May-Jun 2005
Linearly -π- Extended Porphyrins: Synthesis of Novel Tetrabenzoylporphyrins
507
Dimethyl 3,3'-Dimethyl-4,4'-(p-methoxybenzoyl)pyrroyl-
methane-2,2'-dicarboxylate (5c).
give 9 (300 mg, 85%) as white crystals from ethanol mp 123.3
-1
1
°C; ir: NH 3272, CO 1733, CO 1666, CO 1645 cm ; H nmr
(CDCl ): δ 2.12 (s, 3H, CH ), 2.23 (s, 3H, CH ), 5.11 (s, 2H, -
3
3
3
This compound was obtained as colourless crystals, mp > 250
CH -), 5.38 (s, 2H, -CH -), 7.45 (m, 8H, Ar-H), 7.77 (m, 2H, Ar-
-1
1
2
2
°C; ir: NH 3360, CO 1720, CO 1640 cm ; H nmr (CDCl ): δ
3
13
H), 9.62 (s, 1H, NH). C nmr: 12.3, 20.8, 57.4, 66.3, 119.8,
124.7, 128.2, 128.3, 128.4, 128.6, 129.3, 132.7, 133.5, 135.8,
139.5, 160.9, 171.5, 193.1 ppm; ms: ei, m/z (%): 391 (M ) (25),
2.11 (s, 6H, 2CH ), 3.85 (s, 6H, 2CH ), 3.91 (s, 6H, 2-OCH ),
3
3
3
4.05 (s, 2H, -CH -), 6.98 (d, J = 14 Hz, 4H), 7.85 (d, J = 14 Hz,
2
+
13
2H), 11.10 (s, 2H, 2NH); C nmr: 12.8, 24.0, 51.4, 55.4, 113.5,
331 (45), 240 (58), 91(100).
113.8, 118.7, 123.1, 127.6, 132.1, 132.2, 132.3, 137.5, 161.4,
Anal. Calcd. for C H NO : C, 70.58; H, 5.41. Found: C,
+
23 21
5
163.5, 193.3 ppm; ms: EI, m/z (%): 558 (M ) (25), 423 (48), 406
70.45; H, 5.38.
(25), 359 (20), 135 (100).
Anal. Calcd for C H N O : C, 66.66; H, 5.41. Found: C,
66.45; H, 5.11.
31 30
2
8
3,3'-Dibenzoyl-4,4'-dimethyl-2,2'-dipyrrolylmethane-5,5'-dicar-
boxylic Acid (10).
Dibenzyl 3,3'-Dimethyl-4,4'-dibenzoylpyrroylmethane-2,2'-
Dicarboxylate (5d).
A solution of 5d (100 mg, 0.18 mmol), in tetrahydrofurane (10
ml) was shaken in an atmosphere of hydrogen in the presence of
10% Pd-C (50 mg) until absorption of hydrogen was no longer
observed. After removal of the catalyst by filtration and evapora-
tion of the solvent, the residue was crystallised from
dichloromethane to give 10 (72 mg, 99%) as colourless crystals
This compound was obtained as colourless crystals, mp 198.4
-1
1
°C; ir: NH 3362, CO 1719, CO 1628 cm ; H nmr (CDCl ): δ
3
2.05 (s, 6H, 2CH ), 4.11 (s, 2H, -CH ), 5.93 (s, 4H, 2 -CH -Ph),
3
2
2
7.44 (m, 16H, Ar-H), 7.81(m, 4H, Ar-H), 11.15 (s, 2H, 2NH);
1
13
mp (decomp.) >200 °C; H nmr (dimethyl sulfoxide-d ): δ 1.06
C nmr: 12.9, 24.19, 65.9, 118.7, 122.9, 127.9, 128.1, 128.2,
6
(s, 6H, 2CH ), 3.94 (s, 2H, -CH ), 7.39 (m, 4H, Ar-H), 7.51 (m,
128.4, 128.5, 129.7, 132.7, 136.1, 138.2, 139.5, 160.7,
3
2
+
6H, Ar-H), 11.67 (s, 2H, 2NH), 12.30 (s, 2H, carboxylic acid);
194.6ppm; ms: esi 650.5 (M ) for C H N O .
41 34
2 6
13
C nmr: 11.8, 59.6, 119.0, 122.2, 122.3, 126.3, 128.2, 128.7,
Anal. Calcd for C H N O : C, 75.68; H, 5.27. Found: C,
41 34
2 6
128.8, 132.1, 135.8, 139.4, 162.1, 192.6 ppm.
2,8,12,18-Tetrabenzoyl-3,7,13,17-tetramethylporhyrin (11a).
Method A.
75.55; H, 5.22.
8-Benzoyl-3,7-dimethyl-4-phenyl-1H-pyrrolo[3,2-f]indolizine
(6).
This compound was obtained as pale yellow crystals, mp > 300
A solution of dipyrrolylmethanedicarboxylic acid 10 (125 mg,
0.26 mmol) and formaldehyde (37%) (3.5 ml) in
dichloromethane/methanol mixture (120 ml) (4:1) was refluxed
for 5 min under an atmosphere of Argon. After the addition of
hydrobromic acid (48%) (1 ml) as one portion the solution turned
immediately to deep pink then was allowed to reflux for 1 h. The
reaction mixture was then allowed to stirr at room temperature
for 20 h. DDQ was added (180 mg, 0.8 mmol) and the cloudy
mixture was stirred at room temperature for additional 20 h. The
mixture was concentrated under vacuum and the residue was dis-
solved in 500 ml dichloromethane and washed with water. The
-1 1
°C; ir: NH 3364, CO 1680 cm ; H nmr (dimethyl sulfoxide-d ):
6
δ 1.59 (s, 3H, -CH ), 1.81 (s, 3H, -CH ), 6.61 (s, 1H), 7.21 (s,
3
3
13
1H), 7.45 (m, 10H, Ar-H), 8.10 (s, 1H), 10.85 (s, 1H); C nmr:
11.23, 13.47, 96.1, 107.1, 108.1, 109.6, 119.6, 127.1, 127.4,
128.0, 128.2, 128.7, 128.9, 129.7, 130.1, 132.2, 137.7, 138.5,
+
144.0, 188.0 ppm; ms: EI, m/z (%): 364 (M ) (100), 287 (20),
259 (10), 232 (10), 182 (5).
Anal. Calcd. for C H N O: C, 82.39; H, 5.53. Found: C,
25 20
2
82.31; H, 5.43.
Benzyl 4-benzoyl-3,5-dimethyl pyrrole 2-carboxylate (8).
dichloromethane layer was dried over MgSO and chro-
matographed on a Grade 3 alumina column. A deep violet frac-
tion was collected and evaporation under vacuum gave 11a as a
4
Was prepared from benzoylacetone (7) and benzyl 2-oximinace-
toacetate (2d) as mentioned [22]. This compound was obtained as
colourless crystals (petroleum ether/ethylacetate, 4:1), mp 120-121
violet powder (26 mg, 25%) from CHCl /methanol mp > 300 °C;
1
3
°C; ir: NH 3277, CO 1669, CO 1644; H nmr (CDCl ): 2.20 (s, 3H,
3
1
H nmr (CDCl ): δ -3.25 (s, 2H), 1.58 (s, 12H), 7.95 (m, 8H),
3
CH ), 2.25 (s, 3H, CH ), 5.28 (s,2H, -CH -), 7.41 (m, 8H), 7.75
3
3
2
7.42 (m, 4H), 7.62 (m, 4H) 8.15 (m, 4H), 9.91 (s, 2H), 10.28 (s,
13
(m, 2H), 9.21 (s,1H, NH). C nmr: 12.4, 13.5, 66.1, 118.1, 123.3,
128.1, 128.3, 128.4, 128.6, 129.15, 129.8, 132.2, 135.9, 137.0,
140.18, 161.3, 193.8; ms, esi: 333.3 (M ).
+
2H); ms: ei, m/z (%): 782 (M ) (55), 105 (50), 77 (25), 44 (100).
Anal. Calcd. for C H N O : C, 79.78; H, 4.89. Found: C,
+
52 38
4 4
79.56; H, 4.65.
Anal. Calcd. for C H NO : C, 75.66; H, 5.74. Found: C,
21 19
3
75.55; H, 5.48.
2,8,12,18-Tetrabenzoyl-3,7,13,17-tetramethyl-5,10,15,20-tetra-
phenylporhyrin (11b).
Benzyl 5-Acetoxymethyl-4-benzoyl-3-methylpyrrole-2-car-
boxylate (9).
This compound was prepared using 10 and benzaldehyde by
the previous procedure. Following chromatography as described
for 11a, the product was recrystallised from chloroform-
methanol to give the title porphyrin (32 mg, 26%) as dark violet
In a stream of Ar, lead(IV) acetate (1.00 g, 2.26 mmol) was
added to a solution of benzylpyrrole 2-carboxylate (8) (300 mg,
0.77 mmol) in acetic acid (10 ml), and the mixture was stirred for
7 h at 90 °C. After the excess lead(IV) acetate was decomposed
by ethylene glycol, the mixture was poured into ice-water and
extracted with dichloromethane. The dichloromethane layer was
1
crystals mp > 300 °C; H nmr (CDCl ): δ -1.95 (s, 2H), 2.41 (s,
3
12H), 7.38 (m, 8H), 7.51 (m, 4H), 7.71 (m, 6H), 7.81 (m, 8H),
+
8.15 (m, 4H), 9.61 (s, 2H); ms: ei, m/z (%): 936 (M +2) (40),
+
+
935 (M +1) (8), 934 (M ) (100), 105 (95).
washed with H O and dried over anhydrous MgSO . After evap-
2
4
Anal. Calcd. for C H N O : C, 82.21; H, 4.96. Found: C,
82.01; H, 4.78.
oration of the solvent under vacuum, the residue was purified by
column chromatography (petroleum ether/ethylacetate, 4:1) to
64 46
4 4