Synthesis of tetrazoloquinoline-based mono- and bisphosphonate esters as potent anti-inflammatory agents

Article abstract of DOI:10.1002/jhet.968

Several new α-alkoxy- and α-hydroxyphosphonate derivatives of tetrazole-quinolines were synthesized from the reaction of 2-azidoquinolines 3-carboxaldehyde 1a,b with trialkyl phosphites and dialkyl phosphites. On the other hand, azaphospholes 12a,b were obtained by treating 1a,b with tris(dimethylamino)phosphine. Furthermore, Perkin-type condensation of 1a,b and tetraethyl methylenebisphosphonate provided the corresponding tetrazoloquinoline-based bisphosphonate esters 14a,b. Based on the prediction results (PASS program), the anti-inflammatory activity of the prepared compounds was determined in vivo by the acute carrageenin-induced paw edema in rats. Many of the new compounds exhibit considerable anti-inflammatory properties at a dose of 50 mg/kg body weight. Especially 14a and 14b revealed remarkable activities compared with indomethacin, which was used as a reference standard in this study.

Full text of DOI:10.1002/jhet.968

January 2013
Synthesis of Tetrazoloquinoline-Based Mono- and Bisphosphonate
33
Esters as Potent Anti-Inflammatory Agents
*
Wafaa M. Abdou, Rizk E. Khidre, and Abeer A. Shaddy
Chemical Industries Division, National Research Centre, Dokki, Cairo D-12622, Egypt
*
E-mail: wabdou@link.net
Received February 18, 2011
DOI 10.1002/jhet.968
View this article online at wileyonlinelibrary.com.
Several new α-alkoxy- and α-hydroxyphosphonate derivatives of tetrazole-quinolines were synthesized
from the reaction of 2-azidoquinolines 3-carboxaldehyde 1a,b with trialkyl phosphites and dialkyl phos-
phites. On the other hand, azaphospholes 12a,b were obtained by treating 1a,b with tris(dimethylamino)
phosphine. Furthermore, Perkin-type condensation of 1a,b and tetraethyl methylenebisphosphonate
provided the corresponding tetrazoloquinoline-based bisphosphonate esters 14a,b. Based on the prediction
results (PASS program), the anti-inflammatory activity of the prepared compounds was determined in vivo
by the acute carrageenin-induced paw edema in rats. Many of the new compounds exhibit considerable
anti-inflammatory properties at a dose of 50 mg/kg body weight. Especially 14a and 14b revealed remark-
able activities compared with indomethacin, which was used as a reference standard in this study.
J. Heterocyclic Chem., 50, 33 (2013).
INTRODUCTION
our research work. The approach is achieved by reacting
2-azido-3-carbaldehyde-quinolines 1a and 1b with trialkyl
phosphites 3a–3c, dialkyl phosphites 7a–7c, tris(dimethy-
lamino)phosphine 8, and Horner–Emmons reagent 13.
The study focused on the preferable attack of the phospho-
rus reagents at the carbonyl or the azide group in the
bifunctional substrates 1a and 1b. Furthermore, the
prospective potency of our products for treating the inflam-
matory disease was based on the results of the prediction
that had been carried out, in the earlier stage. The
computer-assisted molecular modeling (CAMM), predic-
tion of activity spectra for substances (PASS) program,
was adopted for designing—in silico—the structures of
potentially active molecules for future synthesis. Later
on, the in vivo activity of the synthesized phosphonates
and bisphosphonates in the rat adjuvant model was also
studied in terms of structure–activity relationships.
The presence of quinolines in an abundant number of
natural products and pharmaceutically active compounds
continues to fuel the desire to develop new and/or
improved methods for their synthesis [1–4]. Many repre-
sentatives have found clinical uses for the treatment of
tumor diseases [5,6]. There have also been reviews on
quinoline derivatives and their antibiotic properties in
multidrug resistant Enterbacter aerogenes isolates [7].
Relatively few reports about synthesis and bioactivity of
quinolines incorporating a mono- or a bisphosphonate
moiety are reported in the literature [8–10].
As part of our program on the application of phosphorus
compounds in pharmaceutical synthesis, we have been
involved over the last two decades or so in the invention and
dpaerveedlovpiamaepnptliocfatipohnoosfphpohnoosphsuobrusstitrueategdenNts-thoeCteꢀrocNycmleusltpiprele-
bonds [11–17]. Biological activity studies of selected products
have been investigated, and the results showed that some of
new phosphonates and specially the diphosphonates have rec-
ognized responses to the chronic inflammatory associated with
cutaneous granuloma formation and erosive arthritis [11,12].
In this account, we describe our study on the synthesis of
phosphono substituted quinolines containing a highly
bioactive tetrazole moiety [18–20] as a development of
RESULTS AND DISCUSSION
The reaction procedure for the preparation of the
titled compounds, tetrazoloquinoline-based mono- and
diphosphonate esters, and the course of the reactions
were depicted in Schemes 1–6. The required starting
materials 2-(λ5-triaz-1-en-2yl)quinoline-3-carbaldehyde
(known as 2-azidoquinoline-3-carbaldehyde 1a) and the new
© 2013 HeteroCorporation

34
W. M. Abdou, R. E. Khidre, and A. A. Shaddy
Vol 50
Scheme 1
Scheme 3
R1
CHO
Cl
R1
CHO
N N
HOH
1a,b
+
P(O Pr-i)3
4 (R= Pr-i)
NaN3
3c
N
DMSO
N
N
OH
1a,b
Aa,b
O
7
1a, R1 = H
1b, R1 = Me
R1
9
P(OR)2
5 c,f
+
1
N
5
N
6-methyl-2-(λ5-triaz-1-en-2-yl)-quinoline-3-carbaldehyde
(known as 2-azido-6-methylquinoline-3-carbaldehyde, 1b)
were prepared according to the literature with little modifica-
tion in ∼80% yield by treating the parent chloride Aa or Ab
with sodium azide in dimethylsulfoxide (DMSO; Scheme 1)
[21,22].
Treatment the azide 1a with trimethyl 3a or triethyl
phosphite 3b in toluene solution, and heating the reaction
mixture under reflux for ∼4 h led to the formation of
dialkyl alkoxy (tetrazolo[1,5-a]-quinolin-6-yl)methylpho-
sphonates 5a,b in ≥80% yield. A plausible mechanism
for the formation of tetrazolophosphonates 5a,b is displayed
in Scheme 2. On heating, the equilibrium between tetrazole
2 and its isomeric 2-azidoquinoline 1 presents exclusively at
the tetrazole 2. The last observation is consistent with the
earlier characterization data reported for the azide 1
[21,22]. Compound 2 is then intercepted by the nucleophilic
attack of the phosphite-phosphorus on the carbonyl-carbon
in 2 to give the dipolar species 4, which is followed by intra-
molecular group translocation to yield 5a or 5b.
N
N
6a b
,
6a, R1= H, R = Pr-i
6b, R1= Me, R = Pr-i
around δ 27 ppm. Their IR spectra revealed the absence
of stretching vibration bands at 1710 and 2100 cm−1
regions, related to the carbonyl and the azido group
of the azides 1a,b. Instead, they showed strong bands
at 1185 cm−1
at 1036, 1256 cm−1 that assigned to P
ꢀ
O
assigned to the tetrazole ꢀstrCetcahnindgP and
¼
O
vibrations. In the 1H-NMR spectrum of compound 5a,
the exocyclic methine proton (aldehydic) present in the
spectrum of 1a at δ 10.35 ppm, was displayed at δ 5.75
2
(d, JP–H = 18.8 Hz) ppm; the deshielding of the methane
proton signal is clearly due to the phosphorus entity.
13C-NMR data also confirmed the assigned structure.
In a similar way, the reaction products of 1b with
trimethyl and triethyl phosphites were assigned the
analogous structures 5d (84%) and 5e (87%). Nevertheless,
treatment of 1a,b with triisopropyl phosphite 3c afforded a
mixture of the expected analogues 5c,f (∼47%) together
with α-hydroxyphosphonates 6a,b (∼10%, Scheme 3).
This behavior is not unexpected as the bulky isopropyl
group would impede the alkyl migration in the second step,
allowing a partial hydrolysis with fortuitous moisture at the
stage of the dipolar intermediate 4 to give the side-products
6a,b, along with 5c,f. It is known that lengthening the alkyl
radicals in trialkyl phosphites results in reduction of their
migration aptitude [23].
The composition of the structure 5 was based on the
recorded elemental analyses, molecular weight determina-
tions mass spectroscopy (MS), and spectroscopic data.
Compounds 5a,b showed the 31P-NMR chemical shifts
Scheme 2
R1
R1
CHO
N
CHO
Toluene
N
N N
N
N
Furthermore, compounds 6a,b were unequivocally
obtained in (∼90% yield) when 1a,b were allowed to react
1a, R1= H
1b, R1= Me
N
2a,b
N
P(OR)3
3a-c
a,
b,
R= Me; R= Et
Scheme 4
c
, R= i-Pr
O
O
R1
O
OR
H
Toluene
TEA /
O
(RO)2P
H
R1
6a-f
R1
9
+
P(OR)3
7
1
P(OR)2
N
N3
7a-c
N
N
N
5
12
N
N
a, R = Pr-i,
b, R = Et,
c, R = Me
1a,b
N
N
N
5
4
1
Cpd. R1
6a
R
Cpd. R1
R
R1
H
Cpd R1
R
1
3
R , R as in and
Cpd.
R
5a
H
i-Pr 6d Me Et
Me
Me 5d Me Me
H
5b
5c
Et
5e
6b Me i-Pr 6e
6c Et 6f
H
Et
Me
i-Pr
H
i-Pr
Me
5f
H
Me Me
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Synthesis of Tetrazoloquinoline-Based Mono- and Bisphosphonate
January 2013
35
Esters as Potent Anti-Inflammatory Agents
Scheme 5
the aldehydic-carbonyl group and extrusion of a molecule
of H2O (Perkin-type condensation). Perkin reaction has been
previously described for a similar reaction of the bisphospho-
nate 13 with aldehydes [24]. Ethylidenebis-phosphonates
and the relevant phosphonic acids belong to an important
class of compounds used for the treatment of bone diseases,
such as osteoporosis, hypocalcemia, inflammation, and
rheumatoid arthritis [25,26].
PHARMACOLOGY
The prospective potency of our products for treating the
inflammatory disease was based on the results of the predic-
tion that had been carried out, in the earlier stage. The
CAMM and PASS program was adopted for designing—in
silico—the structures of potentially active molecules for
future synthesis.
Anti-inflammatory screening. An initial evaluation of
anti-inflammatory activity of the synthesized compounds
5a–f, 6a–f, 12a,b, and 14a,b as well as the substrates 1a
and 1b, was determined in vivo by the acute carrageenin-
induced paw edema standard method in rats [27,28].
Carrageenin, which is a sulfated polysaccharide, extracted
from sea weed has been extensively used to induce
inflammation in a number of animal species. Furthermore,
the carrageenin-induced rat hind paw edema is now
routinely used for the assay of anti-inflammatory agents.
The reproducibility and the fact that the edema depends
entirely on a local inflammatory reaction devoid of antigenic
properties has made carrageenin a most widely used
phlogistic agent in experimental pharmacology, and a
good correlation has been shown to exist between the
antiphologistic and anti-inflammatory effects of several drugs.
In all experiments, carrageenin was administered into the
left hind paw. Anti-inflammatory activity of the synthesized
compounds 5a–f, 6a–f, 12a,b, and 14a,b as well as 1a and
1b (at a dose 50 mg/kg body weight) was measured at
successive time intervals (1, 2, and 4 h after carrageenin
injection) and compared with that of indomethacin at the same
dose, which was used as a reference standard (Table 1).
However, when the rats were reused, carrageenin injection
was given into the right hind paw (Figs. 1 and 2).
with di-isopropyl phosphite (7a) in refluxed toluene in the
presence of triethylamine (TEA). Similar treatment of 1a,b
with dialkyl phosphite 7b,c afforded α-hydroxyphospho-
nates 6c–f (Scheme 4).
Conversely, o-azidoquinolinecarbaldehydes 1a,b react
with tris(dimethylamino)phosphine 8 in dry tetrahydofuran
(THF) at r.t. (24 h) to give triazenylidene-phosphoranes
9a,b as a water-sensitive fine powder, quite stable for few
days in a desiccator (Scheme 5-i). When a protonating agent
(e.g., 2 mL of H2O) is present in the reaction medium, the
reaction is markedly accelerated leading to the formation
of azaphospholes 12a,b (∼80%). Obviously, compounds
12a,b were formed through the initial formation of the
phosphineimines 10a,b, followed by quenching a molecule
of H2O to give the intermediates 11 with concomitant loss
of dimethylamine (HNMe2). Stabilization of 11 via extru-
sion of another mole of dimethylamine resulted in the
formation of the azaphospholes 12a and 12b (Scheme 5-ii).
Furthermore, the behavior of compounds 1a,b toward
the active Horner–Emmons reactant, tetraethyl methylene-
bisphosphonate (13) was next investigated. A mixture of
1.3 equivalent of 13 and o-azidocarbaldehydes 1a,b
in alcoholic sodium ethoxide solution was stirred at
room temperature for 6 h. After the usual workup,
the respective ethane-1,1-ylide-diphosphonates 14a,b
(∼73% yield) were isolated. The gem-diphosphonate
structure 14 was delineated by IR, NMR and MS spectra.
The recorded data in Table 1 show that 12 of 16 newly
synthesized compounds have moderate to good anti-
Scheme 6
tions of C
¼
C, P
14a exhibited abꢀsorption bands due to the stretching vibra-
O
ꢀ
C, P O and tetrazole ring at 1618,
¼
1030, 1254 and 1180 cm−1, respectively, in its IR spectra.
The 31P-NMR spectrum of 14a showed a sharp singlet at δp
(DMSO): 18.4 ppm. The 1H and 13C data are also in accord
with the assigned structure (see the “EXPERIMENTAL”
section). The formation of 14a,b can be rationalized as
occurring in Scheme 6 through the condensation of 13 with
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

36
W. M. Abdou, R. E. Khidre, and A. A. Shaddy
Vol 50
Table 1
Anti‐inflammatory activity of new products 5a‐f, 6a‐f, 12a,b, 14a,b, and 1a,b in acute carrageenin induced paw edema in rats.
Mean swellinga volume (mL; percentage inhibition of edema)
Compound
1 h
2 h
4 h
Potencyd (%)
Control
Ab
5a
5b
5c
5d
5e
5f
6a
6b
6c
6d
6e
0.568 0.192c (00.0)
0.272 0.011c (52.1)
0.278 0.028c (51.0)
0.286 0.033c (49.6)
0.558 0.055c (8.8)
0.322 0.024c (43.3)
0.364 0.039c (35.9)
0.588 0.055c (8.8)
0.422 0.028c (25.7)
0.495 0.045c (12.9)
0.392 0.062c (31.0)
0.408 0.027c (28.2)
0.338 0.055c (40.4)
0.347 0.034c (38.9)
0.247 0.032c (56.5)
0.256 0.026c (54.9)
0.211 0.025c (62.8)
0.228 0.023c (59.8)
0.510 0.034c (12.3)
0.558 0.055c (8.8)
0.649 0.067c (00.0)
0.354 0.015c (45.4)
0.368 0.031c (43.3
0.372 0.067c (42.6)
0.552 0.092c (15.1)
0.388 0.059c (40.2)
0.378 0.102c (41.7)
0.551 0.092c (15.1)
0.498 0.062c (23.2)
0.562 0.077c (13.4)
0.392 0.055c (39.5)
0.447 0.076c (31.1)
0.442 0.062c (31.8)
0.444 0.062c (31.5)
0.326 0.039c (49.7)
0.317 0.037c (51.1)
0.297 0.032c (54.2)
0.308 0.024c (52.5)
0.552 0.092c (15.1)
0.562 0.077c (13.4)
0.869 0.058c (00.0)
0.442 0.034c (49.1)
0.460 0.038c (47.0)
0.472 0.057c (45.6)
0.750 0.050c (13.7)
0.532 0.094c (38.7)
0.502 0.112c (42.2)
0.784 0.066c (9.8)
0.725 0.052c (16.5)
0.742 0.066c (14.6)
0.557 0.048c (35.9)
0.566 0.066c (34.8)
0.538 0.048c (38.0)
0.586 0.079c(32.5)
0.436 0.048c (49.8)
0.425 0.045c (51.0)
0.403 0.030c (53.6)
0.401 0.033c (53.8)
0.818 0.079c (9.8)
0.830 0.050c (5.0)
–
100
95.7
92.8
27.8
78.8
85.9
19.9
33.6
29.6
73.1
70.8
77.4
66.2
101.4
103.9
109.2
109.6
11.8
10.2
6f
12a
12b
14a
14b
1a
1b
SEM, standard error of the mean.
aData are means of two independent determinations at least, and the deviation in absorbance values was less than 10%.
bA, Indomethacin (used as a reference standard), each value represents the mean of two independent experiments with six animals in each group.
cStatistical significance of results was established using the Student’s test from the standard at P < 0.05.
dPotency was expressed as percentage edema inhibition of the tested compounds relative to percentage edema inhibition of A at 4‐h effect.
inflammatory properties when compared with the available
indomethacin-drug, without toxic side effect. The
bisphosphonates 14a, 14b and the azaphospholes 12a,
12b possess maximum inhibitory effect at all detected
time intervals when compared with the standard group.
Nevertheless, the substrates 1a, 1b, and the mono-
phosphonates (P(O)(OiPr)2): 5c, 5f, and 6a,b showed
poor effect as anti-inflammatory agents. Other com-
pounds, that is 6c–f, 5a, 5b, 5d, and 5e have displayed
moderate to good effects on inhibitory properties,
especially at 1 h.
showed the highest anti-inflammatory activity, which is in
accord to other similar studies in the literature [25,26].
Additionally, it has been also noticed that substitution
of quinoline-3-carboxyaldehyde with a methyl group at
the 6-position reduced the observed anti-inflammatory
activity (i.e., 5d < 5a). On the other hand, it has been
observed that the phosphor esters with a methoxy group
(i.e., 5a and 6e) improved the observed anti-inflammatory
activities compared with the case of using an ethoxy group as
observed in compounds 5b and 6c. Similar result is hold for
iso-propoxy group, which explains the role of the alkoxy-
phosphor ester length in reflecting the pharmacological
properties: i-PrO < EtO < MeO.
Structure–activity correlation based on the obtained results
indicates that the bisphosphonate compounds 14a and 14b
Figure 2. Anti-inflammatory activity potency (after 4 h) of the tested com-
pounds relative to indomethacin which was used as a reference standard.
[Color figure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
Figure 1. Mean edema volume (mL) of the compounds at successive
time intervals. [Color figure can be viewed in the online issue, which is
available at wileyonlinelibrary.com.]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Synthesis of Tetrazoloquinoline-Based Mono- and Bisphosphonate
January 2013
37
Esters as Potent Anti-Inflammatory Agents
Toxicity of the promised products. Toxicological studies of
the most promisingly synthesized anti-inflammatory
active compounds 12a and 14a were performed using
medium lethal dose, 50%, (LD50) standard method in
mice in 500, 750, and 1000 mg/kg (body weight), i.e.,
10- to 20-fold of the used anti-inflammatory effective
dose. However, no toxic symptoms or mortality rates
were observed after 24 h postadministrations explaining
the safe behavior of the used doses.
148.6 (2-CN3), 129.5 (4-C), 136.8, 132.5, 129.8, 128.2, 125.7,
(7-C, 5-C, 6-C, 8-C, 10-C,), 112.3 (3-C), 20.9 (6-C-CH3); EI-MS:
m/z (%): 212 [M+](15), 184 [M+−N2] (57), 170 [M+−N3] (100).
Anal. Calcd for C11H8N4O (212.2): C, 62.26; H, 3.80; N, 26.40.
Found: C, 62.34; H, 3.85; N, 26.46.
Reactions of 2-azidoquinolines-3-carbaldehyde 1a,b with
trimethyl- (3a) and triethyl phosphites (3b). Preparation of
compounds 5a,b,d,e. To a solution of (4 mmol) of the azide
(1a, 0.79 g or 1b, 0.85 g) in 25 mL of dry toluene at 0°C (5.2
mmol) of freshly distilled 3a or 3b was added dropwise with
stirring. After the addition was complete, the reaction mixture
was refluxed for ≈4–6 h (thin layer chromatography (TLC)),
and the solvent was evaporated to dryness. The residue was
washed several times with light petroleum (40–60°C), and
crystallized from the proper solvent to give 5a,b (from 1a and
3a,b) or 5d,e (from 1b and 3a,b), respectively.
CONCLUSION
In conclusion, we were successful in synthesizing a
variety of phosphorylated tricyclic system in good to excel-
lent yields, without toxic side effects. The convenience and
novelty of this work is reflected in its several advantages,
such as mild reaction conditions, short reaction time, and
easy workup procedure, without the need to chromato-
graphic purification. The investigation showed that
notwithstanding 2-azidoquinolines 1a and 1b react mainly
in the tautomeric tetrazole-form (Schemes , 2–4 and 6), the
involvement of the azido group in some reactions was also
occurred (Scheme 5), which reflects the versatility of the
azido group and the phosphorus reagents as well.
Dimethyl [methoxy(tetrazolo[1,5-a]quinolin-6-yl)methyl]
phosphonate (5a). This compound was obtained as light orange
needles, 1.03 g (80%); mp 218–220°C (MeCN); IR: νmax
P
ꢀ
O,
free 1256, tetrazole 1185, P
ꢀ ꢀ
O
C 1036 cm−1; 1H-NMR (CDCl3):
δ 2.84 (d, 4JP H = 3.7 Hz, 3H, H3COC), 3.97 (d, 3JP H = 11.4 Hz,
ꢀ
ꢀ
6H, H3COP), 5.75 (d, 2JP H = 18.8 Hz, 1H, HC-P), 7.90–8.12 (2m,
ꢀ
2H, 9- and 10-HAr), 8.45 (s, 1H, 7-HAr), 8.56, 8.75 (2d, JH H = 6.8
ꢀ
Hz, 2 × 1H, 8-, 11-HAr); 13C-NMR δ (CDCl3): 133.8
(d, 3JP C = 8.6 Hz, C-5), 130.9 (d, 2JP C = 14.7 Hz, 6-C), 124.6
ꢀ
ꢀ
(d, 3JP
= 8.4 Hz, 7-C), 139.5, 134.8, 130.1, 128.6, 123.5,
ꢀ
C
1
114.7 (12-, 10-, 13-, 8-, 9-, 11-C-Ar), 79.8 (d, JP
= 144 Hz,
ꢀ
C
P-C), 62.0 (d, 3JP C = 8.4 Hz, CH3OC), 54.2 (d, 2JP C = 13.8 Hz,
ꢀ
ꢀ
CH3OP); 31P-NMR (CDCl3): δ 26.8; EI-MS: m/z (%): 322 [M+] (8),
306 (17), 284 (26), 257 (28), 186 (15), 129 [33, C9H6N], 109 [100,
P(O)(OMe)2]. Anal. calcd for C13H15N4O4P (322.3): C, 48.45; H,
4.69; N, 17.39; P, 9.61. Found: C, 48.53; H, 4.71; N, 17.32; P, 9.71.
Diethyl [ethoxy(tetrazolo[1,5-a]quinolin-6-yl)methyl]
EXPERIMENTAL
General. Melting points were determined with open capillary
tube on an electrothermal (variable heater) melting point apparatus
and were uncorrected. IR spectra were recorded on a PerkinElmer
spectrophotometer model 297 using KBr disc. NMR spectra were
p1h.1o9spgh(o8n2a%te);(5mbp). 2T1h0is–2c1o2m°pCou(CndHCwla3s);oIbRta:iνnmedaxaPsꢀyeOllo,wfrecery1s2ta6l1s,,
1
measured with a JEOL E.C.A-500 MHz (13C: 125.7 MHz, H:
1
tetrazole 1160, P
ꢀ
O
ꢀ
C 1080 cm−1; H-NMR (CDCl3): δ 0.99
500 MHz, 31P: 202.4 MHz) spectrometer. 31P-NMR spectra
4
(t, JH
= 6.5 Hz, 3H, H3C.CO), 1.28 (dt, JH
= 6.6, JP
=
ꢀ
H
ꢀ
H
ꢀ
H
1
3.8 Hz, 6H, H3C.COP), 3.9 (dq, JH H = 6.5, 4JP H = 2.5 Hz, 2H,
were recorded with H3PO4 (85%) as external reference. H- and
ꢀ
ꢀ
13C-NMR spectra were recorded with trimethylsilane as internal
standard in CDCl3 or DMSO-d6. Chemical shifts (δ) are given in
ppm. The mass spectra were performed at 70 eV on an MS-50
Kratos (A.E.I.) spectrometer provided with a data system. The
appropriate precautions in handling moisture-sensitive compounds
were observed. All international principles and local regulations
concerning the care and use of laboratory animals were
considered during the pharmacological screening.
3
H2C.CO), 4.08 (dq, JH
= 6.6, JP
= 5.2 Hz, 4H, H2COP),
ꢀ
H
ꢀ
H
2
5.58 (d, JP
= 21.2 Hz, 1H, HC-P), 7.89, 8.13 (2m, 2 × 1H,
ꢀ
H
9- and 10-HAr), 8.43 (s, 1H, 7-HAr), 8.66, 8.78 (2d, JH
=
H
ꢀ
8.2 Hz, 2 × 1H, 8-, 11-HAr); 13C-NMR (CDCl3): δ 132.4 (d,
3JP
= 8.6 Hz, 5-C), 130.8 (d, JP
= 14.7 Hz, 6-C), 124.8
2
ꢀ
ꢀ
C
C ꢀ
C
(d, 3JP
= 8.4 Hz, 7-C), 140.2, 136.6, 135.4, 128.3, 122.8,
1
114.7 (12-, 13-, 10-, 8-, 9-, 11-CAr), 79.8 (d, JP
= 167 Hz,
C ꢀ
ꢀ
P-C), 65.0 (d, 3JP C = 8.4 Hz, CH2OC), 62.2 (d, 2JP C = 11.4
ꢀ
Hz, CH2OP), 16.8 (d, 3JP
= 9.2 Hz, CH3C.OP), 15.7
Preparation of 2-azidoquinolines-3-carbaldehyde 1a,b. To a
solution of (26 mmol) of 2-chloroquinoline-3-carbaldehyde
(4.98 g) or 2-chloro-6-methylquinoline-3-carbaldehyde (5.35 g)
in 15 mL of DMSO, 2 g of sodium azide (30 mmol) was added,
and the resulting mixture was heated at 90°C for 4 h. The
precipitated product was collected, washed with acetone, and
dried to give 1a and 1b, respectively.
2-Azidoquinoline-3-carbaldehyde (1a). This compound was
obtained as straw yellow crystals 4.12 g (80%); mp 260–262°C
(lit. [21]: mp 260°C).
ꢀ
C
(CH3C.O); 31P-NMR (CDCl3): δ 27.2 ppm; EI-MS: m/z (%):
364 [M+] (7), 332 (25), 308 (33), 273 (61), 258 (52), 155 (27),
138 [100, P(O)(OEt)2], 135.3 (88), 129 [57, C9H6N]. Anal.
calcd for C16H21N4O4P (364.3): C, 52.75; H, 5.81; N, 15.38; P,
8.50. Found: C, 52.83; H, 5.88; N, 15.31; P, 8.55.
Dimethyl [methoxy(9-methyltetrazolo[1,5-a]quinolin-6-yl)
methyl]phosphonate (5d). This compound was obtained as yellow
crystals, 1.13 g (84%); mp 196–198°C (EtOH); IR: νmax
P
ꢀ
O,
free 1258, tetrazole 1177, P
ꢀ
O
ꢀ
C 1055 cm−1; 1H-NMR
4
2-Azido-6-methylquinoline-3-carbaldehyde (1b). This compound
(CDCl3): δ 2.22 (s, 3H, H3C-9Ar), 2.78 (d, JP
= 4.7 Hz, 3H,
ꢀ
H
3
2
was obtained as orange crystals, 4.25 g (77%); mp 235–236°C; IR:
H3CO), 3.85 (d, JP
= 10.5 Hz, 6H, H3COP), 5.48 (d, JP
=
H
ꢀ
H
ꢀ
1
νmax
C
¼
O 1699, N3 2105 cm−1; H-NMR (CDCl3): δ 2.54 (s, 3H,
17.6 Hz, 1H, HC-P), 7.82, 7.99 (2s, 2 × 1H, 7- and 8-H-Ar), 7.82,
7.94 (2d, JH
= 8.4 Hz, 2×1H, 10- and 11-HAr); 13C-NMR
6-Ar-CH3), 7.66 (d, JH H = 6.6 Hz, 1H, 7-CH), 7.82 (s, 1H, 5-CH),
ꢀ
ꢀ
H
3
2
8.02 (d, JH
= 6.6 Hz, 8-CH), 8.66 (s, 1H, 4-CH), 10.72 (s, 1H,
(CDCl3): δ 135.5 (d, JP
= 7.5 Hz, 5-C), 130.6 (d, JP
= 17
C
ꢀ
H
ꢀ
C
ꢀ
O); 13C-NMR (CDCl3): δ 182.6 (C
O), 153.5 (9-C),
¼
3
HC
¼
Hz, 6-C), 126.4 (d, JP
= 6.4 Hz, 7-C), 141.0, 136.2, 132.3,
ꢀ
C
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

38
W. M. Abdou, R. E. Khidre, and A. A. Shaddy
Vol 50
4
126.9, 126.0, 117.8 (12-, 10-, 9-, 8-, 13-, 11-CAr), 78.9 (d,
JH
= 6.4, JP
= 6.5 Hz, 12H, [iso-(H3C)2CꢁO]2P), 2.24 (s,
ꢀ
4
ꢀ
H
H
1JP C = 136 Hz, C-P), 62.2 (d, 3JP C = 6.4 Hz, CH3OC), 52.8
3H, H3C-9Ar), 4.12 (d.sept, JH
= 6.5, JP
= 2.6 Hz, 1H,
H
ꢀ
ꢀ
ꢀ
H
ꢀ
(d, 2JP
=10.5 Hz, CH3OP), 20.8 (CH3-9Ar); 31P-NMR
HCCꢁO), 4.64 (d.sept, JH
= 6.5, JP
= 8.4 Hz, 2H, HCOP),
3
ꢀ
C
ꢀ
H
ꢀ
H
(CDCl3): δ 28.4; EI-MS: m/z (%): 336 [M+] (15), 322 (28), 306
(27), 284 (36), 257 (68), 186 (55), 129 [44, C9H6N], 109 [100,
P(O)(OMe)2]. Anal. calcd for C14H17N4O4P (336.3): C, 50.00; H,
5.10; N, 16.66; P, 9.21. Found: C, 50.09; H, 5.18; N, 16.62; P, 9.26.
Diethyl [ethoxy(9-methyltetrazolo[1,5-a]quinolin-6-yl)methyl]
phosphonate (5e). This compound was obtained as yellow
crystals, 1.32 g (87%); mp 184–185°C (CHCl3); IR: νmax
5.62 (d, JP
= 22.2 Hz, 1H, HC-P), 7.95 (s, 7-HAr), 7.89, 8.03
2
ꢀ
H
(2m, 2 × 1H, 10- and 11-HAr), 8.10 (s, 8-HAr);13C-NMR (CDCl3):
δ 133.8 (d, 3JP C = 8.6 Hz, C-5), 131.7 (d, 2JP C = 13.8 Hz, 6-C),
ꢀ
ꢀ
3
126.7 (d, JP
= 8.2 Hz, 7-C), 139.8, 134.3, 132.3, 128.6, 125.5,
ꢀ
C
1
116.7 (12-, 10-, 13-, 8-, 9-, 11-C-Ar), 79.4 (d, JP
= 182.8 Hz,
ꢀ
C
3
2
CH-P), 73.2 (d, JP
= 11.8 Hz, CHOP), 70.6 (d, JP
= 10.8
C
ꢀ
C
ꢀ
Hz, CHOC), 25.2 (d, 3JP C = 4.6 Hz, CH3CꢁOP), 22.3 (CH3CꢁO),
ꢀ
P
ꢀ
O, free 1254, tetrazole 1185, P
NMR (CDCl3): δ 1.22–1.26 (m (2 × dt), 3H and 6H, H3C.CO
ꢀ
O
ꢀ
C 1086 cm−1
;
1H-
20.7 (CH3-9Ar); 31P-NMR (CDCl3): δ 26.7 ppm; EI-MS: m/z (%):
421 [M++1] (18), 378 (16), 333 (11), 288 (28), 259 (68), 273 (44),
229 (62), 166 [100, P(O)(OCMe2)2], 129 [37, C9H6N]. Anal. calcd
for C20H29N4O4P (420.4): C, 57.13; H, 6.95; N, 13.33; P, 7.37.
Found: C, 57.21; H, 7.03; N, 13.27; P, 7.42.
and H3C.COP), 2.32 (s, 3H, H3C-9Ar), 3.53 (dq, JH
= 6.5,
= 6.6, JP =
H H
ꢀ
H
3
4JP
= 2.5 Hz, 2H, H2CO), 4.08 (dq, JH
ꢀ
H
ꢀ
ꢀ
5.2 Hz, 4H, H2COP), 5.58 (d, 2JP
= 20.7 Hz, 1H, HC-P),
ꢀ
H
7.80, 7.98 (2s, 2 × 1H, 7- and 8-H-Ar), 7.84, 7.96 (2d, JH
=
H
Diisopropyl [hydroxy(tetrazolo[1,5-a]quinolin-6-yl)methyl]
phosphonate (6a). This compound was obtained as orange crystals,
ꢀ
8.4 Hz, 2 × 1H, 10- and 11-HAr); 13C-NMR (CDCl3): δ 133.0
3
2
(d, JP
= 8.2 Hz, 5-CAr), 130.9 (d, JP C= 14.7 Hz, 6-CAr),
OH 3345, P
ꢀ
O,
159 mg (11%); mp 244°C (MeOH);ꢀIRC: ν1035 cm−1; 1H-NMR
ꢀ
C
ꢀ
max
3
124.6 (d, JP
= 8.4 Hz, 7-CAr), 139.5, 134.8, 130.1, 128.6,
bonded 1240, tetrazole 1186, P
ꢀ
O
ꢀ
C
1
4
123.5, 113.7 (12-, 10-, 13-, 8-, 9-, 11-C-Ar), 79.8 (d, JP
=
(DMSO-d6): δ 1.11, 1.24 (2dd, JH
= 6.2 Hz, JP
= 5.5 Hz,
= 6.4, JP = 5.4
H H
ꢀ
C
ꢀ
H
ꢀ
H
144 Hz, P-C), 62.0 (d, 3JP
= 8.4 Hz, CH3OC), 54.2 (d,
12H, [iso-(H3C)2CꢁO]2P), 4.44 (d. sept, JH
3
ꢀ
C
ꢀ
ꢀ
2JP
= 13.8 Hz, CH3OP). 63.7 (d, JP
= 7.4 Hz, CH2OC),
Hz, 2H, HCOP), 5.98 (d, 2JP H = 21.6 Hz, 1H, HC-P), 7.84, 8.05
3
ꢀ
C
ꢀ
C
ꢀ
61.8 (d, 2JP
= 12.5 Hz, CH2OP), 20.4 (CH3-9Ar), 16.4 (d,
(2m, 2 × 1H, 10- and 9-HAr), 8.23 (s, 1H, 7-HAr), 8.44, 8.68
ꢀ
C
3JP
=
9.2 Hz, CH3CꢁOP), 15.8 (CH3CꢁO); 31P-NMR
(2d, JH
= 8.2 Hz, 2 × 1H, 8- and 11-HAr), 9.58 (s.br, 1H,
ꢀ
C
ꢀ
H
(CDCl3): δ 26.2 ppm; EI-MS: m/z (%): 378 [M+] (15), 363(13),
333 (53), 272 (17), 268 (11), 184 (78), 138 [100, P(O)(OEt)2],
135.3 (88), 129 [57, C9H6N]. Anal. calcd for C17H23N4O4P
(378.4): C, 53.96; H, 6.13; N, 14.81; P, 8.19. Found: C, 54.03;
H, 6.22; N, 14.83; P, 8.23.
OH, exchang. with D2O); 13C-NMR (DMSO-d6): δ 136.4 (d,
3JP
(d, JP
= 8.5 Hz, C-5), 133.2 (d, JP
= 10.8 Hz, 7-C-Ar), 140.1, 136.4, 128.3, 125.6, 124.3,
113.6 (12-, 10-, 13-, 8-, 9-, 11-C-Ar), 74.4 (d, JP
= 14.7 Hz, 6-C), 124.8
2
ꢀ
C
ꢀ
C
3
ꢀ
C
1
= 168.8 Hz,
C
ꢀ
2
3
C-P), 71.2 (d, JP
= 14.8 Hz, CHOP), 24.1 (d, JP
= 4.6
ꢀ
C
ꢀ
C
Reactions of 1a,b with triisopropyl phosphite (3c). Preparation
of 5c, 5f, and 6a,b. Compound 1a or 1b (4 mmol) in 25 mL of dry
toluene was treated with 5.2 mmol of freshly distilled 3c. The
reaction mixture was heated under reflux for 4 h and the solvent
was evaporated under vacuum to dryness. The residue was
washed several times with light petroleum (40–60°C). Fractional
crystallization from toluene afforded first 5c or 5f. Crystallization
of the residue from MeCN afforded 6a or 6b, respectively.
Diisopropyl [isopropoxy(tetrazolo[1,5-a]quinolin-6-yl)
methyl]phosphonate (5c).. This compound was obtained as yellow
Hz, CH3CHOP); 31P-NMR (DMSO-d6): δ 24.8 ppm; EI-MS: m/z
(%): 365 [M++1] (22), 333 (14), 274 (31), 259 (50), 229 (52), 166
[100, P(O)(OCMe2)2], 129 [42, C9H6N]. Anal. calcd for
C16H21N4O4P (364.4): C, 52.75; H, 5.81; N, 15.38; P, 8.50.
Found: C, 52.67; H, 5.77; N, 15.40; P, 8.43.
Diisopropyl [hydroxy(9-methyltetrazolo[1,5-a]quinolin-6-yl)
methyl] phosphonate (6b). This compound was obtained as yellow
max, OH
c3r3y3s5ta,lsP,ꢀ152 mg (10%); mp 211–213°C (MeOH); IR: ν
O, bonded 1228, tetrazole 1176, P
ꢀ
Oꢀ
C 1105 cm−1;
1H-NMR (DMSO-d6): δ 1.24, 1.28 (2dd, JH H = 6.4, 4JP H = 6.4
ꢀ
ꢀ
Hz, 12H, [iso-(H3C)2CꢁO]2P), 2.26 (s, 3H, H3C-9Ar), 4.28 (d.sept,
P
ꢀ
crystOal,sf,r7ee2912m5g4,(t4e5tr%azoylieel1d1);82m,pPꢀ232–234°C (toluene); IR: ν
Oꢀ
JH
ꢀ
= 6.2, JP
= 7.6 Hz, 2H, HCOP), 6.02 (d, JP
= 22.4
H
max
C 1110 cm−1; 1H-NMR
3
2
H
ꢀ
H
ꢀ
(DMSO-d6]: δ 1.01 (d, JH
= 7.2, 6H, iso-(H3C)2HCO), 1.13,
Hz, 1H, HC-P), 7.95 (s, H-8Ar), 7.89, 8.03 (2d, JH H = 6.5, 2 × 1H,
ꢀ
H
ꢀ
1.26 (2dd, JH H = 7.2, 4JP H = 5.5 Hz, 12H, [iso-(H3C)2CꢁO]2P),
10- and 11-HAr), 8.10 (s, 1H, 7-H), 9.63 (s.br, 1H, OH,
exchang. with D2O); 13C-NMR (DMSO-d6): δ 136.3 (d,
3JP C = 8.5 Hz, C-5), 131.8 (d, 2JP C = 14.4 Hz, 6-C), 126.6
= 8.2 Hz, 7-C), 141.2, 134.3, 132.6, 126.8, 122.6,
116.2 (12-, 10-, 13-, 8-, 9-, 11-C-Ar), 73.4 (d, JP
ꢀ
ꢀ
4.12 (sept, JH H = 7.2, 4JP H = 2.4 Hz, 1H, HCOC), 4.64 (d.sept,
ꢀ
3
ꢀ
2
JH
= 7.2, JP
= 6.4 Hz, 2H, HCOP), 5.62 (d, JP
= 22.2
ꢀ
H
ꢀ
H
ꢀ
H
ꢀ
3
ꢀ
Hz, 1H, HC-P), 7.89, 8.03 (2m, 2 × 1H, 10- and 9-HAr), 8.13 (s,
(d, JP
ꢀ
C
1
1H, 7-HAr), 8.64, 8.76 (2d, JH
= 8.2 Hz, 2 × 1H, 8-, 11-HAr);
= 177 Hz,
ꢀ
H
ꢀ
C
13C-NMR (DMSO-d6): δ 134.7 (d, 3JP C = 8.2 Hz, C-5), 130.5 (d,
CH-P), 61.6 (d, JP
= 10.8 Hz, CHOP), 20.3 (CH3-9Ar), 16.6
3
ꢀ
ꢀ
C
2JP
= 12.7 Hz, 6-C), 125.4 (d, JP C= 8.8 Hz, 7-C-Ar), 139.8,
(d, JP
= 8.6 Hz, CH3CHOP); 31P-NMR (DMSO-d6): δ 23.8
C
3
3
ꢀ
C
ꢀ
ꢀ
136.4, 129.1, 126.6, 123.6, 113.9 (12-, 10-, 13-, 8-, 9-, 11-C-Ar),
ppm; EI-MS: m/z (%): 379 [M++1] (20), 333 (14), 288 (30), 273
(65), 259 (66), 229 (36), 166 [100, P(O)(OCMe2)2], 129 [42,
C9H6N]. Anal. calcd for C17H23N4O4P (378.4): C, 53.96; H, 6.13;
N, 14.81; P, 8.19. Found: C, 53.88; H, 6.06; N, 14.74; P, 8.27.
The reaction of 2-azidoquinolines-3-carbaldehyde 1a,b with
dialkyl phosphites 7a–c. Preparation of compounds 6a–f. A
mixture of (4 mmol) of (1a, 0.79 g or 1b, 0.85 g) and 5.2 mmol
of diisopropyl (7a), diethyl (7b) or dimethyl phosphite (7c) was
refluxed in 25 mL dry toluene containing 0.7 mL TEA for
≈6–10 h (TLC). The solvent was evaporated under vacuum
to dryness, followed by washing the residue several times
with light petroleum (40–60°C), and crystallization from the
proper solvent to give 6a–f, respectively.
81.4 (d, 1JP
= 154.4 Hz, C-P), 71.2 (d, 2JP
= 12.8 Hz,
ꢀ
C
ꢀ
C
3
3
CHOP), 68.0 (d, JP
= 5.8 Hz, CHCO), 24.1 (d, JP
= 4.6
C
ꢀ
C
ꢀ
Hz, CH3CHOP), 22.3 (CH3C.O); 31P-NMR (DMSO-d6): δ 26.8
ppm; EI-MS: m/z (%): 407 [M++1] (15), 364 (13), 333 (22), 274
(18), 259 (48), 229 (55), 166 [100, P(O)(OCMe2)2], 129 [33,
C9H6N]. Anal. calcd for C19H27N4O4P (406.4): C, 56.15; H, 6.70;
N, 13.39; P, 7.62. Found: C, 56.22; H, 6.75; N, 13.32; P, 7.70.
Diisopropyl [isopropoxy(9-methyltetrazolo[1,5-a]quinolin-6-
yl)methyl] phosphonate (5f). This compound was obtained as
max
1
Pꢀ
oranOge, cfrreyesta1l2s6, 08,0t8etmragzo(l4e81%18);8m, Ppꢀ203–205°C (toluene); IR: ν
Oꢀ
C 1081 cm−1; H-NMR
(CDCl3): δ 1.03 (d, JH H = 6.4, 6H, (H3C)2HCO), 1.25, 1.28 (2dd,
ꢀ
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Synthesis of Tetrazoloquinoline-Based Mono- and Bisphosphonate
January 2013
39
Esters as Potent Anti-Inflammatory Agents
Diisopropyl [hydroxy(tetrazolo[1,5-a]quinolin-6-yl)methyl]
phosphonate (6a). This compound was obtained as orange
crystals, 1.36 g (94%), which was identical with the product
previously obtained (TLC, IR, and MS spectra).
Diisopropyl [hydroxy(9-methyltetrazolo[1,5-a]quinolin-6-yl)
methyl] phosphonate (6b). This compound was obtained as orange
crystals, 1.32 mg (87%), which was identical with the product
previously obtained (TLC, IR, and MS spectra).
Dimethyl [hydroxy(9-methyltetrazolo[1,5-a]quinolin-6-yl)
methyl]phosphonate (6f). This compound was obtained as orange
OH
c3r3y4s0ta,lsP,ꢀ1.14 g (88%); mp 213–215°C (acetone); IR: ν
O, bonded 1228, tetrazole 1180, P
ꢀOꢀ
C 1062 cm−1;
max
1H-NMR (CDCl3): δ 2.26 (s, 3H, H3C-9-Ar), 3.88 (d, 3JP H = 10.8
ꢀ
Hz, 6H, H3COP), 6.04 (d, 2JP H = 18.6 Hz, 1H, HC-P), 7.76, 7.88
ꢀ
(2s, 2 × 1H, 7- and 8-H-Ar), 7.82, 7.94 (2d, JH
= 8.4 Hz,
ꢀ
H
2 × 1H, 10- and 11-HAr), 9.56 (s br, 1H, OH, exchang. with
3
Diethyl [hydroxy(tetrazolo[1,5-a]quinolin-6-yl)methyl]
phosphonate (6c). This compound was obtained as yellow crystals,
D2O); 13C-NMR (CDCl3): δ 135.6 (d, JP
= 7.5 Hz, 5-C),
ꢀ
C
132.2 (d, 2JP C = 14.3 Hz, 6-C), 126.8 (d, 3JP C = 5.4 Hz, 7-C),
ꢀ
ꢀ
1.15 g (86%); mp 225–228°C (EtOH); IR: νmax OH 3379, P
ꢀ
O,
140.06, 136.1, 132.0, 126.8, 126.4, 116.7 (12-, 9-, 10-, 8-, 13-,
1
2
chelated 1228, tetrazole 1184, P
ꢀ
O
ꢀ
C 1085 cm−1; 1H-NMR
11-CAr), 74.8 (d, JP
= 144 Hz, C-P), 54.2 (d, JP
=10.5
ꢀ
C
ꢀ
C
(DMSO-d6): δ 1.32 (dt, JH
= 6.6, 4JP
= 4.8 Hz, 6H,
Hz, CH3OP), 20.6 (CH3-9Ar); 31P-NMR (CDCl3): δ 24.2 ppm;
EI-MS: m/z (%): 322 [M+] (16), 321 [M+−1] (23), 284 (31),
257 (36), 186 (65), 129 [80, C9H6N], 109 [100, P(O)(OMe)2].
Anal. calcd for C13H15N4O4P (322.2): C, 48.45; H, 4.69; N,
17.39; P, 9.61. Found: C, 48.54; H, 4.78; N, 17.34; P, 9.69.
The reaction of 1a,b with tris(dimethylamino)phosphine (8).
Preparation of compounds 9a and 9b. Aminophosphine 8
(0.85 mL, 5.2 mmol) in 5 mL dry THF was added dropwise
to 1a (0.79 g, 4 mmol) or 1b (0.85 g, 4 mmol) in 5 mL
THF. The reaction mixture was stirred at r.t. for ≈24 h
(TLC). The precipitate was collected and washed several
times with light petroleum (40–60°C) to give 9a and 9b,
respectively. Compounds 9a,b are pure enough for carrying
out the spectroscopic analyses and are stable for few days
at −10°C.
ꢀ
H
ꢀ
H
3
H3CꢁCOP), 4.18 (dq, JH
= 6.8, JP
= 5.7 Hz, 4H, H2COP),
ꢀ
H
ꢀ
H
2
6.06 (d, JP
= 20.4 Hz, 1H, HC-P), 7.91, 8.13 (2m, 2 × 1H,
ꢀ
H
10- and 9-HAr), 8.25 (s, 1H, 7-HAr), 8.56, 8.66 (2d, JH
= 8.2
H
ꢀ
Hz, 2 × 1H, 8-, 11-HAr), 9.66 (s.br, 1H, OH, exchang. with D2O);
13C-NMR (DMSO-d6): δ 134.2 (d, 3JP C = 8.8 Hz, 5-C), 136.6 (d,
ꢀ
2JP
= 12.7 Hz, 6-C), 126.4 (d, JP
= 8.4 Hz, 7-C), 139.9,
3
ꢀ
C
ꢀ
C
136.6, 135.8, 128.7, 125.8, 114.8 (12-, 13-, 10-, 8-, 9-, 11-CAr),
76.3 (d, 1JP C = 148 Hz, C-P), 61.6 (d, 2JP C = 10.4 Hz, CH2OP),
ꢀ
ꢀ
16.6 (d, 3JP C = 9.2 Hz, CH3CꢁOP); 31P-NMR (DMSO-d6): δ 25.4
ꢀ
ppm; EI-MS: m/z (%): 335 [M+−1] (28), 308 (39), 273 (26), 258
(42), 155 (21), 138 [100, P(O)(OEt)2], 135.3 (57), 129 [37, C9H6N].
Anal. calcd for C14H17N4O4P (336.3): C, 50.00; H, 5.10; N, 16.66;
P, 9.21. Found: C, 50.07; H, 5.08; N, 16.62; P, 9.29.
Diethyl [hydroxy(9-methyltetrazolo[1,5-a]quinolin-6-yl)
methyl]phosphonate (6d). This compound was obtained as yellow
crystals, 1.19 g (85%); mp 205–207°C (MeCN); IR: νmax OH 3385,
2-{3-[Tris(dimethylamino)phosphoranylidene]triaz-1-en-1-yl}
quinoline-3-carbaldehyde (9a). This compound was obtained as
1
P
ꢀ
O, chelated 1224, tetrazole 1180, P ꢀ
NMR (DMSO-d6): δ 1.24 (dt, JH = 6.6, JP
H
ꢀ
O
C 1065 cm−1; H-
yellow material, 1.3 g (90%); mp 290–292°C; IR: νmax
1722, P
N 1355, [P(NMe2)3] 1335, 860 cm−1; 1H-NMR (CDCl3):
δ 2.48, 2.63 (2d, JP = 10.8 Hz, 18H, PN(CH3)2), 7.34, 7.77
H
C O
¼
4
= 3.2 Hz, 6H,
¼
ꢀ
H
ꢀ
3
H3C.COP), 2.32 (s, 3H, H3C-9Ar), 4.08 (dq, JH
= 6.6,
ꢀ
H
ꢀ
3JP H = 5.2 Hz, 4H, H2COP), 6.08 (d, 2JP H = 20.7 Hz, 1H, HC-P),
(2d, JH
= 7.8 Hz, 2 × 1H, 5- and 8-HAr), 8.02–8.36 (2m,
ꢀ
ꢀ
ꢀ
H
7.80, 7.98 (2s, 2 × 1H, 7- and 8-HAr), 7.84, 7.96 (2d, JH
= 8.4
2 × 1H, 6- and 7-HAr), 8.55 (s, 1H, 4-HAr), 10.2 (s (br), 1H,
HC O), 155.8 (2-CAr),
O); 13C-NMR (CDCl3): δ 184.3 (C
132.3 (4-CAr), 111.7 (3-CAr), 150.6, 135.8, 132.3, 129.6, 125.4,
ꢀ
H
Hz, 2 × 1H, 10- and 11-HAr), 9.36 (s.br, 1H, OH, exchang. with
¼
¼
2
D2O); 13C-NMR (DMSO-d6): δ 132.7 (d, 3JP C = 7.8 Hz, C-5),
ꢀ
2
3
130.4 (d, JP
= 15.6 Hz, 6-C), 126.4 (d, JP
= 8.8 Hz, 7-
124.7 (9-, 5-, 7-, 10-, 8-, 6-CAr), 38.2 (d, JP
= 28 Hz, P[N
ꢀ
C
ꢀ
C
ꢀ
C
CAr), 140.08, 134.6, 131.3, 128.2, 124.6, 116.4 (12-, 10-, 13-, 8-,
(CH3)2]3); 31P-NMR (CDCl3): δ 38.6 ppm; EI-MS: m/z (%): 362
[M++1] (13), 333 (21), 170 [M+−91(N2 + Me2N)3P)] (100). Anal.
calcd for C16H24N7OP (361.4): C, 53.18; H, 6.69; N, 27.13; P,
8.57. Found: C, 53.09; H, 6.66; N, 27.06; P, 8.63.
9-, 11-CAr), 73.9 (d, 1JP C = 146 Hz, C-P), 61.5 (d, 2JP C = 10.8
ꢀ
ꢀ
Hz, CH2OP), 20.4 (CH3-9Ar), 18.2 (d, 3JP C = 8.8 Hz, CH3C.OP);
ꢀ
31P-NMR (DMSO-d6): δ 24.7 ppm; EI-MS: m/z (%): 349 [M+−1]
(25), 321(30), 268 (18), 184 (48), 138 [100, P(O)(OEt)2], 135.3
(58), 129 [25, C9H6N]. Anal. calcd for C15H19N4O4P (350.3): C,
51.43; H, 5.47; N, 15.99; P, 8.84. Found: C, 51.51; H, 5.44; N,
15.94; P, 8.89.
6-Methyl-2-{3-[tris(dimethylamino)phosphoranylidene]triaz-1-en-
1-yl}quinoline-3-carbaldehyde (9b). This compound was obtained
as an orange substance, 1.35 g (90%); mp 276–278°C; IR: νmax
C
¼
O 1718, P
(CDCl3): δ 2.45, 2.64 (2d, JP
¼
N 1360, [P(NMe2)3] 1322, 855 cm−1; 1H-NMR
3
= 10.8 Hz, 18H, PN(CH3)2),
Dimethyl [hydroxy(tetrazolo[1,5-a]quinolin-6-yl)methyl]
phosphonate (6e). This compound was obtained as orange crystals,
ꢀ
H
2.55 (s, 3H, H3C-6-Ar), 7.55 (s, 1H, 5-HAr), 7.97, 7.66 (2d,
JH = 6.5 Hz, 2 × 1H, 7-, 8-HAr), 8.68 (s, 4-HAr), 10.26
1.03 g (84%); mp 240–242°C (acetone); IR: νmax OH 3324, P
ꢀ
O,
ꢀ
H
O); 13C-NMR (CDCl3): δ 183.8 (C
O), 155.3
¼
chelated 1228, tetrazole 1173, P
ꢀ ꢀ
O
C 1080 cm−1; 1H-NMR
(s, 1H, HC
¼
(DMSO-d6): δ 3.88 (d, 3JP
= 11.5 Hz, 6H, H3COP), 6.05
(2-CAr), 131.7 (4-C), 111.4 (3-C), 149.4, 136.8, 131.5, 130.7,
ꢀ
H
2
(d, 2JP H = 20.4 Hz, 1H, HC-P), 7.88, 8.18 (2m, 2 × 1H, 10- and
123.4 (9-, 7-, 6-, 5-, 8-, 10-CAr), 38.5 (d, JP
= 30.2 Hz, P
C
ꢀ
ꢀ
[N(CH3)2]3), 20.6 (CH3-Ar); 31P-NMR (CDCl3): δ 40.3 ppm;
EI-MS: m/z (%): 376 [M++1] (17), 347 (21), 184 [M+−191,
(N2 + Me2N)3P)] (100). Anal. calcd for C17H26N7OP (375.4):
C, 54.39; H, 6.98; N, 26.12; P, 8.25. Found: C, 54.45; H, 6.89;
N, 26.05; P, 8.15.
9-HAr), 8.47 (s, 1H, 7-HAr), 8.57, 8.77 (2d, JH
= 8.2 Hz,
ꢀ
H
2 × 1H, 8-, 11-HAr), 9.44 (s br, 1H, OH, exchang. with D2O);
13C-NMR (DMSO-d6): δ 134.4 (d, 3JP
= 8.6 Hz, C-5),
ꢀ
C
133.8 (d, 2JP C = 14.7 Hz, 6-C), 124.4 (d, 3JP C = 8.4 Hz, 7-C),
ꢀ
ꢀ
139.8, 136.4, 134.6, 127.6, 123.8, 113.4 (12-, 10-, 8-, 13-, 9-,
1
2
The reaction of 1a,b with aminophosphine 8 in the presence
of a protonating agent. Preparation of compounds 12a and 12b.
Aminophosphine 8 (0.85 mL, 5.2 mmol) in 10 mL of THF was
added in one portion to a mixture of 4 mmol of the azide (1a,
0.79 g or 1b, 0.85 g) and 2 mL of H2O in 10 mL THF. The
reaction mixture was heated under reflux 2 h. The solvent was
11-C-Ar), 74.8 (d, JP
= 136 Hz, C-P), 52.5 (d, JP
= 11.8
ꢀ
C
ꢀ
C
Hz, CH3OP); 31P-NMR (DMSO-d6): δ 24.4 ppm; EI-MS: m/z (%):
308 [M+] (6), 307 [M+−1] (17), 284 (46), 257 (28), 186 (25),
129 [43, C9H6N], 109 [100, P(O)(OMe)2]. Anal. calcd for
C12H13N4O4P (308.2): C, 46.76; H, 4.25; N, 18.18; P, 10.05.
Found: C, 46.85; H, 4.19; N, 18.11; P, 10.11.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

40
W. M. Abdou, R. E. Khidre, and A. A. Shaddy
Vol 50
(%): 469 [M++1] (16), 440 (11), 426 (32), 289 (62),152 (100). Anal.
calcd for C19H26N4O6P2 (468.4): C, 48.72; H, 5.60; N, 11.96; P,
13.23. Found: C, 48.78; H, 5.55; N, 11.89; P, 13.16.
evaporated to dryness; the residue was washed several times with
cyclohexane and crystallized from the proper solvent to give 12a
and 12b, respectively.
(Z)-Diethyl (1-(diethoxyphosphino)-2-(9-methyltetrazolo[1,5-a]
quinolin-4-yl)vinyl)-phosphonate (14b). This compound was obtained
as yellow crystals, 1.39 g (72%); mp 201–202°C (CH2Cl2) cm−1; IR:
2-(Dimethylamino)-1,2-dihydro-3H-[1,2]azaphospholo[5,4-b]
quinoline-3-one 2-oxide (12a). This compound was obtained as
NH 3405, C O 1728, P
NMR (CDCl3): δ 2.88 (d, JP
¼
yellow crystals, 0.8 g (77ꢀ%)O; m1p25167,2P–-1N7R4°C13(2C0H, 8C38l )c;mIR−1:;ν H-
2
2
max
1
ν
max C
¼
C, ylide 1614, P
ꢀ
O, free 1248, tetrazole 1174, P
ꢀ
O
ꢀ
= 6.8,
H
C
1
1082 cm−1; H-NMR (DMSO-d6): δ 1.28, 1.33 (2dt, JH
3
= 10.4 Hz, 6H, H3CNP), 7.54,
H
= 7.8 Hz, 2 × 1H, 5- and 8-HAr), 8.07-8.31 (m,
ꢀ
ꢀ
4JP
= 3.9 Hz, 12H, [H3C.COP]2), 2.64 (s, 3H, H3C-9Ar),
H
7.68 (2d, JH
2 × 1H, 6- and 7-HAr), 8.61(d, JP
ꢀ
ꢀ
H
4
4
3.88, 4.26 (2dq, JH
= 6.8, JP
= 10.5 Hz, 1H, HC
= 6.5 Hz, 8H, H2COP), 5.88
CP2), 7.89, 8.03 (2m, 3 × 1H, 7-,
=2.8 Hz, 1H, 4-CH), 9.82
H
ꢀ
H
ꢀ
H
ꢀ
3
1
(s.br, 1H, HN); 13C-NMR (CDCl3): δ 192 (d, JP
= 136 Hz,
C
(t, JP
¼
ꢀ
H
ꢀ
10- and 11-HAr), 8.43 (s, 8-HAr); 13C-NMR (DMSO-d6): δ 143.7
C=O), 150.6 (d, 2JP C = 13.6 Hz, 2-CAr), 133.7 (d, 3JP C = 6.8
ꢀ
ꢀ
4
4
Hz, 4-CAr), 110.5 (d,2JP C= 136 Hz, 3-CAr), 156.7, 134.2,
(d, JP
= 4.5 Hz, 5-CAr), 135.4 (d, JP
= 4.8 Hz, 7-CAr),
C
ꢀ
C
ꢀ
ꢀ
133.3 (d, 2JP C = 28 Hz, CH
¼
C, ylide), 129.6 (d, JP
= 7.2 Hz, 6-C), 140.06, 136.1,
= 129.2
1
133.6, 131.5, 124.4, 122.7, (9-, 7-, 5-, 8-, 6-, 10-CAr), 37.5 (d,
ꢀ
ꢀ
C
), 114.5 (d, 3JP
2JP
= 30.8 Hz, 6H, PNCH3); 31P-NMR (CDCl3): δ 14.8 ppm;
Hz, P
ꢀ
C¼
ꢀ
C
ꢀ
C
EI-MS: m/z (%): 262 [M++1] (18), 217 (37), 174 (55), 137 (100).
Anal. calcd for C12H12N3O2P (261.2): C, 55.18; H, 4.63; N,
16.09; P, 11.86. Found: C, 55.23; H, 4.59; N, 16.05; P, 11.81.
2-(Dimethylamino)-6-methyl-1,2-dihydro-3H-[1,2]azaphospholo
[5,4-b]quinoline-3-one 2-oxide (12b). This compound was obtained
as yellow crystals, 937 mg (85%); mp 162–164°C (MeCN); IR: νmax
132.0, 126.8, 126.4, 116.7 (12-, 9-, 10-, 8-, 13-, 11-CAr), 62.8 (d,
2JP
= 9.8 Hz, CH2OP), 20.4 (CH3-9Ar), 16.1 (d, JP
= 4.6
3
ꢀ
C
ꢀ
C
Hz, CH3COP); 31P-NMR (DMSO-d6): δ 22.6 ppm; EI-MS: m/z
(%): 483 [M++1] (12), 454 (18), 440 (15), 426 (48), 289 (67), 152
(100). Anal. calcd for C20H28N4O6P2 (482.4): C, 49.79; H, 5.85;
N, 11.61; P, 12.84. Found: C, 49.85; H, 5.79; N, 11.59; P, 12.91.
Anti-inflammatory activity experiments in vivo; carrageenin-
induced edema. Materials and Methods. Animals. All
experiments have been conducted on adult Wistar strain
albino rats of either sex, weighing between 150 and 200 g.
Animals were kept in colony cages under identical housing
NH 3424, C
¼
O 1726, P
ꢀ
O 1256, PNMe 1328, 835 cm−1; 1H-NMR
3
(CDCl3): δ 2.45 (s, 3H, H3C-6Ar), 2.85 (d, JP
= 11.6 Hz, 6H,
ꢀ
H
H3CNP), 7.27, 7.54 (2d, JH
= 6.5 Hz, 2 × 1H, 7-, 8-CH), 7.58
ꢀ
H
(s, 1H, 5-HC), 8.63 (d, 4JP H = 2.8 Hz, 1H, 4-HAr), 9.84 (s.br, 1H,
ꢀ
HN); 13C-NMR (CDCl3): δ 190.2 (d, 1JP C = 140 Hz, C=O), 150.7
ꢀ
2
3
conditions at an ambient temperature of 25°C
2°C and
(d, JP
= 11.6 Hz, 2-CAr), 136.8 (d, JP
= 9.6 Hz, 4-CAr),
= 14.5 Hz, 3-CAr), 156.4, 132.4, 131.5, 130.7,
ꢀ
C
ꢀ
C
110.5 (d, 2JP
45–55% relative humidity with 12 h light–dark cycle in the
departmental animal room and fed on standard diet. Animals were
acclimatized for a weak before use.
Experimental model of inflammation. Carrageenin-induced
paw edema was used throughout the investigation.
Standard drug Indomethacin (A), substrates (1a, 1b), and
synthesized compounds (5a–f, 6a–f, 12a,b, 14a,b) and solutions.
(a) Powder of the pure carrageenin was used and fresh suspension
was prepared in distilled water to make 1% carrageenin solution;
(b) fresh tested compound solutions were made by adding 10 mg
of the compound in 500 mg carboxymethyl cellulose and 50 mL
distilled water.
Experimental Inflammation. It was produced by the following
method: carrageenin-induced paw edema in rats: 1% carrageenin
suspension was prepared as a homogeneous solution in distilled
water. A volume of 0.1 mL of carrageenin solution was injected
through a 26-gauge needle into the plantar surface of the left hind
paw below the plantar aponeurosis. The volume of the paw was
measured before and at different intervals for 4 h after injection of
carrageenin. The difference in the paw volume before and after
administration of the phlogistic agent was taken as the measure of
pedal edema. The compounds whose effects have been studied on
this particular model were administered as per schedule; (c)
measurement of paw volume: the volume of hind paw of the rats
up to the ankle joint was measured by plathysmographically by
the mercury displacement method. The ankle joint of the rats was
marked with a skin marking pencil and the paw was dipped in the
mercury, so that the mark on the paw coincides with a prefixed
line kept constant on the syringe. The level of the mercury was
every time brought to the level of this line by adjusting the height
of the displaced mercury. The difference in the paw volume
before and after injection of the phlogistic agents was taken as a
measure of pedal edema. The change in paw volume was
expressed in “mL” of mercury displaced.
ꢀ
C
2
129.6, 123.8 (9-, 7-, 6-, 5-, 8-, 10-CAr), 37.8 (d, JP
= 29.5 Hz,
C
ꢀ
CH3NP), 20.8 (CH3-6Ar); 31P-NMR (CDCl3): δ 14.2 ppm; EI-MS:
m/z (%): 276 [M++1](14), 231 (22), 203 (52), 156 (100). Anal. calcd
for C13H14N3O2P (275.2): C, 56.73; H, 5.13; N, 15.27; P, 11.25.
Found: C, 56.78; H, 5.07; N, 15.19; P, 11.15.
The reaction of 1a,b with tetraethyl methylenebisphosophonate
(13). Preparation of compounds 14a and 14b. To a stirred solution
of 1.49 mL of the bisphosphonate (13, 5.2 mmol) and 10 mmol of
Na in 10 mL EtOH was added dropwise to a solution of 4 mmol
of the azide (1a, 0.79 g or 1b, 0.85 g) in 15 mL EtOH at 0°C. The
resulting mixture was allowed to warm to r.t. under stirred for
≈6 h (TLC). HCl (1N) was added (at –5°C) until the pH of the
reaction mixture became acidic, followed by extraction with
AcOEt (3mL × 50 mL), and the combined organic phase was
dried over anh. Na2SO4. After removal of the solvent, under
vacuum, the resulting residue was washed several times with light
petroleum (40–60°C), and crystallized from the proper solvent to
give 14a or 14b, respectively.
(Z)-Diethyl (1-(diethoxyphosphino)-2-(tetrazolo[1,5-a]quinolin-4-
yl)vinyl)phosphonate (14a). This compound was obtained as
orange crystals, 1.38 g (74%); mp 250–252°C (CHCl3); IR:
νmax
C
ꢀ
¼
C, ylide 1618, P
ꢀ
O, free 1254, tetrazole 1180,
C 1030 cm−1; H-NMR (DMSO-d6): δ 1.22, 1.34 (2dt,
= 6.6, 4JP
= 4.8 Hz, 12H, [H3C.COP]2), 4.14 ( 2dq,
1
P
JH
ꢀ
O
ꢀ
ꢀ
H
ꢀH
ꢀ
ꢀ
JH H = 6.6, 3JP H = 5.6 Hz, 8H, H2COP), 5.55 (t, 3JP H = 10.5
Hz, 1H, HC = CP2), 7.78–7.85 (m, 2 × 1H, 9- and 10-HAr), 8.65
(s, 1H, 7-HAr), 8.72, 8.86 (2d, 2 × 1H, 8-, 11-HAr); 13C-NMR
(DMSO-d6): δ 143.6 (d, 4JP
= 4.5 Hz, 5-CAr), 133.8 (d,
ꢀ
C
4JP C = 2.7 Hz, 7-CAr), 133.1 (d, 2JP C = 22 Hz, CH=C, ylide),
ꢀ
ꢀ
1
3
128.8 (d, JP
= 129.2 Hz, P-C=), 114.5 (d, JP
= 7.2 Hz,
ꢀ
C
ꢀ
C
6-CAr), 138.1, 134.8, 133.1, 131.1, 127.9, 123.9 (12-, 8-, 11-, 9-,
2
3
10-, 13-CAr), 61.8 (d, JP
= 9.8 Hz, CH2OP), 16.3 (d, JP
=
ꢀ
C
ꢀ
C
4.6 Hz, CH3C.OP); 31P-NMR (DMSO-d6): δ 18.4 ppm; EI-MS: m/z
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Synthesis of Tetrazoloquinoline-Based Mono- and Bisphosphonate
January 2013
41
Esters as Potent Anti-Inflammatory Agents
The anti-inflammatory activity was expressed as percentage in-
hibition of edema volume in the treated animals in comparison
with the control group.
A. C.; Liu, N.; Keenan, R. M.; Lin-Goerke, J.; Sarisky, R. T.; Wiggall,
K. J.; Zimmerman, M. N.; Duffy, K. J. J Med Chem 2006, 49, 971.
[2] Yamashkin, S. A.; Oreshkina, E. A. Chem Heterocycl Compd
2006, 42, 803.
[3] Lavilla, R. Curr Org Chem 2004, 8, 715.
[4] Dascombe, M. J.; Drew, G. B. M.; Philip, G.; Ismail, F. M. D.
Front Drug Des Discov 2007, 3, 559.
ðVc ꢀ VtÞ
% Inhibition of edema ¼
ꢂ 100
Vc
[5] Meth-Cohn, O. Heterocycles 1993, 35, 539.
[6] Rajendran, S. P.; Manonmani, M.; Vijayalakshmi, S. Org Perp
Proceed Int 1994, 26, 383.
[7] Mahmoud, A.; Chevalier, J.; Davin-Regli, A.; Barbe, J.; Pages,
J. M. Curr Drug Targets 2006, 7, 843.
where Vc and Vt are the volumes of edema for the control and tested
substance-treated animal groups, respectively, while potency of the
tested compounds was calculated regarding Indomethacin, reference
standard, treated group according to the following equation:
[8] Pokalwar, R. U.; Hangarge, R. V.; Kategaonkar, A. H.; Shin-
gare, M. S. Russ J Org Chem 2009, 45, 430.
%Potency
[9] Pokalwar, R. U.; Hangarge, R. V.; Maske, P. V.; Shingare, M.
S. Arkivoc 2006, 11, 196.
[10] Coppola, G. M.; Hardtmann, G. E.; Pfister, O. R. J Org Chem
1976, 41, 825.
[11] Abdou, W. M.; Khidre, M. D.; Khidre, R. E. Eur J Med Chem
2009, 44, 526.
[12] Abdou, W. M.; Ganoub, N. A.; Geronikaki, A.; Sabry, E. Eur J
Med Chem 2008, 43, 1015.
[13] Abdou, W. M.; Shaddy, A. A.; Sediek, A. A. J Chem Res 2009, 8.
[14] Abdou, W. M.; Ganoub, N. A.; Sabry, E. Z Naturforsch 2009,
46b, 1057.
[15] Abdou, W. M.; Sediek, A. A.; Khidre, M. D. Monatsh Chem
2008, 139, 617.
[16] Abdou, W. M.; Shaddy, A. A. Lett Org Chem 2008, 5, 569.
[17] Abdou, W. M.; Khidre, R. E. Monatsh Chem 2010,
141, 219.
[18] (a) Koldobskii, G. I. Russ J Org Chem 2006, 42, 469;
(b) Myznikov, L. V.; Hrabalek, A.; Koldobskii, G. I. Chem Heterocycl
Compd 2007, 43, 1.
[19] Varadaraji, D.; Suban, S. S.; Ramasamy, V. R.; Kubendiran,
K.; Raguraman, J. S. K. G., Nalilu, S. K., Pati, H. N. Org Commun
2010, 3:3, 45.
[20] Modarresi Alam, A. R.; Nasrollahzadeh, M. Turk J Chem
2009, 33, 267.
[21] Cmoch, P.; Stefaniak, L.; Webb, G. A. Magn Reson Chem
1997, 35, 237.
[22] Kategaonkar1, A. H.; Sapkal1, S. B.; Madje, B. R.; Shingate1,
B. B.; Shingare1, M. S. Chem Heterocycl Compd 2010, 46, 754.
[23] Gilyarov, V. A.; Kudryavtsev, R. V.; Kabachnik, M. I. Zh
Obshch Khim 1966, 36, 708.
[24] Petkova, N. I.; Nikolova, R. D.; Bojilova, A. G.; Rodios, N.
A.; Kopf, J. Tetrahedron 2009, 65, 1639.
[25] Baron, R. A.; Tavaré, R.; Figueiredo, A. C.; Błażewska, K. M.;
Kashemirov, B. A.; McKenna, C. E.; Ebetino, F. H.; Taylor, A.; Rogers,
M. J.; Coxon, F. P.; Seabra, M. C. J Biol Chem 2009, 248, 6861.
[26] Fleisch, H. Endocr Rev 1998, 19, 80.
% Edema inhibition of tested compound treated group
¼
% Edema inhibition of indomethacin treated group
ꢂ100
Toxicity of the evaluated promised substituted quinoline
heterocycles phosphor esters. The LD50 determination of the
most promising synthesized anti-inflammatory active agents (12a
and 14a) was determined by the standard known LD50 method in
mice. Albino mice weighing 20–25 g were divided into six groups
of eight mice each. Administrations of the tested compounds (12a
and 14a) dissolved in the same vehicle solution in 500, 750, and
1000 mg/kg (body weight) were given intraperitoneally. The
control groups were given in buffer solution only. The toxic
symptoms, mortality rates, and postmortem findings in each group
were recorded 24 h postadministration.
LD50 of the tested compounds were calculated according to the
following formula:
X
LD50 ¼ Dm ꢀ ðz ꢂ dÞ=n
where Dm is the largest dose which kill all animals, z is the mean
of dead animals between two successive groups, d is the constant
factor between two successive doses, n is the number of animals
in each group, Σ is the sum of (z × d).
Acknowledgments. Financial support from the Egyptian Academy
of Scientific Research and Technology is gratefully acknowledged.
We thank the National Central Lab of Toxicology, Cairo, Egypt,
for carrying out the pharmacological screening.
REFERENCES AND NOTES
[27] Wintar, C. A.; Risley, E. A.; Nuss, G. W. Proc Soc Exp Biol
Med 1962, 111, 544.
[28] Di Rosa, M.; Giroud, J. P.; Willoughby, D. A. J Pathol 1971,
104, 15.
[1] Tedesco, R.; Shaw, A. N.; Bambal, R.; Chai, D.; Concha, N.
O.; Darcy, M. G.; Dhanak, D.; Fitch, D. M.; Gates, A.; Gerhardt, W.
G.; Halegoua, D. L.; Han, C.; Hofmann, G. A.; Johnston, V. K.; Kaura,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet