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3.12 (3H, s, 7-CH3), 3.18 (3H, s, 17-CH3), 3.34 (3H, s, 3-
CH3), 3.59–3.64 (4H, m, 2,18-CH2CH3), 5.38 (2H, s,
10-CH2Ar), 7.55 (2H, d, JZ8 Hz, 10-Ar-H), 7.84 (2H, d,
JZ8 Hz, 10-Ar-H), 8.97 (1H, s, 20-H), 9.14 (1H, s, 15-H),
11.54 (1H, s, 5-CHO); MALDI-TOF-MS m/z 752.3 (C45-
H50N4O3NiC, calcd 752.3); UV–vis (CH2Cl2) 432, 659
(3H, t, JZ7 Hz, 18-CH2CH3), 1.04 (3H, t, JZ8 Hz,
14-CH2CH3), 1.24 (3H, s, 19-CH3), 1.31 (9H, s, 16-Ar-
C(CH3)3), 1.50 (3H, t, JZ7 Hz, 20-CO2CH2CH3), 1.68 (3H,
t, JZ8 Hz, 8-CH2CH3), 1.71 (3H, t, JZ8 Hz, 4-CH2CH3),
2.22–2.28 (1H, m, 14-CH2CH3), 2.36–2.41 (1H, m, 18-
CH2CH3), 2.61–2.69 (1H, m, 14-CH2CH3), 2.69–2.75 (1H,
m, 18-CH2CH3), 3.307 (3H, s, 9-CH3), 3.309 (3H, s,
13-CH3), 3.51 (3H, s, 3-CH3), 3.73 (2H, q, JZ8 Hz,
8-CH2CH3), 3.87 (2H, q, JZ8 Hz, 4-CH2CH3), 3.98 (1H, t,
JZ4 Hz, 18-H), 4.43–4.50 (2H, m, 20-CO2CH2CH3), 5.35
(2H, s, 16-CH2Ar), 7.12 (1H, d, JZ8 Hz, 16-Ar-H), 7.40
(1H, d, JZ8 Hz, 16-Ar-H), 7.72 (1H, d, JZ8 Hz, 16-Ar-H),
8.51 (1H, s, JZ8 Hz, 16-Ar-H), 9.33 (1H, s, 6-H), 9.49 (1H,
s, 21-H), 9.56 (1H, s, 11-H); MALDI-TOF-MS m/z 766.4
(C49H58N4OC4 , calcd 766.5); UV–vis (CH2Cl2) 428, 498,
1
(b) nm. Porphyrin 20: H NMR (500 MHz, CDCl3) d 0.88
(6H, t, JZ7 Hz, 13,17-CH2CH3), 1.32 (9H, s, 15-
Ar-C(CH3)3), 1.71 (6H, t, JZ8 Hz, 3,7-CH2CH3), 2.44
(4H, q, JZ7 Hz, 13,17-CH2CH3), 3.11 (6H, s, 12,18-CH3),
3.17 (6H, s, 2,8-CH3), 3.72 (4H, q, JZ8 Hz, 3,7-CH2CH3),
5.38 (2H, s, 15-CH2Ar), 7.54 (2H, d, JZ8 Hz, 15-Ar-H),
7.84 (2H, d, JZ8 Hz, 15-Ar-H), 9.10 (2H, s, 10,20-H),
11.58 (1H, s, 5-CHO); MALDI-TOF-MS m/z 752.3 (C45-
H50N4O3NiC, calcd 752.3); UV–vis (CH2Cl2) 432,
649(b) nm.
1
529, 569, 636, 696 nm. Purpurin 4: H NMR (500 MHz,
CDCl3) d K0.39 (1H, s, pyrrole-NH), 0.36 (1H, s, pyrrole-
NH), 0.90 (3H, t, JZ8 Hz, 8-CH2CH3), 0.96 (3H, t, JZ
8 Hz, 4-CH2CH3), 1.16 (3H, s, 19-CH3), 1.35 (9H, s, 6-Ar-
C(CH3)3), 1.57 (3H, t, JZ7 Hz, 20-CO2CH2CH3), 1.69 (3H,
t, JZ8 Hz, 14-CH2CH3), 1.78 (3H, t, JZ8 Hz, 18-
CH2CH3), 2.02–2.07 (1H, m, 8-CH2CH3), 2.37–2.42 (1H,
m, 4-CH2CH3), 2.57–2.67 (2H, m, 4,8-CH2CH3), 2.96–3.03
(1H, m, 18-CH2CH3), 3.16 (3H, s, 9-CH3), 3.23–3.26 (1H,
m, 18-CH2CH3), 3.36 (3H, s, 3-CH3), 3.39 (3H, s, 13-CH3),
3.66–3.76 (2H, m, 14-CH2CH3), 4.02–4.04 (1H, dd, JZ
9 Hz, 3 Hz, 18-H), 4.51–4.56 (2H, m, 20-CO2CH2CH3),
5.44 (2H, s, 6-CH2Ar), 7.56 (1H, d, JZ8 Hz, 6-Ar-H), 7.65
(1H, d, JZ8 Hz, 6-Ar-H), 7.84 (1H, d, JZ8 Hz, 6-Ar-H),
8.21 (1H, d, JZ8 Hz, 6-Ar-H), 8.62 (1H, s, 16-H), 9.48 (1H,
s, 11-H), 9.50 (1H, s, 21-H); MALDI-TOF-MS m/z 766.4
(C49H58N4OC4 , calcd 766.5); UV–vis (CH2Cl2) 433, 499,
536, 574, 634, 693 nm.
4.1.12. Nickel 10-(3-carbethoxypropenyl)-3,7,13,17-
tetraethyl-2,8,12,18-tetramethyl-5-[4-(10,10,10-trimethy-
lacetylmethyl)phenyl]porphyrin (21). Porphyrin 19
(950 mg, 1.26 mmol) and 3.5 g (10 mmol) of (carbethoxy-
methylene)triphenyl phosphorane in 400 mL of dry toluene
were refluxed overnight in the dark. An additional 3.5 g
(10 mmol) of phosphorane was added and the refluxing was
continued over a second night. After cooling, the solution
was reduced to 10% of the original volume and purified by
column chromatography (silica gel, 1:24 ethyl acetate/
toluene). Pure porphyrin 21 (987 mg, 95% yield) was
1
obtained. H NMR (300 MHz, CDCl3) d 0.68 (3H, t, JZ
8 Hz, 7-CH2CH3), 1.01 (3H, t, JZ8 Hz, 3-CH2CH3), 1.33–
1.38 (12H, m, 5-Ar-C(CH3)3, 10-CO2CH2CH3) 1.61–1.73
(6H, m, 13,17-CH2CH3), 2.34–2.52 (4H, m, 3,7-CH2CH3),
3.02 (3H, s, 2-CH3), 3.17 (3H, s, 8-CH3), 3.28 (3H, s, 18-
CH3), 3.38 (3H, s, 12-CH3), 3.67–3.75 (4H, m, 13,17-
CH2CH3), 4.31 (2H, q, JZ7 Hz, 10-CO2CH2CH3), 5.40
(1H, d, JZ16 Hz, 10-(20-CH2–)), 5.42 (2H, s, 5-CH2Ar),
7.58 (2H, d, JZ8 Hz, 5-Ar-H), 7.93 (2H, d, JZ8 Hz, 5-Ar-
H), 9.14 (1H, s, 15-H), 9.27 (1H, s, 20-H), 9.77 (1H, d, JZ
16 Hz, 10-(10-CH2–)); MALDI-TOF-MS m/z 822.38 (C49-
H56N4O4NiC, calcd 822.37); UV–vis (CH2Cl2) 422, 545,
578 nm.
4.1.14. 20-Carbethoxy-4,8,14,18-tetraethyl-16-(4-hydro-
xymethylphenyl)-3,9,13,19-tetramethylpurpurin (23).
Purpurin 3 (100 mg, 0.130 mmol) was dissolved in 80 mL
of freshly distilled tetrahydrofuran and 20 mL of methanol.
To this solution, 4 mL of 10% aqueous potassium hydroxide
was added and the stirring continued for 17 h. The reaction
mixture was poured into dichloromethane and washed with
dilute citric acid and water (4!). The organic layer was
dried over Na2SO4 and concentrated to give 88 mg of
product (99% yield). 1H NMR (300 MHz, CDCl3) d K0.64
(1H, s, pyrrole-NH), 0.17 (1H, s, pyrrole-NH), 0.63 (3H, t,
JZ7 Hz, 18-CH2CH3), 1.04 (3H, t, JZ7 Hz, 14-CH2CH3),
1.25 (3H, s, 19-CH3), 1.50 (3H, t, JZ7 Hz, 20-CO2CH2-
CH3), 1.67 (3H, t, JZ8 Hz, 8-CH2CH3), 1.72 (3H, t, JZ
8 Hz, 4-CH2CH3), 2.28–2.38 (2H, m, 14,18-CH2CH3),
2.61–2.71 (2H, m, 14,18-CH2CH3), 3.30 (3H, s, 9-CH3),
3.31 (3H, s, 13-CH3), 3.51 (3H, s, 3-CH3), 3.69–3.77 (2H,
m, 8-CH2CH3), 3.86 (2H, q, JZ8 Hz, 4-CH2CH3),
3.99–4.09 (1H, m, 18-H), 4.44–4.50 (2H, m, 20-CO2CH2-
CH3), 4.96 (2H, s, 16-Ar-CH2OH), 7.15–7.18 (1H, m, 16-
Ar-H), 7.38–7.42 (1H, m, 16-Ar-H), 7.64–7.72 (1H, m, 16-
Ar-H), 8.44–8.52 (1H, m, 16-Ar-H), 9.34 (1H, s, 6-H), 9.47
(1H, s, 21-H), 9.56 (1H, s, 11-H); MALDI-TOF-MS m/z
668.4 (C43H48N4OC3 , calcd 668.4); UV–vis (CH2Cl2) 428,
530, 569, 600, 641, 696 nm.
4.1.13. 20-Carbethoxy-4,8,14,18-tetraethyl-3,9-13,19-
tetramethyl-16-[4-(10,10,10-trimethylacetylmethyl)phe-
nyl]purpurin (3) and 20-carbethoxy-4,8,14,18-tetra-
ethyl-3,9,13,19-tetramethyl-6-[4-(10,10,10-trimethylace-
tylmethyl)phenyl]purpurin (4). A solution of porphyrin 21
(1.0 g, 1.2 mmol) and 150 mL of trifluoroacetic acid was
stirred at room temperature for 3 days. The solution was
poured into dichloromethane and neutralized with NaHCO3
(aqueous). The organic layer was washed with water (3!),
dried over Na2SO4 and concentrated. The crude product,
porphyrin 22, was dissolved in 200 mL of dry toluene and
refluxed with 1 mL of 1,8-diazabicyclo[5.4.0]undec-7-ene
(DBU) for 6 h. The solvent was removed and the product
purified by column chromatography (silica gel, 1:24 ethyl
acetate/toluene) to give purpurins 3 and 4. Each was
re-crystallized from dichloromethane and methanol, to give
438 mg (53% yield) of purpurin 3 and 274 mg (33% yield)
of purpurin 4. 1D (1H) and 2D (COSY, ROESY, HMBC and
HMQC) NMR techniques were used to characterize both
purpurins. Purpurin 3: 1H NMR (500 MHz, CDCl3) d
K0.64 (1H, s, pyrrole-NH), 0.14 (1H, s, pyrrole-NH), 0.56
4.1.15. 20-Carbethoxy-4,8,14,18-tetraethyl-16-(4-
formylphenyl)-3,9,13,19-tetramethylpurpurin (24). Pur-
purin 23 (88 mg, 0.13 mmol) was dissolved in 20 mL of