Synthesis and biological screening of 4-(3,3-dimethylspiro{bicyclo[2.2.1] heptan-2,5′-isoxazoline-2}- 3′-yl)-2-aryl-2,3-dihydro-1H-1,5- benzodiazepines

Article abstract of DOI:10.1002/jhet.194

A series of novel 4-(3,3-dimethylspiro{bicyclo[2.2.1]heptan-2,5′- isoxazoline-2}-3′-yl)-2-phenyl-2,3-dihydro-1H-1,5-benzodiazepines were synthesized. These molecules were screened in vitro for their antifungal and antibacterial activity, and none of the t

Full text of DOI:10.1002/jhet.194

144
Synthesis and Biological Screening of
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-2}-
30-yl)-2-aryl-2,3-dihydro-1H-1,5-benzodiazepines
Vol 48
Tahira Naqvi,a Deepali Mahajan,a Rattan Lal Sharma,a Inshad Ali Khan,b and
Kamal K. Kapoora*
aDepartment of Chemistry, University of Jammu, Jammu 180006, India
bDepartment of Biotechnology, Indian Institute of Integrative Medicine (CSIR), Jammu 180001, India
*E-mail: k2kapoor@yahoo.com
Received June 5, 2008
DOI 10.1002/jhet.194
Published online 6 October 2010 in Wiley Online Library (wileyonlinelibrary.com).
A series of novel 4-(3,3-dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-2}-30-yl)-2-phenyl-2,3-
dihydro-1H-1,5-benzodiazepines were synthesized. These molecules were screened in vitro for their
antifungal and antibacterial activity, and none of the tested compounds showed promising antimicrobial
or antifungal activity.
J. Heterocyclic Chem., 48, 144 (2011).
INTRODUCTION
In view of the pharmaceutical activities associated
with isoxazoles and diazepines, we wished to synthesize
a hybrid molecule of type 1 incorporating these moieties
as its part structures, with a dimethyl bicycloheptyl as a
lipophillic portion hooked on probably to ease the entry
into the cells, and to increase the lipid solubility of the
title compounds.
Synthesis of hybrid molecules with more than one
bioactive moiety as part of their structure is an area of
intense research interest these days [1], because these
molecules can be used to act against single target or
they can be made to perform in a way, so that these
pharmacophores act collectively on two different targets,
or they can enhance each others activity.
Isoxazoles are an important class of heterocyclic com-
pounds of pharmacological importance and so are the
benzodiazepines. Isoxazoles possess a plethora of bio-
logical activities, for instance, bactericidal, antifungal
[2], antileprous, anti-inflammatory, and antiviral [3].
They are also known to act as immunosuppressant [4].
Benzodiazepines exhibit wide spectrum of pharmacolog-
ical activity, including hypnotic, sedative, anxiolytic,
anticonvulsant, muscle relaxant, and amnesic properties,
which are mediated by slowing down the central nerv-
ous system [5]. Benzodiazepines are well known for
their strong muscular relaxing properties and can be use-
ful in the treatment of muscular spasms for example tet-
anus or spastic disorders [6], and much recently, they
are found to have antiplatelet and antileukemic activity
[7]. Studies [8] have shown that lipophilicity of a mole-
cule is a very important parameter in terms of its bio-
logical activity, because molecules having lipophilic
substituent permeate easily through the lipid membrane
by interacting with the hydrophobic interiors of the
membrane.
RESULTS AND DISCUSSION
30-Aceto-3,3-dimethylspiro{bicyclo[2.2.1]heptan-2,50-iso-
xazoline-2} (2), obtained [9] from the reaction of cam-
phene and acetone, upon Claisen-Schmidt condensation
[10] with aromatic aldehyde (3a) generated 30-cinnam-
oyl-3,3-dimethylspiro{bicyclo{2.2.1]heptan-2,50-isoxazo-
line-2} (4a). 4a was further condensed [11] with o-phenyl
enediamine to yield target compound 4-(3,3-dimethylspiro
{bicyclo[2.2.1]heptan-2,50-isoxazoline-2}-30-yl)-2-phenyl-
2, 3-dihydro-1H-1,5-benzodiazepine (5a). Its formation
was supported by the disappearance of a resonance at
C
V
2010 HeteroCorporation

January 2011
Synthesis and Biological Screening of 4-(3,3-Dimethylspiro{bicyclo[2.2.1]
heptan-2,50-isoxazoline-2}-30-yl)-2-aryl-2,3-dihydro-1H-1,5-benzodiazepines
145
Scheme 1. Preparation of 4-(3,3-dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-2}-30-yl)-2-aryl-2,3-dihydro-1H-1,5-benzodiazepines. Aryl: a
¼ C6H5; b ¼ 4-OCH3C6H4; c ¼ 3-NO2C6H4; d ¼ 4-CH3 C6H4; e ¼ 4-Cl C6H4; f ¼ 2-Cl C6H4; g ¼ 3-Br C6H4; h ¼ 3, 4-(OCH3)2 C6H3; i ¼ 3,
4-OCH2OAC6H3; j ¼ a-C10H9.
1
20 mL), and brine (1 ꢀ 20 mL). The organic layer was dried
over anhydrous Na2SO4 and concentrated in vacuo. The resi-
due was chromatographed (pet. ether-ethyl acetate) to give 2
as colorless oil.
d 8.5 (d, J ¼ 16 Hz), characteristic for 4a in the H
NMR spectrum of 5a, coupled with the appearance of
signals at d 3.0–3.2 (4H, CH2 at C-3 of the benzodiaze-
pine ring and CH2 at C-4 of the isoxazoline ring), a
broad singlet at d 3.9 (for NH) and a doublet at d 5.1
(1H, CH at C-2 of benzodiazepine ring). Following the
similar protocol, a range of compounds (5a-j) was syn-
thesized using various aldehydes (3) (Scheme 1).
General Procedure for the synthesis of chalcones 4a-
j. To an ethanolic solution (10 mL) of 30-aceto-3,3-dimethyl-
spiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-2}
2 (1.0 mmol)
and aromatic aldehyde (1.0 mmol) was added an aqueous solu-
tion (0.5 mL) of NaOH (0.04 g, 1.0 mmol) with stirring at
room temperature, till the completion of reaction (TLC). On
cooling, the reaction mixture solid product was obtained,
which was filtered, washed with cold water and recrystallized
from hot ethanol.
General Procedure for the synthesis of 1,5 benzodiaze-
pines 5a-j. A mixture of 30-cinnamoyl-3,3-dimethylspiro{bicy-
clo{2.2.1]heptan-2,50-isoxazoline-2} 4 (1.0 mmol) and o-phen-
ylene diamine (0.10 g, 1.0 mmol) in a round bottom flask, was
added of SbCl3/Al2O3 (0.12g, 10.0 mol %) and heated on an
oil bath at 100ꢁC for 1 h or till the completion of reaction
(TLC). On completion of reaction, the reaction mixture was
taken in ethyl acetate (20 mL) and filtered off, residue was
given washings with ethyl acetate (2 ꢀ 5 mL). The combined
organic layers were washed with water (2 ꢀ 10 mL), saturated
aqueous NaCl (1 ꢀ 10 mL) and dried over Na2SO4 and con-
centrated in vacuo to give the crude product, which was puri-
fied by column chromatography, using mixtures of ethyl ace-
tate and petroleum ether as eluents.
30-Aceto-3,3-dimethylspiro{bicyclo[2.2.1]heptan-2,50-iso-
xazoline-2} (2). This compound was isolated as colorless oil;
yield 69%; IR (KBr) t (cmꢂ1): 1720, 1400; 1H NMR (200
MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–
1.37 (4H, m, CH, CH2), 1.55–1.60 (4H, m, CH2), 2.40 (3H, s,
CH3), 2.90 (2H, s, CH2); 13C NMR (50 MHz, CDCl3): d 18.5,
21.9, 22.9, 23.2, 26.1, 31.5, 32.5, 39.4, 46.5, 47.4; Anal.
Calcd. for C13H19NO2: C, 70.56; H, 8.65; N, 6.33. Found: C,
70.84; H, 8.77; N, 6.14. MS: m/z ¼ 221(Mþ); Rf ¼ 0.73.
30-Cinnamoyl-3,3-dimethylspiro{bicyclo{2.2.1]heptan-2,50-
isoxazoline-2} (4a). This compound was isolated as amor-
phous off-white solid; mp 142–144ꢁC; yield 74%; IR (KBr) t
(cmꢂ1): 2932, 1655, 1592, 1566, 1508; 1H NMR (200 MHz,
CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–1.37
(4H, m, CH, CH2), 1.55 (4H, m, CH2), 3.10 (2H, s, CH2),
7.37–7.44 (3H, m, CH), 7.56–7.66 (3H, m, CH), 7.77–7.85
(1H, d, J ¼ 16 Hz, CH); 13C NMR (50 MHz, CDCl3): d 18.5,
The synthesized compounds [30-cinnamoyl-3,3-dime-
thylspiro{bicyclo{2.2.1]heptan-2,50-isoxazoline-2}
(4)
and 4-(3,3-dimethylspiro{bicyclo[2.2.1]heptan-2,50-iso-
xazoline-2}-30-yl)-2-aryl-2,3-dihydro-1H-1,5-benzodiaze-
pines (5) were screened for their antibacterial and anti-
fungal activities but did not show any effect upto con-
centrations of 180 lg/mL.
EXPERIMENTAL
General Experimental. Melting points were measured in
open capillaries on Perfit melting points apparatus and are
uncorrected. Infrared spectra on KBr were recorded on
Brucker-4800 infrared spectrometer. NMR and EIMS/HRMS
spectra were recorded on Brucker AC-400(400 MHz and 100
MHz) and JEOL D-300 mass spectrometer, respectively. Ele-
mental analysis was carried out by Heraeus CHNS rapid ana-
1
lyzer. H and 13C chemical shifts are reported in parts per mil-
lion (ppm) from tetramethylsilane as internal standard. All
experiments were performed in oven dried glass apparatus.
SISCO silica was used as adsorbent for thin layer chromatog-
raphy (TLC) (0.5-mm thick plates), and TLC plates were
eluted with 1:9 ratio of ethyl acetate and n-hexane. The
column chromatography was performed over silica gel (60–
120 mesh) with graded solvent systems of ethyl acetate-petro-
leum ether (60–80).
General Procedure for the synthesis of isoxazole 2. A
mixture of camphene (1.36 g, 10.0 mmol) and iron (III) nitrate
nonahydrate (4.04 g, 10.0 mmol) in acetone (50 ml) was
refluxed with stirring for 6 h. The reaction mixture was filtered
through celite under suction. The filtrate was concentrated
in vacuo, the residue was dissolved in ethyl acetate (100 ml),
and washed with aqueous NaHCO3 (1 ꢀ 20 mL), water (3 ꢀ
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

146
T. Naqvi, D. Mahajan, R. L. Sharma, I. A. Khan, and K. K. Kapoor
Vol 48
21.9, 22.9, 26.2, 31.2, 39.5, 46.5, 106.7, 119.3, 126.5, 126.8,
132.4, 136.7, 141.7, 156.6, 181.8; Anal. Calcd for C20H23NO2:
C, 77.64; H, 7.49; N, 4.53. Found: C, 77.50; H, 7.63; N, 4.69.
MS: m/z ¼ 309(Mþ); Rf ¼ 0.68.
NMR (50 MHz, CDCl3): d 21.9, 21.8, 23.5, 24.5, 25.0, 34.2,
36.4, 48.8, 49.1, 102.4, 120.9, 129.5, 130.1, 133.4, 152.7,
161.4, 160.3, 166.1; Anal. Calcd. for C20H22ClNO2: C, 69.86;
H, 6.45; N, 4.07. Found: C, 70.01; H, 6.30; N, 4.25; MS: m/z
¼ 343(Mþ); Rf ¼ 0.62.
30-(p-Methoxycinnamoyl)-3,3-dimethylspiro{bicyclo[2.2.1]
heptan-2,50-isoxazoline-2} (4b). This compound was isolated
as amorphous yellow solid; mp 134–136ꢁC; yield 79%; IR
30-(m-Bromocinnamoyl)-3,3-dimethylspiro{bicyclo{2.2.1]
heptan-2,50-isoxazoline-2} (4g). This compound was isolated
as cream colored solid; mp 138–140ꢁC; yield 76%; IR (KBr) t
(cmꢂ1): 2899, 1645, 1592, 1566, 1510; 1H NMR (200 MHz,
CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–1.37
(4H, m, CH, CH2), 1.55 (4H, m, CH2), 2.03–2.15 (2H, m,CH),
3.10 (2H, s, CH2), 7.23–7.31 (2H, m, CH), 7.48–7.66 (4H, m,
CH), 7.79–7.87 (1H, d, J ¼ 15.9 Hz, CH); 13C NMR (50
MHz, CDCl3): d 22.6, 23.3, 24.7, 26.5, 25.9, 34.1, 35.4, 48.8,
49.1, 102.4, 120.9, 129.6, 131.0, 132.4, 151.7, 160 .5, 171.3,
175.1; Anal. Calcd. for C20H22BrNO2: C, 61.86; H, 5.71; N,
3.61. Found: C, 61.99; H, 5.90; N, 3.79; MS: m/z ¼ 388(Mþ);
Rf ¼ 0.63.
1
(KBr) t (cmꢂ1): 2920, 1675, 1590, 1566, 1518; H NMR (200
MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–
1.37 (4H, m, CH, CH2), 1.55 (4H, m, CH2), 3.1 (2H, s, CH2),
3.9 (3H, s, OCH3), 6.95 (1H, d, J ¼ 8.7 Hz, CH), 7.48–7.66
(4H, m, CH), 7.79–7.87 (1H, d, J ¼ 16 Hz, CH); 13C NMR
(50 MHz, CDCl3): d 21.6, 23.8, 24.7, 25.6, 25.9, 34.1, 35.4,
48.8, 49.1, 102.4, 120.9, 129.6, 130.1, 132.4, 151.7, 160.4,
170.3, 174.1; Anal. Calcd. for C21H25NO3: C, 74.31; H, 7.42;
N, 4.13. Found: C, 74.05; H, 7.65; N, 4.33. MS: m/z ¼
339(Mþ); Rf ¼ 0.63.
30-(m-Nitrocinnamoyl)-3,3-dimethylspiro{bicyclo[2.2.1]
heptan-2,50-isoxazoline-2} (4c). This compound was isolated
as off white solid; mp 150–152ꢁC; yield 80%; IR (KBr) t
(cmꢂ1): 2902, 1665, 1572, 1566, 1500, 1335; 1H NMR (200
MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–
1.37 (4H, m, CH, CH2), 1.55 (4H, m, CH2), 3.1 (2H, s, CH2),
7.56–7.85 (3H, m, ArCH, CH), 7.90–7.94 (2H, m, ArCH), 8.23–
8.27 (1H, d, J ¼ 16 Hz, CH); 13C NMR (50 MHz, CDCl3): d
21.8, 22.6, 24.2, 26.6, 25.8, 34.8, 35.3, 48.0, 49.3, 102.3, 120.3,
129.5, 130.1, 132.4, 141.7, 144.4, 159.2, 184.4; Anal. Calcd. for
C20H22N2O4: C, 67.78; H, 6.26; N, 7.90. Found: C, 67.91; H,
6.48; N, 7.72. MS: m/z ¼ 354(Mþ). Rf ¼ 0.58.
30-(3,4-Dimethoxycinnamoyl)-3,3-dimethylspiro{bicyclo
{2.2.1]heptan-2,50isoxazoline-2} (4h). This compound was
isolated as white solid; mp 119–121ꢁC; yield 60%; IR (KBr) t
1
(cmꢂ1): 2982, 1645, 1599, 1576; H NMR (200 MHz, CDCl3):
d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–1.37 (3H, m, CH,
CH2), 1.55 (4H, m, CH2), 2.03–2.15 (2H, m), 3.10 (2H, s,
CH2), 3.85 (3H, s, OCH3), 3.90 (3H, s, OCH3), 6.44–6.54 (2H,
m, CH), 7.54–7.62 (2H, m, CH), 8.02–8.10 (1H, d, J ¼ 16 Hz,
CH); 13C NMR (50 MHz, CDCl3): d 20.6, 22.8, 23.7, 25.6,
25.9, 34.1, 35.4, 48.8, 49.1, 101.4, 119.9, 128.6, 130.1, 132.4,
151.7, 160.4, 169.3, 172.1; Anal. Calcd. for C22H27NO4: C,
71.52; H, 7.37; N, 3.79. Found: C, 71.70; H, 7.59; N, 3.95;
MS: m/z ¼ 369(Mþ); Rf ¼ 0.62.
30-(p-Methylcinnamoyl)-3,3-dimethylspiro{bicyclo{2.2.1]
heptan-2,50-isoxazoline-2} (4d). This compound was isolated
as creamish yellow solid; mp 118–120ꢁC; yield 80%; IR
(KBr) tcmꢂ1: 2932, 1655, 1592, 1566, 1508; 1H NMR (200
MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–
1.37 (4H, m, CH, CH2), 1.55 (4H, m, CH2), 2.38 (3H, s, CH3),
3.1 (2H, s, CH2), 7.19–7.27 (2H, m, CH), 7.51–7.59 (3H, m,
CH), 7.75–7.83 (1H, d, J ¼ 15.9 Hz, CH); 13C NMR (50
MHz, CDCl3): d 21.9, 22.7, 24.5, 25.5, 25.9, 34.2, 35.4, 48.8,
49.1, 102.4, 120.9, 129.1, 130.1, 132.4, 141.7, 144.4, 159.3,
184.4; Anal. Calcd. for C21H25NO2: C, 77.98; H, 7.79; N,
4.33. Found: C, 77.80; H, 7.93; N, 4.58. MS: m/z ¼ 323(Mþ);
Rf ¼ 0.61.
30-(3-(1,3-Benzodioxolyl-5)propen-2-oyl)-3,3-dimethylspiro
{bicyclo{2.2.1]heptan-2,50isoxazoline-2} (4i). This compound
was isolated as off white solid; mp 146–148ꢁC; yield 68%; IR
1
(KBr) t (cmꢂ1): 2980, 1655, 1562, 1556, 1518; H NMR (200
MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–
1.37 (4H, m, CH, CH2), 1.55 (4H, m, CH2), 3.10 (2H, s, CH2),
6.02 (2H, s, CH), 6.81–6.84 (1H, d, J ¼ 8.1 Hz, CH), 7.09–
7.13 (2H, m, CH), 7.38–7.46 (1H, d, J ¼ 15.9 Hz, CH), 7.68–
7.76 (1H, d, J ¼ 16 Hz, CH); 13C NMR (50 MHz, CDCl3): d
22.9, 24.5, 25.5, 25.9, 34.2, 35.4, 44.1, 48.8, 49.1, 102.1,
107.3, 109.1, 120.1, 126.0, 144.1; Anal. Calcd. for
C21H23NO4: C, 71.37; H, 6.56; N, 3.96. Found: C, 71.55; H,
6.73; N, 3.79; MS: m/z ¼ 353(Mþ); Rf ¼ 0.58.
30-(p-Chlorocinnamoyl)-3,3-dimethylspiro{bicyclo{2.2.1]
heptan-2,50-isoxazoline-2} (4e). This compound was isolated
as yellow solid; mp 159–160ꢁC; yield 69%; IR (KBr) t
(cmꢂ1): 2922, 1645, 1592, 1566, 1548; 1H NMR (200 MHz,
CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s, CH3), 1.29–1.37
(4H, m, CH, CH2), 1.55 (4H, m, CH2), 3.1 (2H, s, CH2), 7.36–
7.40 (2H, m, CH), 7.52–7.60 (3H, m, CH), 7.71–7.79 (1H, d, J
¼ 16 Hz, CH); 13C NMR (50 MHz, CDCl3): d 22.9, 23.8,
24.5, 25.5, 25.8, 34.1, 35.4, 48.8, 49.1, 102.4, 120.9, 129.1,
130.1, 132.3, 151.7, 154.4, 160.3, 174.6; Anal. Calcd. for
C20H22ClNO2: C, 69.86; H, 6.45; N, 4.07. Found: C, 69.99; H,
6.66; N, 4.24. MS: m/z ¼ 343(Mþ); Rf ¼ 0.61.
30-(3-(a-Naphthyl)-prop-2-enoyl)-3,3-dimethylspiro {bicyclo
{2.2.1]heptan-2,50isoxazoline-2} (4j). This compound was iso-
lated as pale yellow oil; yield 72%; IR (KBr) t (cmꢂ1): 2992,
1
1645, 1582, 1566, 1508; H NMR (200 MHz, CDCl3): d 1.01
(3H, s, CH3), 1.10 (3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2),
1.55 (4H, m, CH2), 3.20 (2H, s, CH2), 7.40–7.74 (4H, m, CH),
7.85–7.92 (4H, m, CH), 8.63–8.71 (1H, d, J ¼ 15.8 Hz); 13C
NMR (50 MHz, CDCl3): d 21.1, 22.9, 25.9, 27.7, 34.2, 35.5,
48.8, 49.1, 102.6, 123.8, 124.3, 125.9, 126.7, 127.4, 129.0,
131.6, 132.2, 134.2, 141.0, 159.2, 184.3; Anal. Calcd. for
C24H25NO2: C, 80.19; H, 7.01; N, 3.90. Found: C, 80.37; H,
7.19; N, 4.03; MS: m/z ¼ 359(Mþ); Rf ¼ 0.56.
30-(o-Chlorocinnamoyl)-3,3-dimethylspiro{bicyclo{2.2.1]
heptan-2,50-isoxazoline-2} (4f). This compound was isolated
as viscous oil; yield 65%; IR (KBr) t (cmꢂ1): 2949, 1657,
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-2}
-30-yl)-2-phenyl-2,3-dihydro-1H-1,5-benzodiazepine (5a). This
compound was isolated as pale yellow solid; mp 120–122ꢁC;
yield 80%; IR (KBr) t (cmꢂ1): 3375, 2931, 2878, 1607, 1569,
1
1592, 1566, 1508; H NMR (200 MHz, CDCl3): d 1.01 (3H, s,
CH3), 1.10 (3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55
(4H, m, CH2), 3.1 (2H, s, CH2), 7.36–7.40 (2H, m, CH), 7.52–
7.60 (3H, m, CH), 7.71–7.79 (1H, d, J ¼ 16 Hz, CH); 13C
1
1482; H NMR (200 MHz, CDCl3) d 1.01 (3H, s, CH3), 1.10
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

January 2011
Synthesis and Biological Screening of 4-(3,3-Dimethylspiro{bicyclo[2.2.1]
heptan-2,50-isoxazoline-2}-30-yl)-2-aryl-2,3-dihydro-1H-1,5-benzodiazepines
147
(3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55 (4H, m,
CH2), 2.9–3.0 (2H, m, CH2), 3.20–3.30 (2H, m, CH), 3.95
(1H, brs, NH), 5.11–5.15 (1H, d, J ¼ 8.7 Hz, CH), 6.78–6.82
(1H, d, J ¼ 7.7 Hz, ArCH), 6.93–7.12 (4H, m, ArCH), 7.20–
7.33 (4H, m, ArCH); 13C NMR (50 MHz, CDCl3): d 22.5,
23.4, 23.1, 25.5, 28.8, 35.1, 35.3, 37.5, 48.1, 49.2, 68.9, 105.3,
120.8, 120.9, 126.2, 127.8, 128.7, 131.2, 137.5, 139.2, 142.3,
160.5, 163.6; Anal. Calcd. for C26H29N3O: C, 78.16; H, 7.32;
N, 10.52. Found: C, 78.35; H, 7.57; N, 10.69. MS: m/z ¼
399(Mþ); Rf ¼ 0.57.
CH2), 2.92–3.30 (4H, m, CH2), 3.93 (1H, brs, NH), 5.05–5.14
(1H, m, CH), 6.76–6.77 (1H, d, J ¼ 7.3 Hz, ArCH), 6.8–7.28
(7H, m, ArCH); 13C NMR (50 MHz, CDCl3): d 19.5, 22.8,
23.1, 26.0, 28.8, 35.1, 35.6, 37.5, 47.1, 48.2, 68.9, 105.3,
120.8, 120.9, 126.2, 127.8, 129.7, 137.5, 139.2, 142.3, 160.5;
Anal. Calcd. for C26H28ClN3O: C, 71.96; H, 6.50; N,
9.68. Found: C, 72.11; H, 6.66; N, 9.47; MS: m/z ¼ 433(Mþ);
Rf ¼ 0.56.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-
2}-30-yl)-2-(o-chlorophenyl)-2,3-dihydro-1H-1,5-benzodiazepine
(5f). This compound was isolated as pale yellow thick liquid;
yield 78%; IR (KBr) t (cmꢂ1): 3365, 2933, 2877, 1667, 1599;
1H NMR (200 MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s,
CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55 (4H, m, CH2), 2.92–
3.30 (4H, m, CH2), 3.93 (1H, brs, NH), 5.05–5.14 (1H, m,
CH), 6.76–6.77 (1H, d, J ¼ 7.3 Hz, ArCH), 6.80–7.28 (7H, m,
ArCH); 13C NMR (50 MHz, CDCl3): d 21.5, 22.8, 24.1, 25.5,
28.8, 35.1, 35.6, 37.5, 48.1, 49.2, 68.9, 105.3, 120.8, 126.2,
127.8, 129.7, 130.2, 137.5, 140.2, 143.3, 170.6, 182.7; Anal.
Calcd. for C26H28ClN3O: C, 71.96; H, 6.50; N, 9.68. Found:
C, 71.79; H, 6.68; N, 9.45; MS: m/z ¼ 433(Mþ). Rf ¼ 0.57.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-
2}-30-yl)-2-(m-bromophenyl)-2,3-dihydro-1H-1,5-benzodiaze-
pine (5g). This compound was isolated as thick viscous liquid;
yield 81%; IR (KBr) tcmꢂ1: 3380, 2951, 1607, 1559; 1H
NMR (200 MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s,
CH3), 1.29–1.37 (4H, m), 1.55 (4H, m), 3.02–3.25 (4H, m,
CH2), 3.95–4.0 (1H, brs, NH), 5.13–5.18 (1H, m, CH), 6.84–
6.85 (1H, d, J ¼ 1.4 Hz, ArCH), 6.99–7.27 (5H, m, ArCH),
7.30–7.50 (2H, m, ArCH); 13C NMR (50 MHz, CDCl3): d
22.5, 24.5, 34.8, 35.0, 43.6, 44.0, 48.5, 48.5, 49.1, 68.9, 98.3,
120.7, 120.8, 123.1, 125.1, 128.0, 129.0, 130.0, 131.2, 138.9,
147.3, 159.8; Anal. Calcd. for C26H28BrN3O: C, 65.27; H,
5.90; N, 8.78. Found: C, 65.09; H, 6.11; N, 8.94; MS: m/z ¼
478(Mþ). Rf ¼ 0.56.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-
2}-30-yl)-2-(p-methoxyphenyl)-2,3-dihydro-1H-1, 5-benzo-
diazepine (5b). This compound was isolated as pale yellow
solid; mp 118–120ꢁC; yield 82%; IR (KBr) t (cmꢂ1): 3335,
1
2930, 2878, 1607; H NMR (200 MHz, CDCl3): d 1.01 (3H, s,
CH3), 1.10 (3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55
(4H, m, CH2), 2.92–3.30 (4H, m, CH2), 3.90 (3H, s, OCH3),
3.93 (1H, brs, NH), 5.05–5.14 (1H, m, CH), 6.76–6.77 (1H, d,
J ¼ 1.3 Hz, ArCH), 6.80–7.28 (7H, m, ArCH); 13C NMR (50
MHz, CDCl3): d 21.5, 23.8, 23.1, 25.5, 28.8, 35.1, 35.3, 37.5,
48.1, 49.2, 68.9, 105.3, 120.8, 120.9, 126.2, 127.8, 129.7,
130.2, 137.5, 139.2, 142.3, 160.5, 161.6; Anal. Calcd. for
C27H31N3O2: C, 75.49; H, 7.27; N, 9.78. Found: C, 75.64; H,
7.44; N, 9.96; MS: m/z ¼ 429(Mþ); Rf ¼ 0.57.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazo-
line-2}-30-yl)-2-(m-nitrophenyl)-2,3-dihydro-1H-1,5-benzodiaze-
pine (5c). This compound was isolated as orange color solid;
mp 168–170ꢁC; yield 78%; IR (KBr) t (cmꢂ1): 3385, 2921,
1
2878, 1607, 1570, 1345; H NMR (500 MHz, CDCl3): d 1.01
(3H, s, CH3), 1.10 (3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2),
1.55 (4H, m, CH2), 3.05–3.10 (4H, m, CH2), 4.0 (1H, brs,
NH), 5.30–5.39 (1H, m, CH), 6.85–6.86 (1H, d, J ¼ 7.9 Hz,
ArCH), 7.02 (1H, d, J ¼ 1.5 Hz, ArCH), 7.03 (1H, d, J ¼ 8.3
Hz, ArCH), 7.26–7.27 (1H, m, ArCH), 7.5 (1H, m, ArCH),
7.69 (1H, m, ArCH), 8.1 (1H, m, ArCH), 8.3 (1H, s, ArCH);
13C NMR (125 MHz, CDCl3): d 22.1, 22.2, 22.6, 24.1, 25.0,
25.4, 43.3, 43.5, 48.1, 48.4, 48.6, 48.7, 48.8, 68.9, 100.9,
120.5, 120.6, 121.0, 121.6, 122.7, 127.8, 129.4, 129.6, 129.7,
132.4, 138.2, 146.6, 148.4, 159.7; Anal. Calcd. for
C26H28N4O3: C, 70.25; H, 6.35; N, 12.60. Found: C, 70.44; H,
6.51; N, 12.82. MS: m/z ¼ 444(Mþ); Rf ¼ 0.55.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-
2}-30-yl)-2-(m,p-dimethoxyphenyl)-2,3-dihydro-1H-1,5-benzodia-
zepine (5h). This compound was isolated as thick viscous liq-
uid; yield 81%; IR (KBr) t (cmꢂ1):3375, 2931, 2878, 1607,
1
1569; H NMR (200 MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10
(3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55 (4H, m,
CH2), 3.10–3.35 (4H, m, CH2), 3.88 (3H, s, OCH3), 3.90 (3H,
s, OCH3), 4.0–4.10 (1H, brs, NH), 5.01–5.25 (1H, m, CH)
6.44–6.54 (2H, m, ArCH), 7.54–7.62 (4H, m, ArCH); 13C
NMR (50 MHz, CDCl3): d 20.5, 24.5, 34.8, 35.0, 35.4, 43.6,
44.0, 48.5, 48.5, 49.1, 68.9, 98.3, 120.7,123.1, 125.1, 128.0,
129.0, 130.0, 130.7, 138.9, 147.32, 159.8; Anal. Calcd for
C28H33N3O3: C, 73.18; H, 7.24; N, 9.14. Found: C, 73.37; H,
7.45; N, 9.33; MS: m/z ¼ 459(Mþ). Rf ¼ 0.54.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-
2}-30-yl)-2-(p-methylphenyl)-2,3-dihydro-1H-1,5-benzodiaze-
pine (5d). This compound was isolated as pale yellow solid;
mp 138–140ꢁC; yield 77%; IR (KBr) t (cmꢂ1):3395, 2941,
1
2878, 1617, 1579; H NMR (200 MHz, CDCl3): d 1.01 (3H, s,
CH3), 1.10 (3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55
(4H, m, CH2), 2.20 (3H, s, CH3), 2.92–3.30 (4H, m, CH2),
3.93 (1H, brs, NH), 5.05–5.14 (1H, m, CH), 6.76–6.77 (1H, d,
J ¼ 7.3 Hz, ArCH), 6.80–7.28 (7H, m, ArCH); 13C NMR (50
MHz, CDCl3): d 21.5, 23.8 23.1, 25.5, 28.8, 35.1, 35.3, 37.5,
48.1, 49.2, 68.9, 105.3, 120.8, 120.9, 126.2, 127.8, 129.7,
130.2, 137.5, 139.2, 142.3, 160.5, 161.6; Anal. Calcd. for
C27H31N3O: C, 78.42; H, 7.56; N, 10.16. Found: C, 78.59; H,
7.71; N, 10.28; MS: m/z ¼ 413(Mþ); Rf ¼ 0.58.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-
2}-30-yl)-2-(1,3-benzodioxolyl-5)-2,3-dihydro-1H-1,5-benzodiaze-
pine (5i). This compound was isolated as thick liquid; yield
80%; IR (KBr) t (cmꢂ1): 3335, 2942, 2888, 1607, 1569; 1H
NMR (200 MHz, CDCl3): d 1.01 (3H, s, CH3), 1.10 (3H, s,
CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55 (4H, m, CH2), 2.85–
3.01 (1H, m, CH), 3.23–3.28 (3H, m, CH2), 4.10 (1H, brs,
NH), 5.03–5.07 (1H, m, CH), 5.89 (2H, s, CH2), 6.68–6.86
(4H, m, ArCH), 6.92–7.24 (3H, m, ArCH); 13C NMR (50
MHz, CDCl3): d 22.8, 23.1, 24.6, 25.6, 26.9, 35.4, 37.4, 48.6,
49.2, 69.2 101.5, 106.8, 119.6, 120.8, 121.1, 127.9, 130.0,
139.4, 148.2, 161.7; Anal. Calcd. for C27H29N3O3: C, 73.11;
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-
2}-30-yl)-2-(p-chlorophenyl)-2,3-dihydro-1H-1,5-benzodiazepine
(5e). This compound was isolated as pale yellow solid; mp
141–143ꢁC; yield 79%; IR (KBr) t (cmꢂ1): 3354, 2931, 2878,
1
1610, 1599; H NMR (200 MHz, CDCl3): d 1.01 (3H, s, CH3),
1.10 (3H, s, CH3), 1.29–1.37 (4H, m, CH, CH2), 1.55 (4H, m,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

148
T. Naqvi, D. Mahajan, R. L. Sharma, I. A. Khan, and K. K. Kapoor
Vol 48
REFERENCES AND NOTES
H, 6.59; N, 9.47. Found: C, 73.27; H, 6.81; N, 9.65; MS: m/z
¼ 443 (Mþ). Rf ¼ 0.53.
[1] Meunier, B. Acc. Chem Res 2008, 41, 69.
4-(3,3-Dimethylspiro{bicyclo[2.2.1]heptan-2,50-isoxazoline-2}
-30-yl)-2-(a-naphthyl)-2,3-dihydro-1H-1,5-benzodiazepine (5j). This
compound was isolated as thick viscous liquid; yield 74%; IR
[2] (a) Kang, Y. K.; Shin, K. J.; Yoo, K. H.; Seo, K. J.; Hong,
C. Y.; Lee, C. S.; Park, S. Y.; Kim, D. J.; Park, S. W. Bioorg Med
Chem Lett 2000, 10, 95; (b) Tsubotani, S.; Funabashi, Y.; Takamoto,
M.; Hakoda, S.; Harada, S. Tetrahedron 1991, 47, 8079.
1
(KBr) t (cmꢂ1): 3375, 2931, 2878, 1627, 1549; H NMR (200
MHz, CDCl3): d 1.01 (3H, s, CH3), 1.1 (3H, s, CH3), 1.29–
1.37 (4H, m, CH, CH2), 1.55 (4H, m, CH2), 3.20–3.43 (4H, m,
CH2), 4.1 (1H, brs, NH), 5.03–5.07 (1H, m, CH), 7.40–7.74
(6H, m, ArCH), 7.85–7.92 (6H, m, ArCH); 13C NMR (50
MHz, CDCl3): d 21.1, 22.9, 25.9, 27.7, 34.2, 35.5, 48.8, 49.1,
102.6, 123.8, 124.3, 125.9, 126.7, 127.4, 129.0, 131.6, 132.2,
134.2, 141.0, 159.2, 184.3; Anal. Calcd. for C30H31N3O: C,
80.14; H, 6.95; N, 9.35. Found: C, 80.33; H, 7.09; N, 9.52.
MS: m/z ¼ 449(Mþ). Rf ¼ 0.56.
[3] (a) Kochetov, K. N.; Sokolov, D. S. Adv Heterocycl Chem
1963, 2, 365; (b) In USAN and USP Dictionary of Drug Names; Griffiths,
M. C., Ed; US Pharmacopoeia convention: Rockville, MD, 1982; (c)
Pathak, D.; Jindal, D. P. Asian J Chem 1998, 10, 813; (c) Giranda, V. L.;
Russo, G. R.; Felock, P. J.; Bailey, T. R.; Draper, T.; Aldous, D. J.; Guiles,
J.; Dutko, F. J.; Diana, G. O.; Pevear, D. C. Acta Cryst D 1995, 51, 496.
[4] Millan, D. S.; Prager, R. H.; Brand, C.; Hart P. H. Tetrahe-
dron.2000, 56, 811.
[5] (a) Schutz, H. In Benzodiazepines; Springer: Heidelberg,
1982; (b) Landquist, J. K. In Comprehensive Heterocyclic Chemistry;
Katritzky, A. R.; Rees C. W., Eds. Pergamon: Oxford, 1984; Vol. 1,
pp 166; (c) Fryer, R. I. In Comprehensive Heterocyclic Chemistry;
Taylor, E. C. Ed.; Wiley: New York, 1991; Vol. 50, Chapter II; (d)
Randall, L. O.; Kappel, B. In Benzodiazepines; Garattini, S.; Musini,
E.; Randall, L. O., Eds.; Raven Press: New York, 1973; pp 27.
[6] McLean, M. J.; Macdonald, R. L. J Pharmacol Exp Ther
1988, 244, 789.
General
Procedure
for
Antimicrobial
Activity
Screening. Antibacterial and antifungal activities of benzodia-
zepine analogues were performed using microdilution method
[12–14] against two gram positive strains (Staphylococcus aur-
eus ATCC 29313, methicillin resistant S. aureus), two gram
negative strains (Escherichia coli ATCC 25922, Pseudomonas
aeruginosa ATCC 27853 ), two yeast strains (C. albicans
ATCC 22019, C. albicans V-01-27853), and two filamentous
fungi (Aspergillus fumigatus LSI-II, Aspergillus niger ATCC
16404 ). Antibacterial testing was performed in Muller Hinton
Broth ( Becton-Dickenson, Cockeysville, MD) where as for
antifungal testing RPMI 1640 with L-glutamine (Sigma-
Aldrich, St. Louis, MO) buffered to pH 7.0 supplemented with
[7] Ramajayam, R.; Giridhar, R.; Yadav, M. R.; Balaraman, R.;
Djaballah, H.; Shum, D.; Radu, C. Eur J Med Chem 2008, 43, 2004;
doi: 10.1016/j.ejmech.2007.11.023.
[8] (a) Kim, Y. M.; Farrah, S.; Baney, R. H. Int J Antimicrobial
Agents 2007, 29, 217; (b) Lien, E. J.; Hansch, C.; Anderson, S. M. J Med
Chem 1968, 11, 430; (c) Hunt, W. A. Adv Exp Med Biol 1975, 56, 195.
[9] Itoh, K.; Sakamaki, H.; Nakazato, N.; Horiuchi, A.; Horn,
E.; Horiuchi, A. C. Synthesis 2005, 20, 3541.
0.165
M 3-(N-morpholino) propanesulfonic acid (sigma-
aldrich) was used. The stock solution of the compounds was
prepared in dimethyl sulfoxide. The minimum inhibitory con-
centration (MIC) of the compounds was determined by serial
2-fold diluting the solution in the 100 lL volume of aforemen-
tioned media in a 96-well U bottom microtitre plate. The final
concentrations of compounds ranged from 128 to 0.25 lg/mL.
Amphotetricin B and ciprofloxacin (16–0.03 lg/mL) (both
from Sigma-Aldrich) were used as standard antifungal and
antibacterial agents, respectively. The bacterial and fungal sus-
pension of the overnight grown bacterial and fungal was pre-
pared in sterile normal saline, and the density was adjusted to
0.5 Mcfarland. The bacterial cultures were further diluted and
added in 100 lL volume at final inoculums of 1 ꢀ 105 CFU/
mL. For fungal cultures, 1 ꢀ 103 CFU/mL was used. The
plates were incubated at 37ꢁC for 24 h for bacterial cultures
and 48 h for fungal cultures. The plates were read visually,
and the minimum concentration of the compound showing no
turbidity was recorded as MIC.
[10] Harwood, L. M.; Moody, C. J. In Experimental Organic
Chemistry: Primciples and Practice; Blackwell Scientific Publications:
Oxford, London, 1989.
[11] Ganai, B. A.; Kumar, S.; Andotra, C. S.; Kapoor, K. K.
Synth Commun 2006, 36, 803.
[12] National committee for Clinical Laboratory Standards. Ref-
erence Method for Broth Dilution Antifungal Susceptibility Testing of
Yeasts: Approved Standard. NCCLS Document M27-A2. National
Committee for Clinical laboratory Standards: Wayne, PA, 2002.
[13] National committee for Clinical Laboratory Standards. Refer-
ence Method for Broth Dilution Antifungal Susceptibility Testing of Fila-
mentous Fungi: Approved Standard. NCCLS Document M38-A. National
Committee for Clinical laboratory Standards: Wayne, PA; 2002.
[14] National committee for Clinical Laboratory Standards.
Methods for Dilution Antimicrobial Susceptibility Tests for Bacterial
that Grow Aerobically: Approved Standard. NCCLS Document M7-
A5. National Committee for Clinical laboratory Standards: Wayne,
PA; 2000.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet