Soluble Tetrabenzo- and Tetranaphtho[2,3]porphyrins
1414.49; UV-vis, DMF, λmax nm (ꢀ) 426 (305,000), 565 (17,-
000), 618 (160,000). Anal. Calcd for C76H84N4O16Pd: C, 64.47;
H, 5.98; N, 3.96. Found: C, 64.29; H, 5.62; N, 4.03. Yield of
Pt-6b: 84%. 1H NMR (pyridine-d5, 80 °C) δ 9.99 (s, 4H), 9.46
(s, 8H), 4.92 (t, 16H, J ) 7 Hz); 2.16 (m, 16H), 1.80 (m, 16H),
1.23 (t, 24H, J ) 7.5 Hz); 13C NMR (pyridine-d5, 50 °C) δ 168.8,
137.3, 134.8, 132.6, 122.6, 98.1, 66.8, 31.8, 20.2, 14.5; MALDI-
TOF m/z 1503.49, calcd 1503.55; UV-vis, pyridine, λmax nm
(ꢀ) 416 (170,000), 557 (19,000), 609 (165,000). Anal. Calcd for
C76H84N4O16Pt: C, 60.67; H, 5.63; N, 3.72. Found: C, 59.84;
H, 5.23; N, 3.92.
Fe tetrabenzoporphyrin (Fe-6b). Porphyrin 6b (27 mg,
0.02 mmol) was dissolved in propionic acid (10 mL). FeCl2‚
4H2O (100 mg, 0.5 mmol) and iron wire (∼100 mg) were added,
and the mixture was refluxed under Ar for ∼1 h. The
conversion was monitored by UV-vis spectroscopy (solvent
DMF), and the reaction was stopped when the free-base
Q-band (λmax ) 673 nm) disappeared. The mixture was filtered,
the filtrate was evaporated to dryness, and the remaining
material was washed with methanol-pyridine mixture and
dried in a vacuum. The product was isolated as a blue-green
amorphous solid. Yield of Fe-6b: 20 mg, 74%. 1H NMR
(pyridine-d5) δ 11.38 (s, 4H), 10.12 (s, 8H), 4.72 (t, 16H, J ) 7
Hz); 1.92 (m, 16H), 1.59 (m, 16H), 1.02 (t, 24H, J ) 7.5 Hz);
13C NMR (pyridine-d5) δ 169.5, 143.2, 143.3, 131.2, 121.7, 98.3,
66.4, 31.5, 19.9, 14.2; MALDI-TOF m/z 1365.17, calcd 1364.52;
UV-vis, pyridine, λmax nm (ꢀ) 422 (110,000), 446 (99,500), 613
(100,000). Anal. Calcd for C76H84N4O16Fe: C, 66.86; H, 6.20;
N, 4.10. Found: C, 66.29; H, 6.45; N, 3.98.
5,8-Dialkoxy-1,4-dihydronaphthalenes (8b,c). Synthesis
of compound 8b generally followed the procedure described
for the synthesis of 5,8-dimethoxy-1,4-dihydronaphthalene
8a.45 Ethyl bromoacetate was used in the present synthesis
instead of dimethyl sulfate. Yield of 8b: 85%, colorless solid,
mp 117-118 °C. 1H NMR (CDCl3) δ 6.50 (s, 2H), 5.87 (s, 2H),
4.56 (s, 4H), 4.24 (q, 4H, J ) 7.5 Hz), 3.35 (s, 4H), 1.28 (s,
6H); 13C NMR (CDCl3) δ 174.2, 169.4, 125.7, 123.5, 108.5, 66.2,
61.3, 24.4, 14.3. Anal. Calcd for C18H22O6: C, 64.66; H, 6.63.
Found: C, 64.50; H, 6.58. Compound 8c was synthesized using
a similar procedure. A mixture of 5,8-dihydroxy-1,4-dihy-
dronaphthalene 7 (3.24 g, 20 mmol), ethyl 3-bromobutirate
(11.7 g, 9.0 mL, 60 mmol), NaI (1.5 g, 10 mmol) and K2CO3
(15 g) was refluxed in acetone (100 mL) for 48-60 h. The solid
was filtered off, washed with CH2Cl2 (100 mL), and the filtrate
was evaporated under reduced pressure. The resulting mater-
ial was recrystallized from ethyl alcohol to afford 2c as a
cream-colored solid. Yield of 8c: 5.45 g, 69%, mp 117-118 °C.
1H NMR (CDCl3) δ 6.58 (s, 2H), 5.86 (s, 2H), 4.13 (q, 4H,
3J(H,H) ) 6.5 Hz), 3.93 (t, 4H, J ) 6 Hz), 3.25 (s, 4H), 2.51 (t,
4H, J ) 7.5 Hz), 2.10 (m, 4H), 1.25 (t, 6H, J ) 7.5 Hz); 13C
NMR (CDCl3) δ 173.5, 150.4, 124.9, 123.8, 108.2, 67.2, 60.6,
31.2, 25.1, 24.5, 14.5. Anal. Calcd for C22H30O6: C, 67.67; H,
7.74. Found: C, 67.52; H, 7.77.
R-Chlorosulfones (9b,c). Synthesis of compounds 9b,c
generally followed the procedure described earlier for the
synthesis of R-chlorosulfone 9a.41 The products were purified
by flash chromatography on a silica gel column (eluent 9a,
CH2Cl2-THF, 20:1; 9b, CH2Cl2) with subsequent crystalliza-
tions from ether-petroleum ether mixtures. Yield of 9b: 65%,
yellowish solid, mp 111-112 °C. 1H NMR (CDCl3) δ 7.95-7.53
(m, 5H), 6.53 (s, 2H), 4.85 (m, 1H), 4.85 (m, 1H), 4.57 (s, 2H),
4.53 (s, 2H), 4.23 (m, 4H), 3.74 (m, 1H), 3.48-3.26 (m, 4H),
1.26 (m, 6H); 13C NMR (CDCl3) δ 174.3, 169.1, 150.4, 150.1,
138.2, 134.2, 129.4, 129.1, 123.4, 122.7, 109.8, 109.5, 66.5, 66.3,
64.4, 61.4, 51.8, 30.5, 24.6, 20.2, 14.3. Anal. Calcd for C24H27-
ClO8S: C, 56.41; H, 5.33. Found: C, 56.46; H, 5.27. Yield of
9c: 75%, yellowish solid, mp 86-87 °C. 1H NMR (CDCl3) δ
7.92-7.55 (m, 5H), 6.60 (s, 2H), 4.86 (m, 1H), 4.13 (m, 4H),
3.90 (m, 4H), 3.70 (m, 1H), 3.38-3.15 (m, 4H), 2.47 (m, 4H),
2.10 (m, 4H), 1.25 (m, 6H); 13C NMR (CDCl3) δ 173.5, 173.4,
150.4, 150.1, 138.4, 134.3, 129.5, 129.1, 122.3, 121.5, 109.2,
108.9, 67.4, 67.2, 64.5, 60.7, 52.0, 31.2, 31.1, 30.7, 25.0, 20.4,
14.5. Anal. Calcd for C28H35ClO8S: C, 59.30; H, 6.22. Found:
C, 59.27; H, 6.18.
Pyrrole Ester (10b). Compound 10b was prepared from
R-chlorosulfone 9c and tert-butyl isocyanoacetate following the
procedure described previously for the synthesis pyrrole ester
10a.41 The product was purified by flash chromatography on
a short silica gel column (eluent CH2Cl2-THF, 20:1), followed
by recrystallization from methanol. Yield of 10b: 77%, light
1
yellow crystals, mp 103-104 °C. H NMR (CDCl3) δ 8.92 (br
s, 1H), 6.81 (d, 1H, J ) 2.5 Hz), 6.64 (s, 2H), 4.14 (m, 4H),
4.03 (m, 2H), 3.98 (t, 4H, J ) 6 Hz), 3.80 (m, 2H), 2.55 (m,
4H), 2.13 (m, 4H), 1.57 (s, 9H), 1.25 (m, 6H); 13C NMR (CDCl3)
δ 173.6, 173.5, 161.7, 151.1, 150.8, 125.7, 125.3, 124.2, 119.3,
119.2, 118.1, 108.0, 107.9, 80.6, 67.3, 67.2, 60.6, 60.5, 31.3, 31.2,
28.7, 25.2, 25.1, 23.0, 21.2, 14.4, 14.3. Anal. Calcd for C29H39-
NO8: C, 65.77; H, 7.42; N, 2.64. Found: C, 65.71; H, 7.29; N,
2.66.
Pyrrole (11b). tert-Butyl ester 10b (300 mg, 0.57 mmol)
was dissolved in CH2Cl2 (15 mL), and the solution was flushed
with Ar for 5 min under stirring. The mixture was cooled on
an ice bath, TFA (10 mL) was added, and the mixture was
refluxed for 30 min. CH2Cl2 (20 mL) was added to the mixture,
after which it was poured into a beaker with ice-cold solution
of Na2CO3 (10% aqueous, 100 mL). The resulting mixture was
transferred into a separatory funnel, the organic layer was
separated, the water phase was additionally extracted with
CH2Cl2 (2 × 30 mL), and the combined organic solutions were
washed with 10% aqueous Na2CO3 (50 mL). After drying over
K2CO3, the solution was passed through a short silica gel
column (eluent CH2Cl2-THF, 20:1), and the solvent was
evaporated to yield the product as a colorless solid. Yield of
11b: 255 mg, 98%. 1H NMR (CDCl3) δ 8.09 (br s, 1H), 6.67 (d,
2H, J ) 2 Hz), 6.63 (s, 2H), 4.14 (q, 4H, J ) 8 Hz), 3.98 (t, 4H,
J ) 6 Hz), 3.85 (s, 4H), 2.56 (t, 4H, J ) 7 Hz), 2.14 (m, 4H),
1.26 (t, 6H, J ) 7 Hz); 13C NMR (CDCl3) δ 173.7, 151.0, 126.8,
117.4, 113.1, 108.2, 67.4, 60.6, 31.5, 25.2, 21.2, 14.3.
Tetranaphtho[2,3]porphyrins (13a,b). The syntheses of
porphyrins 13a,b from pyrroles 11a,b generally followed the
procedure, described above for the synthesis of TCHPs 5a,b.
The pyrrole (11a or 11b, 1.2 mmol) was dissolved in benzene
(60 mL), and the solution was flushed with Ar. Formaldehyde
(37% aqueous solution, 0.11 mL) and TsOH‚H2O (30 mg, 0.16
mmol) were added to the mixture under vigorous stirring, and
the mixture was refluxed for 4-5 h under Ar and then stirred
overnight on air. The solvent was evaporated, and the remain-
ing material was treated with DDQ (100 mg, 4 mmol). In the
case of 13a, the reaction was performed in refluxing dioxane,
whereas in the case of 13b, DDQ was added to the solution in
CH2Cl2 at room temperature. In the latter case, the oxidation
also could be done using p-chloranil (100 mg, 4 mmol) in
refluxing toluene. The progress of the reaction was monitored
by UV-vis spectroscopy (13a in DMF; 13b in CH2Cl2). The
spectrum changed gradually from the etio type, corresponding
to the porphyrins of type 12 (Scheme 2) to characteristic TNP
spectrum with an intense Q-band at ∼720 nm.
In the case of 13a, a green residue precipitated from the
reaction mixture. It was collected by centrifugation and
washed with pyridine and THF. For further purification, it
was recrystallized from refluxing PhCN and dried in a vacuum.
Yield of 13a: 25%, dark green powder. MALDI-TOF m/z
949.07, calcd 950.33; UV-vis, pyridine, λmax nm (ꢀ) (86500),
471 (198,000), 656 (29,500), 721 (191,000). Anal. Calcd for
C60H46N4O8: C, 75.77; H, 4.88; N, 5.89. Found: C, 75.24; H,
4.99; N, 5.75.
In the case of 13b, the reaction mixture was washed with
10% aqueous Na2SO3, with 10% aqueous Na2CO3, dried over
K2CO3 and reduced in volume of about 5 mL. Acetonitrile (60
mL) was added, resulting in formation of a green precipitate.
The precipitate was collected by centrifugation, washed with
acetonitrile and methanol and dried in a vacuum. Yield of
13b: 33%, green powder. 1H NMR (pyridine-d5-PhNO2-d5, 1:1,
50 °C) δ 11.51 (s, 4H), 10.92 (s, 8H), 4.71 (br t, 16H), 4.56 (q,
J. Org. Chem, Vol. 70, No. 23, 2005 9571