-(3-(furan-2-ylmethylene)-2,5-
dioxopyrrolidin-1-yl)-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl)acetate (32) (Figure 4).
1
13
The formation of arylidinyl succinimides was also confirmed from H- Cꢀ heteronuclear
single quantum coherence spectroscopy (HSQC) for one of the compound, i.e. compound 23,
wherein a cross peak for H3a-C3a was observed in the range δ 7.70–7.72 and 135.79 ppm in the
1
13
H and Cꢀ NMR spectra, respectively (Figure S24). Further, the cross peaks for the aromatic
protons (H-5', H-6' & H-8') and carbons (C-5', C-6' & C-8') of the benzoxazine ring revealed that
C-5' appeared at δ 114.57 ppm, while C-6' and C-8' resonated at δ 115.64 and 120.94 ppm,
respectively, in the 13C NMR spectrum. Moreover, H- C correlation also divulged that the
aromatic carbons of the 4-methylbenzylidene unit, i.e. C-3''' & C-5''' and C-2''' & C-6''' appeared
at δ 129.93 and 130.34, respectively. The peaks at δ 164.55 and 167.43 ppm were assigned to C-
1
13
3
' and C-1, respectively, using heteronuclear multiple bond correlation spectroscopy (HMBC)
(Figure S25).
6

The antibacterial screening of all the synthesized benzoxazine based arylidinyl succinimide
derivatives was carried out against both Gram-positive and Gram-negative bacterial strains using
disc diffusion assay with some modifications.[29,30] To evaluate the antimicrobial activity against
three pathogenic bacterial strains namely B. cereus, B. subtilis and P. aeruginosa, the disc diffusion
assay was performed at a concentration of 250 μg/disc. However, the screening results revealed
that these compounds are not suitable targets against the bacterial strains studied as no noticeable
antibacterial activity at the tested concentration was observed.
2
.2. Crystallography
A single crystal structure of compound 32 was collected on Oxford Diffraction Xcalibur
CCD diffractometer with graphite monochromatic MoKα radiation (graphite crystal
monochromator, λ = 0.71073 Å) at RT. Computations were carried out using WinGX-2014
graphical user interface. The structure was solved by direct methods using SIR 92. Data were
refined and extended using SHELXL software. Non-hydrogen atoms were refined anisotropically.
The molecular structure of compound 32 was created by using Olex2 program Figure 4 and its
structure refinement is shown in Table 1. Carbon bound hydrogen atoms were included in idealized
positions and refined using a riding model. Crystallographic data (excluding structure factors) for
the structure have been deposited with the Cambridge Crystallographic Data Center with CCDC
no. 1543052 for compound 32. The data can be obtained free of charge from the CCDC via
www.ccdc.cam.ac.uk.
3
. Conclusions
In summary, a total of twenty novel benzoxazine based arylidinyl succinimide derivatives
(23–42) were synthesized, two of these (23/31) were hydrolyzed to yield their corresponding acids
7

(37/42). The acid 37 was further conjugated with different amines to form the amide derivatives
1
13
3
8-41. All of the synthesized compounds were fully characterized by H and C NMR, UV, FT-
IR, and high resolution mass spectroscopy (HRMS). These compounds were subjected to
antibacterial activity screening against both gram-positive (B. cereus and B. subtilis) and gram-
negative bacteria (P. aeruginosa) at a concentration of 250 µg/disc. However, no noticeable zone
of inhibition was developed by these compounds. These preliminary results can facilitate the
design and synthesis of newer pharmacophores with improved antibacterial efficacy.
4
. Experimental Section
4
.1. Chemistry
4
.1.1. Materials and methods
The organic solvents were dried and distilled prior to their use. Reactions were monitored
by precoated TLC plates (Merck silica gel 60F254); the spots were visualized either by UV light,
or by spraying with 5% alcoholic FeCl solution. Silica gel (100–200 mesh) was used for column
3
chromatography. All the chemicals and reagents were procured from Spectrochem Pvt. Ltd., India
and Sigma-Aldrich Chemicals, USA. Melting points were measured on a Buchi M-560 apparatus
and are uncorrected. Infrared spectra were recorded on a Perkin-Elmer FT-IR model 9
1
13
spectrometer. The H and C NMR spectra were recorded on JEOL ECX-400P (400 MHz, 100.5
MHz) NMR spectrometer using tetramethylsilane as an internal standard. The chemical shift
values are on δ scale and the coupling constant values (J) are in Hertz. The UV data were recorded
on Cary 300 UV-Vis spectrophotometer, Agilent Technologies. The HRMS data was recorded on
Q-TOF LCMS, Agilent Technology-6530.
8

4
.1.2. General procedure for the synthesis of benzoxazine based arylidinyl
succinimide derivatives (23–36)
In a 100 ml round bottom flask, ethyl 2-(7-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3-oxo-
2
H-benzo[b][1,4]oxazin-4(3H)-yl)acetate (22) (1gꢀ, 3.03 mmol,
1
equivalent) and
triphenylphosphine (0.87gꢀ, 3.33 mmol, 1.1 equivalent) were dissolved in ethanol (50mlꢀ). After
o
stirring at 25 C for 10–15 minutes, aromatic aldehyde (3.03 mmol, 1 equivalent) was added slowly
along with stirring. The reaction mixture was allowed to stir for 24 h. The progress of the reaction
was monitored by TLC (MeOH:CHCl
evaporated under reduced pressure. The solid residue so obtained was purified by column
chromatography (MeOH:CHCl :: 1:49) to afford the desired benzoxazine based arylidinyl
succinimide derivative (23–36) in 64-80% isolated yield.
.1.2.1. (E)-Ethyl 2-(7-(3-(4-methylbenzylidene)-2,5-dioxopyrrolidin-1-yl)-3-oxo-2H-
benzo[b][1,4]oxazin-4(3H)-yl)acetate (23). The reaction of ethyl 2-(7-(2,5-dioxo-2,5-dihydro-
H-pyrrol-1-yl)-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl)acetate (22) (1gꢀ, 3.03 mmol) with 4-
3
:: 1:19). On completion of the reaction, the solvent was
3
4
1
methylbenzaldehyde (0.36gꢀ, 3.03 mmol) gave the title compound 23 as a white solid (0.92gꢀ, 70%)
o
by following the general procedure; M. Pt.: 256-258 C; R
f
: 0.52 (MeOH:CHCl :: 1:49); UV
3
(MeOH) λmax: 213 & 301 nm; IR (KBr) νmax: 3446, 2998, 1767, 1749, 1691, 1651, 1514, 1376,

1 1
1
7
274, 1201, 1099, 948, 842.08, 724, 696 cm ; H NMR (400MHzꢀ, CDCl
3
): δ 1.29 (t, 3H, J =
.3Hzꢀ, H-2''''), 2.41 (s, 3H, C-4''' -CH ), 3.73 (d, 2H, J = 2.2Hzꢀ, H-4''), 4.25 (q, 2H, J = 7.3Hzꢀ,
3
H-1''''), 4.66 (s, 2H, H-2), 4.72 (s, 2H, H-2'), 6.84 (d, 1H, J = 8.8Hzꢀ, H-5'), 7.07 (dd, 1H, J = 2.2
8.8Hzꢀ, H-6'), 7.10 (d, 1H, J = 2.2Hzꢀ, H-8'), 7.29 (d, 2H, J = 8.7Hzꢀ, H-3''' & H-5'''), 7.43 (d,
&
1
3
2
1
H, J = 8.7Hzꢀ, H-2''' & H-6'''), 7.70-7.72 (m, 1H, H-3a) ppm; Cꢀ NMR (100.5MHzꢀ, CDCl
3
): δ
4.09 (C-2''''), 21.51 (C-4''' -CH ), 34.24 (C-4''), 42.98 (C-2), 61.95 (C-1''''), 67.35 (C-2'), 114.57
3
9

(
C-5'), 115.64 (C-6'), 120.94 (C-8'), 121.44, 127.87 & 128.71 (C-7', C-10' & C-3''), 129.93 (C-3'''
C-5'''), 130.34 (C-2''' & C-6'''), 131.18 (C-1'''), 135.79 (C-3a), 141.13 (C-4'''), 145.20 (C-9'),
64.55, 167.43, 169.96 & 172.96 (C = O) ppm; HRMS: m/z [M + Na] + Calculated for C24
57.1376; found: 457.1374.
&
1
4
H
22
N
2
6
O :
4
.1.3. General procedure for ester hydrolysis (37/42)
In a 100 ml round bottom flask, the ester (3 mmol) (23/31) was suspended in 10 ml of THF
o
and the solution cooled to 0 C. A solution of lithium hydroxide (2M) prepared in 10 ml of
deionized water, was added drop wise to the flask and the reaction mixture was allowed to stir at
2
5oC for 4–6 h. The progress of the reaction was monitored by TLC (MeOH:CHCl
:: 1:9). On
3
completion of the reaction, THF was evaporated and the resultant aqueous solution was washed
with diethyl ether (2 × 80 ml). The precipitation of the product was achieved by acidification of
the aqueous layer with NaHSO
washed with petroleum ether to yield the desired acid (37/42) in quantitative yield.
.1.3.1. (E)-2-(7-(3-(4-Methylbenzylidene)-2,5-dioxopyrrolidin-1-yl)-3-oxo-2H-
4
(3M). The precipitated solid so obtained, was filtered, dried and
4
benzo[b][1,4] oxazin-4(3H)-yl)acetic acid (37). The hydrolysis of (E)-ethyl 2-(7-(3-(4-
methylbenzylidene)-2,5-dioxopyrrolidin-1-yl)-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl)acetate
(23) (1.30gꢀ, 3 mmol) gave the title compound 37 as a white solid in quantitative yield by following
o
the general procedure; M. Pt.: 328-330 C; R
f
: 0.20 (MeOH:CHCl :: 1:10); UV (MeOH) λmax: 301
3
nm; IR (KBr) νmax: 3478, 3075, 1787, 1776, 1668, 1663, 1587, 1312, 1248, 1295, 1068, 873, 724,

1 1
6
2
96 cm ; H NMR (400MHzꢀ, DMSO-d
6
): δ 2.35 (s, 3H, C-4''' -CH ), 3.79 (s, 2H, H-4''), 4.66 (s,
3
H, H-2), 4.76 (s, 2H, H-2'), 7.01-7.04 (m, 2H, H-6' & H-8'), 7.17 (d, 1H, J = 8.2Hzꢀ, H-5'), 7.30
(d, 2H, J = 7.5Hzꢀ, H-3''' & H-5'''), 7.51 (brs, 1H, H-3a), 7.57 (d, 2H, J = 7.7Hzꢀ, H-2''' & H-6''')
1
0

1
3
ppm; Cꢀ NMR (100.5MHzꢀ, DMSO-d
6
): δ 21.06 (C-4''' -CH
3
), 34.14 (C-4''), 42.50 (C-2), 66.94
(C-2'), 115.34 (C-5'), 115.57 (C-6'), 121.55 (C-8'), 124.05, 127.98 & 128.56 (C-7', C-10' & C-3''),
1
1
29.72 (C-3''' & C-5'''), 130.41 (C-2''' & C-6'''), 131.40 (C-1'''), 132.83 (C-3a), 140.07 (C-4'''),
44.40 (C-9'), 164.39, 169.26, 170.00 & 173.46 (C = O) ppm; HRMS: m/z [M + H] + Calculated
for C22
H
18
N
2
6
O : 407.1243; found: 407.1235.
4
.1.4. General procedure for the synthesis of amides (38–41)
To a stirred solution of acid 37 (1gꢀ, 2.46 mmol, 1 equivalent) in ethanol (30mlꢀ), was added
amine (2.71 mmol, 1.1 equivalent), N-methylmorpholine (NMM) (0.59 ml, 5.41 mmol, 2.2
equivalent) and 1-hydroxybenzotriazole (HOBt) (0.057gꢀ, 0.37 mmol, 0.15 equivalent) along with
o
stirring. The resulting reaction mixture was cooled (0 C) under an ice-bath, followed by the
addition of 1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide (EDC.HCl) (0.56gꢀ, 2.95 mmol, 1.2
o
equivalent) in portions with stirring continued at 0 C for 15–20 minutes. The reaction was then
o
allowed to proceed for 3–4 h at 25 C and the progress of the reaction was monitored by TLC
(
MeOH:CHCl
pressure and the solid residue so obtained was dissolved in ethyl acetate (100 ml) and washed with
% NaHCO solution (3 × 50 ml), water (3 × 50 ml) and brine solution (3 × 50 ml). The combined
organic layer was finally dried over anhydrous Na SO and the solvent was evaporated to obtain
3
:: 1:19). On completion of the reaction, ethanol was removed under reduced
5
3
2
4
the crude product, which was further subjected to column chromatography (MeOH:CHCl :: 1:49)
3
to afford the desired amide derivative (38-41) in 30-35% isolated yield.
4
.1.4.1. (E)-N-(sec-Butyl)-2-(7-(3-(4-methylbenzylidene)-2,5-dioxopyrrolidin-1-yl)-3-oxo-
H-benzo[b][1,4]oxazin-4(3H)-yl)acetamide (38). The reaction of (E)-2-(7-(3-(4-
methylbenzylidene)-2,5-dioxopyrrolidin-1-yl)-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl)acetic
2
1
1

acid (37) (1gꢀ, 2.46 mmol) with butan-2-amine (0.2gꢀ, 2.71 mmol) gave the title compound 38 as
o
a white solid (0.4gꢀ, 35%) by following the general procedure; M. Pt.: 265-267 C; R
f
: 0.45
(
MeOH:CHCl :: 1:99); UV (MeOH) λmax: 211 & 301 nm; IR (KBr) νmax: 3448, 3299, 2968, 2345,
3

1
1
1
751, 1764, 1706, 1690, 1648, 1516, 1367, 1164, 1054, 806, 708 cm ; H NMR (400MHzꢀ,
): δ 0.83 (t, 3H, J = 7.32Hzꢀ, H-4''''), 1.10 (d, 3H, J = 6.10Hzꢀ, H-1''''), 1.40-1.45 (m, 2H, H-
''''), 2.41 (s, 3H, C-4''' -CH ), 3.73 (d, 2H, J = 2.4Hzꢀ, H-4''), 3.85-3.92 (m, 1H, H-2''''), 4.42-4.57
m, 2H, H-2), 4.72 (s, 2H, H-2'), 5.94 (d, J = 7.9Hzꢀ, NH), 7.08-7.10 (m, 2H, J = 9.7Hzꢀ, H-5' &
H-6'), 7.27-7.29 (m, 3H, H-8', H-3''' & H-5'''), 7.42 (d, 2H, J = 7.9Hzꢀ, H-2''' & H-6'''), 7.71 (t, 1H,
CDCl
3
3
3
(
1
3
J = 2.4Hzꢀ, H-3a) ppm; Cꢀ NMR (100.5MHzꢀ, CDCl
3
): δ 10.21 (C-4''''), 20.25 (C-1''''), 21.53 (C-
4
1
3
''' -CH
3
), 29.43 (C-3''''), 34.27 (C-4''), 46.64 (C-2''''), 47.03 (C-2), 67.56 (C-2'), 115.53, 116.11,
21.40, 128.25, 128.82, 129.95 (C-3''' & C-5'''), 130.36 (C-2''' & C-6'''), 131.17 (C-1'''), 135.88 (C-
a), 141.17 (C-4'''), 145.22 (C-9'), 165.30, 166.31, 169.97 & 172.96 (C = O) ppm; HRMS: m/z [M
+
H] + Calculated for C26
H
27
N
3
5
O : 462.2029; found: 462.2005.
4
.2. Biology
4
.2.1. Pathogens
The pathogenic strains of bacteria, namely B. cereus (MTCC 430), B. subtilis (MTCC 121)
and P. aeruginosa (MTCC 741) were procured from Institute of Microbial Technology,
Chandigarh (India).
4
.2.2. Materials
1
2

Mueller Hinton agar, Nutrient broth and sterile filter paper discs (6 mm) were procured
from HiMedia, Mumbai, India. Gentamicin and DMSO, used in the assay were purchased from
Sigma-Aldrich Chemicals, USA.
4
.2.3. Antibacterial activity assay
Kirby-Bauer disc susceptibility test with some minor modifications was used to determine
the inhibitory potency of bacterial growth by the synthesized compounds.[29,30] Sterile filter paper
discs (6mmꢀ in diameter) were placed in the respective grid of each Mueller Hinton agar plate
already seeded with the target test organisms. The samples at a concentration of 250 µg/disc were
o
impregnated on the filter paper discs and then kept at 37 C for overnight incubation. Gentamicin
was used in the assay as a positive control. The zone of inhibition was recorded by using HiMedia
Antibiotic Zonescale. All the assays were carried out in triplicates.
Acknowledgements
Financial support from the University of Delhi and Department of Science and Technology,
Government of India is gratefully acknowledged for the award of the DU-DST Purse Grant II. We
would like to thank Dr. Hemant K. Gautam for screening the antibacterial activity of the
compounds. AKS and SP are thankful to UGC and CSIR respectively, for the award Junior/Senior
Research Fellowships.
Supporting Information
1
13
2
Full experimental detail, H, C & D NMR spectra, HRMS and crystal data. This material
can be found via the “Supplementary Content” section of this article’s webpage.
References
1
3

[
[
[
[
1]Dua, R.; Shrivastava, S.; Sonwane, S. K.; Srivastava, S. K. Adv. Biol. Res. 2011, 5, 120–144.
2]Valverde, M. G.; Torroba, T. Molecules 2005, 10, 318–320.
3]Liu, R. S. Pure Appl. Chem. 2001, 73, 265–269.
4](a) La, D. S.; Belzile, J.; Bready, J. V.; Coxon, A.; DeMelfi, T.; Doerr, N.; Estrada, J.; Flynn,
J. C.; Flynn, S. R.; Graceffa, R. F.; Harriman, S. P.; Larrow, J. F.; Long, A. M.; Martin, M.
W.; Morrison, M. J.; Patel, V. F.; Roveto, P. M.; Wang, L.; Weiss, M. W.; Whittington, D.
A.; Teffera, Y.; Zhao, Z. Y.; Polverino, A. J.; Harmange, J. C. J. Med. Chem. 2008, 51,
1
2
695–1705; (b) Ilas, J.; Jakopin, Z.; Bonrstnar, T.; Stegnar, M.; Kikelj, D. J. Med. Chem.
008, 51, 5617–5629.
[
5]Huang, M. Z.; Luo, F. X.; Mo, H. B.; Ren, Y. G.; Wang, X. G.; Ou, X. M.; Lei, M. X.; Liu, A.
P.; Huang, L.; Xu, M. C. J. Agric. Food Chem. 2009, 57, 9585–9592.
[
[
6]Ilas, J.; Tomasic, T.; Kikelj, D. J. Med. Chem. 2008, 51, 2863–2867.
7]Hasui, T.; Matsunaga, N.; Ora, T.; Ohyabu, N.; Nishigaki, N.; Imura, Y.; Igata, Y.; Matsui, H.;
Motoyaji, T.; Tanaka, T.; Habuka, N.; Sogabe, S.; Ono, M.; Siedem, C. S.; Tang, T. P.;
Gauthier, C.; De Meese, L. A.; Boyd, S. A.; Fukumoto, S. J. Med. Chem. 2011, 54, 8616–
8
631.
[
8]Giubellina, N.; Stabile, P.; Laval, G.; Perboni, A. D.; Cimarosti, Z.; Westerduin, P.; Cooke, J.
W. B. Org. Process Res. Dev. 2010, 14, 859–867.
[
[
[
9]Pritchard, K. M.; Al-Rawi, J.; Bradley. C. Eur. J. Med. Chem. 2007, 42, 1200–1210.
10]Honda, T.; Terao, T.; Aono, H.; Ban, M. Bioorg. Med. Chem. 2009, 17, 699–708.
11]Fringuelli, R.; Pietrella, D.; Schiaffella, F.; Guarraci, A.; Perito, S.; Bistoni, F.; Vecchiarelli,
A. Bioorg. Med. Chem. 2002, 10, 1681–1686.
[
12]Salvati, M. E.; Balog, A.; Shan, W.; Wei, D. D.; Pickering, D.; Attar, R. M.; Geng, J.; Rizzo,
C. A.; Gottardis, M. M.; Weinmann, R.; Krystek, S. R.; Sack, J.; Anc, Y.; Kish, K. Bioorg.
Med. Chem. Lett. 2005, 15, 271–276.
[
[
[
[
[
13]Wrobel, J.; Dietrich, A.; Woolson, S. A.; Millen, J.; McCaleb M.; Harrison, M. C.; Hohman,
T. C.; Sredy, J.; Sullivan, D. J. Med. Chem. 1992, 35, 4613–4627.
14]Singh, S. B.; Zink, D. L.; Heimbach, B.; Genilloud, O.; Teran, A.; Silverman, K. C.; Lingham,
R. B.; Felock, P.; Hazuda, D. J. Org. Lett. 2002, 4, 1123–1126.
15]Trapp, J.; Jochum, A.; Meier, R.; Saunders, L.; Marshall, B.; Kunick, C.; Verdin, E. G. P.;
Sippl, W.; Jung, M. J. Med. Chem. 2006, 49, 7307–7316.
16]Jindal, D. P.; Bedi, V.; Jit, B.; Karkra, N.; Guleria, S.; Bansal, R.; Palusczak, A.; Hartmann,
R. W. Il Farmaco 2005, 60, 283–290.
17]Machado, A. L.; Lima, L. M.; Araujo-Jr, J. X.; Fraga, C. A. M.; Koatz, V. L. G.; Barreiro, E.
J. Bioorg. Med. Chem. Lett. 2005, 15, 1169–1172.
[
[
18]Badru, R.; Anand, P.; Singh, B. Eur. J. Med. Chem. 2012, 48, 81–91.
19]Chung, K. W.; Park, Y. J.; Choi, Y. J.; Park, M. H.; Ha, Y. M.; Uehara, Y.; Yoon, J. H.; Chun,
P.; Moon, H. R.; Chung, H. Y. Biochim. Biophys. 2012, 1820, 962–969.
20]Obniska, J.; Zejc, A.; Karolak-Wojciechowska, J. Il Farmaco 1999, 54, 423–429.
21]Fredenhagen, A.; Tamura, S. Y.; Kenny, P. T. M.; Komura, H.; Naya, Y.; Nishiyama, K.;
Sugiura, M.; Kita, H. J. Am. Chem. Soc. 1987, 109, 4409–4411.
[
[
[
22]Isaka, M.; Rugseree, N.; Maithip, P.; Kongsaeree, P.; Prabpai, S.; Thebtaranonth, Y.
Tetrahedron 2005, 61, 5577–5583.
[
[
23]Nagano, E.; Haga, T.; Sato, R.; Morita, K. EP0170191B1, 1989.
24]Chakrabarti, R.; Misra, P.; Vikramadithyan, R. K.; Premkumar, M.; Hiriyan, J.; Datla, S. R.;
Damarla, R. K. B.; Suresh, J.; Rajagopalan, R. Eur. J. Pharmacol. 2004, 491, 195–206.
1
4

[
[
25]Jin, L.; Agag, T.; Ishida, H. Eur. Polym. J. 2010, 46, 354–363.
26]Khan, A.; Prasad, S.; Parmar, V. S.; Sharma, S. K. J. Heterocyclic Chem. 2016, 53, 1264–
1
275.
[
27]Anderluh, M.; Cesar J.; Stefanic, P.; Kikelj, D.; Janes, D.; Murn, J.; Nadrah, K.; Tominc, M.;
Addicks, E.; Giannis, A.; Stegnar, M.; Dolenc, M. S. Eur. J. Med. Chem. 2005, 40, 25–49.
28]Kume, T.; Goto, T.; Kamochi, A.; Yagi, S. U.S., 4798620, 1989.
29]Pathak, R.; Kumar, R.; Gautam, H. K. Indian J. Microbiol. 2013, 53, 130–136.
30]Yadav, S.; Mahato, M.; Pathak, R.; Jha, D.; Kumar, B.; Deka, S. R.; Gautam, H. K.; Sharma,
A. K. J. Mater. Chem. B 2014, 2, 4848–4861.
[
[
[
1
5

Figure 1. Benzoxazine derivatives of biological importance.
1
6

Figure 2. Synthetic succinimides of biological importance.
1
7

Figure 3. Benzoxazine fused cyclic imides.
1
8

Figure 4. Molecular structure of compound 32. Hydrogen atoms have been removed for clarity.
1
9

Scheme 1. Synthesis of benzoxazine based arylidinyl succinimide derivatives; Reagents and
o
o
conditions: i. 2-Chloroacetyl chloride, K
iii. Ethyl 2-bromoacetate, K CO
2
CO
3
, CH
3
CN, 25 C, 4 h; ii. K
2
CO
3
, DMF, 100 C, 3 h;
o
o
2
3
o
, acetone, 60 C, 12 h; iv. 10% Pd/C, HCOONH
4
o
, MeOH, 25 C,
O, THF, 25 C, 2hꢀ; vii. PPh ,
3
h; v. Furan-2,5-dione, THF, 25 C, 3 h; vi. CH
1
3
COONa, (CH
3
CO)
2
3
R CHO, EtOH, 25oC, 24 h.
2
0

o
2
Scheme 2. (i) LiOH (2M), THF:H2O, 25 C, 2 h; (ii) R NH
methylmorpholine, EtOH, 25 C, 4 h.
2
, HOBt, EDC.HCl, N-
o
2
1