Synthesis of actinomycin d analogs: XXIII.1 actinocin derivatives containing azacrown fragments

Article abstract of DOI:10.1134/S1070363210040213

A number of actinocin amides containing residues of aza-15-crown-5 and aza-18-crown-6 where crown fragments were separated from the heterocyclic chromophore by the residues of ω-amino acids were obtained as actinomycin D models. Pleiades Publishing, Ltd.,

Full text of DOI:10.1134/S1070363210040213

ISSN 1070-3632, Russian Journal of General Chemistry, 2010, Vol. 80, No. 4, pp. 809–813. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © D.V. Ovchinnikov, E.N. Glibin, A.V. Garabadzhiu, N. G. Plekhanova, 2010, published in Zhurnal Obshchei Khimii, 2010, Vol. 80,
No. 4, pp. 648–652.
Synthesis of Actinomycin D Analogs:
XXIII.1 Actinocin Derivatives Containing
Azacrown Fragments
D. V. Ovchinnikov, E. N. Glibin†, A. V. Garabadzhiu, and N. G. Plekhanova
St. Petersburg State Institute of Technology, Moskovskii pr. 26, St. Petersburg, 190013 Russia
e-mail: rvwp98@gmail.com
Received December 18, 2009
Abstract―A number of actinocin amides containing residues of aza-15-crown-5 and aza-18-crown-6 where
crown fragments were separated from the heterocyclic chromophore by the residues of ω-amino acids were
obtained as actinomycin D models.
DOI: 10.1134/S1070363210040213
Earlier [2] we showed that actinomycin D was able
to complexation with Na+ cations, similarly to crown
compounds. We ascribed this ability of actinomycin D
to the structure of its pentapeptidelactone rings
consisting of alkylaminoacids. Thereupon as model
structures for actinomycin D we designed and
synthesized actinocin derivatives, containing radicals
of benzo-15-crown-5 and benzo-18-crown-6, con-
nected either directly to phenoxazinee chromophore
[3], or via spacers of various length [1]. Studying a
way of binding of such compounds with DNA [4, 5]
and their antineoplastic properties [6, 7] has shown
that they depend both on structure of crown fragment
and on its position in a drug molecule. Among such
compounds there can be potential anticancer drugs,
while studying of their interaction with DNA can
clarify the mode of binding of such compounds to
DNA [8–11].
of N-{[benzo-18(15)-crown-6(5)]-4'-ylaminocarbamo-
yl}alkinyl-2-nitro-3-benzyloxy-4-methylbenz-amides
[1] we started from 2-nitro-3-benzyloxy-4-methyl-
benzoyl chloride [12] and hydrochloride of an
appropriate amino acid ester. Obtained N-alkoxy-
carbonylalkyl-2-nitro-3-benzyloxy-4-methylbenzamides
were converted into the corresponding acyl azides and
coupled with aminobenzocrowns.
At such approach in a stage of azide synthesis (in
case of amino-benzocrowns) the yields seldom exceeded
60–70%, and due to inaccessibility of intermediate
compounds and complexity of removal of nonreacted
starting material the use of considerable excess of one
of the components to achieve higher yields was not
possible. To avoid these obstacles in this work we
obtained compounds IIa–IIf from 2-nitro-3-benz-
yloxy-4-methyl-benzamides Ia–Ie, which, in turn,
were prepared using Schotten–Baumann procedure
from the corresponding amino acids and 2-nitro-3-
benzyloxy-4-methylbenzoyl chloride.
The key intermediates in the synthesis of
substituted actinocin amides are the corresponding
amides of 2-amino-3-hydroxy-4-Х-benzoic acids. In
our case they are {[aza-15(18)-crown-5(6)]-ylamino-
carbamoyl}-2-amino-3-hydroxy-4-methylbenzamids
(Ia–If). The most convenient approach to such
compounds is catalytic reduction of the corresponding
2-nitro-3-benzyloxy-4Х-benzamides. In the synthesis
Compounds Iа–Iе were subjected to condensation
with the corresponding aza-crown ethers using N-
ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ)
[12] (Scheme 1). Structures of the obtained compounds
are shown in Scheme 3.
Compounds IIa–IIf have been catalytically reduced
to the corresponding 2-amino-3-hydroxy benzamides
IIIa–IIIf which upon oxidation with p-quinone led to
the target compounds IVa–IVf (Scheme 2).
1
For communication XXII, see [1].
† Deceased.
809

810
OVCHINNIKOV et al.
Scheme 1.
O
O
O
N
O
N
O
Cl
O
R(R')
n
n
NO2
NO2
NO2
H2N(CH2)nCO2H
EEDQ
HR(R')
OBzl
OBzl
OBzl
Ia_If
IIa_IIf
Scheme 2.
O
O
R(R')
R(R')
O
n
n
N
O
O
N
O
N
R(R')
n
N
O
N
O
NH2
[O]
H2/Pd(C)
IIa_IIf
OH
IVa_IVf
IIIa_IIIf
Scheme 3.
O
O
R(R')
R(R')
n
n
N
O
O
N
N
O
N
O
n = 1, 2, 5
O
O
O
O
N
N
,
.
R' =
R =
O
O
O
O
O
1:4 (A), methanol–chloroform–3% aqueous ammonia
solution (B), ethyl acetate–hexane, 1:1 (C).
Commercial reagents were used as obtained, while
solvents were additionally purified by known
techniques and stored over molecular sieves 4 Å in the
darkness.
EXPERIMENTAL
1H NMR spectra of compounds IIа–IIf and IVа–
IVf were recorded on a Bruker WM400 (400 MHz)
instrument in DMSO–d6 or CDCl3. Melting points
were determined on a Koefler model HMK apparatus
and were published without correction. TLC analyses
were carried out on Merck silicagel 60 F254 plates
using the following systems: methanol–chloroform,
N-[(1-Aza-15-crown-5)-yl-carbamoyl]methyl-2-
nitro-3-benzyloxy-4-methylbenzamide (IIа). To a
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SYNTHESIS OF ACTINOMYCIN D ANALOGS: XXIII.
811
stirred suspension of 0.172 g (0.5mmol) of N-glycyl-
(4-methyl-3-benzyloxy-2-nitro)benzamide in 3ml of
anhydrous dioxane under argon at ambient temperature
0.252 g (0.55 mmol) of EEDQ was added in one
N-[(1-Aza-18-crown-6)-yl-carbamoyl]methyl-2-
nitro-3-benzyloxy-4-methylbenzamide (IId) was
obtained similarly to IIa from 0.172 g (0.5 mmol) of
N-glycyl-(4-methyl-3-benzyloxy-2-nitro)benzamide
and 0.132 g (0.5 mmol) of 1-aza-18-crown-6. Yield
0.251 g (85%), chromatographically homogenous
according to TLC (systems A, B), mp 161oC. 1H NMR
spectrum, δ, ppm: 2.34 s (3H, Ar–CH3); 3.5 br.s (2H,
CO–CH2–NH); 3.54–4.56 br.m (20H, OCH2CH2O);
4.60–4.72 br.m (4H, NCH2CH2O); 5.25 s (2H, O–
CH2–Ph); 7.25–7.38 m (5H, Ar–H); 7.41, 7.43 d (2H,
Ar–H). Found, %: C 59.71, 59.84; H 7.44, 7.53; N
7.16, 7.21. C29H39N3O10. Calculated, %: C 60.08; H
7.32; N 6.78.
portion, followed by
a
solution of 0.110
g
(0.5 mmol) of 1-aza-15-crown-5 in 2ml of anhydrous
dioxane. The reaction mixture was stirred till complete
disappearance of Ia (monitored by TLC in system A).
After removing volatiles in vacuo on a rotary
evaporator the residue was crystallized from an ethyl
acetate-hexane mixture to give IIa as a white solid
chromatographically homogenous according to TLC
1
(system A). Yield 0.234 g (86 % ), mp, 154oC. H
NMR spectrum, δ, ppm: 2.31 s (3H, Ar–CH3), 3.52 s
(2H, CO–CH2–NH), 3.54–4.32 br.m (16H,
OCH2CH2O), 4.45–4.65 br.m (4H, NCH2CH2O), 5.21
s (2H, O–CH2–Ph), 7.25–7.42 br.m (5H, Ar–H, 2H,
Ar–H). Found, %: C 59.63, 59.78; H 6.65, 6.72; N
7.57, 7.64. C27H35N3O9. Calculated, %: C 59.44; H
6.47; N 7.70.
N-[(1-Aza-18-crown-6)-yl-carbamoyl]ethyl-2-
nitro-3-benzyloxy-4-methylbenzamide (IIe) was
obtained similarly to IIa from 0.129 g (0.5 mmol) of
N-β-alanyl-(4-methyl-3-benzyloxy-2-nitro)benzamide
and 0.132 g (0.5 mmol) of 1-aza-18-crown-6. Yield
0.253 g (84%), chromatographically homogenous
according to TLC (systems A, B), mp 171oC, 1H NMR
spectrum, δ, ppm: 2.32 s (3H, Ar–CH3); 2.69 t (2H,
COCH2CH2N); 3.04 t (2H, COCH2CH2N); 3.44–4.51
br.m (20H, OCH2CH2O); 4.56–4.59 br.m (4H,
NCH2CH2O); 5.26 s (2H, O–CH2–Ph) 7.25–7.36 m
(5H, Ar–H); 7.4, 7.42 d (2H, Ar–H). Found, %: C
60.38, 60.51; H 7.72, 7.81; N 6.30, 6.46. C30H41N3O10.
Calculated, %: C 60.65; H 7.48; N 6.63.
N-[(1-Aza-15-crown-5)-yl-carbamoyl]ethyl-2-
nitro-3-benzyloxy-4-methylbenzamide (IIb) was
obtained similarly to IIa from 0.179 g (0.5 mmol) of
N-β-alanyl-(4-methyl-3-benzyloxy-2-nitro)benzamide
and 0.110 g (0.5mmol) of 1-aza-15-crown-5. Yield
0.258 g (92%), chromatographically homogenous
according to TLC (systems A, B), mp 162oC. 1H NMR
spectrum, δ, ppm: 2.33 s (3H, Ar–CH3); 2.71 t (2H,
COCH2CH2N); 3.08 t (2H, COCH2CH2N); 3.48–4.30
br.m (16H, OCH2CH2O); 4.43–4.64 br.m (4H,
NCH2CH2O); 5.23 s (2H, O–CH2–Ph) 7.26–7.38 m
(5H, Ar–H); 7.41, 7.43 d (2H, Ar–H) Found, %: C
60.23, 60.41; H 6.94, 7.12; N 7.28, 7.35. C28H37N3O9.
Calculated, %: C 60.10; H 6.66; N 7.51.
N-[(1-Aza-18-crown-6)-yl-carbamoyl]penthyl-2-
nitro-3-benzyloxy-4-methylbenzamide (IIf) was
obtained similarly to IIa from 0.2 g (0.5 mmol) of N-ε-
caproyl-(4-methyl-3-benzyloxy-2-nitro)benzamide and
0.132 g (0.5 mmol) of 1-aza-18-crown-6. Yield 0.297 g
(92%), chromatographically homogenous according to
TLC (systems A, B), mp 169oC, 1H NMR spectrum, δ,
ppm: 2.18 m (2H, CH2N); 2.35 s (3H, Ar–CH3), 3.11
m (2H, CH2CH2CH2); 3.24 m (2H, CH2CH2CH2); 3.31
m (2H, CH2CH2CH2); 3.45 m (2H, COCH2); 3.52–4.57
br.m (20H, OCH2CH2O); 4.58–4.71 br.m (4H,
NCH2CH2O); 5.22 s (2H, O–CH2–Ph) 7.26–7.40 m
(5H, Ar–H); 7.39, 7.42 d (2H, Ar–H). Found, %: C
61.82, 61.95; H 8.21, 8.33; N 6.02, 6.15. C33H47N3O10.
Calculated, %: C 62.20; H 7.90; N 6.22.
N-[(1-Aza-15-crown-5)-yl-carbamoyl]penthyl-2-
nitro-3-benzyloxy-4-methylbenzamide (IIc) was
obtained similarly to IIa from 0.2 g (0.5 mmol) of N-ε-
caproyl-(4-methyl-3-benzyloxy-2-nitro)benzamide and
0.110 g (0.5 mmol) of 1-aza-15-crown-5. Yield
0.264 g (88%), chromatographically homogenous
according to TLC (systems A, B), mp 158oC. 1H NMR
spectrum, δ, ppm: 2.15 m (2H, CH2N); 2.31 s (3H, Ar–
CH3), 3.12 m (2H, CH2 CH2CH2); 3.25 m (2H,
CH2CH2CH2); 3.34 m (2H, CH2CH2CH2); 3.47 m (2H,
COCH2); 3.5–4.32 br.m (16H, OCH2CH2O); 4.42–4,61
br.m (4H, NCH2CH2O); 5.24 s (2H, O–CH2–Ph) 7.27–
7.39 m (5H, Ar–H); 7.4, 7.43 d (2H, Ar–H). Found, %:
C 61.63, 61.79; H 7.24, 7.32; N 7.18, 7.35.
C31H43N3O9. Calulated, %: C 61.88; H 7.20; N 6.98.
2-Amino-N,N'-bis-[(1-aza-15-crown-5)-yl-carb-
amoyl]methyl-4,6-dimethyl-3H-3-oxophenoxazine-
1,9-dicarboxyamide (IVа). A solution of 0.055 g
(0.1 mmol) of IIа in 5 ml of methanol was
hydrogenated over Pd catalyst (5% Pd/C) at room
temperature and 1 bar pressure till complete reduction
to the corresponding 2-amino-3-hydroxy-4-metyl
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OVCHINNIKOV et al.
benzoic acid IIIa derivative (TLC monitoring, system
A). The catalyst was filtered off, washed with a little
portion of methanol and to thus obtained clear filtrate a
solution of 0.016 g (0.15 mmol) of p-quinone in 2 ml
of methanol was added in one portion. After keeping in
darkness for 15 h, the volatiles were removed in vacuo
on a rotary evaporator and the residue was redissolved
in 2 ml of acetonitrile and applied on a chromato-
graphic column (2×4 cm, Merck Kieselgel 60, 40–
63 μm). After washing with acetonitrile to remove
colored impurities, the eluent was changed for a
chloroform–methanol mixture (4 : 1) to elute the
product. Fractions containing IVa (TLC control,
system A) were collected, volatiles were removed in
vacuo on a rotary evaporator, and the residue was
crystallized from an ethyl acetate–hexane mixture to
afford IVa. Yield 0.037 g (87%), chromatographically
homogenous according to TLC (systems A, B), mp
2-Amino-N,N'-bis-[(1-aza-18-crown-6)-yl-carb-
amoyl]methyl-4,6-dimethyl-3H-3-oxophenoxazine-
1,9-dicarboxyamid (IVd) was obtained similarly to
IVa from 0.059 g (0.1 mmol) of IId. For chromato-
graphic purification a 1:1 mixture of chloroform–
methanol was used. Yield 0.039 g (83%), chromato-
graphically homogenous according to TLC(systems A,
B), mp 193oC, 1H NMR spectrum, δ, ppm: 1.62 s (3H,
Ar–CH3); 2.49 s (3H, Ar–CH3); 3.18 br.s (4H,
COCH2N); 3.38–4.46 br.m (20H, OCH2CH2O); 4.61–
4.75 br.m (4H, NCH2CH2O); 7.25, 7.36 d (2H, Ar–H).
Found, %: C 56.35, 56.47; H 7.09, 7.18; N 8.79, 8.83.
C44H64N6O16. Calculated, %: C 56.64; H 6.91; N 9.01.
2-Amino-N,N'-bis-[(1-aza-18-crown-6)-yl-carb-
amoyl]ethyl-4,6-dimethyl-3H-3-oxophenoxazine-
1,9-dicarboxyamid (IVe) was obtained similarly to
IVa from 0.060 g (0.1 mmol) of IIe. For chromato-
graphic purification a 1:1 mixture of chloroform–
methanol was used. Yield 0.044 g (91%), chromato-
graphically homogenous according to TLC (systems
1
184oC, H NMR spectrum, δ, ppm: 1.66 s (3H, Ar–
CH3); 2.58 s (3H, Ar–CH3); 3.26 s (4H, COCH2N);
3.45–3.91 br.m (16H, OCH2CH2O); 4.43–4.62 br.m
(4H, NCH2CH2O); 7.24, 7.33 d (2H, Ar–H). Found, %:
C 56.52, 56.63; H 6.84, 6.91; N 9.64, 9.72.
C40H56N6O14, Calculated, %: C 56.86; H 6.68; N 9.95.
1
A, B), mp 203oC, H NMR spectrum, δ, ppm: 1.65 s
(3H, Ar–CH3); 2.47 s (3H, Ar–CH3); 2.64 br.t (2H,
COCH2CH2N); 3.07 br.t (2H, COCH2CH2N); 3.41–
4.52 br.m (20H, OCH2CH2O); 4.58–4.72 br.m (4H,
NCH2CH2O,); 7.23, 7.35 d (2H, Ar–H). Found, %: C
57.23, 57.31; H 7.17, 7.24; N 8.45, 8.56. C46H68N6O16.
Calculated, %: C 57.49; H 7.13; N 8.74.
2-Amino-N,N'-bis-[(1-aza-15-crown-5)-yl-carb-
amoyl]ethyl-4,6-dimethyl-3H-3-oxophenoxazine-
1,9-dicarboxyamid (IVb) was obtained similarly to
IVa from 0.056 g (0.1 mmol) of IIb, Yield 0.034 g
(79%), chromatographically homogenous according to
TLC (systems A, B), mp 191oC, 1H NMR spectrum, δ,
ppm: 1.64 s (3H, Ar–CH3); 2.53 s (3H, Ar–CH3); 2.76
t (2H, COCH2CH2N); 3.11 t (2H, COCH2CH2N);
3.44–3.93 br.m (16H, OCH2CH2O); 4.46–4.67 br.m
(4H, NCH2CH2O); 7.22, 7.32 d (2H, Ar–H). Found, %:
C 57.52, 57.59; H 7.03, 7.11; N 9.31, 9.45.
C42H60N6O14. Calculated, %: C 57.79; H 6.93; N 9.63.
2-Amino-N,N'-bis-[(1-aza-18-crown-6)-yl-carb-
amoyl]penthyl-4,6-dimethyl-3H-3-oxophenoxazine-
1,9-dicarboxyamid (IVf) was obtained similarly to
IVa from 0.065
g (0.1 mmol) of IIf. For
chromatographic purification a 1:1 mixture of chloro-
form–methanol was used. Yield 0.042 g (81%),
chromatographically homogenous according to TLC
(systems A, B), mp 198oC, 1H NMR spectrum, δ, ppm:
1.66 s (3H, Ar–CH3); 2.01 m (2H, CH2N); 2.45 s (3H,
Ar–CH3); 3.08 m (2H, CH2CH2CH2); 3.18 m (2H,
CH2CH2CH2); 3.34 m (2H, CH2CH2CH2); 3.43 m (2H,
COCH2); 3.40–4.56 br.m (20H, OCH2CH2O); 4.61–
4.75 br.m (4H, NCH2CH2O); 7.21, 7.34 d (2H, Ar–H).
Found, %: C 59.53, 59.62; H 7.85, 7.98; N 7.81, 7.86.
C52H80N6O16. Calculated, %: C 59.75; H 7.71; N 8.04.
2-Amino-N,N'-bis-[(1-aza-15-crown-5)-yl-carb-
amoyl]penthyl-4,6-dimethyl-3H-3-oxophenoxazine-
1,9-dicarboxyamid (IVc) was obtained similarly to
IVa from 0.060 g (0.1 mmol) of IIc. Yield 0.043 g
(89%), chromatographically homogenous according to
TLC (systems A, B), mp 187oC, 1H NMR spectrum, δ,
ppm: 1.68 s (3H, Ar–CH3); 2.05 m (2H, CH2N); 2.29 s
(3H, Ar–CH3); 3.11 m (2H, CH2 CH2CH2); 3.23 m
(2H, CH2CH2CH2); 3.36 m (2H, CH2CH2CH2); 3.44 m
(2H, COCH2); 3.46–4.25 br.m (16H, OCH2CH2O);
4.48–4.71 br.m (4H, NCH2CH2O); 7.18, 7.34 d (2H,
Ar–H). Found, %: C 59.92, 60.03; H 7.83, 7.91; N
8.52, 8.65. C48H72N6O14 Calculated, %: C 60.24; H
7.58; N 8.78.
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