184
M.A. Abdulhamid et al. / Polymer 130 (2017) 182e190
Scheme 1. Synthetic route of carbocyclic pseudo Tr o€ ger's base (CTB) (VI).
ꢀ
1
mp ¼ 224.5 ꢀC. 1H NMR and 13C NMR showed that the product
contained three isomers. Recrystallization was performed to obtain
only one isomer as a light yellow powder. The structure of the pure
isomer was confirmed by single-crystal XRD (Fig. S1). The crystal-
final product; mp ¼ 215.6 C. H NMR (400 MHz, CDCl
H), 7.18 (d, 2H, J ¼ 8 Hz), 7.03 (d, 2H, J ¼ 7.6 Hz), 5.02 (d, 2H,
J ¼ 5.6 Hz), 3.3 (m, 2H), 2.4 (t, 2H, J ¼ 3.2 Hz), 2.29 (s, 6H), 1.66 (s,
3
): 7.40 (s,
2
13
2
3
H). C NMR (100 MHz, CDCl ): 139.4, 137.4, 130.9, 129.9, 128.2,
127.8, 72.6, 39.1, 29.5, 21.2.
lographic data for VII b were deposited in the Cambridge Structural
1
Database (CCDC 1545077). H NMR (400 MHz, CDCl
3
): 7.90 (s, 2H),
2
5
.3.3. Synthesis of 6,12-dichloro-2,8-dimethyl-5,6,11,12-tetrahydro-
,11-methanodibenzo[a,e][8]annulene (V) (Scheme 1b)
6.94 (s, 2H), 3.45 (m, 2H), 3.32 (dd, 2H, J ¼ 12 Hz), 2.91 (d, 2H,
13
J ¼ 17.2 Hz), 2.49 (s, 6H), 2.19 (t, 2H, J ¼ 2.8 Hz). C NMR (100 MHz,
CDCl ): 147.3, 140.3, 139.4, 133.7, 131.7, 125.2, 39.3, 31.9, 28.2, 20.3.
2
,8-Dimethyl-5,6,11,12-tetrahydro-5,11-methanodibenzo[a,e][8]
3
annulene-6,12-diol (v) (2 g, 7.13 mmol) was suspended in SOCl
2
(
30 mL) and 0.3 mL DMF were added. The solution was refluxed
2.3.6. Synthesis of 2,8-dimethyl-3,9-diamine-5,6,11,12-tetrahydro-
5,11-methanodibenzo[a,e][8]annulene (VIII b, CTBDA) (Scheme 2)
2,8-Dimethyl-3,9-dinitro-5,6,11,12-tetrahydro-5,11-
methanodibenzo[a,e][8]annulene (VII b) (0.4 g, 1.2 mmol) was
suspended in 20 mL ethanol followed by the addition of Pd/C (0.2 g)
overnight and SOCl
product was dried at 100 C for 3 h. The resulting product (2.1 g,
2
was removed by vacuum. The collected
ꢀ
ꢀ
1
yield: 93%) was obtained as an off-white solid; mp ¼ 191.0 C. H
NMR (400 MHz, CDCl
): 6.19 (d, 2H, J ¼ 8 Hz), 7.08 (d, 2H, J ¼ 7.6 Hz),
.02 (s, 2H), 5.05 (d, 2H, J ¼ 1.6 Hz), 3.54 (m, 2H), 2.67 (t, 2H,
3
7
2 4 2
and 2 mL N H $H O. The mixture was refluxed for 3 h under ni-
trogen and then cooled down to room temperature, precipitated in
13
J ¼ 2.8 Hz), 2.26 (s, 6H). C NMR (100 MHz, CDCl
3
): 137.9, 133.8,
1
33.6, 131.6, 130, 129.3, 62.2, 40.9, 21.0, 18.7.
water and filtrated. The white solid was dried in the vacuum oven
ꢀ
ꢀ
1
for 24 h at 60 C (0.26 g, yield: 80%); mp ¼ 192.2 C. H NMR
(400 MHz, DMSO-d
): 6.44 (d, 2H, J ¼ 4 Hz), 6.40 (d, 2H, J ¼ 3.6 Hz),
4.46 (br s, 4H), 3.1 (d, 2H, J ¼ 18 Hz), 3.0 (m, 4H), 2.47 (m, 2H), 1.9 (s,
2
.3.4. Synthesis of 2,8-dimethyl-5,6,11,12-tetrahydro-5,11-
6
methanodibenzo[a,e][8]annulene (VI) (Scheme 1b)
,12-Dichloro-2,8-dimethyl-5,6,11,12-tetrahydro-5,11-
methanodibenzo[a,e][8]annulene (V) (5 g, 15.8 mmol) was dis-
solved in THF (250 mL) and LiAlH (2.4 g, 63 mmol) was added in
portions over 30 min. The reaction was refluxed overnight and the
resulting mixture was then poured on ice (200 g) and HCl (6 N,
13
6
6
6H). C NMR (100 MHz, DMSO-d ): 144.6, 139.3, 130.5, 122.4, 120.2,
114.3, 39.0, 32.8, 18.0, 17.4. The same synthetic procedure was
applied to the produce the 2,8-dimethyl-(3,9)(1,7)(4,10)-diamine-
5,6,11,12-tetrahydro-5,11-methanodibenzo[a,e] [8]annulene (VIII a,
iCTBDA). The NMR spectrum of iCTBDA is shown in Fig. S2.
4
100 mL) was added. The solution was extracted with dichloro-
methane three times, dried over MgSO , filtered and then the sol-
4
2.3.7. Synthesis of 4,10-dimethyl-3,9-dinitro-6H,12H-5,
vent was removed by rota-evaporation. The resulted light orange
methanodibenzo[b,f][1,5] diazocine (IX) (Scheme 3)
powder was washed by n-hexane/DCM: 4/1 to afford VI (3 g, yield:
4,10-Dimethyl-3,9-dinitro-6H,12H-5,methanodibenzo[b,f][1,5]
diazocine (IX) was synthesized by a previously reported procedure
[40]. 2-Methyl-3-nitroaniline (5 g, 32.86 mmol) and para-
formaldehyde (2.07 g, 69.01 mmol, 2.1 equiv) were dissolved in
trifluoroacetic acid (TFA) (65 mL) to form a black-colored solution.
ꢀ
1
7
6%) as a white powder product; mp ¼ 109.5 C. H NMR (400 MHz,
CDCl
): 7.11 (d, 2H, J ¼ 7.6 Hz), 6.94 (d, 2H, J ¼ 7.6 Hz), 6.78 (s, 2H),
.29 (m, 2H), 3.25 (d, 2H, J ¼ 5.2 Hz), 2.81 (d, 2H, J ¼ 16 Hz), 2.24 (s,
3
3
6
13
H), 2.13 (t, 2H, J ¼ 2.8 Hz). C NMR (100 MHz, CDCl
3
): 138.2, 135.4,
134.4, 129.9, 128.7, 126.7, 39.5, 32.56, 29.1, 21.0.
The reaction was stirred for 48 h and then poured into H
2
O
(200 mL) to yield an intensely yellow precipitate. Aq. NaOH (6 N)
2
.3.5. Synthesis of 2,8-dimethyl-1,7(4,10)(3,9)-dinitro-5,6,11,12-
was added to this suspension to afford a basic solution (pH ¼ 9). The
tetrahydro-5,11-methanodibenzo[a,e][8]annulene (VII a) and 2,8-
dimethyl-3,9-dinitro-5,6,11,12-tetrahydro-5,11-methanodibenzo
precipitate was filtered off and washed with hot acetone. Yellow
1
crystals were obtained with 85% yield. H NMR (400 MHz, CDCl
3
):
[
a,e][8]annulene (VII b) (Scheme 2)
,8-Dimethyl-5,6,11,12-tetrahydro-5,11-methanodibenzo[a,e][8]
annulene (VI) (1.25 g, 5 mmol) was dissolved in 50 mL acetonitrile
CH CN) followed by the addition of KNO (1.12 g, 11.1 mmol) and
6.56 (d, 2H, J ¼ 8.4 Hz), 6.93 (d, 2H, J ¼ 8.4 Hz), 4.67 (d, 2H,
13
2
J ¼ 17.6 Hz), 4.32 (s, 2H), 4.01 (d, 2H, J ¼ 17.6 Hz), 2.59 (s, 6H).
C
3
NMR (100 MHz, CDCl ): 149.8, 147.3, 132.9, 128.8, 124.9, 119.8, 67.2,
(
3
3
55.4, 13.5.
then trifluoroacetic anhydride (TFAA) (5.2 mL, 35.7 mmol) was
added dropwise. After stirring for 1 h at room temperature the
reaction was poured on ice and then extracted with dichloro-
methane (DCM). The crude product was purified by silica gel col-
umn chromatography using DCM/n-hexane: 1/1 as an eluent. The
product was obtained as a yellow powder (0.8 g, yield: 47%);
2.3.8. Synthesis of 4,10-dimethyl-3,9-diamino-6H,12H-5,
methanodibenzo[b,f][1,5]-diazocine (X) (TBDA) (Scheme 3)
4,10-Dimethyl-3,9-dinitro-6H,12H-5, methanodibenzo[b,f][1,5]-
diazocine (IX) (1 g, 2.94 mmol) was suspended in 100 mL ethanol
followed by the addition of Fe powder (2.22 g, 39.7 mmol) and