M.E. Khalifa
Journal of Molecular Structure 1229 (2021) 129843
[29]. Therefore, a molecular docking analysis was performed on the
synthesized compounds compared to Reversine to explore a cre-
ative class of Aurora inhibitors based on purine scaffold and realize
the binding modus of each molecule in the Aurora enzyme active
site.
2.4.2.2. 8-((2-Hydroxynaphthalen-1-yl)diazenyl)-1,3-dimethyl-3,7-
dihydro-1H-purine-2,6-dione (9). Scarlet red crystals (3.7 g, 53 %).
M.p. > 300°C. IR: νmax= 3341 (OH), 3059 (NH), 1688 (CO), 1649
(CO), 1540 (C=N) and 1406 (CH3) cm−1
.
1H NMR: δ/ppm= 3.29
(s, 3H, CH3–N1), 3.40 (s, 3H, CH3–N3), 6.44–7.95 (m, 6H, Ar–H),
8.85 (s, 1H, OH), 11.28 (s, 1H, NH–N7). 13C NMR: δ/ppm= 28.39
(C–N1 purine), 30.21 (C–N3 purine), 123.15, 123.45, 126.32, 126.51,
127.09, 128.70, 129.34, 140.17, (8C–naphthyl), 126.27 (C5–purine),
135.98 (C–N–naphthyl), 146.04 (C8–purine), 150.90 (C6–purine),
151.66 (C2–purine), 154.48 (C4–purine), 159.95 (C-OH–naphthyl).
MS (m/z, %): 350 (M+, 100). HRMS calc. for C17 H14 N6O3: 350.1127,
Found: 350.1181.
2. Experimental
2.1. Chemicals and instrumentations
Chemicals and instrumentations involved in this research are
fully identified and described elsewhere [30] and in supplemen-
tary file (S1).
2.4.2.3. 8-((1-Hydroxynaphthalen-2-yl)diazenyl)-1,3-dimethyl-3,7-
dihydro-1H-purine-2,6-dione (10). Reddish brick crystals (4.6 g, 66
%), M.p. > 300°C. IR: νmax= 3339 (OH), 3141 (NH), 1684 (CO),
2.2. Biological Analysis
The cultured cancer cells (DS Pharma Biomedical Co., Ltd., Os-
aka, Japan), cytotoxicity assay method and statistical analysis were
previously reported [30] and fully described in supplementary file
(S1). The relative cell viability in percentage was calculated accord-
1638 (CO), 1574 (C=N) and 1409 (CH3) cm−1
.
1H NMR: δ/ppm=
3.29 (s, 3H, CH3–N1), 3.44 (s, 3H, CH3–N3), 6.42–8.10 (m, 6H,
Ar–H), 8.99 (s, 1H, OH), 11.29 (s, 1H, NH–N7). 13C NMR: δ/ppm=
28.22 (C–N1), 30.17 (C–N3), 118.28 (C–N–naphthyl), 123.11, 123.42,
124.59, 125.05, 125.70, 129.34, 129.49, 135.98 (8C–naphthyl),
126.24 (C5–purine), 146.01 (C8–purine), 151.79 (C6–purine), 151.60
(C2–purine), 156.56 (C4–purine), 172.57 (C–OH–naphthyl). MS
(m/z, %): 350 (M+, 89). HRMS calc. for C17 H14 N6O3: 350.1127,
Found: 350.1181.
Abs570 treated sample
% Cell viability =
× 100.
(1)
Abs570 untreated sample
2.3. Docking methodology
The molecular docking technique was performed by using MOE
2015.10 software (The Chemical Computing Group Inc., Montreal,
2.4.2.4. 4-Amino-2-((1,3-dimethyl-2,6-dioxo-2,3,6,7-tetrahydro-
1H-purin-8-yl)diazenyl)-3-methyl-6-oxo-6,7-dihydrothieno[2,3-
b]pyridine-5-carbonitrile (11). Reddish brown crystals (4.4 g,
53 %). M.p. > 300°C. IR: νmax= 3335 (NH2), 3141 (NH), 2188
2.4. Synthesis
(CN), 1689 (CO), 1659 (CO), 1569 (C=N) and 1421 (CH3) cm−1
.
1H NMR: δ/ppm
=
2.46 (s, 3H, CH3–thienopyridine), 3.29 (s,
2.4.1. 8-Amino-1,3-dimethyl-3,4,5,7-tetrahydro-1H-purine-2,6-dione
(2)
3H, CH3–N1), 3.42 (s, 3H, CH3–N3), 4.22 (s, 2H, NH2), 10.70 (s,
1H, NH-pyridyl), 11.30 (s, 1H, NH–N7). 13C NMR: δ/ppm = 6.49
(CH3-thienopyridine), 27.89 (C-N1 purine), 30.24 (C–N3 purine),
81.42 (C5–thienopyridine), 112.69 (C2–thienopyridine), 113.21
A mixture of 8-chloro-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-
dione (1; 0.43 g, 20 mmol) and excess amount of concentrated am-
monia solution (20 mL) in ethanol (20 mL) was heated at 100 °C
in a sealed tube for 2 h. The reaction mixture was allowed to cool
at room temperature and left overnight. The collected product (2)
was washed with cold spirit several times and recrystallized from
ethanol to yield colorless powder (2.4 g, 61 %). M.p. > 310 °C (Lit.
≡
(C9–thienopyridine), 117.56 (C N), 128.14 (C5–purine), 134.32 (C3–
thienopyridine), 146.01 (C8–purine), 150.75 (C6–purine), 151.49
(C2–purine), 151.75 (C4–purine), 159.95 (C8–thienopyridine),
166.33 (C6–thienopyridine), 172.88 (C4–thienopyridine). MS (m/z,
%): 411 (M+, 34). HRMS calc. for C16 H13N9O3S: 411.0862, Found:
411.0891.
2.4.2. General method for preparation of 8-substituted
2.4.3. Synthesis of (Z)-N-(1,3-dimethyl-2,6-dioxo-2,3,6,7-tetrahydro-
1H-purin-8-yl)-2-(phenylamino)-2-thioxoacetohydrazonoyl cyanide
(13)
diazenyl-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione derivatives
(8–11)
A soln. of 8-amino-1,3-dimethyl-3,4,5,7-tetrahydro-1H-purine-
2,6-dione 2 (3.90 g, 20 mmol) in 5% HCl soln. (20 mL) was cooled
to 0–5 °C, and then NaNO2 (1.38 g, 20 mmol) was added in four
portions. The mixture was slow stirred for 1.5 h for complete di-
azotization. Coupler components (4–7) (1.88 g, 2.88 g, 2.88 g and
4.10 g, respectively, 20 mmol) were added in small portions with
continuous slow stirring at cold condition for further 1 h. The
yielded precipitates (4–7) were filtered off, washed with cold wa-
ter, dried and recrystallized from ethanol.
2-Phenylthiocarbamoyl derivative 7 (4.4 g, 20 mmol) was sus-
pended in 25 mL EtOH and 20% aq. KOH (30 mL). The mixture
was kept in refrigerator overnight. A freshly cooled solution of di-
azonium chloride 3 (4.2 g, 20 mmol), which freshly prepared by
adding cold sodium nitrite solution (1.38 g, 20 mmol) to cold sus-
pension of 2 (3.9 g, 20 mmol) in 12 mL concentrated HCl, was then
added dropwise with stirring to the cold suspension of (7). The re-
action mixture was allowed to stir at (0–5 °C) for additional 2 h
and kept overnight in refrigerator. The solid azo product (13) was
filtered off, dried and recrystallized from ethanol-DMF mixture as
2.4.2.1. 8-((4-Hydroxyphenyl)diazenyl)-1,3-dimethyl-3,7-dihydro-1H-
purine-2,6-dione (8). Brownish red crystals (3.4 g, 57 %). M.p. >
300°C. IR: νmax= 3165 (NH), 1687 (CO), 1651 (CO), 1550 (C=N) and
yellowish orange crystals (4.5 g, 59 %). M.p. > 300°C. IR: νmax
=
3204 (NH), 2202 (CN), 1644 (CO), 1597 (CO), 1539 (C=N) and 1442
1418 (CH3) cm−1
.
1H NMR: δ/ppm= 3.20 (s, 3H, CH3–N1), 3.41 (s,
(CH3) cm−1
.
1H NMR: δ/ppm= 3.14 (s, 3H, CH3–N1), 3.33 (s, 3H,
3H, CH3–N3), 6.79–7.91 (m, 4H, Ar–H), 9.98 (s, 1H, OH), 11.52 (s,
1H, NH–N7). 13C NMR: δ/ppm= 28.39 (C–N1), 30.21 (C–N3 purine),
116.14, 116.87, 127.09, 128.70 (4C–phenyl), 119.24 (C–N–phenyl),
126.27 (C5–purine), 146.04 (C8–purine), 150.91 (C6–purine), 151.68
(C2–purine), 154.49 (C4–purine), 159.95 (C–OH). MS (m/z, %):
300 (M+, 25.4). HRMS calc. for C13H12N6O3: 300.0971, Found:
300.0987.
CH3–N3), 7.24–7.44 (m, 5H, Ar–H), 8.64 (s, 1H, NH–purine), 9.77
(s, 1H, NH–Ph), 10.87 (s, 1H, C=N-NH). 13C NMR: δ/ppm= 28.23
(C–N1 purine), 30.21 (C–N3 purine), 108.36 (C=N-NH), 118.71 (CN),
122.34 (C5–purine), 124.17, 124.94, 125.71, 128.96, 129.31, 139.98
(6C–phenyl), 144.01 (C8–purine), 149.56 (C4–purine), 151.56 (C2–
purine), 153.08 (C6–purine), 180.15 (C=S). MS (m/z, %): 382 (M+,
51). HRMS calc. for C16 H14 N8O2S: 382.0960, Found: 382.0953.
2