Synthesis and DNA strand breakage activity of some 1,4-diazepines

Article abstract of DOI:10.1248/cpb.51.27

Reactions of 1,3-propanediamine with α-dicarbonyl compounds (1a - e) were examined and various condensed heterocyclic compounds such as 1,4-diazepines (2) and 3-pyrimidine derivatives (3) were obtained. Some of 1,4-diazepines (2) showed DNA strand breakag

Full text of DOI:10.1248/cpb.51.27

January 2003
Chem. Pharm. Bull. 51(1) 27—31 (2003)
27
Synthesis and DNA Strand Breakage Activity of Some 1,4-Diazepines
Nobuko MIBU, ,a Miho YUKAWA,a Nobuhiro KASHIGE,a Yukiko IWASE,a Yoshinobu GOTO,a
*
a
Fumio MIAKE,a Tadatoshi YAMAGUCHI,b Shigeru ITO,c and Kunihiro SUMOTO
a Faculty of Pharmaceutical Sciences, Fukuoka University; 8–19–1 Nanakuma, Jonan-ku, Fukuoka 814–0180, Japan:
b Faculty of Hygiene, Miyazaki Medical College; Kiyotake-cho, Miyazaki 889–1601, Japan: and c Institute of Biomaterials
and Bioengineering, Tokyo Medical and Dental University; Chiyoda-ku, Tokyo 101–0062, Japan.
Received July 26, 2002; accepted September 17, 2002
Reactions of 1,3-propanediamine with a-dicarbonyl compounds (1a—e) were examined and various con-
densed heterocyclic compounds such as 1,4-diazepines (2) and 3-pyrimidine derivatives (3) were obtained. Some
of 1,4-diazepines (2) showed DNA strand breakage activity.
Key words 1,4-diazepine; 1,3-pyrimidine; DNA strand breakage; plasmid pBR322; a-dicarbonyl; 1,3-propanediamine
Study of compounds having DNA breakage activity is azepine-type compound 2ꢀe8) in a one-pot reaction and evalu-
valuable because the DNA strand breakage process is in- ate their DNA breakage activities.
volved in various biological stages such as inflammation,
mutagenesis, carcinogenesis, or aging.1) The elucidation of Results and Discussion
DNA breakage activity may contribute to the clarification
Reactions of a-dicarbonyls (1a—e) with PD To syn-
of such important biological phenomena. Recently, we re- thesize a variety of the target DHDA derivatives, reactions of
ported2—5) that some pyrazine-related derivatives and other a-dicarbonyls (1a—e) with PD were attempted. The isolated
heterocyclic compounds derived from the reaction of 2,3-bu- products are shown in Charts 1 and 2.
tanedione with ethylenediamine derivatives show significant
DNA strand breakage activities.
The results are summarized in Table 1 and the physical
data are listed in Table 2. The structures of the products were
In our recent report,5) we obtained a 6,7-dihydro-5H-1,4- established by spectroscopic methods (1H- and 13C-NMR),
diazepine derivative (DHDA) (2b) having a 7-membered the results of which are summarized in Table 3. Full assign-
ring similar to that of the 6-membered ring system, and some ments of these signals were confirmed by their H–1H shift
1
of the products showed DNA breakage activity. The chem- correlation spectroscopy (1H–1H COSY), H-detected het-
1
istry of 1,4-diazepine has attracted much attention because of eronuclear multiple-quantum coherence (HMQC), and het-
the unique pharmacological activity toward central the ner- eronuclear multiple-bond correlation (HMBC) spectra. The
vous system (CNS) as observed in 1,4-benzodiazepines.6) By general procedure is as follows. The, a-dicarbonyl com-
contrast, simple monocyclic 1,4-diazepines have received pound was added to a solution of PD in the proper solvent,
less attention, with the exception of the 2,3-dihydro-1H-1,4- the resulting mixture was heated or refluxed, and purification
diazepine system.7) Regarding the 6,7-dihydro-5H-1,4-di- performed to give the products. As shown in Table 1, the re-
azepine (2) system as well as the corresponding unsaturated
system, the preparation of these analogues is known to be
difficult8) and occasionally unsuccessful. To obtain further in-
formation on pyrazine analogues, we investigated the reac-
tion of 1,3-propanediamine (PD) with a-dicarbonyl com-
pounds. In this paper, we describe the synthesis of 6,7-dihy-
dro-5H-1,4-diazepines (2b—d)9,10) and a related 1,4-di-
Chart 2
Chart 1
∗ To whom correspondence should be addressed. e-mail: mibu@fukuoka-u.ac.jp
© 2003 Pharmaceutical Society of Japan

28
Vol. 51, No. 1
Table 1. Reactions of PD with a-Dicarbonyls (1a—e)
Ratio of
1 : PD : (additive)
Entry
1
Solvent
Conditions
Products (Yield %)
3a (89)
3ꢀa (17)
3b (89)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1a
1a
1b
1b
1b
1c
1c
1c
1d
1d
1d
1d
1e
1e
1 : 1
1 : 1
1 : 1
1 : 2
1 : 1
1 : 1
1 : 1
1 : 1
Ether
EtOH
Ether
Ether
CHCl3
Ether
CH3CN
CH3CN
Benzene
Benzene
Benzene
EtOH
Reflux 40 min
65 °C 5 min, rt 1 d
Reflux 1 h
Reflux 8 h
Reflux 7 d
Reflux 3 h
80 °C 1 h
Reflux 1 d
Reflux 1 d
Reflux 5 h
Reflux 4 d
Reflux 1 d
85 °C 20 min
rt 7 h
2b (6),
2b (15)
5b (80)
3c (98)
3c (14)
2c (18),
2c (78)
2d (2),
1 : 1
2 : 1
4d (14),
4d (25),
6d (9)
6d (7)
1 : 1 : 0.04 (TsOH)
1 : 1 : 1 (AcOH)
1 : 1
2d (70)
2d (85)
2ꢀe (64),
2ꢀe (trace),
CH3CN
H2O
4ꢀe (1)
4ꢀe (37)
2 : 1
a) The yield of 2b (6%) was calculated by NMR analysis of the distilled fraction.
Table 2. Physical Data for Compounds (2—4)
Analysis (%)
Calcd (Found)
mp/bp (°C)
(Recryst solvent)
Formula HR-MS m/z
IR (cmꢂ1
(KBr)
)
Compd.
Formula
Calcd (Found)
C
H
N
2b
2c
60—65/
1 mmHg
C7H12N2·H2O
C12H14N2·0.25H2O
C17H16N2
59.12
(58.97
9.92
9.86
19.70
19.99)
C14H25N4 (2MꢃH)ꢃ
249.2079
1645 (CꢁN)
(249.2070)
Oil
75.56
(75.50
7.66
7.45
14.69
14.42)
C12H15N2 (MꢃH)ꢃ
187.1235
1635 (CꢁN)
1605 (CꢁN)
1580 (CꢁC of Ph)
1610 (CꢁN)
(187.1238)
2d
2ꢀe
3a
3ꢀa
3c
114—116
(EtOH)
82.22
(82.14
6.49
6.52
11.28
11.18)
C17H17N2 (MꢃH)ꢃ
249.1391
1575 (CꢁC of Ph)
(249.1391)
174—178
(EtOH)
C9H14N2
71.96
(71.71
9.39
9.19
18.65
18.66)
C9H13N2 (MꢂH)ꢃ
149.1078
3340 (NH)
1630 (CꢁC)
1610 (CꢁN)
3500 (NH)
(149.1085)
153—158
(Ether)
C11H14N2O
69.45
(69.24
7.42
7.43
14.73
14.78)
C11H15N2O (MꢃH)ꢃ
191.1185
1640 (CꢁO)
(191.1191)
187—189
(EtOH)
C11H14N2O
69.45
(69.42
7.42
7.38
14.73
14.69)
C11H15N2O (MꢃH)ꢃ
191.1185
3365 (br, NH, OH)
1630 (CꢁN)
(191.1181)
90—92
(Ether)
C12H16N2O·H2O
C31H26N2O2
69.34
(69.36
7.95
7.76
13.48
13.54)
C12H17N2O (MꢃH)ꢃ
205.1341
3315 (NH)
1675 (CꢁO)
1595 (CꢁC of Ph)
1665 (CꢁO)
1625 (CꢁN)
(205.1342)
4d
114—116
(AcOEt)
81.20
(81.17
5.72
5.81
6.11
6.06)
C31H27N2O2 (MꢃH)ꢃ
459.2073
(459.3069)
1580 (CꢁC of Ph)
actions of a-dicarbonyls (1b—e) gave the desired DHDA- mation rate was estimated at more than 95% yield by moni-
1
type compounds (2b—d) and the similar compound 2ꢀe in toring of the reaction mixture with the H-NMR spectrum,
good yields. However, in the case of phenylglyoxal (1a) with the isolated yield (15%) was quite low because of the diffi-
ether as a solvent, we could not obtain the DHDA derivative culty of trapping it in distillation. Alternatively, refluxing a
2a (R1ꢁPh, R2ꢁH), and the hexahydropyrimidine (HHP) de- solution of the isolated 3b in CHCl3 gave 2b by a ring-expan-
rivative (3a) was the sole product (89%) (see entry 1). Using sion reaction in 26% yield (see Method B in Experimental).
EtOH as a solvent, a tetrahydropyrimidine derivative (3ꢀa)
The reaction of 1-phenyl-1,2-propanedione (1c) and PD
was isolated in 17% yield (see entry 2). In a similar manner, was similar to that of 1b. Eggleston and Jackels11) reported
3b was isolated in excellent yield (89%) (entry 3). In this the formation of 3c in the reaction of 1c and PD in CCl4 or
entry, a small amount of 2b (6%) was also obtained. In the CD3OD. However, they did not mention the formation of the
reaction of mole ratio (1b : PDꢁ1 : 2), the propylene-bridged diazepine derivative 2c. The reaction under the conditions of
HHP derivative (5b) was obtained in good yield as unstable low temperature with ether as a solvent afforded HHP-type
crystals (entry 4). Recently,5) we reported the isolation of 2b 3c as the sole product (entry 6), and we found that the condi-
with the reaction of 1b and PD after 7-d refluxing in CHCl3 tion of higher temperature under prolonged heating resulted
(entry 5, see Method A in Experimental). Although the for- in the predominant formation of DHDA-type 2c (entries 7

January 2003
29
Table 3. 1H- and 13C-NMR Spectral Data of Compounds (2—6)
1H-NMR
Compound
N–CH2–
N–CH2–CH2–
Me or Ph or other
2ba)
2ca)
3.21 (4H, t, Jꢁ6.9)
3.35 (2H, t, Jꢁ6.7, H-7)
3.44 (2H, t, Jꢁ6.7, H-5)
3.55 (4H, m)
2.18 (2H, qu, Jꢁ6.9)
2.28 (2H, qu, Jꢁ6.7)
2.08 (3H, s, Me)
2.12 (3H, s, Me), 7.41—7.45 (3H, m, m-, p-PhH), 7.57—7.59 (2H, m,
o-PhH)
7.28—7.32 (4H, m, m-PhH), 7.33—7.37 (2H, m, p-PhH), 7.60—7.62
(4H, m, o-PhH)
1.76 (2H, qu, Jꢁ6.4, H-7), 2.21—2.24 (2H, m, H-8), 2.34 (2H, t, Jꢁ6.4,
H-6), 4.93 (1H, t, Jꢁ4.6, H-9), 6.57 (1H, br s, NH)
1.5 (1H, br s, NH), 5.03 (1H, s, H-2), 7.44—7.48 (2H, m, m-PhH), 7.54—
7.58 (1H, m, p-PhH), 8.04—8.08 (2H, m, o-PhH)
2da)
2ꢀea)
3aa)
2.36 (2H, m)
3.05—3.08 (2H, m, H-2)
3.45 (2H, t, Jꢁ5.2, H-4)
3.02—3.09 (2H, m)
2.02—2.06 (2H, m, H-3)
1.48—1.60 (2H, m)
3.28—3.34 (2H, m)
3ꢀab)
3ca)
3.27 (4H, t, Jꢁ5.8)
1.72 (2H, q, Jꢁ5.8)
5.03 (1H, s, PhCH–), 7.25 (1H, tm, Jꢁ7.3, p-PhH), 7.31 (2H, tm, Jꢁ7.3,
m-PhH), 7.46 (2H, dm, Jꢁ7.6, o-PhH)
2.62—2.68 (2H, m)
2.92—2.97 (2H, m)
3.55 (4H, t, Jꢁ6.7)
1.35—1.45 (1H, m)
1.55—1.60 (1H, m)
2.06 (2H, qu, Jꢁ6.7)
1.42 (3H, s, Me), 2.15 (2H, br s, NH), 7.41 (2H, tm, Jꢁ7.9, m-PhH), 7.52
(1H, tm, Jꢁ7.3, p-PhH), 8.49 (2H, dm, Jꢁ7.3, o-PhH)
7.30—7.34 (4H, m, m-PhAH), 7.37—7.40 (2H, m, p-PhAH), 7.41—7.44
(4H, m, m-PhBH), 7.54—7.58 (2H, m, p-PhBH), 7.61—7.63 (4H, m, o-
PhAH), 7.86—7.88 (4H, m, o-PhBH)
1.92—1.97 (4H, m, H-5), 2.35—2.38 (4H, m, H-4), 2.45—2.48 (4H, m,
H-6), 5.42 (2H, t, Jꢁ4.7, H-3)
1.05 (6H, s, MeA), 1.90 (6H, s, MeB)
4da)
4ꢀea)
2.93 (4H, t, Jꢁ6.9)
1.82 (2H, qu, Jꢁ6.9)
5bc)
3.40 (4H, t, Jꢁ6.7,
CꢁN–CH2–)
2.57—2.64, 2.75—2.80
(4H, m, H-4,6)
3.38 (4H, t, Jꢁ6.7, H-3)
3.50—3.59 (4H, m, H-1)
1.99 (2H, qu, Jꢁ6.7,
CꢁN–CH2 CH2–),
1.22—1.31, 1.50—1.62
(2H, m, H-5)
6da)
1.97—2.08 (4H, m)
7.24—7.28 (4H, m, m-PhBH), 7.28—7.35 (6H, m, p-PhBH, m-PhCH),
7.35—7.39 (2H, m, p-PhCH), 7.39—7.44 (4H, m, m-PhAH), 7.54—7.58
(2H, m, p-PhAH), 7.59—7.64 (8H, m, o-PhBH, -PhCH), 7.84—7.88 (4H,
m, o-PhAH)
13C-NMR
Compound
N–CH2–
N–CH2–CH2–
Me or Ph or other
2ba)
2ca)
47.91
32.14
32.15
22.9
48.34 (C-7)
48.58 (C-5)
48.93
23.98 (Me), 127.19 (o-C of Ph), 128.63 (m-C of Ph), 130.49 (p-C of Ph),
135.56 (C-Ph), 167.63 (C-3), 168.74 (C-2)
127.43 (o-C of Ph), 128.55 (m-C of Ph), 130.45 (p-C of Ph), 136.24 (C-
Ph), 166.76 (C-2,3)
22.77 (C-7), 23.87 (C-8), 26.65 (C-6), 101.28 (C-9), 141.21 (C-9a),
162.32 (C-5a)
71.78 (C-2), 128.59 (m-C of Ph), 129.06 (o-C of Ph), 133.49 (p-C of Ph),
134.79 (C-Ph), 196.70 (CꢁO)
75.30 (PhCH–), 127.51 (o-C of Ph), 128.74 (p-C of Ph), 129.23 (m-C of
Ph), 143.10 (C-Ph), 162.29 (C-2)
29.28 (Me), 76.75 (C-2), 127.91 (m-C of Ph), 132.61 (p-C of Ph), 130.19
(o-C of Ph), 135.84 (C-Ph), 204.35 (CꢁO)
127.24 (o-C of PhA), 128.53 (m-C of PhA), 129.17, 129.19 (o-, m-C of
PhB), 130.70 (p-C of PhA), 134.50 (p-C of PhB), 134.71 (C-PhB), 135.34
(C-PhA), 166.68 (CꢁN), 198.86 (CꢁO)
2da)
2ꢀea)
3aa)
3ꢀab)
3ca)
31.99
45.19 (C-2)
51.53 (C-4)
41.29
28.63 (C-3)
28.17
41.91
42.45
51.18
21.59
26.09
4da)
32.22
4ꢀea)
5bc)
6da)
40.97
28.35
23.50 (C-5), 24.55 (C-4), 37.93 (C-6), 111.09 (C-3), 140.59 (C-2), 195.80
(C-1)
13.28 (MeB), 29.80 (MeA), 73.72 (C-2), 173.06 (CꢁN)
42.61 (C-4,6)
57.31 (CꢁN–CH2–)
51.60
27.09 (C-5)
32.92 (CꢁN–CH2–CH2–)
32.16
127.18, 127.24 (o-C of PhB, PhC), 128.55, 128.60 (m-C of PhB, p-C of
PhC), 129.15, 129.19 (o-, m-C of PhA), 130.54, 130.69 (p-C of PhB, PhC),
134.51 (p-C of PhA), 134.74 (C-PhA), 135.31 (C-PhC), 135.91 (C-PhB),
165.42 (PhB–CꢁN–), 166.59 (PhC–CꢁN–), 198.85 (CꢁO)
51.72
a) Measured in CDCl3. b) Measured in CD3OD. c) Measured in ether-d10
.
and 8). The reaction of 1d and PD resulted in a trace forma- time, or employment of a solvent having higher polarity
tion of cyclized products, and intermolecular polymeric con- enhanced cyclization to give DHDA (2d) in good yields
densation was accelerated to give mainly multiple condensed (entries 11, 12).
compounds 4d12) and 6d (entries 9 and 10). In this reaction,
Our recent observation5) in the reaction of 1b and PD by
the addition of an acid catalyst such as p-toluenesulfonic acid 1H-NMR spectra suggested that an initial intermediate is a
(TsOH) or acetic acid (AcOH), prolongation of reaction common imino ketone I (diastereomers E and Z) (Chart 3).

30
Vol. 51, No. 1
These two diastereomers are apparently convertible through tween the ortho-aromatic HB of the benzoyl group and H1ꢀ
3, and both the E and Z isomer could afford HHP (3). On the of ꢁN–CH2– was observed, but no NOE between the ortho-
other hand, cyclization to DHDA (2) proceeds only via the aromatic HA of benzylidene-imine and H1ꢀ of ꢁN–CH2–
Z isomer because of its steric demand. In some benzil- was observed. This apparently indicates that the predominant
monoimines (for example, N-(1-phenylethyl)-1-benzoyl-ben- isomer of imino ketone 7 exists in the Z form. The steric en-
zylidene-imine) assigned the Z configuration around the ergy and population of Id(Z) and Id(E) were calculated by
CꢁN bond it has been established that the planes containing molecular dynamics (MD)15) using the Merck molecular
CꢁO and CꢁN groups (conjugated with two phenyl groups force field (MMFF)16) parameters. The results of calculation
bonded to them) take nearly orthogonal features to minimize showed that the steric energy of Id(Z) is lower than that of
the dipolar repulsion between them.13) The structural resem- Id(E) by an energy difference of 5.64 kcal/mol and the popu-
blance of imino ketone Id (R1ꢁR2ꢁPh) and the above ben- lation of Id(Z) is estimated at almost 100%. The failure of
zoyl-imines may be responsible for the predominant forma- the isolation of 3cꢀ (R1ꢁMe, R2ꢁPh) can also be attributable
1
tion of Id(Z) and no formation of HHP (3d). Although H- to the predominant formation of the imino ketone Ic
NMR studies on the 1 : 1 condensation of 1d with PD were (R1ꢁPh, R2ꢁMe) rather than the imino ketone Icꢀ (R1ꢁMe,
undertaken, this reaction was quite complicated and many R2ꢁPh).17) Cyclic a-dicarbonyl compound 1,2-cyclohexane-
condensation products prevented the assignment of Id(Z) and dione (1e) easily reacted with PD to produce a diazepine-
Id(E) in the spectra of the reaction mixture. Therefore we type compound 2ꢀe in 64% yield together with formation of a
tried to analyze the reaction using a simplified model system. trace of trimethylene-bridged dimeric 4ꢀe (1%) (entry 13).
Thus we synthesized 2-(3-dimethylaminopropylimino)-1,2- Our further trial of the reaction of mole ratio (1e : PDꢁ2 : 1)
diphenyl-ethanone (7) as a model for an imino ketone struc- in water afforded 4ꢀe predominantly, and a trace of 2ꢀe was
ture to reveal the configuration around the CꢁN bond (see detected by TLC, but the trial of isolation was unsuccessful
Chart 4). The NMR spectra of 7 indicated the presence of (entry 14). We observed the tendency for intermolecular
two diastereomers in a proportion of 95 : 5.14) In addition, in multiple condensation to take place and give polymeric com-
the nuclear Overhauser effect spectroscopy (NOESY) experi- pound 4d or 6d in the case of the reactions with 1d. Details
ment on the predominant isomer of 7, a significant NOE be- of these reaction conditions and experimental results are
summarized in Table 1.
Evaluation of DNA strand breakage activities by reac-
tion products (2—4) The DNA strand breakage activity
data are shown in Table 4. For comparison, the activities of
2,3-dihydropyrazine derivatives (DHP1 and DHP2) are also
listed in Table 4. These DNA strand breakage activities were
remarkably accelerated by the addition of cupric ion (Cu2ꢃ),
which may stimulate the production of active radicals, result-
ing in DNA strand breakage.18) The activity was based on the
Chart 3
Chart 4
Chart 5
Table 4. DNA Single-strand Breakage Activities of the Condensation Products (2—4) and 2,3-Dihydropyrazine Derivatives (DHP)
Real amounts of remaining ccc-DNA (%)a)
Without Cu2ꢃ, incubation for 3 h
With Cu2ꢃ (1 mM), incubation for 1 h
Compound
0.1 mM
1 mM
5 mM
10 mM
0.1 mM
1 mM
5 mM
10 mM
2b
2c
2d
2ꢀe
3a
99
100
100
96
96
100
100
88
94
100
100
71
93
99
99
62
96
96
94
94
100
84
71
93
99
86
97
65
97
88
75
59
87
86
67
51
78
77
66
78
87
94
95
100
6
3ꢀa
3b
3c
4d
DHP1b)
DHP2b)
94
91
76
0
97
64
0
a) The values of remaining ccc-DNA listed here were estimated by the control experiments with or without Cu2ꢃ
.
b) Data were taken from the ref. 4). DHP1: 2,3-dihydro-
5,6-dimethylpyrazine, DHP2: 2,3-dihydro-2,2,5,6-tetramethylpyrazine.

January 2003
31
evaporation of CH2Cl2 under reduced pressure, the residual yellow solid was
sublimed at 80—90 °C (oven temperature)/1 mmHg using a Kugel Role dis-
tillation instrument to give 3b (918 mg, 64.6%) as a colorless bar: mp
ꢄ25 °C. A solution of 3b (918 mg) in CHCl3 (20 ml) was refluxed for 7 d
followed by treating the resulting solution as described above in Method A
remaining amounts of covalently closed circular duplex DNA
(ccc-DNA) of plasmid pBR322, and the smaller value in
Table 4 represents higher activity. As shown in Table 4, 2b
showed high activity in the compounds tested by this proce-
dure (in the presence of Cu2ꢃ). In the absence of Cu2ꢃ, 2ꢀe to give 2b (205 mg, 26%).
2-(3-Dimethylamino-propylimino)-1,2-diphenyl-ethanone (7) Under
resulted in the highest activity and this activity was not accel-
erated by the addition of 1 mM Cu2ꢃ, the reason of which is
ambiguous at this moment. To the best of our knowledge, no
report has dealt with the DNA strand breakage activity of
such 1,4-diazepine derivatives. Further studies of these sim-
ple heterocycles are under investigation.
a nitrogen stream, a solution of benzil (1d) (3 mmol) and N,N-dimethyl-1,3-
propanediamine (3 mmol) in MeOH (25 ml) was refluxed for 6 h, the solvent
was removed in vacuo, and the residue was purified by flash chromatography
(CH2Cl2/MeOH as solvent) to give 7 as a reddish-brown oil (348 mg, 39%).
IR (neat) cmꢂ1: 1680 (CꢁO), 1630 (CꢁN), 1595 and 1580 (aromatic CꢁC).
1H-NMR (CDCl3) d: 1.86 (2H, m, H2ꢀ), 2.18 (6H, s, Me), 2.33 (2H, m,
H3ꢀ), 3.48 (2H, t, Jꢁ7.0, H1ꢀ), 7.35 (2H, m, meta-PhA), 7.40 (1H, m, para-
PhA), 7.47 (2H, m, meta-PhB), 7.60 (1H, m, para-PhB), 7.71 (2H, m, ortho-
PhA), 7.91 (2H, m, ortho-PhB). 13C-NMR (CDCl3) dC: 29.00 (C-2ꢀ), 45.34
(Me), 51.95 (C-1ꢀ), 57.52 (C-3ꢀ), 127.20 (ortho-PhA), 128.57 (meta-PhA),
129.17 (ortho-, meta-PhB), 130.71 (para-PhA), 134.51 (para-PhB), 134,75
(C-PhB), 135.33 (C-PhA), 166.43 (CꢁN), 198.90 (CꢁO). Positive HR-
FAB-MS: 295.1805 [MꢃH]ꢃ (Calcd for C19H23N2O: 295.1810). Anal. Calcd
for C19H22N2O: C, 77.52; H, 7.53; N, 9.52. Found: C, 77.74; H, 7.58; N,
9.53.
Experimental
Melting points were determined using a micro melting point apparatus
(Yanagimoto MP-S3) without correction. IR spectra were measured with a
Shimadzu FTIR-8100 IR spectrophotometer. Low- and high-resolution mass
spectra (LR-MS and HR-MS) were taken with a JEOL JMS HX-110 double-
focusing model equipped with a FAB ion source interfaced with a JEOL
1
JMA-DA 7000 data system. H- and 13C-NMR spectra were obtained on a
JEOL JNM a-500. Chemical shifts were expressed in d ppm downfield from
1
Assay of DNA Strand Breakage Activity The assay of the DNA strand
breakage activity of some compounds synthesized above were carried out
using ccc-DNA of plasmid pBR322 as a substrate as described in a previous
paper.3) The results of this assay of the condensation products including 1,4-
diazepines are summarized in Table 4.
an internal tetramethylsilane (TMS) signal for H-NMR and the carbon sig-
nal of the corresponding solvent [CDCl3 (77.0 ppm), and CD3OD
(49.0 ppm), and ether-d10 (65.3 ppm)] for 13C-NMR. Microanalyses were
performed with a Yanaco MT-6 CHN Corder. Routine monitoring of reac-
tions was carried out using precoated Kieselgel 60F254 plates (E. Merck).
Flash column chromatography was performed on silica gel (Fuji Silysia FL-
60D) with a UV detector. Commercially available starting materials were
used without further purification.
Acknowledgments We thank Ms. Shoko Ikeyama and Ms. Reiko
Takahira for their technical assistance.
General Procedure for the Reaction of a-Dicarbonyls (1a—e) with PD
To a stirred solution of PD (46 mmol) in the solvent (20 ml) mentioned in
Table 1 was added a solution of the selected a-dicarbonyl compound (1)
(46 mmol) in the same solvent (30 ml) dropwise at 0 °C, and the resulting
mixture was stirred for 30 min. Then about 1.5 g of solid KOH was added
for dehydration. In the case of 1b and 1c, the resulting solution was concen-
trated and allowed to stand at ꢂ10 °C overnight, and then the precipitated
material was collected by filtration, washed with the solvent used above, and
dried in a vacuum. In the other case (1a, 1d, or 1e), the solvent was removed
under a vacuum and the residue was purified by flash chromatography
(CH2Cl2/n-hexane–EtOAc as solvent). The structures of the products were
determined by elemental analysis and spectroscopic methods. The yields and
physical data of the compounds (2—6) are summarized in Tables 1, 2, and 3.
Some additional data on multiple condensed compounds 4ꢀe, 5b, and 6d are
shown below.
References and Notes
1) Sohal R. S., Weindruch R., Science, 273, 59—63 (1996).
2) Sumoto K., Irie M., Mibu N., Miyano S., Nakashima Y., Watanabe K.,
Yamaguchi T., Chem. Pharm. Bull., 39, 792—794 (1991).
3) Kashige N., Yamaguchi T., Mishiro N., Hanazono H., Miake F.,
Watanabe K., Biol. Pharm. Bull., 18, 653—658 (1995).
4) Yamaguchi T., Eto M., Harano K., Kashige N., Watanabe K., Ito S.,
Tetrahedron, 55, 675—686 (1999).
5) Yamaguchi T., Ito S., Mibu N., Sumoto K., Heterocycles, 57, 11—16
(2002).
6) Tucker H., Le Count D. J., “Comprehensive Heterocyclic Chemistry
II,” Vol. 9, ed. by Newkome G. R., Elsevier, Oxford, 1996, pp. 151—
182, 1039—1146.
7) Sharp J. T., “Comprehensive Heterocyclic Chemistry II,” Vol. 7, ed. by
Lwowski W., Elsevier, Oxford, 1984, pp. 594—651, 784—867.
8) 2ꢀe: McDougall R. H., Malik S. H., J. Chem. Soc. C, 1969, 2044—
2051 (1969).
9) 2d: Arnold D. R., Abraitys V. Y., McLeod D., Jr., Can. J. Chem., 49,
923—935 (1971).
10) 2d: Bai L., Zhang S., Li S., Wang G., Huaxue Xuebao, 45, 1009—
1013 (1987).
11) 3c: Eggleston D. S., Jackels S. C., Inorg. Chem., 19, 1593—1599
(1980).
12) 4d was isolated from the condensation of benzil with PD in the pro-
portion of 2 : 1. See: Welsh W. A., Reynolds G. J., Henry P. M., Inorg.
Chem., 16, 2558—2561 (1977).
13) Garcia-Ruano J. L., Henao M. A., Molina D., Perez-Ossorio R.,
Plumet J., Tetrahedron Lett., 33, 3123—3126 (1979).
14) Minor isomer 7(E) was detected by a signal of d: 3.64 (t, Jꢁ7.1, H1ꢀ)
and the other signals could not be assigned because their small signals
were complicated with those of major isomer 7(Z).
15) Mohamadi F., Richrds N. G. J., Guida W. C., Liskamp R., Lipton M.,
Caufield C., Chang G., Hendrickson T., Still W. C., J. Comput. Chem.,
11, 440—467 (1990).
16) Halgren T. A., J. Comput. Chem., 17, 490—519 (1996).
17) The apostrophized compound 3cꢀ or Icꢀ means reversed structure of
the two substituents R1 and R2 for the original type 3c or Ic.
18) Some amines have been shown to cause DNA strand breakage in the
presence of Cu2ꢃ by generation of hydroxyl radicals. For example see:
Hadi N., Singh S., Ahmad A., Zaidi R., Neurosci. Lett., 308, 83—86
(2001).
2,2-(Trimethylenediamino)dicyclo-hex-2-enone (4ꢀe): Yellow needles, mp
55—56 °C (ether). IR (KBr) cmꢂ1: 3375 (NH), 1675 (CꢁO), 1620 (CꢁC).
Positive HR-FAB-MS m/z: 263.1763 [MꢃH]ꢃ (Calcd for C15H23N2O2:
263.1760). The data of 1H- and 13C-NMR (CDCl3) are shown in Table 3.
N,Nꢀ-Bis-[1-(2-methylhexahydropyrimidin-2-yl)ethylidene]propane-1,3-
diamine (5b): Unstable colorless crystals. IR (KBr) cmꢂ1: 3300 (NH), 1630
(CꢁN). Positive HR-FAB-MS m/z: 345.2738 [MꢃNa]ꢃ (Calcd for
1
C17H34N6Na: 345.2743). The data of H- and 13C-NMR (CDCl3) are shown
in Table 3.
2-(3-{2-[3-(2-Oxo-1,2-diphenylethylideneamino)propylimino]-1,2-
diphenylethylidenamino}propylimino)-1,2-diphenylethanone (6d): Pale yel-
low solid. Positive HR-FAB-MS: 707.3382 [MꢃH]ꢃ (Calcd for C48H43N4O2:
707.3386). The data of 1H- and 13C-NMR (CDCl3) are shown in Table 3.
6,7-Dihydro-2,3-dimethyl-5H-1,4-diazepine (2b). Method A A solu-
tion of PD (740 mg, 10 mmol) in CHCl3 (10 ml) was added to an ice-cooled
solution of 1b (860 mg, 10 mmol) in CHCl3 (20 ml) under stirring and al-
lowed to stand at room temperature. After being stirred for 30 min at room
temperature and then refluxed for 7 d, the resulting solution was concen-
trated under slightly reduced pressure. The residual reddish oil was distilled
using a Kugel Role distillation instrument and the distillate at 60—65 °C
(oven temperature)/1 mmHg was collected to give 2b (187 mg, 15.1%) as a
colorless oil. The physical data are summarized in Tables 2 and 3.
Method B A solution of PD (764 mg, 10.3 mmol) in CH2Cl2 (10 ml)
was added dropwise to an ice-cooled solution of 1b (860 mg, 10 mmol) in
CH2Cl2 (20 ml) under stirring and allowed to stand at room temperature.
After being stirred for 30 min at room temperature, the solution became an
opaque yellow color with separated water. The next day the CH2Cl2 layer
was separated by decantation and was dried with anhydrous Na2SO4. After