Creation of concave-shaped conformation in crystal structures using an iminodicarbonyl linker. An application to solid-state intramolecular [4 + 4] photocycloaddition reactions of 2-pyridone derivatives

Article abstract of DOI:10.1246/bcsj.78.1127

Single-crystal X-ray structures of 6 carboxamides possessing two units of 2-pyridone moieties connected with an iminodicarbonyl linker were examined to show the usefulness of this linker for the creation of concave-shaped conformation in crystal structure

Full text of DOI:10.1246/bcsj.78.1127

Ó 2005 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 78, 1127–1131 (2005) 1127
Creation of Concave-Shaped Conformation in Crystal Structures
Using an Iminodicarbonyl Linker. An Application to Solid-State
Intramolecular [4 þ 4] Photocycloaddition Reactions of 2-Pyridone
Derivatives
Hyuma Masu, Ken Ohmori,1 Keiki Kishikawa,1 Makoto Yamamoto,1
ꢀ
Kentaro Yamaguchi,2 and Shigeo Kohmoto
Division of Quality Materials Science, Graduate School of Science and Technology,
Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522
1Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University,
1-33, Yayoi-cho, Inage-ku, Chiba 263-8522
2Faculty of Pharmaceutical Sciences at Kagawa Campus, Tokushima Bunri University,
Shido, Sanuki, Kagawa 769-2193
Received November 15, 2004; E-mail: kohmoto@faculty.chiba-u.jp
Single-crystal X-ray structures of 6 carboxamides possessing two units of 2-pyridone moieties connected with an
iminodicarbonyl linker were examined to show the usefulness of this linker for the creation of concave-shaped confor-
mation in crystal structures. In all cases, the carboxamides showed concave-shaped conformations in which two 2-pyri-
done moieties faced each other. Their solid-state [4 þ 4] photocycloaddition was carried out, and their reactivity was
considered based on geometrical parameters (distances, angles, and torsion angles) obtained from the single-crystal
X-ray analysis.
Solid-state photochemistry1 is advantageous over that in so-
lution in terms of stereoselectivity, owing to the rigidity of the
conformation of the reactants in the crystalline state. However,
this rigidity of conformation is often problematic. If molecules
to be reacted have incorrect conformations, it is difficult to ad-
just their conformations to reactive ones because of their im-
mobility in the crystalline state. In order to carry out a photo-
chemical reaction between two chromophores in the solid
state, it is required to place them in a desirable location in
which the distance between the chromophores should be with-
in a certain range, and also their molecular orbitals should be
well overlapped.2 Therefore, in the case of intramolecular sol-
id-state reaction between two reactive chromophores, it is es-
sential to choose the proper linker that has a tendency to place
the two linking chromophores in a concave-shape with the
above-mentioned requirements. During the course of our study
on an intramolecular photocycloaddition of aromatic com-
pounds in the solid state, we found that an iminodicarbonyl
group was a satisfactory linker for this purpose,3 and achieved
an absolute asymmetric synthesis in the solid-state [4 þ 4]
photocycloaddition of aromatic chain imides.4 The two aro-
matic chromophores linked by an iminodicarbonyl linker are
forced to face each other to create a concave-shaped conforma-
tion in the crystalline state. We have also shown the usefulness
of this linker for the construction of aromatic foldamers.5 In
this paper, we further demonstrate the usefulness of this intri-
guing linker for creating concave-shaped conformations of ar-
omatic compounds in the crystalline state. Intramolecular sol-
id-state [4 þ 4] photocycloadditions of 2-pyridone derivatives
are employed to attest to the effectiveness of this linker to cre-
ate such conformations as a further example.
Results and Discussion
Six 2-pyridone derivatives (1a–f) possessing two 2-pyridone
moieties connected with an iminodicarbonyl linker were pre-
pared to examine their conformations in the crystalline state.
The effectiveness of an iminodicarbonyl linker for the creation
of concave-shape conformations was evaluated by a single-
crystal X-ray diffraction analysis and their reactivity in intra-
molecular photocycloaddition in the solid-state (Scheme 1,
Table 1). Their single-crystal X-ray diffraction analysis
showed that they adopted concave-shaped conformations in
all cases. Their conformations were independent of the sub-
O
O
O
R2
O
R2
O
O
N
N
h
ν
N
R1
N
R1
solid-state
O
O
N
N
R1
R1
R1 R2
1a : Bn i-Pr
1b : Bn n-Bu 1e : Me n-Pr
1c : Bn Bn 1f : Me Bn
2a - f
R1 R2
1d : Me i-Pr
Scheme 1.
Published on the web June 6, 2005; DOI 10.1246/bcsj.78.1127

1128 Bull. Chem. Soc. Jpn., 78, No. 6 (2005)
Concave-Shaped Conformation in Crystal
Table 1. Crystallographic Data of Compounds 1a–1f and 2a
1a
1b
1c
1d
1e
1f
2a
Formula
F. W.
C29H27N3O4
481.55
C30H29N3O4
495.58
C33H27N3O4
529.59
C17H19N3O4
329.35
C17H19N3O4
329.35
C21H19N3O4
377.40
C29H27N3O4
481.55
Crystal system
Space group
tetragonal
P41212
17.168 (3)
17.168 (3)
8.467 (2)
90.000
monoclinic
P21=a
monoclinic
P21=a
monoclinic
C2=c
monoclinic
P21=n
monoclinic
P21=c
monoclinic
P21=a
ꢀ
a/A
18.771 (1)
22.567 (2)
12.440 (3)
99.92 (1)
5190 (1)
8
18.708 (2)
22.823 (2)
12.858 (1)
100.378 (8)
5400.0 (9)
8
27.354 (4)
13.567 (1)
16.434 (2)
125.401 (9)
4971 (1)
12
27.851 (3)
13.0681 (8)
16.030 (2)
122.219 (8)
4936.0 (9)
12
9.268 (2)
20.502 (4)
10.258 (2)
110.507 (3)
1825.5 (6)
4
15.935 (4)
23.222 (4)
14.534 (3)
114.21 (2)
4904 (1)
8
ꢀ
b/A
ꢀ
c/A
ꢁ/deg
ꢀ 3
V/A
Z
2495.6 (8)
4
radiation
T/K
RðFÞ
Mo Kꢂ
273
0.0437
Cu Kꢂ
298
0.0626
Cu Kꢂ
298
0.0555
Cu Kꢂ
298
0.0642
Cu Kꢂ
298
0.0525
Mo Kꢂ
173
0.0402
Cu Kꢂ
298
0.0569
Table 2. Geometrical Parameters (d, ꢀ1, and ꢀ2) and Photo-
chemical Reactivity of 2-Pyridone Derivatives in Solid-
StateaÞ
O
O
R1
O
R2
O
N
R1
N
d
R2
N
O
θ1
O
N
R1
R1
θ2
d/A ꢀ1/ꢁ ꢀ2/ꢁ ꢀ1 þ ꢀ2 Time/h Conv./%
ꢀ
1a
3.66 36.9
3.76 41.3
3.80 42.1
3.66 37.7
3.73 38.2
3.71 39.1
21.1
25.1
26.7
24.9
27.2
26.7
58.0
66.4
68.8
62.6
65.4
65.8
7
36
96
8
8
30
ꢂ99
1bbÞ
1cbÞ
1dbÞ
1ecÞ
1f
31
76
ꢂ99
95
96
a) Reaction was carried out at ca. 23 ꢁC. b) Parameters are giv-
en as average values of those of two independent molecules in
the unit cell. c) Parameters are given as average values of
those of three independent molecules in the unit cell.
X-ray diffraction analysis. They are iꢁn the range of 3.66–3.80
ꢁ
ꢀ
A (d), 36.9–42.1 (ꢀ1), and 21.1–27.2 (ꢀ2). These values indi-
cate that two 2-pyridone moieties are reasonably overlapped,
and should be photo-reactive in a [4 þ 4] cycloaddition mode
in the solid state.4 It is known that 2-pyridone derivatives un-
dergo a photochemical [4 þ 4] cycloaddition reaction,7 which
is an efficient and direct method to prepare eight-membered
carbocyclic rings, such as the carbocyclic skeleton of Taxol.8
However, examples of solid-state photoreaction of 2-pyridones
were limited. Some examples reported intramolecular 1,4-
electrocyclizations.9 Their intermolecular [4 þ 4] photodimeri-
zations have been found in inclusion complexes,10 and very
few show intermolecular reactions without the aid of host
molecules.11 If the solid-state intramolecular [4 þ 4] photocy-
cloadditions of 1a–1f occur efficiently, it proves that an imino-
dicarbonyl is an eminent linker for creating a concave-shape in
the crystalline state.
Fig. 1. ORTEP diagrams of a side view (a) and a top view
(b), and packing diagram (c) of 1a.
stituents at the imide and 2-pyridone’s nitrogen atoms. The X-
ray structure of 1a is shown in Fig. 1 as an example. In its
structure, the two 2-pyridone rings take the trans, syn-relation.
It is known that two 2-pyridone moieties prefer to orient in an
anti-parallel manner due to dipole–dipole interaction between
the two pyridone carbonyls.6 Its packing diagram shows that
the molecule has curled so as to have a compact conformation.
Intermolecularly, no stacking was observed. Table 2 gives the
geometrical parameters, the distance (d) between the centroids
of two 2-pyridone rings, the angle (ꢀ1) created with the two 2-
pyridone ring planes, and the torsion angle (ꢀ2) between the
two 2-pyridone ring planes, obtained from their single-crystal
Prior to their solid-state photochemical reactions, their pho-
tocycloadditions were carried out in benzene irradiated with a

H. Masu et al.
Bull. Chem. Soc. Jpn., 78, No. 6 (2005) 1129
with bulky substituents have a fairly stable atropisomeric con-
formation.15 Therefore, 2-pyridone derivatives 1 can also be
considered to be a combination of two units of atropisomeric
amides. These tendencies seem to be a unique characteristic
of the iminodicarbonyl linker, which is advantageous over oth-
er linkers. Some examples showed that linkers with the length
of three atoms, similar to the length of iminodicarbonyl, such
as propano16 and 2-azapropano,17 were ineffective to place the
two linking aromatic rings facing each other in their crystalline
state.
The present results show that an iminodicarbonyl is a useful
linker for the creation of a concave-shape in aromatic crystal
engineering, though the stereochemistry of the cycloadducts
obtained in the solid-state photochemical reactions is the same
as that observed in reactions occurring in solution.
Experimental
General. Common commercial reagents were used as re-
ceived from commercial suppliers without further purification.
IR spectra were measured on KBr pellets. UV–vis absorption
1
spectra are reported in ꢃmax and "max. H and 13C NMR spectra
were obtained in CDCl3. Chemical shifts are reported in delta
(ꢄ) units, parts per million (ppm) relative to TMS as an internal
standard. Coupling constants J are in Hz. A certain amount of sol-
vent molecules or water was included in several compounds upon
crystallization. This was taken into account in calculations of ele-
mental analysis. Unless otherwise noted, each spectrum was mea-
sured at room temperature.
Materials. 1,10-Dibenzyl-3,30-(N-isopropyliminodicarbonyl)-
di-2-pyridone (1a): 2-Hydroxynicotinic acid (3.00 g, 21.6 mmol)
was added to a water–methanol (7:1) solution (40 mL) of KOH
(85%, 2.86 g, 43.4 mmol). Then, benzyl bromide (5.20 mL,
43.7 mmol) was added to this solution. After being refluxed for
6.5 h, additional KOH (85%, 1.30 g, 19.7 mmol) was added to this
solution and refluxed further (2 h). After cooling to room temper-
ature, the solution was evaporated to half of the volume and acidi-
fied with an aqueous 10% HCl solution (25 mL). The yellow pre-
cipitate was collected by vacuum filtration and dried to give 1-
benzyl-2-oxo-1,2-dihydropyridine-3-carboxylic acid (yield 4.59
g, 93%).
Thionyl chloride (2.06 mL, 28.4 mmol) was added to the car-
boxylic acid (1.30 g, 5.68 mmol) in dry toluene (30 mL). After
the solution was heated at 80 ꢁC for 21 h with stirring, excess thi-
onyl chloride and toluene were evaporated. Isopropylamine (0.265
mL, 3.11 mmol), triethylamine (0.790 mL, 5.69 mmol), and dry
toluene (40 mL) were added to the mixture, and then the solution
was refluxed for two days with stirring. After cooling to room
temperature, the solution was washed with a saturated aqueous so-
lution of NaHCO3, and then with an aqueous 1 mol/L HCl solu-
tion. The separated organic phase was dried over MgSO4, filtered,
and evaporated. The residue was purified by silica-gel column
chromatography with hexane/ethyl acetate (3:2) as the eluent.
Further purification by recrystallization from hexane/chloroform
gave 1a as yellow crystals (0.390 g, 28%). In a similar way as
for 1a, other carboxamides 1b–1f were prepared in 49, 58, 29,
28, and 37% yields, respectively.
Fig. 2. ORTEP diagram (a) and packing diagram (b) of 2a.
high-pressure mercury lamp through a Pyrex filter. In all cases,
the corresponding [4 þ 4] photocycloadducts were obtained in
an almost quantitative yield. The stereochemistry of [4 þ 4]
photocycloadducts was unequivocally determined to be trans,
syn by the single-crystal X-ray diffraction analysis of 2a
(Fig. 2). The trans stereochemistry was reported in the intra-
molecular photocycloadditions of 2-pyridone derivatives in
solution,12 which was interpreted in terms of a dipole–dipole
interaction between the two pyridone carbonyls.
A solid-state photochemical reaction was carried out on a
finely ground sample of 2-pyridone derivatives placed between
two slide glasses. The irradiation of 1a–f with a high-pressure
ꢁ
mercury lamp in the solid state at ca. 23 C afforded the cor-
responding [4 þ 4] adducts 2a–f, which were the same prod-
ucts as those obtained in their solution photochemistry. The
geometrical parameters indicate that the larger their values be-
ꢀ
come, less reactivity is observed. Compounds 1b (d ¼ 3:76 A)
ꢀ
and 1c (d ¼ 3:80 A) with relatively large values of d required
a longer irradiation time for the reaction. Even after irradiation
for 36 and 96 h, the conversion for 1b and 1c was 31 and 76%,
respectively. These compounds also have larger values of ꢀ1
and ꢀ2 (1b: ꢀ1 þ ꢀ2 ¼ 66:4ꢁ, 1c: ꢀ1 þ ꢀ2 ¼ 68:8ꢁ) than those
of the others. In contrast, other 2-pyridone derivatives gave
conversions from 95% to almost quantitative after 7–30ꢁh irra-
ꢀ
diation. They have values of 3.66–3.71 A and 58.0–65.8 for d
and (ꢀ1 þ ꢀ2), respectively. The conformation of 1a was re-
flected in the stereochemistry of the cycloadduct 2a, which
suggested that cycloaddition occurred in a stereoselective way.
It is known that an amide unit prefers to take the cis confor-
mation,13 and that the folded conformations of aromatic amide
oligomers are more stable than those of aliphatic amides.14
Since an iminodicarbonyl linker can be considered as a se-
quential combination of two amide units, 2-pyridone deriva-
tives 1 might have a tendency to form a concave-shaped fold-
ing conformation. It is also known that some aromatic amides
1,10-Dibenzyl-3,30-(N-ꢁisopropyliminodicarbonyl)di-2-pyri-
done (1a): mp 211–213 C. IR (KBr) 2971 (br), 1655 (s), 1584
(s), 1548 (s), 1270 (m) cmꢃ1. UV–vis (CH3CN) ꢃmax ("), 243
(7300), 283 (3500), 341 (9300) nm. 1H NMR (CDCl3, 500
MHz) ꢄ 7.42 (dd, J ¼ 7:5, 2.2 Hz, 2H), 7.35–7.34 (m, 6H),

1130 Bull. Chem. Soc. Jpn., 78, No. 6 (2005)
Concave-Shaped Conformation in Crystal
7.29–7.27 (m, 4H), 7.14–7.13 (m, 2H), 5.60 (t, J ¼ 6:9 Hz, 2H),
5.04 (m7, J ¼ 6:9 Hz, 1H), 4.91 (s, 4H), 1.51 (d, J ¼ 6:7 Hz,
6H). 13C NMR (CDCl3, 125 MHz) ꢄ 169.4 (s), 159.2 (s), 141.5
(d), 140.1 (d), 135.2 (s), 129.0 (d), 128.9 (d), 128.4 (d), 105.2
(d), 52.5 (t), 49.4 (d), 20.5 (q). MS (EI) m=z 481 [Mþ]. Anal.
Calcd for C29H27N3O4: C, 72.33; H, 5.65; N, 8.73%. Found: C,
72.01; H, 5.63; N, 8.66%.
C, 66.83; H, 8.07; N, 11.13%. Found: C, 66.51; H, 5.07; N,
11.07%.
Photocycloaddition in Solid-State. Ground crystals of 1a
(0.020 g, 0.042 mmol) were placed between two glass plates.
The sandwiched sample was placed in a transparent polyethylene
bag. UV irradiation was carried out externally on this sample with
a 400 W high-pressure mercury lamp through a Pyrex filter for 6 h
at ca. 23 ꢁC in a water bath. Without purification, 2a was obtained
as a pure product in quantitative yield. The cycloadduct 2a was
recrystallized from hexane/ethyl acetate to give colorless crystals.
In a similar way as for 2a, other [4 þ 4] photocycloadducts 2b–2h
were obtained. The irradiation time and their yields are given in
Table 2.
1,10-Dibenzyl-3,3ꢁ0-(N-butyliminodicarbonyl)di-2-pyridone
1
(1b): mp 167–169 C (yellow crystals). H NMR (CDCl3, 500
MHz) ꢄ 7.49 (dd, J ¼ 7:1, 2.2 Hz, 2H), 7.37–7.26 (m, 10H),
7.16 (dd, J ¼ 6:9, 2.1 Hz, 2H), 5.62 (t, J ¼ 6:7 Hz, 2H), 4.92
(s, 4H), 3.98 (br, 2H), 1.76 (m, J ¼ 7:6 Hz, 2H), 1.42 (m6, J ¼
7:3 Hz, 2H), 0.94 (t, J ¼ 7:3 Hz, 3H). 13C NMR (CDCl3, 125
MHz) ꢄ 169.4 (s), 159.3 (s), 141.7 (d), 140.1 (d), 135.3 (s),
129.0 (d), 128.9 (d), 128.4 (d), 128.3 (s), 105.3 (d), 52.5 (t),
45.3 (t), 30.6 (t), 20.3 (t), 13.9 (q). MS (EI) m=z 495 [Mþ]. Anal.
Calcd for C30H29N3O4: C, 72.71; H, 5.90; N, 8.48%. Found: C,
72.61; H, 5.87; N, 8.39%.
1,10-Dibenzyl-3,30-(N-benzyliminodicarbonyl)di-2-pyridone
(1c): mp. 169–171 ꢁC (yellow crystals). IR (KBr) 3067 (m), 3031
(m), 1656 (s), 1582 (s), 1549 (s), 1244 (s) cmꢃ1. UV–vis (CH3CN)
ꢃmax ("), 257 (3200), 285 (2500), 343 (10000) nm. 1H NMR
(CDCl3, 400 MHz) ꢄ 7.54 (td, J ¼ 7:1, 2.1 Hz, 4H), 7.35–7.17
(m, 13H), 7.14 (dd, J ¼ 5:9, 2.2 Hz, 2H), 5.66 (t, J ¼ 6:9 Hz,
2H), 5.20 (s, 2H), 4.91 (s, 4H). 13C NMR (CDCl3, 125 MHz) ꢄ
169.3 (s), 159.2 (s), 142.1 (d), 140.3 (d), 137.5 (s), 135.3 (s),
128.8 (d), 128.3 (d), 128.2 (d), 127.9 (d), 127.7 (s), 126.8 (d),
105.2 (d), 52.4 (t), 48.6 (t). MS (EI) m=z 529 [Mþ]. Anal. Calcd
for C33H27N3O4: C, 74.84; H, 5.14; N, 7.93%. Found: C, 74.84;
H, 5.10; N, 7.87%.
1,10-Dimethyl-3,30-(N-isopropyliminodicarbonyl)di-2-pyri-
done (1d): mp. 220–222 ꢁC (yellow crystals). IR (KBr) 2976
(w), 1657 (s), 1590 (s), 1549 (s), 1268 (s) cmꢃ1. UV–vis (CH3CN)
ꢃmax ("), 252 (2700), 282 (2700), 340 (10000), 374 (4700) nm.
1H NMR (CDCl3, 500 MHz) ꢄ 7.75 (dd, J ¼ 7:3, 2.1 Hz, 2H),
7.24 (dd, J ¼ 6:6, 2.3 Hz, 2H), 6.04 (t, J ¼ 6:9 Hz, 2H), 4.98
(m7, J ¼ 6:9 Hz, 1H), 3.41 (s, 6H), 1.52 (d, J ¼ 6:7 Hz, 6H).
13C NMR (CDCl3, 125 MHz) ꢄ 169.3 (s), 159.8 (s), 141.5 (d),
141.3 (d), 128.6 (s), 104.9 (d), 49.5 (d), 37.9 (q), 20.3 (q). MS
(EI) m=z 329 [Mþ]. Anal. Calcd for C17H19N3O4: C, 62.00; H,
5.81; N, 12.76%. Found: C, 61.73; H, 5.80; N, 12.71%.
3,11-Dibenzyl-7-isopropyl-3,7,11-triazatetracyclo[7.2.2.2.2,5
-
05,9]pentadeca-12,14-diene-4,6,8,10-tetrone (2a): mp 158–160
ꢁC. IR (KBr) 2979 (w), 1784 (m), 1714 (s), 1676 (s), 1454 (m),
1370 (s), 1264 (s) cmꢃ1. UV–vis (CH3CN) ꢃmax ("), 258 (160)
nm. 1H NMR (CDCl3, 500 MHz) ꢄ 7.33–7.26 (m, 6H), 7.14–
7.12 (m, 4H), 6.36 (d, J ¼ 7:7 Hz, 2H), 6.26 (ddd, J ¼ 8:1, 4.7,
2.2 Hz, 2H), 5.06 (d, J ¼ 15 Hz, 2H), 4.56 (m7, J ¼ 7:0 Hz,
1H), 4.09 (m, 2H), 3.67 (d, J ¼ 15 Hz, 2H), 1.53 (d, J ¼ 7:0
Hz, 3H), 1.50 (d, J ¼ 7:0 Hz, 3H). 13C NMR (CDCl3, 125
MHz) ꢄ 172.6 (s), 168.2 (s), 135.1 (s), 133.6 (d), 132.1 (d),
128.9 (d), 128.2 (d), 61.9 (s), 57.9 (d), 50.5 (t), 45.4 (d), 19.4
(q), 19.0 (q). MS (EI) m=z 481 [Mþ]. Anal. Calcd for
C29H27N3O4: C, 72.33; H, 5.65; N, 8.73%. Found: C, 72.23; H,
5.63; N, 8.64%.
3,11-Dibenzyl-7-butyl-3,7,11-triazatetracyclo[7.2.2.2.2,505,9]-
pentadeca-12,14-diene-4,6,8,10-tetrone (2b): 1H NMR (CDCl3,
500 MHz) ꢄ 7.34–7.13 (m, 10H), 6.39 (d, J ¼ 8:2 Hz, 2H), 6.28
(m, 2H), 5.10 (d, J ¼ 15 Hz, 2H), 4.09 (m, 2H), 3.75 (dt,
J ¼ 13, 7.0 Hz, 1H), 3.69–3.65 (m, 3H), 1.76–1.66 (m, 2H),
1.42 (sext, J ¼ 7:3 Hz, 2H), 0.97 (t, J ¼ 7:3 Hz, 3H). 13C NMR
(CDCl3, 125 MHz) ꢄ 172.7 (s), 168.2 (s), 135.1 (s), 133.7 (d),
132.1 (d), 129.0 (d), 128.2 (d), 128.2 (d), 62.4 (s), 57.8 (d), 50.6
(t), 39.9 (t), 29.6 (t), 19.8 (t), 13.7 (q). MS (EI) m=z 495 [Mþ].
Anal. Calcd for C30H29N3O4: C, 72.71; H, 5.90; N, 8.48%. Found:
C, 72.42; H, 5.87; N, 8.34%.
3,7,11-Tribenzyl-3,7,11-triazatetracyclo[7.2.2.2.2,505,9]penta-
deca-12,14-diene-4,6,8,10-tetrone (2c): mp. 160–162 ꢁC. IR
(KBr) 3061 (w), 1787 (m), 1717 (s), 1672 (s), 1398 (m), 1245
(m) cmꢃ1. UV–vis (CH3CN) ꢃmax ("), 259 (970) nm. 1H NMR
(CDCl3, 500 MHz) ꢄ 7.44 (d, J ¼ 7:3 Hz, 2H), 7.37–7.26 (m,
9H), 7.12 (dd, J ¼ 7:7, 1.7 Hz, 4H), 6.37 (d, J ¼ 8:0 Hz, 2H),
6.28 (ddd, J ¼ 8:1, 4.7, 2.1 Hz, 2H), 5.10 (d, J ¼ 15 Hz, 2H),
4.94 (d, J ¼ 15 Hz, 1H), 4.82 (d, J ¼ 15 Hz, 1H), 4.08 (m,
2H), 3.65 (d, J ¼ 15 Hz, 2H). 13C NMR (CDCl3, 125 MHz) ꢄ
172.4 (s), 168.0 (s), 135.0 (s), 134.7 (s), 133.7 (d), 131.9 (d),
129.0 (d), 128.8 (d), 128.2 (d), 128.1 (d), 127.9 (d), 62.5 (s),
57.7 (d), 50.5 (t), 43.5 (t). MS (EI) m=z 530 [MHþ]. Anal. Calcd
for C33H27N3O4: C, 74.84; H, 5.14; N, 7.93%. Found: C, 74.76; H,
5.09; N, 7.88%.
1,10-Dimethyl-3,30-(N-propyliminodicarbonyl)di-2-pyridone
(1e): mp. 190–191 ꢁC (yellow crystals). IR (KBr) 2960 (w), 1657
.
(s), 1585 (m), 1546 (s), 1082 (m), 768 (m) cmꢃ1 1H NMR
(CDCl3, 500 MHz) ꢄ 7.79 (dd, J ¼ 7:0, 2.2 Hz, 2H), 7.24 (dd,
J ¼ 6:6, 2.1 Hz, 2H), 6.06 (t, J ¼ 7:1 Hz, 2H), 3.96 (br, 2H),
3.41 (s, 6H), 1.78 (m6, J ¼ 7:7 Hz, 2H), 0.99 (t, J ¼ 7:3 Hz,
3H). 13C NMR (CDCl3, 125 MHz) ꢄ 169.3 (s), 159.9 (s), 141.9
(d), 141.4 (d), 128.0 (s), 105.0 (d), 46.9 (t), 38.0 (q), 21.9 (t),
11.5 (q). MS (EI) m=z 329 [Mþ]. Anal. Calcd for C17H19N3O4:
C, 62.00; H, 5.81; N, 12.76%. Found: C, 61.94; H, 5.77; N,
12.73%.
1,10-Dimethyl-3,30-(N-benzyliminodicarbonyl)di-2-pyridone
(1f): mp. 206–208 ꢁC (yellow crystals). IR (KBr) 3063 (w), 1693
(m), 1656 (s), 1593 (s), 1549 (s), 1295 (m) cmꢃ1. UV–vis
(CH3CN) ꢃmax ("), 252 (4500), 282 (4200), 341 (10000), 372
(6000) nm. 1H NMR (CDCl3, 500 MHz) ꢄ 7.77 (dd, J ¼ 7:1,
2.2 Hz, 2H), 7.54 (d, J ¼ 7:4 Hz, 2H), 7.39–7.18 (m, 5H), 6.02
(t, J ¼ 6:9 Hz, 2H), 5.19 (s, 2H), 3.36 (s, 6H). 13C NMR (CDCl3,
125 MHz) ꢄ 169.1 (s), 159.7 (s), 142.2 (d), 141.8 (d), 137.5 (s),
128.2 (d), 127.8 (d), 127.3 (s), 126.7 (d), 104.9 (d), 48.4 (t),
37.9 (q). MS (EI) m=z 377 [Mþ]. Anal. Calcd for C21H19N3O4:
3,11-Dimethyl-7-isopropyl-3,7,11-triazatetracyclo[7.2.2.2.ꢁ2,5
-
05,9]pentadeca-12,14-diene-4,6,8,10-tetrone (2d): mp. 170 C.
IR (KBr) 2988 (w), 1784 (w), 1719 (s), 1673 (s), 1458 (w),
1399 (m), 1265 (m) cmꢃ1. UV–vis (CH3CN) ꢃmax ("), 258
(540) nm. 1H NMR (CDCl3, 500 MHz) ꢄ 6.62–6.56 (m, 2H),
6.36 (dd, J ¼ 8:7, 0.8 Hz, 2H), 4.53 (m7, J ¼ 7:0 Hz, 1H), 4.23
(m, 2H), 2.89 (s, 6H), 1.50 (d, J ¼ 7:0 Hz, 3H), 1.48 (d, J ¼
7:1 Hz, 3H). 13C NMR (CDCl3, 125 MHz) ꢄ 172.6 (s), 168.0
(s), 132.8 (d), 132.0 (d), 62.0 (s), 61.3 (d), 45.2 (d), 35.3 (q),
19.2 (q), 18.9 (q). MS (EI) m=z 329 [Mþ]. Anal. Calcd for

H. Masu et al.
Bull. Chem. Soc. Jpn., 78, No. 6 (2005) 1131
C17H19N3O4: C, 62.00; H, 5.81; N, 12.76%. Found: C, 61.73; H,
5.69; N, 12.83%.
5
H. Masu, M. Sakai, K. Kishikawa, M. Yamamoto, K.
Yamaguchi, and S. Kohmoto, J. Org. Chem., 70, 1423 (2005).
R. Matsushima and K. Terada, J. Chem. Soc., Perkin
Trans. 2, 1985, 1445.
3,11-Dimethyl-7-propyl-3,7,11-triazatetracyclo[7.2.2.2.2,505,9]-
pentadeca-12,14-diene-4,6,8,10-tetrone (2e): 1H NMR (CDCl3,
500 MHz) ꢄ 6.63–6.57 (m, 2H), 6.37 (dd, J ¼ 8:5, 0.9 Hz, 2H),
4.24 (m, 2H), 3.70 (dt, J ¼ 13:1, 7.1 Hz, 1H), 3.61 (dt,
J ¼ 13:1, 7.1 Hz, 1H), 2.90 (s, 6H), 1.73 (m6, J ¼ 7:4 Hz, 2H),
0.97 (t, J ¼ 7:3 Hz, 3H). 13C NMR (CDCl3, 125 MHz) ꢄ 172.8
(s), 168.0 (s), 132.6 (d), 132.4 (d), 62.6 (s), 61.5 (d), 41.5 (t),
35.6 (q), 20.9 (t), 11.0 (q). Anal. Calcd for C17H19N3O4: C,
62.00; H, 5.81; N, 12.76%. Found: C, 61.71; H, 5.78; N, 12.71%.
3,11-Dimethyl-7-benzyl-3,7,11-triazatetracyclo[7.2.2.2.2,505ꢁ,9]-
pentadeca-12,14-diene-4,6,8,10-tetrone (2f): mp. 177–179 C.
6
7
a) W. A. Ayer, R. Hayatsu, P. de Mayo, S. T. Reid, and
J. B. Stothers, Tetrahedron Lett., 18, 648 (1961). b) G. Slomp,
F. A. Mackellar, and L. A. Paquette, J. Am. Chem. Soc., 83,
4472 (1961).
8
a) S. McN. Sieburth, J. Chen, K. Ravindran, and J. Chen,
J. Am. Chem. Soc., 118, 10803 (1996). b) Y. Lee, K. F. McGee,
Jr., J. Chen, D. Rucando, and S. McN. Sieburth, J. Org. Chem.,
65, 6676 (2000).
9
a) L. C. Wu, C. J. Cheer, G. Olovsson, J. R. Scheffer, and
IR (KBr) 3067 (w), 1790 (m), 1718 (s), 1662 (s), 1395 (m) cmꢃ1
.
J. Trotter, Tetrahedron Lett., 38, 3135 (1997). b) K. Tanaka, T.
Fujiwara, and Z. Urbanczyk-Lipkowska, Org. Lett., 4, 3255
(2002).
UV–vis (CH3CN) ꢃmax ("), 258 (650) nm. 1H NMR (CDCl3, 500
MHz) ꢄ 7.40–7.25 (m, 5H), 6.61–6.56 (m, 2H), 6.34 (d, J ¼ 7:9
Hz, 2H), 4.91 (d, J ¼ 15 Hz, 1H), 4.79 (d, J ¼ 15 Hz, 1H),
4.22 (m, 2H), 2.88 (s, 6H). 13C NMR (CDCl3, 125 MHz) ꢄ
172.4 (s), 167.8 (s), 134.7 (s), 132.6 (d), 132.2 (d), 128.8 (d),
127.9 (d), 127.6 (d), 62.7 (s), 61.4 (d), 43.3 (t), 35.6 (q). MS
(EI) m=z 377 [MHþ]. Anal. Calcd for C21H19N3O4: C, 66.83;
H, 5.07; N, 11.13%. Found: C, 66.52; H, 5.09; N, 11.12%.
X-ray Crystallography. An X-ray crystallographic analysis
was undertaken using a Rigaku AFC7S four-circle diffractometer
(for 1b, 1c, 1d, 1e, and 2a) or Bruker Samrt1000 CCD diffractom-
eter (for 1a and 1f). The crystals were mounted on glass fibers.
A structure solution was carried out with the programs SIR 97
(Altomare et al., 1999) or SHELXS 97 (Sheldrick, 1997). For
refining the structures, performing a structure analysis, and
producing crystallographic illustrations, the program TEXSAN
(Rigaku/MSC, 1998) was used. In all of the structures, H atoms
were included at their calculated positions. Other details are
described in CIF files for each compound.
10 a) K. Tanaka and F. Toda, Nippon Kagaku Kaishi, 1984,
141. b) M. Kuzuya, A. Noguchi, N. Yokota, T. Okuda, F. Toda,
and K. Tanaka, Nippon Kagaku Kaishi, 1986, 1756. c) T. Odani
and A. Matsumoto, CrystEngComm., 4, 467 (2002).
11 S. Kohmoto, T. Noguchi, H. Masu, K. Kishikawa, M.
Yamamoto, and K. Yamaguchi, Org. Lett., 6, 683 (2004).
12 S. M. Sieburth, K. F. McGee, Jr., and T. H. Al-Tel, J. Am.
Chem. Soc., 120, 587 (1998).
13 a) K. Yamaguchi, G. Matumura, H. Kagechika, I.
Azumaya, Y. Ito, A. Itai, and K. Shudo, J. Am. Chem. Soc.,
113, 5474 (1991). b) A. Itai, Y. Toriumi, S. Saito, H. Kagechika,
and K. Shudo, J. Am. Chem. Soc., 114, 10649 (1992). c) I.
Azumaya, I. Okamoto, S. Nakayama, A. Tanatani, K. Yamaguchi,
K. Shudo, and H. Kagechika, Tetrahedron, 55, 11237 (1999). d)
S. Kohmoto, H. Masu, C. Tatsuno, K. Kishikawa, M. Yamamoto,
and K. Yamaguchi, J. Chem. Soc., Perkin Trans. 1, 2000, 4464.
14 a) M. J. Marsella, I. T. Kim, and F. Tham, J. Am. Chem.
Soc., 122, 974 (2000). b) K. Nakamura, H. Okubo, and M.
Yamaguchi, Org. Lett., 3, 1097 (2001). c) H. Adams, C. A.
Hunter, K. R. Lawson, J. Perkins, S. E. Spev, C. J. Urch, and
J. M. Sanderson, Chem.—Eur. J., 7, 4863 (2001). d) D. Zhao
and J. S. Moore, J. Org. Chem., 67, 3548 (2002). e) I. Huc,
Eur. J. Org. Chem., 2004, 17.
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