Synthesis, antitumor activity, and anti-HIV-1 testing of certain heterocyclic systems containing an adamantane nucleus

Article abstract of DOI:10.1002/1521-4184(200010)333:10<323::AID-ARDP323>3.0.CO;2-U

A new series of substituted 2-(1-adamantyl)-4H-3,1-benzoxazin-4-ones and 2-(1-adamantyl)-3-amino or alkyl-3,4-dihydroquinazolin-4-ones have been synthesized and tested for their antitumor and antiviral activities. Among the tested compounds, compounds 5a and 5b exhibited a broad spectrum antitumor activity with full panel (MG-MID) median growth inhibition (GI₅₀) values of 3.2 and 4.9 μM respectively. Meanwhile, compounds 5c, 5d, 5h, 5i, and 5j showed moderate selectivity towards leukemia cell lines. On the other hand, compounds 4a and 4b possessed moderate Anti-HIV-1 potency with EC₅₀ values of 50.3 and 69.2 μM respectively. Detailed synthesis, spectroscopic, and biological data are reported.

Full text of DOI:10.1002/1521-4184(200010)333:10<323::AID-ARDP323>3.0.CO;2-U

Full Papers
Synthesis, Antitumor Activity, and Anti-HIV-1 Testing of Certain
Heterocyclic Systems Containing an Adamantane Nucleus
Magda A. El-Sherbeny
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, P. O. Box 22452, Riyadh 11495, Saudi Arabia
Key Words: Adamantane; benzoxazinones; quinazolinones; antitumor; antiviral activity
Summary
A new series of substituted 2-(1-adamantyl)-4H-3,1-benzoxazin-
4-ones and 2-(1-adamantyl)-3-amino or alkyl-3,4-dihydroquin-
azolin-4-ones have been synthesized and tested for their antitumor
and antiviral activities. Among the tested compounds, compounds
5a and 5b exhibited a broad spectrum antitumor activity with full
panel (MG-MID) median growth inhibition (GI50) values of 3.2
and 4.9 µM respectively. Meanwhile, compounds 5c, 5d, 5h, 5i,
and 5j showed moderate selectivity towards leukemia cell lines.
On the other hand, compounds 4a and 4b possessed moderate
Anti-HIV-1 potency with EC50 values of 50.3 and 69.2 µM respec-
tively. Detailed synthesis, spectroscopic, and biological data are
reported.
Scheme 1
Introduction
As a part of our ongoing research
program on heterocyclic com-
pounds which may serve as leads
for designing novel antiviral and
[1–5]
antitumor agents
, we consid-
ered the well-known activity of the
adamantane nucleus. This nucleus
has recently received considerable
attention, many of its substituted
derivatives proved to possess an-
[6–8]
[9–13]
timicrobial
, antiviral
,
[14–17]
and antitumor
activities. In
view of these facts and as a con-
tinuation of our previous efforts, it
seemed of interest to widen our
investigation to a new series of
substituted 2-(1-adamantyl)-4H-
3,1-benzoxazin-4-ones 4a–d, N-
(1-adamantoyl)anthranilic acid
hydrazides 5a–d, 2-(1-adamant-
oylamino)-N-alkylbenzamides
5e–j, and 2-(1-adamantyl)-3-
amino or alkyl-3,4-dihydroquina-
zolin-4-ones 7a–g in order to
explore their antitumor and antivi-
ral activities. The type of substi-
Scheme 2
tuents utilized to derivatize these compounds was selected to tion is an attempt to identify novel lead compounds for future
determine their effect with regard to activity. This investiga- development as antitumor and/or antiviral agents.
Arch. Pharm. Pharm. Med. Chem.
© WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0365-6233/00/1010/0323 $17.50 +.50/0

324
El-Sherbeny
ing out the aminolysis of 4b–d using n-butanol, the anthra-
nilic acid hydrazides 5b,c and the benzamides 5e–j interme-
diates that formed initially underwent cyclization to the
corresponding 3,4-dihydroquinazolin-4-ones 7a–g. In addi-
tion, the same compounds 7a–g were also obtained when
5b–j were heated with polyphosphoric acid (PPA) at 150 °C
for 2 h. Reaction of 5b or 5c with the appropriate aldehyde in
ethanol yielded the corresponding hydrazones 8a–d in good
yields (Scheme 2, Table 1).
Results and Discussion
Chemistry
Scheme 1 outlines the synthetic pathway used to obtain
compounds 4a–d. N-(1-Adamantoyl)substituted anthranilic
acids 3a–d were obtained through the reaction of the appro-
priate anthranilic acid 1a–d with 1-adamantanecarbonyl
chloride 2 in the presence of triethylamine. Upon cyclization
of 3a–d using acetic anhydride, substituted 2-(1-adamantyl)-
4H-3,1-benzoxazin-4-ones 4a–d were obtained in good
yields (Scheme 1, Table 1). Aminolysis of 4a–d using hydra-
Biology
zine hydrate, primary or secondary amines can proceed ac-
Antitumor Screening
[18]
cording to Errede et al.
via nucleophilic attack at C of
4
the oxazine ring to afford N-(1-adamantoyl) substituted an-
Antitumor screening was performed at the National Cancer
thranilic acid hydrazides 5a–d, 2-(1-adamantoylamino)-N- Institute (NCI), Bethesda, Maryland, USA. The synthesized
alkyl-substituted benzamides 5e–j, and 1-(2-methoxy- Compounds were subjected to the NCI in vitro disease-ori-
[19, 20]
phenyl)-4-[2-(1-adamantoylamino)-substituted benzoyl]- ented human cells screening panel assay
. About 60 cell
piperazines 6a–c respectively (Scheme 2, Table 1).On carry- lines of nine tumor subpanels were incubated with five con-
Table 1. Physical properties and molecular formulae of the synthesized compounds.
—————————————————————————————————————————————————————————————
Comp.
X
R
Solvent
Mp. (°C)
Yield % Formulae*
—————————————————————————————————————————————————————————————
3a
3b
3c
3d
4a
4b
4c
4d
5a
5b
5c
5d
5e
5f
5-Br
–
EtOH-H2O
EtOH-H2O
EtOH
237–239
235–237
185–187
221–222
195–197
185–186
205–207
165–166
165–167
171–173
220–222
155–157
138–139
151–153
97–99
65
70
73
68
50
57
55
53
57
55
58
60
50
59
55
60
63
66
50
49
44
50
48
40
43
46
42
45
60
69
70
73
C18H20BrNO3
C18H20ClNO3
C19H23NO3
5-Cl
–
5-CH3
4,5-(OCH3)2
6-Br
–
–
EtOH-H2O
CHCl3
C20H25NO5
–
C18H18BrNO2
C18H18ClNO2
C19H21NO2
6-Cl
–
EtOH
6-CH3
6,7-(OCH3)2
5-Br
–
CHCl3
–
EtOH
C20H23NO4
NH2
Benz. Pet.- ether
Benz. Pet.- ether
CHCl3-EtOH
CHCl3-EtOH
CH3OH-H2O
CH3OH-H2O
CH3OH-H2O
EtOH-H2O
EtOH-H2O
EtOH-H2O
EtOH
C18H22BrN3O2
C18H22ClN3O2
C19H25N3O2
C20H27N3O4
C20H25ClN2O2
C21H28N2O2
C22H30N2O4
C21H27ClN2O2
C22H30N2O2
C23H32N2O4
C29H34ClN3O3
C30H37N3O3
C31H39N3O5
C18H20ClN3O
C19H23N3O
5-Cl
NH2
5-CH3
4,5-(OCH3)2
5-Cl
NH2
NH2
C2H5
C2H5
C2H5
C3H7
C3H7
C3H7
–
5-CH3
4,5-(OCH3)2
5-Cl
5g
5h
5i
155–157
143–145
103–105
131–133
121–123
141–143
165–167
183–185
205–207
181–183
175–176
187–189
178–179
243–245
238–239
215–216
228–229
5-CH3
4,5-(OCH3)2
5-Cl
5j
6a
6b
6c
7a
7b
7c
7d
7e
7f
5-CH3
4,5-(OCH3)2
6-Cl
–
EtOH
–
EtOH
NH2
EtOH
6-CH3
6-Cl
NH2
EtOH
C2H5
C2H5
C3H7
C3H7
C3H7
2-thienyl
2-thienyl
5-CH3-2-furyl
5-CH3-2-furyl
CH3OH
C20H23ClN2O
C21H26N2O
6-CH3
6-Cl
CH3OH
CHCl3
C21H25ClN2O
C22H28N2O
6-CH3
6,7-(OCH3)2
5-Cl
CHCl3
7g
8a
8b
8c
8d
CHCl3
C23H30N2O3
C23H24ClN3O2S
C24H27N3O2S
C24H26ClN3O3
C25H29N3O3
EtOH
5-CH3
5-Cl
EtOH
EtOH
5-CH3
EtOH
—————————————————————————————————————————————————————————————
* Analyzed for C, H, N; results were within ± 0.4% of the theoretical values for the formulae given.
Arch. Pharm. Pharm. Med. Chem. 333, 323–328 (2000)

Heterocyclic Systems Containing an Adamantane Nucleus
325
Table 2. Growth inhibitory action (GI50, TGI) of some selected in vitro tumor cell lines (µM)a.
—————————————————————————————————————————————————————————————–
Comp. No.
Leukemia
MOLT-4
Non-small cell
lung cancer
EKVX
Melanoma
Lox IMVI
Ovarian cancer
OVCAR-3
Breast cancer
MCF7
HL-60(TB)
GI50 TGI
GI50
TGI
GI50
TGI
GI50
TGI
GI50
TGI
GI50
TGI
—————————————————————————————————————————————————————————————–
b
5a
2.7
1.3
9.9
4.0
8.2
70.5
85.5
–
3.9
4.9
–
8.0
7.5
75.7
95.0
–
2.6
3.1
–
0.8
1.8
19.5
5b
60.5
–
–
–
28.7
5c
4.9
9.2
8.2
–
13.5
17.6
24.7
28.9
33.1
42.3
40.4
56.3
31.3
28.9
24.6
20.6
15.5
9.9
–
5.9
–
5d
8.8
–
17.4
18.6
34.6
26.4
22.4
51.1
36.9
50.6
48.6
39.9
45.6
2.2
–
7.1
–
98.0
–
7.4
80.0
–
7.9
–
5e
12.0
26.2
37.9
19.6
30.0
44.9
27.7
56.7
78.5
65.3
6.6
–
–
8.6
–
19.8
24.6
29.8
50.5
63.6
70.3
NT
20.4
38.7
32.8
48.0
49.2
63.8
3.5
–
5f
98.6
–
–
26.0
27.5
33.4
39.5
40.5
NT
84.7
95.5
–
–
–
–
5g
–
–
–
–
5h
–
–
–
–
–
5i
–
–
–
–
–
–
5j
–
–
–
–
–
–
8a
–
–
NT c
NT
NT
NT
–
90.9
–
NT
NT
NT
NT
–
70.5
–
8b
–
–
NT
NT
9.5
8c
–
–
NT
83.5
–
NT
17.5
32.1
42.5
92.6
–
8d
–
–
NT
NT
Melphalan
–
–
1.8
–
38.5
–
—————————————————————————————————————————————————————————————–
a Data obtained from NCI’s in vitro disease-oriented human tumor cell screen (see references [19–21] for detail), b GI50, TGI values >100 µM,
c NT, Not tested.
Table 3. Median growth inhibitory concentration (GI50, µM) of in vitro subpanel tumor cell lines.
————————————————————————————————————————————————————
Comp.
No.
Subpanel tumor cell linesa
——————————————————————————————————————
MG-
MIDb
I
II
III
IV
V
VI
VII
VIII
IX
————————————————————————————————————————————————————
5a
1.5
2.0
5.2
6.5
20.1
30.0
37.8
42.5
17.5
29.0
55.6
32.0
42.3
56.7
60.5
79.2
83.0
95.5
42.1
30.0
11.1
26.5
36.0
20.5
24.5
40.4
43.9
60.7
58.2
44.5
80.7
86.5
79.0
17.1
4.3
4.0
3.4
11.7
15.9
13.0
28.0
22.0
26.7
29.0
35.5
63.0
–
3.5
5.9
5.0
9.0
4.5
5.0
3.2
4.9
5b
5c
5.2
18.3
13.0
22.0
21.0
30.0
21.0
35.0
37.1
–
16.0
25.0
27.3
20.5
23.0
36.5
70.0
53.0
79.0
74.4
92.9
77.5
31.9
30.7
28.9
33.0
25.0
28.5
36.5
43.5
61.0
51.5
89.9
81.7
91.4
34.4
29.5
36.0
36.3
24.0
37.3
43.5
85.0
38.7
63.2
86.3
96.2
71.1
34.7
16.5
32.0
25.3
25.2
36.1
36.5
44.3
39.0
71.0
85.5
84.1
83.7
39.0
17.0
11.8
21.5
24.0
28.5
25.6
33.5
34.5
52.5
65.0
77.2
81.0
27.1
5d
3.0
5e
18.7
20.0
22.2
8.2
5f
5g
5h
5i
9.0
5j
11.2
35.0
31.0
32.0
37.5
20.1
8a
8b
–
–
8c
–
–
8d
–
–
Melphalan
38.5
43.0
————————————————————————————————————————————————————
a I, leukemia; II, non-small cell lung cancer; III, colon cancer; IV, CNS cancer; V, melanoma; VI, ovarian cancer; VII, renal cancer;
VIII, prostate cancer; IX, breast cancer. b GI50 full panel mean-graph midpoint (µM).
Arch. Pharm. Pharm. Med. Chem. 333, 323–328 (2000)

326
El-Sherbeny
centrations (0.01–100 µM) for each compound and were used against the nine tumor subpanels used, except compounds 5c,
5d, 5h, 5i, and 5j that showed moderate selectivity at the GI
to create log concentrationversus % growth inhibition curves.
Three response parameters (GI , TGI, and LC ) were cal-
50
level towards leukemia cell lines with ratios of 3.3, 3.9, 3.1,
3.7, and 3.1, respectively, while compounds 5a, 5b, 8b, 8c,
and 8d showed only mild selectivity toward the same leuke-
mia cell lines with ratios of 2.1, 2.5, 2.1, 2.4, and 2.2, respec-
tively (Table 4). The activity of the tested compounds could
be correlated to structure variations and modifications. The
obtained screening results showed that among the tested
compounds, the anthranilic acid hydrazides 5a–d and the
benzamide derivatives 5e–j are the most active members.
Introduction of electronegative moiety (either Br or Cl) at
position 5 of the phenyl ring favored the antitumor activity
rather than methyl or methoxy function as shown by 5a, 5b
> 5c, 5d, GI50 (MG-MID) values 3.2, 4.9, 17.0, and 11.8 µM
respectively. Meanwhile, compounds 5c and 5d showed in-
creased selectivity toward leukemia cell lines (Tables 3,4).
Replacing the amino group of the hydrazides 5b–d with either
ethyl or propyl moieties to afford the corresponding ben-
zamide derivatives 5e–j, decreased the magnitude of activity,
for example 5b > 5e > 5h; GI50 (MG-MID) values 4.9, 21.5,
25.6 µM respectively. Moreover reacting the hydrazids 5b,
5c with aldehydes produced the hydrazones 8a–d with re-
markable decrease in activity. Upon cyclizing 5b–j to the
corresponding quinazolinones, compounds 7a–g were ob-
tained which proved to be inactive towards the used tumor
cell lines.
50
50
culated for each cell line. The GI value corresponds to the
50
compound’s concentration causing 50% decrease in net cell
growth. The TGI value is the compound’s concentration
resulting in total growth inhibition and the LC value is the
50
compound’s concentration causing a net 50% loss of initial
cells at the end of the incubation period (48 h). Subpanel and
full panel mean-graph midpoint values (MG-MID) for certain
agents are the average of individual real and default GI , TGI
50
or LC values of all cells lines in the subpanel or the full
50
[20]
panel, respectively . The NCI antitumor drug discovery
screen has been designed to distinguish between broad-spec-
trum antitumor compounds and tumor or subpanel-selective
[21]
agents
(Tables 2–4).
In this study, the preliminary screening data of NCI indi-
cated that, compounds 4a–d and 6a–c proved to be inactive
towards the used tumor cell line (GI and TGI values
50
> 100 µM), while compounds 5a–j and 8a–d showed cyto-
toxic activity (Tables 2 and 3). With regard to sensitivity
against individual cell lines, compounds 5a and 5b showed
effectiveness against leukemia HL-60 (TB) with GI values
50
of 2.7, 1.3 µM, TGI values of 9.9, 60.5 µM respectively and
leukemia MOLT-4 with GI values of 4.0, 8.2 µM, TGI
50
values of 70.5, 85.5 µM respectively. Moreover compounds
5c–j proved to be effective against the same two cell lines
with GI values of 4.9, 8.8, 12.0, 26.2, 37.9, 19.6, 30.0, and
50
44.9 µM and 9.2, 17.4, 18.6, 34.6, 26.4, 22.4, 51.1, and
36.9 µM, respectively. Non-small cell lung cancer EKVX
Antiviral Testing
In Vitro Anti-Human Immunodeficiency-1 Virus (HIV-1)
proved to be sensitive towards compounds 5a–e with GI
50
values of 3.9, 4.9, 8.2, 7.1, and 8.6 µM respectively. On the
other hand, compounds 5a and 5b are particularly effective
The synthesized compounds were tested against HIV-1
virus by MedivirAB-Sweden. The procedure usedtoevaluate
against melanoma LOX IMVI with GI values of 8.0 and
the anti-HIV-1 potency is designed to detect agents acting at
50
[22]
7.5 µM, TGI values of 75.7, 95.0 µM respectively. Ovarian
any stage of the virus reproductive cycle
. The assay
cancer OVCAR-3 was also sensitive towards compounds
involves the killing of T4 Lymphocytes by HIV-1, com-
5a–d with GI values of 2.6, 3.1, 9.9, and 7.4 respectively.
pounds that interact with virions or virus gene-product to
50
Regarding breast cancer MCF7 higher sensitivity was ob- interfere with viral activities will protect cells from cytolysis.
The median effective concentration (EC ) of the tested com-
served with compound 5a,b with GI values of 0.8, 1.8 µM,
50
50
pounds using infected cells was compared with their cyto-
and TGI values of 19.5, 28.7 µM respectively, and com-
toxic effect (IC ) in uninfected cultures. Infected and
pounds 5c,d; 8a,b with GI values of 5.9, 7.9, 3.5, and 9.5
50
50
uninfected cultures were incubated without test compounds
to serve as controls. Zidovudine (AZT) treated cultures were
also used as a positive control, the screening results are shown
in Table 5
Compounds 4a, 4b proved to possess moderate activity
against HIV-1 cytopathic effect at effective concentrations
µM respectively. With regard to broad spectrum antitumor
activity, the active compounds showed GI < 100 µM against
50
leukemia, non-small cell lung, colon, melanoma, ovarian,
renal, prostate, and breast cancer subpanel cell lines (Ta-
ble 3).
Compounds 5a–d showed effective growth inhibition GI
50
(EC ) of 50.3 and 69.2 µM respectively. Compounds 4c, 4d,
50
(MG-MID) values of 3.2, 4.9, 17.0, and 11.8 µM respectively,
5a, 5b, 5c, and 5d were highly cytotoxic to the uninfected T4
cells at the concentration which showed marginal antiviral
activity in the infected cultures. The rest of the tested com-
pounds didn’t show activity or toxicity at the highest concen-
tration used (200 µM), probably because of a solubility
problem in the cultures media used (Table 5).
In conclusion, the results obtained from this study revealed
that, the anthranilic acid hydrazides 5a–d and benzamide
derivatives 5e–j containing adamantane nucleus exhibited
broad spectrum antitumor activity. Compounds 5a, 5b are the
while compounds 5e–j and 8a,b showed GI (MG-MID)
values of 21.5, 24.0, 28.5, 25.6, 33.5, 34.5, 52.5, and 65.0 µM
respectively. On the other hand, compounds 8c,d are the least
50
effective members of this series with GI (MG-MID) values
50
of 77.2 and 81.0 µM respectively. The ratio obtained by
dividing the compounds full panel MG-MID (µM) by its
individual subpanel MG-MID concentration (µM) is consid-
[21]
ered as a measure for the compound selectivity
. Ratios
between 3 and 6 refer to moderate selectivity, while ratios
greater than 6 indicate selectivity towards the corresponding
cell line-subpanel. Most of the tested compounds proved to
most active antitumor agent in this study GI (MG-MID)
50
be non-selective with broad spectrum antitumor activity values 3.2 and 4.9 µM, respectively, followed by 5c and 5d
Arch. Pharm. Pharm. Med. Chem. 333, 323–328 (2000)

Heterocyclic Systems Containing an Adamantane Nucleus
327
Table 4. Selectivity ratios of the tested compounds towards leukemia sub-
panel (full panel MG-MID/leukemia MG-MID).
Acknowledgments
The author would like to express his gratitude to the NCI, Bethesda,
Maryland, USA for antitumor testing of the compounds. Thanks are also due
to N. G. Johansson, Medivir AB, Sweden for performing the antiviral screen-
ing.
——————————————————————————————
Comp.
Full panel
Leukemia
GI50
MG-MID(µM) MG-MID (µM) Selectivity ratio
——————————————————————————————
5a
5b
5c
5d
5e
5f
3.2
4.9
1.5
2.0
2.1
2.5
3.3
3.9
1.1
1.2
1.3
3.1
3.7
3.1
1.5
2.1
2.4
2.2
Experimental Part
17.0
11.8
21.5
24.0
28.5
25.6
33.5
34.5
52.5
65.0
77.2
81.0
5.2
Synthesis
3.0
Elemental analyses (C, H, N) were performed on a Perkin-Elmer 2400
analyzer (Perkin-Elmer. Norwalk, CT. USA) at the Central Laboratory of the
College of Pharmacy, King Saud University. All compounds were within
± 0.4% of the theoretical values. Melting points were determined in open
capillaries on an electrothermal melting-point apparatus (Electrothermal
Engineering Ltd., Essex, UK) and are uncorrected. 1HNMR spectra were
recorded in DMSO-d6 on a Varian EM 360 (90 MHz) instrument using
tetramethylsilane (TMS) as an internal standard (chemical shift in δppm).
18.7
20.0
22.2
8.2
5g
5h
5i
9.0
5j
11.2
35.0
31.0
32.0
37.5
N-(1-Adamantoyl)-Substituted Anthranilic Acids (3a–d)
8a
8b
8c
8d
1-Adamantanecarbonyl chloride 2 (9.9 g, 0.05 mol), was added portion-
wise to a stirred solution of the appropriate anthranilic acid 1a–d (0.05 mol)
and triethylamine (5.01 ml, 0.05 mol) in dichloromethane (50 ml). The
reaction mixture was then stirred at room temperature for 10 h., the separated
solid was filtered, washed with water, dried, and crystallized (Table 1).
1HNMR (DMSO-d6) 3a: δ 1.74–2.05 (m,15H, adamantyl-H), 6.02 (brs, 1H,
NH), 6.99–7.56 (m, 3H, Ar-H), 9.85(s, 1H, COOH). 3b: δ 1.82–2.09 (m,15H,
adamantyl-H), 6.98–7.94 (m, 4H, Ar-H, NH), 10.02 (s, 1H, COOH). 3c: δ
1.68–2.17 (m,15H, adamantyl-H), 2.43 (s, 3H, CH3), 6.33 (brs, 1H, NH),
7.01–7.82 (m, 3H, Ar-H), 10.50 (s, 1H, COOH).
——————————————————————————————
Table 5. In vitro anti-human immunodeficiency-1 virus (HIV-1) testing
results.
——————————————————————————————
Substituted 2-(1-Adamantyl)-4H-3,1-benzoxazin-4-ones (4a–d)
Comp. No.
——————————————————————————————
IC50a (µM)
EC50b (µM)
A mixture of the appropriate N-(1-adamantoyl) anthranilic acid 3a–d
(0.01 mol) and acetic anhydride (20 ml) was heated under reflux for 4 h.
Excess acetic anhydride was evaporated in vacuo and the obtained solid was
crystallized from the appropriate solvent (Table 1). 1HNMR (DMSO-d6) 4a:
δ 1.71–2.04 (m,15H, adamantyl-H), 7.04–7.66 (m, 3H, Ar-H). 4c: δ 1.71–
2.04 (m,15H, adamantyl-H), 2.23 (s, 3H, CH3), 7.32–7.83 (m, 3H, Ar-H).
4d: δ 1.78–2.11 (m,15H, adamantyl-H), 3.97 (s, 3H, OCH3), 4.01 (s, 3H,
OCH3), 7.01 (s, 1H, Ar-H), 7.50 (s, 1H, Ar-H).
4a
>200.0
>200.0
80.0
50.3
4b
69.2
–
4c
4d
65.8
–
5a
15.8
–
5b
15.1
–
5c
38.9
–
N-(1-Adamantoyl)-Substituted Anthranilic Acid Hydrazides (5a–d) and
2-(1-Adamantoylamino)-N-alkyl-Substituted Benzamides (5e–j)
5d
40.5
–
AZTc
35.6
0.007
Hydrazine hydrate 98% (2.5 ml, 0.05 mol) or the appropriate amine
(0.05 mol) was added dropwise to 4a–d (0.01 mol) over a period of 15 min.
The reaction mixture was stirred at 80 °C for 3 h, evaporated in vacuo and
the obtained residue was triturated with ice-water, filtered, dried, and crys-
tallized (Table 1). 1HNMR (DMSO-d6) 5a: δ 1.77–2.03 (m,15H, adamantyl-
H), 4.55 (brs, 2H, NH2), 6.99–7.63 (m, 4H, Ar-H, NH), 7.99 (brs, 1H, NH).
5d: δ 1.78–2.08 (m,15H, adamantyl-H), 3.97 (s, 3H, OCH3), 4.00 (s, 3H,
OCH3), 4.68 (brs, 2H, NH2), 7.11 (s, 1H, Ar-H), 7.26 (s, 1H, Ar-H), 7.50
(brs, 1H, NH), 8.03 (brs, 1H, NH). 5e: δ 1.06–1.21 (t, 3H, J = 7.0 Hz,
-CH2CH3), 1.74–2.11 (m,15H, adamantyl-H), 2.91–3.01 (q, 2H, J = 7.0 Hz,
CH2CH3), 6.98–7.56 (m, 3H, Ar-H), 8.82 (brs, 1H, NH), 9.22 (brs, 1H, NH).
5g: δ 0.99–1.03 (t, 3H, J = 7.0 Hz,-CH2CH3), 1.72–2.02 (m,15H, adaman-
tyl-H), 2.92–2.99 (q, 2H, J = 7.0 Hz, CH2CH3), 3.97 (s, 3H, OCH3), 3.99 (s,
3H, OCH3), 7.04 (s, 1H, Ar-H), 7.35 (s, 1H, Ar-H), 8.23 (brs, 1H, NH), 8.77
(brs, 1H, NH). 5h: δ 0.98–1.04 (t, 3H, J = 7.0 Hz,-CH2CH3), 1.59–2.01
(m,17H, CH2CH3, adamantyl-H), 3.22–3.40 (m, 2H, NCH2), 6.33 (brs, 1H,
NH), 7.01–7.86 (m, 4H, Ar-H, NH). 5i: δ 1.01–1.06 (t, 3H, J = 7.0 Hz,-
CH2CH3), 1.62–2.05 (m,17H, CH2CH3, adamantyl-H), 2.38 (s, 3H, Ar-
CH3), 3.33–3.41 (m, 2H, NCH2), 6.03 (brs, 1H, NH), 6.77–6.86 (m, 3H,
Ar-H), 8.63 (brs, 1H, NH).
——————————————————————————————
a 50% inhibitory concentration (molar conc. of compounds which cause
50% inhibition of cell growth).
b 50% effective concentration (molar conc. of compounds which cause 50%
protection against HIV cytopathic effect).
c Positive control.
with GI (MG-MID) values of 17.0 and 11.8 µM, respec-
50
tively. Moreover compounds 5c, 5d, 5h, 5i, and 5j showed
particular selectivity toward leukemia cell lines with selec-
tivity ratios of 3.3, 3.9, 3.1, 3.7, and 3.1 respectively. Regard-
ing the anti-HIV-1 activity, only the adamantane containing
benzoxazinone nucleus 4a and 4b showed moderate activity
at effective concentration of 50.3 and 69.2 µM, respectively,
so these ring systems need additional derivatization in the
hope of obtaining more potent antitumor and antiviral agents.
Arch. Pharm. Pharm. Med. Chem. 333, 323–328 (2000)

328
El-Sherbeny
1-(2-Methoxyphenyl)-4-[2-(1-adamantoylamino)-Substituted Benzoyl]-
Antiviral Testing
piperazines (6a–c)
In Vitro Anti-Human Immunodeficiency-1 Virus (HIV-1)
A mixture of the appropriate oxazine 4b–d (0.01 mol) and 1-(2-
methoxyphenyl)piperazine (3.84 g, 0.02 mol) in ethanol (20 ml) was heated
under reflux for 4 h. The reaction mixture was evaporated in vacuo and the
obtained solid was triturated with ice-water, filtered, dried, and crystallized
(Table 1). 1HNMR (DMSO-d6) 6a: δ 1.77–2.01 (m,15H, adamantyl-H),
2.55–2.74 (m, 8H, -CH2-), 3.95 (s, 3H, OCH3), 6.93–7.34 (m, 7H, Ar-H),
8.33 (brs, 1H, NH). 6b: δ 1.71–1.98 (m,15H, adamantyl-H), 2.29 (s, 3H,
CH3), 2.60–2.77 (m, 8H, -CH2-), 3.99 (s, 3H, OCH3), 7.01–7.41 (m, 7H,
Ar-H), 7.98 (brs, 1H, NH).
Compounds were prepared for assay by dissolving in DMSO then diluted
1:100 in cell culture medium before preparing serial dilution and placed in
microtiter trays. T4 lymphocytes (CEM cell line) were added and after a brief
interval (1min or more). HIV-1 was added, resulting in a 1:200 final dilution
of each of the tested compounds. Cultures were incubated 37 °C in 5% CO2
atmosphere for 6 days. Tetrazolium salt XTT was added to all cells and
cultures were incubated to allow formazan colour development by viral cells.
Individual wells were analyzed spectrophotometrically to quantitative for-
mazan production and in addition were viewed microscopically for detection
of viable cells. Results were compared with controls and AZT treated wells
as a positive control and a determination about activity was made as a
Substituted 2-(1-Adamantyl)-3-(amino or alkyl)-3,4-dihydroquinazolin-
4-ones (7a–g)
percentage protection of T4 cells against HIV-1 cytopathic effect [22]
.
Method A
Hydrazine hydrate 98% (2.5 ml, 0.05 mol) or the appropriate amine (0.05
mol) was added dropwise to a stirred solution of 4b–d (0.01 mol) in n-butanol
(50 ml). The reaction mixture was heated under reflux for 14 h. On cooling,
the precipitated solid was filtered, washed with water, dried, and crystallized.
References
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Method B
M. Al-Obaid, Med. Chem. Res. 1996, 6, 148.
A mixture of the appropriate 5b, c, e, f, h, i, j (0.01 mol) and polyphos-
phoric acid (PPA) (5 g) was heated at 150 °C for 2 h. After cooling, the
reaction mixture was poured onto ice-water (100 ml) and neutralized with
10% sodium hydroxide solution. The separated solid was filtered, washed
with water, dried, and crystallized (Table 1). 1HNMR (DMSO-d6) 7a: δ
1.60–1.97 (m,15H, adamantyl-H), 4.55 (brs, 2H, NH2), 6.95–7.59 (m, 3H,
Ar-H). 7b: δ 1.69–1.96 (m,15H, adamantyl-H), 2.28 (s, 3H, CH3), 5.03 (brs,
2H, NH2), 6.96–7.87 (m, 3H, Ar-H). 7c: δ 1.02–1.09 (t, 3H, J = 7.0 Hz,
CH2CH3), 1.63–1.95 (m,15H, adamantyl-H), 2.99–3.37 (q, 2H, J = 7.0 Hz,
CH2CH3), 7.03–7.89 (m, 3H, Ar-H). 7e: δ 0.99–1.03 (t, 3H, J = 7.0 Hz,
CH2CH3), 1.59–1.96 (m,17H, CH2CH3 , adamantyl-H), 2.99–3.11 (t, 2H, J
= 7.0 Hz, NCH2), 7.03–7.92 (m, 3H, Ar-H). 7g: δ 0.97–1.04 (t, 3H, J = 7.0
Hz, CH2CH3), 1.59–1.92 (m,17H, CH2CH3, adamantyl-H), 3.01–3.12 (t, 2H,
J = 7.0 Hz, NCH2), 3.98 (s, 3H, OCH3), 4.01 (s, 3H, OCH3), 7.03 (s, 1H,
Ar-H), 7.42 (s, 1H, Ar-H).
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[4] M. A. El-Sherbeny, F. A. Badria, S. A. Kheira, Med. Chem. Res. 1996,
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2-(1-Adamantoylamino)-N-arylideno-Substituted Benzoic Acid Hydrazides
(8a–d)
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A mixture of 5b and 5c (0.01 mol) and the appropriate aldehyde (0.01 mol)
in ethanol, was heated under reflux for 2 h. After cooling, the separated solid
was filtered, dried, and crystallized (Table 1). 1HNMR (DMSO-d6) 8a: δ
1.69–2.05 (m,15H, adamantyl-H), 7.11–8.12 (m, 6H, Ar-H), 8.25 (brs, 1H,
NH), 8.45 (brs, 1H, NH), 10.12 (s, 1H, =CH). 8b: δ 1.71–2.11 (m,15H,
adamantyl-H), 2.42 (s, 3H, CH3), 7.04–8.17 (m, 6H, Ar-H), 8.27 (brs, 1H,
NH), 8.33 (brs, 1H, NH), 9.98 (s, 1H, =CH). 8c: δ 1.66–2.03 (m,15H,
adamantyl-H), 2.60 (s, 3H, CH3), 6.99–7.97 (m, 6H, Ar-H, NH), 8.34 (brs,
1H, NH), 10.50 (s, 1H, =CH).
[12] A. Chimirri, S. Grasso, A. M. Monforte, P. Monforte, M. Zappala,
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Biological Testing
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Antitumor Activity
Galatulas, J. Pharm. Belg. 1993, 48, 378.
Under a sterile condition, cell lines were grown in RPMI 1640 media
(Gibco, NY, USA) supplemented with 10% fetal bovine serum (biocell, CA,
USA), 5 × 105 cell/ml was used to test the growth inhibition activity of the
synthesized compounds. The concentration of the compounds ranging from
0.01–100 µM were prepared in phosphate buffer saline. Each compound was
initially solubilized in dimethyl sulfoxide (DMSO), however, each final
dilution contained less than 1% DMSO. Solutions of different concentrations
(0.2 ml) were pipetted into separate well of microtiter tray in duplicate. Cell
culture (1.8 ml) containing a cell population of 6 × 104 cells/ml was pipetted
into each well. Controls, containing only phosphate buffer saline and DMSO
at identical dilutions, were also prepared in the same manner. These cultures
were incubated in a humidified incubator at 37 °C. The incubator was
supplied with 5% CO2 atmosphere. After 48 h, cells in each well were diluted
10 times with saline and counted. The counts were corrected for the dilu-
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tion [19,20]
.
Received: February 7, 2000 [FP455]
Arch. Pharm. Pharm. Med. Chem. 333, 323–328 (2000)