Gui-Ting Song, a, b,c Zhi-Gang Xu, a Dian-Yong Tang, a Shi-Qiang Li, a Zhi-Gang Xie, a Hong-Liang
Zhong, a Zhi-Wei Yang, a Jin Zhu, b Jin Zhang,* ,a Zhong-Zhu Chen* ,a a International Academy of Targeted Therapeutics and Innovation, Chongqing University of Arts and
Sciences,319 Honghe Ave., Yongchuan, Chongqing, China, 402160 b Key Laboratory for Asymmetric Synthesis and Chiral Technology of Sichuan Province,
Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, China,610041 c University of Chinese Academy of Sciences, Beijing, China, 100049
Corresponding author: hxxzj2282@163.com, 18883138277@163.com
1. General Information …………………………………………………….…2
2. General Procedures ………………………………………………………….…3
3. NMR Spectra …………………………………………………………..……...10
1

General Information
1
H and
13
C NMR were recorded on a Bruker 400 spectrometer.
1
H NMR data are reported as follows: chemical shift in ppm (δ), multiplicity (s = singlet, d = doublet, t
= triplet, m = multiplet), coupling constant (Hz), relative intensity.
13
C NMR data are reported as follows: chemical shift in ppm (δ). HPLC-MS analyses were performed on a Shimadzu-2020 LC-MS instrument using the following conditions: Shim-pack
VP-ODS C18 column (reverse phase, 150 x 2.0 mm); 20% acetonitrile and 80% water over 6.0 min; flow rate of 0.4 mL/min; UV photodiode array detection from 200 to
300 nm. The products were purified by Biotage Isolera™ Spektra Systems and
Hexane/EtOAc solvent systems. All reagents and solvents were obtained from commercial sources and used without further purification.
Microwave Irradiation Experiments
All microwave irradiation experiments were carried out in a Biotage® Initiator
Classic microwave apparatus with continuous irradiation power from 0 to 400W with utilization of the standard absorbance level of 250W maximum power. The reactions were carried out in 10 mL glass tubes, sealed with microwave cavity. The reaction was irradiated at a required ceiling temperature using maximum power for the stipulated time. Then it was cooled to 50 o
C with gas jet cooling.
2

General procedures for compounds 6 and 11 .
A solution of 2-( N -Boc-amino)-phenyl- isocyanide (0.50mmol), methyl
2-formylbenzoate (0.50mmol) and amino pyridine (0.50mmol) in MeOH (2mL) was added conc. HClO
4
(10

L) at room temperature. The reaction mixture was stirred overnight and monitored by TLC. When no isonitrile was present, the solvent was removed under a nitrogen stream. The residue was dissolved in 5% HCl/AcOH (3mL), sealed and heated in microwave at 180 o
C under stirring for 30 min. After the microwave was cooled to room temperature, the solvent was removed under reduced pressure, the residue dissolved with EtOAc (15mL) and washed with sat. Na
2
CO
3
and brine. The organic layer was dried over anh. MgSO
4
and concentrated. The residue was purified by silica gel column chromatography using a gradient of ethyl acetate/hexane (20-100%) to afford desired products 6 and 11 . benzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]imidazo[4,5-c]isoquinoline (Compound
6 ), light yellow solid, yield 87%.
1
H NMR (400 MHz, CDCl
3
)
δ 9.14 (d,
J = 6.9 Hz, 1H), 8.93 (d, J = 7.8 Hz, 1H), 8.61 (d, J
= 7.8 Hz, 1H), 8.22 (d, J = 8.2 Hz, 1H), 8.13 (d, J = 7.9 Hz,
1H), 7.89-7.75 (m, 2H), 7.73 (t, J = 7.6 Hz, 1H), 7.58 (t, J =
7.5 Hz, 1H), 7.51 (t, J = 7.6 Hz, 1H), 7.43 – 7.33 (m, 1H),
7.10 (t, J = 6.7 Hz, 1H). 13 C NMR (100 MHz, CDCl
3
) δ 147.8, 143.9, 143.3, 131.0,
129.9, 128.2, 127.8, 126.2, 124.8, 124.4, 122.7, 122.2, 121.0, 119.0, 116.0, 113.4,
112.6. LC-MS calculated for C
20
H
13
N
4
[M+H]
+
, 309; found 309.
4-bromobenzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]imidazo[4,5-c]isoquinoline
(Compound 11a ), light yellow solid, yield 78%. 1 H NMR
(400 MHz, CDCl
3
) δ 9.06 (d, J = 6.9 Hz, 1H), 8.82 (d, J =
8.0 Hz, 1H), 8.64 (d, J = 7.8 Hz, 1H), 8.10 (d, J = 8.2 Hz,
1H), 8.05 (d, J = 8.0 Hz, 1H), 7.76 (t, J = 7.4 Hz, 1H),
7.71-7.64 (m, 1H), 7.58 (d, J = 7.2 Hz, 1H), 7.52-7.41 (m,
2H), 6.90 (t, J = 7.1 Hz, 1H).
13
C NMR (100 MHz, CDCl
3
) δ 146.9, 143.1, 139.8,
3

129.9, 128.9, 127.8, 127.5, 126.5, 126.0, 125.0, 123.5, 123.0, 122.3, 121.3, 120.2,
112.2, 112.0, 111.4. LC-MS calculated for C
20
H
12
BrN
4
[M+H]
+
, 387; found 387.
4-bromo-2-methylbenzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]imidazo[4,5-c]isoquin oline (Compound 11b ), light yellow solid, yield 70%. 1 H NMR (400 MHz, CDCl
3
) δ
8.85-8.69 (m, 2H), 8.50 (d, J = 7.6 Hz, 1H), 8.06-8.01 (m,
2H), 7.69 (d, J = 7.3 Hz, 1H), 7.60 (t, J = 6.8 Hz, 1H),
7.52-7.41 (m, 2H), 7.18 (s, 1H), 2.43 (s, 3H). 13 C NMR
(100 MHz, CDCl
3
) δ 146.4, 142.3, 139.1, 130.0, 129.2,
129.0, 128.5, 127.4, 126.6, 125.1, 123.6, 122.0, 121.5,
121.4, 120.7, 119.8, 112.4, 111.2, 17.6. LC-MS calculated for C
21
H
14
BrN
4
[M+H]
+
,
401; found 401.
2-chlorobenzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]imidazo[4,5-c]isoquinoline
(Compound 11c ), light yellow solid, yield 68%.
1
H
NMR (400 MHz, DMSOd
6
) δ 9.24 (s, 1H), 8.78 (d,
J =
8.0 Hz, 1H), 8.48 (d, J = 7.9 Hz, 1H), 8.40-8.30 (m, 1H),
8.09-8.00 (m, 1H), 7.95-7.88 (m, 2H), 7.79 (t, J = 7.4 Hz,
1H), 7.65-7.50 (m, 3H).
13
C NMR (100 MHz,
DMSOd
6
) δ 147.2, 143.8, 141.5, 131.5, 130.3, 129.6, 128.8, 127.6, 126.6, 126.1,
124.5, 122.8, 122.4, 122.2, 120.7, 119.4, 119.1, 115.0. LC-MS calculated for
C
20
H
12
ClN
4
[M+H]
+
, 343; found 343. benzo[4,5]imidazo[2,1-a]pyrazino[2',1':2,3]imidazo[4,5-c]isoquinoline
(Compound 11d ), light yellow solid, yield 71%.
1
H NMR
(400 MHz, CDCl
3
) δ 9.10 (s, 1H), 8.75 (d,
J = 4.1 Hz, 1H),
8.54 (d, J = 7.9 Hz, 1H), 8.29 (d, J = 7.8 Hz, 1H), 7.99-7.84
(m, 2H), 7.83 (d, J = 7.7 Hz, 1H), 7.61 (t, J = 7.5 Hz, 1H),
7.52 (t, J = 7.5 Hz, 1H), 7.36 (dt, J = 15.7, 7.1 Hz, 2H). 13 C
NMR (100 MHz, CDCl
3
) δ 146.3, 144.2, 142.6, 136.3, 130.0, 129.8, 128.4, 128.2,
127.9, 125.7, 124.9, 123.6, 121.8, 121.7, 120.0, 116.2, 111.7. LC-MS calculated for
4

C
19
H
12
N
5
[M+H] + , 310; found 310.
3-methylbenzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]imidazo[4,5-c]isoquinoline
(Compound 11e ), light yellow solid, yield 60%.
1
H NMR
(400 MHz, CDCl
3
) δ 8.96 (d,
J = 7.1 Hz, 1H), 8.88 (d, J
= 8.0 Hz, 1H), 8.54 (d, J = 7.9 Hz, 1H), 8.16 (d, J = 8.2
Hz, 1H), 8.08 (d, J = 8.1 Hz, 1H), 7.80 (t, J = 7.5 Hz,
1H), 7.69 (t, J = 7.6 Hz, 1H), 7.53 (d, J = 12.1 Hz, 2H),
7.46 (t, J = 7.7 Hz, 1H), 6.88 (d, J = 7.1 Hz, 1H), 2.50 (s, 3H).
13
C NMR (100 MHz,
CDCl
3
) δ 147.7, 143.9, 143.8, 136.0, 130.8, 129.7, 129.3, 127.9, 126.1, 124.2, 124.0,
122.6, 122.2, 122.0, 120.9, 117.0, 115.2, 113.2, 21.4. LC-MS calculated for C
21
H
15
N
4
[M+H]
+
, 323; found 323.
1-methylbenzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]imidazo[4,5-c]isoquinoline
(Compound 11f ), light yellow solid, yield 60%.
1
H NMR
(400 MHz, CDCl
3
) δ 8.79 (d,
J = 7.9 Hz, 1H), 8.46 (d, J =
7.9 Hz, 1H), 7.94 (d, J = 8.2 Hz, 1H), 7.79 (d, J = 8.2 Hz,
1H), 7.73 (t, J = 7.5 Hz, 1H), 7.63 (t, J = 7.6 Hz, 1H), 7.57
(d, J = 9.1 Hz, 1H), 7.38 (t, J = 7.6 Hz, 1H), 7.29-7.19 (m,
2H), 6.72 (d, J = 6.7 Hz, 1H), 2.71 (s, 3H).
13
C NMR (100 MHz, CDCl
3
) δ 147.6,
144.5, 142.6, 136.3, 132.5, 130.0, 129.9, 127.1, 126.9, 125.0, 124.9, 123.3, 121.9,
121.5, 120.0, 119.7, 115.3, 114.4, 113.5, 21.2. LC-MS calculated for C
21
H
15
N
4
[M+H] + , 323; found 323.
General procedures for Suzuki reaction.
To a suspension of 11b (0.10mmol) and K
2
CO
3
(28mg, 0.2mmol) in DMF (2.0 mL) was added boronic acid (0.12mmol) and Pd(PPh
3
)
4
(8mg) under nitrogen. The reaction mixture was treated in microwave at 150 o
C for 20 min. After the microwave vial was cooled to room temperature, the solvent was diluted with EtOAc (15mL) and washed with brine (2 x 10mL). The organic layer was dried over anh. MgSO
4
and
5

concentrated. The residue was purified by silica gel column chromatography using a gradient of ethyl acetate/hexane (20-100%) to afford the targeted compound 11b’ .
4-(4-methoxyphenyl)-2-methylbenzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]imidazo[
4,5-c]isoquinoline (Compound 11b’-1 ), light yellow solid, yield 76%. 1 H NMR (400
MHz, CDCl
3
) δ 8.97 (d, J = 8.0 Hz, 1H), 8.70 (s, 1H), 8.56
(d, J = 7.9 Hz, 1H), 8.22-8.13 (m, 2H), 8.05 (d, J = 8.8 Hz,
2H), 7.77 (t, J = 7.2 Hz, 1H), 7.67 (t, J = 7.6 Hz, 1H),
7.61-7.50 (m, 3H), 7.03 (d, J = 8.8 Hz, 3H), 3.86 (s, 3H),
2.48 (s, 4H).
13
C NMR (100 MHz, CDCl
3
) δ 159.3, 140.8,
134.3, 130.5, 129.5, 129.0, 128.3, 127.3, 127.1, 125.3,
124.9, 124.1, 123.0, 122.5, 122.1, 121.7, 119.8, 119.1,
113.1, 112.5, 54.4, 17.9. LC-MS calculated for C
28
H
21
N
4
O [M+H]
+
, 429; found 429.
4-(benzo[d][1,3]dioxol-5-yl)-2-methylbenzo[4,5]imidazo[2,1-a]pyrido[2',1':2,3]im idazo[4,5-c]isoquinoline (Compound 11b’-2 ), light yellow solid, yield 60%.
1
H NMR
(400 MHz, CDCl
3
) δ 9.04 (s, 1H), 8.81 (s, 1H), 8.65 (d,
J =
7.8 Hz, 1H), 8.26-8.19 (m, 2H), 7.84 (t, J = 7.5 Hz, 1H),
7.82-7.72 (m, 2H), 7.66-7.52 (m, 3H), 7.30 (d, J = 3.8 Hz,
1H), 7.00 (d, J = 8.1 Hz, 1H), 6.09 (s, 2H), 2.56 (s, 3H).
13
C
NMR (100 MHz, CDCl
3
+10%CD
3
OD) δ 152.2, 151.8,
145.7, 135.5, 134.3, 133.7, 133.5, 133.3, 132.3, 132.1, 130.6,
129.8, 129.1, 127.1, 126.8, 125.0, 123.6, 117.9, 113.6, 112.5, 105.3, 17.9. LC-MS calculated for C
28
H
19
N
4
O
2
[M+H] + , 443; found 443.
General procedures for compound 17 .
In a 10mL of microwave vial, a solution of isonitrile 13 (0.50 mmol), methyl
2-formylbenzoate 3 (0.50 mmol) and Boc-diamine 12 (0.50 mmol) in MeOH (2mL) was added PPOA (16mg, 0.10mmol) at room temperature and the reaction mixture was stirred overnight. 4-Methylbenzenesulfonic acid (TsOH) (0.5 g) was added to the
6

mixture and heated in microwave irradiation at 120 o C for 30 min. After the microwave vial was cooled to room temperature, the solvent was removed under reduced pressure. Then, the residue was diluted with EtOAc (15mL) and washed with sat. Na
2
CO
3 and brine. The organic layer was dried over MgSO
4
and filtered. The solvent was concentrated and purified by silica gel column chromatography using a gradient of ethyl acetate/hexane (20-100%) to afford the relative targeted product 17 .
N-(tert-butyl)-11H-benzo[4,5]imidazo[2,1-a]isoindole-11-carboxamide
(Compound 17a , light yellow solid, yield 47%).
1
H NMR (400
MHz, CDCl
3
) δ 15.27 (s, 1H), 8.86 (s, 1H), 7.98 – 8.06 (m, 3H),
7.75 (s, 1H), 7.44 (s, 1H), 7.11 (s, 1H), 6.88 (s, 1H), 6.51 (s, 1H),
1.35 (s, 9H).
13
C NMR (100 MHz, CDCl
3
) δ 161.6, 153.1, 145.3,
141.7, 140.8, 134.7, 132.9, 129.2, 128.9, 126.4, 126.0, 124.5,
123.7, 121.4, 115.8, 112.3, 64.7, 52.6, 28.5. LC-MS calculated for C
19
H
20
N
3
O
[M+H]
+
, 306; found 306.
N-(tert-butyl)-7,8-dimethyl-11H-benzo[4,5]imidazo[2,1-a]isoindole-11- carboxamide (Compound 17b , light yellow solid, yield 47%).
1 H NMR (400 MHz,
CDCl
3
) δ 7.91 (s, 1H), 7.76 (s, 1H), 7.51 (s, 1H), 7.36 (s, 2H),
7.11 (s, 1H), 5.61 (s, 1H), 5.28 (s, 1H), 2.31 (s, 6H), 1.20 (s,
9H).
13
C NMR (100 MHz, CDCl
3
) δ 165.0, 156.5, 143.8,
133.7, 132.6, 131.7, 130.4, 129.5, 127.4, 126.7, 124.2, 122.2,
120.0, 116.6, 110.3, 63.4, 52.2, 29.7, 28.6, 20.4. LC-MS calculated for C
21
H
24
N
3
O [M+H]
+
, 334; found 334.
N-(2,6-dimethylphenyl)-11H-benzo[4,5]imidazo[2,1-a]isoindole-11-carboxamide
(Compound 17c , light yellow solid, yield 55%). 1 H NMR (400
MHz, CDCl
3
) δ 8.03 (d, J = 5.0 Hz, 1H), 7.90 (d, J = 5.7 Hz,
1H), 7.80 (d, J = 7.2 Hz, 1H), 7.66 – 7.51 (m, 3H), 7.43 – 7.30
7

(m, 2H), 7.20 – 6.83 (m, 4H), 5.90 (s, 1H), 1.95 (s, 6H). 13 C NMR (100 MHz, CDCl
3
)
δ 165.1, 158.2, 143.6, 135.4, 135.0, 132.0, 131.56, 130.7, 130.1, 128.4, 128.0, 127.4,
124.4, 124.0, 123.6, 122.6, 120.8, 110.0, 62.9, 18.2. LC-MS calculated for C
23
H
20
N
3
O
[M+H]
+
, 354; found 354.
N-(2,6-dimethylphenyl)-7,8-dimethyl-11H-benzo[4,5]imidazo[2,1-a]isoindole-11- carboxamide (Compound 17d , light yellow solid, yield 52%).
1
H NMR (400 MHz,
CDCl
3
) δ 7.98 (s, 1H), 7.82 (s, 1H), 7.51 (s, 1H), 7.43 (s, 2H),
7.29 (s, 1H), 6.98 (d, J = 7.4 Hz, 1H), 6.91 (d, J = 6.7 Hz,
2H), 5.91 (s, 1H), 5.27 (s, 1H), 1.19 (s, 15H). 13 C NMR (100
MHz, CDCl
3
) δ 164.0, 142.5, 134.3, 133.6, 132.0, 131.2,
129.5, 128.9, 128.3, 127.3, 126.9, 123.3, 121.4, 119.3, 114.7,
109.5, 61.9, 28.7, 28.3. LC-MS calculated for C
25
H
24
N
3
O [M+H]
+
, 382; found 382.
N-benzyl-11H-benzo[4,5]imidazo[2,1-a]isoindole-11-carboxamide (Compound 17e , light yellow solid, yield 61%).
1
H NMR (400 MHz,
DMSOd
6
) δ 10.92 (s, 1H), 8.43 (s, 1H), 8.07 (s, 2H), 7.90 (d,
J = 7.2 Hz, 1H), 7.85 – 7.67 (m, 3H), 7.65 – 7.51 (m, 2H),
7.27 (d, J = 6.9 Hz, 3H), 7.09 – 7.04 (m, 2H), 4.24 (s, 4H),
2.43 (s, 3H). 13 C NMR (100 MHz, DMSOd
6
) δ 165.36,
163.96, 161.49, 142.75, 139.46, 133.44, 130.63, 128.80, 127.77, 127.34, 126.67,
125.93, 123.42, 123.14, 122.69, 122.08, 116.30, 66.41, 45.02. LC-MS calculated for
C
22
H
18
N
3
O [M+H]
+
, 340; found 340.
N-benzyl-7,8-dimethyl-11H-benzo[4,5]imidazo[2,1-a]isoindole-11-carboxamide
(Compound 17f , light yellow solid, yield 57%). 1 H NMR
(400 MHz, CDCl
3
) δ 8.20 (s, 1H), 7.73 (d,
J = 7.0 Hz, 1H),
7.37 – 7.22 (m, 7H), 7.00 (s, 1H), 6.73 (s, 1H), 5.78 (s,
1H), 5.56 (s, 1H), 4.42 (d, J = 4.9 Hz, 2H), 2.23 (s, 3H),
8

2.09 (s, 3H). 13 C NMR (100 MHz, CDCl
3
) δ 165.6, 159.9, 156.1, 142.2, 136.6, 128.9,
127.8, 126.8, 125.9, 123.0, 120.5, 119.2, 112.2, 109.0, 61.6, 42.4, 28.7, 28.3. LC-MS calculated for C
24
H
22
N
3
O [M+H]
+
, 368; found 368.
9

Compound 6
10

Compound 6
11

Compound 11a
12

Compound 11a
13

Compound 11b
14

Compound 11b
15

Compound 11c
16

Compound 11c
17

Compound 11d
18

Compound 11d
19

Compound 11e
20

Compound 11e
21

Compound 11f
22

Compound 11f
23

Compound 12a
24

Compound 12a
25

Compound 11b’-1
26

Compound 11b’-2
27

Compound 17a
28

Compound 17a
29

Compound 17b
30

Compound 17b
31

Compound 17c
32

Compound 17c
33

Compound 17d
34

Compound 17d
35

Compound 17e
36

Compound 17e
37

Compound 17f
38

Compound 17f
39

Compound 17a
40