SYNTHESIS OF INTERNALLY ALKYLATED AZULIPORPHYRINS
5
(4.67), 654 (4.14), 680 (sh, 4.12), 735 (sh, 3.78). UV-vis
(30 mL) for 16 h. The solvent was removed under
reduced pressure and the residue purified on a silica
column eluting with 50% dichloromethane-hexanes. A
pale green fraction was collected, followed by a major
green-brown fraction corresponding to palladium(II)
complex 26. A third fraction was subsequently collected
that corresponded to palladium(II) carbaporphyrin
carbaldehyde 28b (1.0 mg, 0.0015 mmol, 5.0%). The
major product was recrystallized from chloroform-
methanol to give 26 (9.2 mg, 0.0137 mmol, 45%) as a
dark solid, mp >300°C. Fraction 1 was further purified
on silica, eluting with 25% dichloromethane-hexanes and
afforded palladium(II) tert-butylbenzocarbaporphyrin
28a (0.5 mg, 0.00074 mmol, 2.4%) as a dark solid.
(1% Et3N-CHCl3): lmax/nm (log e) 375 (4.46), 436
1
(4.46), 462 (4.39), 586 (3.91), 641 (sh, 3.84). H NMR
(500 MHz, CDCl3): d -3.79 (2H, br q, 21-CH2CH3), -2.01
(3H, br t, CH2CH3), 1.61–1.68 (12H, m, 4 × CH2CH3),
3.29 (6H, s, 7,18-CH3), 3.56–3.63 (4H, m), 3.81–3.88
(2H, m), 4.01–4.08 (2H, m) (8,12,13,17-CH2), 8.19–8.27
(3H, m, 22,23,32-H), 9.02 (2H, s, 10,15-H), 9.91 (2H,
br d, J = 9.1 Hz, 21,31-H), 10.32 (2H, s, 5,20-H). 13C
NMR (partial data from HSQC spectrum, CDCl3): d 9.4
(21-CH2CH3), 10.3 (7,18-Me), 16.8 (2 × CH2CH3), 17.4
(2 × CH2CH3), 18.3 (2 × CH2CH3), 18.5 (21-CH2), 18.6
(2 × CH2CH3), 95.4 (10,15-CH), 107.8 (5,20-CH), 137.1
(21,31-CH), 137.4 (22,32-CH), 143.3 (23-CH). HRMS
(ESI) m/z: [M + H]+ calcd. for C38H42N3 540.3373; found
540.3360.
(23-tert-Butyl-8,12,13,17-tetraethyl-7,18-dimethyla-
zuliporphyrinato)palladium(II) (26). UV-vis (CHCl3):
23-tert-Butyl-7,12,13,18-tetraethyl-8,17-dimethyl-
azuliporphyrin dihydrochloride (24b·2HCl). N-methyl
tripyrrane 11 [29] (103 mg, 0.221 mmol) was dissolved
in TFA (1 mL) and stirred for 2 min under nitrogen. The
mixture was diluted with dichloromethane (99 mL),
followed by the immediate addition of 6-tert-butylazu-
lene-1,3-dicarbaldehyde [56] (57.6 mg, 0.240 mmol),
and the solution was left to stir overnight under
nitrogen. The mixture was vigorously shaken with
aqueous ferric chloride solution (0.1%, 200 mL), and
then washed with 10% aqueous hydrochloric acid. The
solvent was evaporated off under reduced pressure and
the residue was recrystallized twice from chloroform-
hexanes to give the tert-butyl N-methylazuliporphyrin
dihydrochloride (113 mg, 0.172 mmol, 78%) as dark
crystals, mp >300°C. UV-vis (CHCl3): lmax/nm (log e)
377 (4.56), 449 (sh, 4.51), 476 (4.81), 592 (4.00), 648
(4.26), 697 (sh, 3.93), 757 (sh, 3.69). UV-vis (1% TFA-
CHCl3): lmax/nm (log e) 371 (4.65), 444 (sh, 4.57), 470
(4.85), 590 (4.04), 648 (4.29), 747 (sh, 3.77). UV-vis (1%
Et3N-CHCl3): lmax/nm (log e) 364 (4.58), 402 (4.56), 457
lmax/nm (log e) 366 (4.62), 415 (4.52), 448 (4.51), 508
(sh, 3.91), 569 (4.20), 659 (3.97), 732 (sh, 3.64). 1H NMR
(500 MHz, CDCl3): d1.57 (9H, s, t-Bu), 1.66 (6H, t, J =
7.7 Hz), 1.70 (6H, t, J = 7.7 Hz) (4 × CH2CH3), 3.16 (6H,
s, 7,18-Me), 3.51–3.58 (8H, m, 4 × CH2CH3), 7.75 (2H,
d, J = 10.8 Hz, 22,32-H), 8.68 (2H, s, 10,15-H), 9.03 (2H,
d, J = 10.8 Hz, 21,31-H), 9.26 (2H, s, 5,20-H). 13C{H}
NMR (125 MHz, CDCl3): d 11.2 (7,18-CH3), 16.7
(2 × pyrrole-CH2CH3), 17.6 (2 × pyrrole-CH2CH3), 19.3
(2 × pyrrole-CH2), 19.7 (2 × pyrrole-CH2), 31.7 (t-Bu),
38.8 (CMe3), 96.4 (10,15-CH), 108.6 (5,20-CH), 125.3,
130.2 (21,31-CH), 133.6 (22,32-CH), 136.2, 140.5, 142.8,
142.9, 147.2, 148.7, 152.8, 159.7, 161.6. HRMS (ESI)
m/z: [M + H]+ calcd. for C40H44N3Pd 672.2570; found
672.2586.
(22-tert-Butyl-7,12,13,18-tetraethyl-8,17,21-trime-
thylbenzo[b]carbaporphyrinato)palladium(II) (28a).
UV-vis (CHCl3): lmax/nm (relative intensity) 348 (0.68),
1
423 (1.00), 633 (sh, 0.185), 694 (0.37). H NMR (500
MHz, CDCl3): d -3.24 (3H, s, 21-Me), 1.73–1.77 (21H,
m, 4 × CH2CH3 and t-Bu), 3.33 (3H, s), 3.36 (3H, s)
(7,18-Me), 3.72–3.78 (8H, m, 4 × CH2CH3), 8.34 (1H,
d, J = 8.5 Hz, 32-H), 9.32 (1H, d, J = 8.5 Hz, 31-H),
9.36 (1H, s, 21-H), 9.55 (1H, s), 9.56 (1H, s) (10,15-H),
10.22 (1H, s), 10.27 (1H, s) (5,20-H). HRMS (ESI) m/z:
[M + H]+ calcd. for C40H46N3Pd 674.2726; found
674.2757.
1
(4.53), 484 (4.61), 630 (sh, 3.96), 669 (sh, 4.53). H
NMR (500 MHz, TFA-d6-DMSO): d -3.54 (1H, s, CH),
-3.48 (3H, s, N-Me), -0.57 (2H, br s, 2 × NH), 1.16 (6H,
t, J = 7.6 Hz) 1.46 (6H, t, J = 7.6 Hz) (4 × CH2CH3), 1.52
(9H, s, t-Bu), 3.33 (6H, s, 7,18-Me), 3.35–3.42 (2H, m),
3.48–3.55 (2H, m), 3.64–3.76 (4H, m), (4 × CH2CH3),
8.77 (2H, d, J = 10.7 Hz, 22, 32-CH), 9.46 (2H, s, 10,15-
H), 10.09 (2H, d, J = 10.7 Hz, 21, 31-CH), 10.44 (2H,
s, 5,20-H). 13C{1H} NMR (125 MHz, TFA-d6-DMSO,
60°C): d 11.8 (7,18-Me), 16.4 (2 × CH2CH3), 16.7
(2 × CH2CH3), 19.75 (2 × CH2CH3), 19.78 (2 × CH2CH3),
31.7 (C(CH3)3), 32.4 (N-Me), 41.0 (C(CH3)3), 97.3
(10,15-CH), 111.2 (5,20-CH), 125.8 (21-CH), 129.4,
141.2, 141.6 (21,31-CH), 141.7, 142.2, 142.4 (22,32-CH),
142.5, 146.4, 153.9, 156.9, 174.2. HR-MS (ESI) m/z:
[M + H]+ calcd for C41H48N3 582.3848, found 582.3847.
Reaction of 24b with palladium(II) acetate. 23-
Methylazuliporphyrin24b·2HCl(20.0mg,0.0305mmol)
was stirred under reflux with palladium(II) acetate
(15.0 mg) in a 50/50 mixture of acetonitrile-chloroform
(7,12,13,18-Tetraethyl-22-formyl-8,17,21-trime-
thylbenzo[b]carbaporphyrinato)palladium(II) (28b).
UV-vis (CHCl3): lmax/nm (relative intensity) 346 (0.79),
429 (1.00), 520 (sh, 0.30), 648 (sh, 0.15), 715 (0.32). 1H
NMR (500 MHz, CDCl3): d -3.20 (3H, s, 21-Me), 1.76
(12H, m, 4 × CH2CH3), 3.34 (3H, s), 3.35 (3H, s) (7,18-
Me), 3.72–3.79 (8H, m, 4 × CH2CH3), 8.71 (1H, d, J =
8.2 Hz, 32-H), 9.50 (1H, d, J = 8.2 Hz, 31-H), 9.58 (1H, s),
9.61 (1H, s) (10,15-H), 9.90 (1H, s, 21-H), 10.36 (1H, s),
10.39 (1H, s) (5,20-H), 10.64 (1H, s, CHO). 13C NMR
(partial data from HSQC spectrum, CDCl3): d 11.48,
11.53 (7,18-Me), 17.46, 17.50 (4 × CH2CH3), 18.31, 18.33
(4 × CH2CH3), 19.3, 19.8 (4 × CH2CH3), 23.4 (21-Me),
106.6, 107.0 (10,15-CH), 107.2, 109.0 (5,20-CH), 123.0
Copyright © 2019 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2019; 23: 5–13