A new synthetic approach to N-arylquinolino[2,3,4-at]porphyrins from β-arylaminoporphyrins

Article abstract of DOI:10.1021/jo800975c

(Chemical Equation Presented) A new reaction leading to porphyrins bearing fused rings is described. Novel N-arylquinolino[2,3,4-at]porphyrins 2 were obtained by thermal oxidative cyclization of β-arylaminoporphyrins 1. The starting β-arylaminoporphyrins were prepared by two routes: (i) nucleophilic displacement of the nitro group from 2-nitro-5,10,15,20- tetraphenylporphyrin by anilines and (ii) palladium-catalyzed amination of bromobenzene derivatives with (2-amino-5,10,15,20-tetraphenylporphyrinato) nickel(II). The N-arylquinolino[2,3,4-at]porphyrins show interesting UV-vis spectra with strong absorption bands in the red region.

Full text of DOI:10.1021/jo800975c

materials for the synthesis of other porphyrin derivatives, namely
by direct nucleophilic substitution of the 2-nitro group by
thiolates,3 alkoxides,4,5 Grignard or organolithium reagents,6 1,3-
dicarbonyl compounds,7 azide ion,8 etc. The conversion of the
nitro group into amino and diazonium groups, along with their
subsequent reactions, represents another important synthetic tool
for porphyrin derivatization.9–13
Here we report the synthesis of 2-arylaminoporphyrins 1 and
their subsequent conversion into novel N-arylquinolino[2,3,4-
at]porphyrins 2. This is a new reaction leading to porphyrins
bearing fused rings.14 Compounds 2 are structurally related with
the ones obtained by treatment of (2-nitro-5,10,15,20-tetraphe-
nylporphyrinato)nickel(II) with triethyl phosphite15 or by thermal
cyclization of (2-azido-5,10,15,20-tetraphenylporphyrinato)n-
ickel(II).16
A New Synthetic Approach to
N-Arylquinolino[2,3,4-at]porphyrins from
ꢀ-Arylaminoporphyrins
Ana M. V. M. Pereira,† Cristina M. A. Alonso,†
Maria G. P. M. S. Neves,† Augusto C. Tome´,†
Artur M. S. Silva,† Filipe A. A. Paz,‡ and
Jose´ A. S. Cavaleiro*,†
Department of Chemistry, UniVersity of AVeiro,
3810-193 AVeiro, Portugal, and Department of Chemistry,
CICECO, UniVersity of AVeiro, 3810-193 AVeiro, Portugal
jcaValeiro@ua.pt
ReceiVed May 20, 2008
Two different approaches were used to prepare the 2-ary-
laminoporphyrins 1: (a) by nucleophilic substitution of the nitro
group of 2-nitro-5,10,15,20-tetraphenylporphyrin (2-NO2-TPP)
by anilines (Scheme 1) and (b) by palladium-catalyzed amination
reactions of (2-amino-5,10,15,20-tetraphenylporphyrinato)nick-
el(II) with bromobenzene derivatives (Scheme 2).
Our studies involving the direct displacement of the nitro
group in 2-NO2-TPP were initiated by refluxing the porphyrin
in aniline under a nitrogen atmosphere. After 20 h, the TLC of
the reaction mixture showed the complete conversion of the
starting porphyrin into one major product and two minor ones.
After the workup, the reaction products were purified by column
chromatography and preparative TLC. The major compound was
identified (vide infra) as the 2-phenylaminoporphyrin 1a (53%
yield), and the other two products were identified as the
unexpected N-phenylquinolino[2,3,4-at]porphyrin 2a (6% yield)
and chlorin 3 (22% yield). Compound 1a and the corresponding
copper and zinc complexes have already been reported.6,17,18
A new reaction leading to porphyrins bearing fused rings is
described. Novel N-arylquinolino[2,3,4-at]porphyrins 2 were
obtained by thermal oxidative cyclization of ꢀ-arylaminopo-
rphyrins 1. The starting ꢀ-arylaminoporphyrins were prepared
by two routes: (i) nucleophilic displacement of the nitro
group from 2-nitro-5,10,15,20-tetraphenylporphyrin by anilines
and (ii) palladium-catalyzed amination of bromobenzene
derivatives with (2-amino-5,10,15,20-tetraphenylporphyri-
nato)nickel(II). The N-arylquinolino[2,3,4-at]porphyrins show
interesting UV-vis spectra with strong absorption bands in
the red region.
(3) Baldwin, J. E.; Crossley, M. J.; DeBernardis, J. Tetrahedron 1982, 38,
685.
(4) Crossley, M. J.; King, L. G. J. Chem. Soc., Perkin Trans. 1 1996, 1251.
(5) Crossley, M. J.; King, L. G.; Simpson, J. L. J. Chem. Soc., Perkin Trans.
1 1997, 3087.
(6) Crossley, M. J.; Harding, M. M.; Tansey, C. W. J. Org. Chem. 1994, 59,
4433.
(7) Giuntini, F.; Faustino, M. A. F.; Neves, M. G. P. M. S.; Tome´, A. C.;
Silva, A. M. S.; Cavaleiro, J. A. S. Tetrahedron 2005, 61, 10454.
(8) Lacerda, P. S. S.; Silva, A. M. G.; Tome´, A. C.; Neves, M. G. P. M. S.;
Silva, A. M. S.; Cavaleiro, J. A. S.; Llamas-Saiz, A. L. Angew. Chem., Int. Ed.
2006, 45, 5487.
(9) Hombrecher, H. K.; Gherdan, V. M.; Ohm, S.; Cavaleiro, J. A. S.; Neves,
M. G. P. M. S.; Condesso, M. F. Tetrahedron 1993, 49, 8569.
(10) Lu¨dtke, K.; Alonso, C. M. A.; Neves, M. G. P. M.; Silva, A. M. S;
Cavaleiro, J. A. S.; Hombrecher, H. K. Heterocycl. Commun. 1997, 3, 503.
(11) Alonso, C. M. A.; Neves, M. G. P. M.; Tome´, A. C.; Silva, A. M. S;
Cavaleiro, J. A. S. Eur. J. Org. Chem. 2004, 3233.
(12) Alonso, C. M. A.; Neves, M. G. P. M. S.; Tome´, A. C.; Silva, A. M. S;
Cavaleiro, J. A. S. Tetrahedron 2005, 61, 11866.
(13) Tome´, J. P. C.; Pereira, A. M; V, M.; Alonso, C. M. A.; Neves,
M. G. P. M. S.; Tome´, A. C.; Silva, A. M. S.; Cavaleiro, J. A. S.; Mart´ınez-
D´ıaz, M. V.; Torres, T.; Rahman, G. M. A.; Ramey, J.; Guldi, D. M. Eur. J.
Org. Chem. 2006, 257.
The chemical and physical properties displayed by porphyrins
render them appealing compounds for several applications.
Medicine, chemistry and physics are widely explored areas
where these compounds have shown promising applications,
namely as agents for cancer photodynamic therapy, as catalysts,
and as novel functional materials.1
The transformation of readily available meso-tetraarylpor-
phyrins into new compounds exhibiting adequate features for a
required application has been the goal of several research groups.
2-Nitroporphyrins2 have been extensively used as starting
(14) For a recent review on this subject, see: (a) Fox, S.; Boyle, R. W.
Tetrahedron 2006, 62, 10039.
(15) Richeter, S.; Jeandon, C.; Gisselbrecht, J.-P.; Graff, R.; Ruppert, R.;
Callot, H. J. Inorg. Chem. 2004, 43, 251.
* To whom correspondence should be addressed.
† Department of Chemistry.
‡ Department of Chemistry, CICECO.
(1) The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guillard, R.,
Eds.; Academic Press: San Diego, 2000; Vol. 6.
(2) Giraudeau, A.; Callot, H. J.; Jordan, J.; Ezhar, I.; Gross, M. J. Am. Chem.
Soc. 1979, 101, 3857.
(16) Shen, D.-M.; Liu, C.; Chen, Q.-Y. Eur. J. Org. Chem. 2007, 2888.
(17) Khan, M. M.; Ali, H.; van Lier, J. E. Tetrahedron Lett. 2001, 42, 1615.
(18) Gao, G.-Y.; Ruppel, J. V.; Allen, D. B.; Chen, Y.; Zhang, X. P. J. Org.
Chem. 2007, 72, 9060.
10.1021/jo800975c CCC: $40.75
Published on Web 08/22/2008
2008 American Chemical Society
J. Org. Chem. 2008, 73, 7353–7356 7353

SCHEME 1. Synthesis of N-Arylaminoporphyrins 1
afforded 2a in 87% yield. Similarly, heating 1b in refluxing
nitrobenzene afforded 2b in 81% yield. These results clearly
show that compounds 2 result from the oxidative cyclization
of the arylaminoporphyrins 1.
In order to study the effect of electron-withdrawing groups
in the oxidative cyclization of the arylaminoporphyrins 1, we
decided to prepare compounds 1c and 1d, but the reaction of
2-NO2-TPP with p-chloroaniline and p-bromoaniline, in o-
dichlorobenzene, did not lead to the required products. There-
fore, we converted 2-NO2-TPP into the corresponding 2-amino
derivative 4 and used it to prepare the corresponding 2-ary-
laminoporphyrins 5 via the palladium-catalyzed amination
methodology (Scheme 2).17,18,20,21 The reaction between 4 and
the commercially available p-bromochlorobenzene and p-
dibromobenzene under palladium-catalyzed conditions afforded,
respectively, compounds 5c (68% yield) and 5d (43% yield).
This methodology was also extended to the reaction of 4 with
bromobenzene and p-bromotoluene affording the expected
products 5a (69% yield) and 5b (78% yield), which are the
corresponding nickel complexes of the arylaminoporphyrins 1a
and 1b.
As indicated in Scheme 2, the amination reactions were
performed in toluene at 100 °C, under a nitrogen atmosphere,
using Pd(OAc)2 as catalyst, rac-BINAP as ligand, and KOtBu
as the base. The reactions were ended after the conversion of
the starting porphyrin 4 into a main product with higher Rf
(monitored by TLC). After workup, the major product was
isolated by preparative TLC and identified as 5 by spectroscopic
data. No N-arylquinolinoporphyrins or hydroxychlorins were
formed in these reactions. Demetalation of compounds 5a-d
with 10% sulfuric acid in dichloromethane afforded the corre-
sponding free-bases 1a-d in ca. 70% yield.
SCHEME 2. Synthesis of N-Arylquinolinoporphyrins 2a-d
via Palladium-Catalyzed Amination Followed by Thermal
Oxidative Cyclization
Compounds 2c and 2d were obtained in 75% and 76% yield,
respectively, by refluxing nitrobenzene solutions of 1c and 1d
for 30 h followed by purification by column chromatography.
It is worth mentioning that the nickel derivatives 5 also led to
the expected N-arylquinolino products when heated in refluxing
nitrobenzene.
The structural elucidation of the new compounds involved
the use of several NMR techniques (1H, 13C, COSY, HSQC,
HMBC, and NOESY), HRMS, and UV-vis. In addition, the
structure of compound 2a was unequivocally confirmed by
single-crystal X-ray diffraction studies (Figure 1).22
(19) Nitrobenzene is frequently used as a dehydrogenating agent in porphyrin
synthesis: Gonsalves, A. M.; Rocha, d’A.; Vareja˜o, J. M. T. B.; Pereira, M. M
J. Heterocycl. Chem. 1991, 28, 635.
(20) Compound 4 has already been used in the preparation of a 4-(porphyrin-
2-ylamino)phthalonitrile via palladium-catalyzed amination: Soares, A. R. M.;
Mart´ınez-D´ıaz, M. V.; Bruckner, A.; Pereira, A. M. V. M.; Tome´, J. P. C.;
Alonso, C. M. A.; Faustino, M. A. F.; Neves, M. G. P. M. S.; Tome´, A. C.;
Silva, A. M. S.; Cavaleiro, J. A. S.; Torres, T.; Guldi, D. M. Org. Lett. 2007, 9,
1557.
(21) There are also some reports regarding the synthesis of aminoporphyrins
via palladium-catalyzed amination of ꢀ-bromo, meso-bromo-, and meso-
halogenophenylporphyrins with amines and amides: (a) Takanami, T.; Hayashi,
M.; Hino, F.; Suda, K. Tetrahedron Lett. 2003, 44, 7353. (b) Chen, Y.; Zhang,
X. P. J. Org. Chem. 2003, 68, 4432. (c) Gao, G.-Y.; Chen, Y.; Zhang, X. P. J.
Org. Chem. 2003, 68, 6215. (d) Gao, G.-Y.; Chen, Y.; Zhang, X. P. Org. Lett.
2004, 6, 1837. (e) Chen, Y.; Fields, K. B.; Zhang, X. P. J. Am. Chem. Soc.
2004, 126, 14718. (f) Chen, Y.; Gao, G.-Y.; Zhang, X. P. Tetrahedron Lett.
2005, 46, 4965. (g) Esdaile, L. J.; Senge, M. O.; Arnold, D. P. Chem. Commun.
2006, 4192.
(22) Crystal data: C50H33N5, M ) 703.81, T ) 150(2) K, monoclinic, space
group P21/n, Z ) 4, a ) 17.7092(7) Å, b ) 10.6971(3) Å, c ) 19.5954(7) Å,
R ) 104.6350(10)°, V ) 3591.7(2) Å3, brown prism with crystal size of 0.20 ×
0.08 × 0.04 mm3. Of a total of 77784 reflections collected; 6113 were
independent (Rint ) 0.0819). Final R1 ) 0.0455 [I > 2σ(I)] and wR2 ) 0.1151
(all data). CCDC 642548. See the Supporting Information for further details on
the crystal solution and refinement.
Preliminary attempts to perform the reaction between 2-NO2-
TPP and p-toluidine (72 h at 180 °C and in the absence of
solvent) did not lead to the expected products. However, when
this reaction was conducted in refluxing o-dichlorobenzene (48
h), compound 1b was obtained in 32% yield, compound 2b was
formed in trace amounts, and no chlorin derivative of type 3
was detected.
When the reaction of 2-NO2-TPP with aniline was performed
in refluxing o-dichlorobenzene, compounds 1a, 2a, and 3 were
again obtained but in a different product yield distribution: 19%
yield, 26% yield, and trace amounts, respectively.
Since the formation of compounds 2 involves the oxidative
cyclization of 1, we decided to study the cyclization of 1a in
refluxing nitrobenzene.19 After 1a was refluxed in nitrobenzene
for 30 h, the TLC of the reaction mixture showed its complete
conversion into 2a. Purification by column chromatography
7354 J. Org. Chem. Vol. 73, No. 18, 2008

FIGURE 2. Visible absorption spectra of compounds 1a, 2a, and 3 in
dichloromethane.
spectra are those from the N-arylquinolino[2,3,4-at]porphyrins
2 which show intense absorption bands at λ ≈ 590-610 and
660 nm.
FIGURE 1. Molecular unit of 2a. Non-hydrogen atoms are represented
In conclusion, two new methodologies were developed for
the synthesis of the novel N-arylquinolino[2,3,4-at]porphyrins
2. The first one involves the reaction of 2-NO2-TPP with aniline
or p-toluidine. These reactions afford mixtures of the corre-
sponding 2-arylaminoporphyrin derivatives 1 and N-arylquino-
lino[2,3,4-at]porphyrins 2 (and the hydroxychlorin 3 in the case
of the reaction with aniline). The second approach involves the
formation of 2-arylaminoporphyrins via palladium-catalyzed
reactions of (2-amino-5,10,15,20-tetraphenylporphyrinato)nick-
el(II) 4 with bromobenzene derivatives. After demetalation to
1a-d, these derivatives are easily converted into derivatives 2
by oxidative cyclization in refluxing nitrobenzene.
as thermal ellipsoids drawn at the 50% level.
1
The H NMR spectra of all the arylaminoporphyrin deriva-
tives (1a-d and 5a-d) are consistent with ꢀ-substituted
porphyrins showing the resonance corresponding to H-3 as a
singlet (or under a multiplet) at ca. δ 8.2 ppm.
1
The H NMR spectra of the N-arylquinolino[2,3,4-at]por-
phyrins 2a-d show interesting features, with the signals of
protons H-18 and H-5′ appearing at low field (δ ∼9.7 ppm). In
compound 2a, for instance, the resonances of these protons
emerge as two doublets at δ 9.67 ppm (J ) 4.5 Hz) and 9.68
ppm (J ) 7.0 Hz), respectively. The COSY and NOESY spectra
of 2a clearly indicate that the signal at δ 9.67 ppm (H-18)
correlates with the resonance of H-17 (δ 8.82 ppm) and the
signal at δ 9.68 ppm (H-5′) correlates with the resonance of
H-4′ (included in the multiplet at δ 7.64-7.90 ppm). The same
pattern is also observed in the spectra of compounds 2b-d.
Compounds 2 show interesting UV-vis spectra with intense
absorption bands in the red region of the visible spectrum, which
make them potential candidates for application in various
scientific areas.
Experimental Section
The UV-vis spectrum of 3 is typical of chlorins showing a
strong Q absorption band at 642 nm (log ε ) 4.4). The mass
spectrum shows a peak at m/z 724 [(M + H)+], differing from
1a in 18 mass units, which is consistent with the addition of
Synthesis of N-Arylquinolino[2,3,4-at]porphyrins 2 from
Arylaminoporphyrins 1. A stirred solution of each 1a-d (ca. 20
mg) in nitrobenzene (2 mL) was kept under reflux for 30 h. The
reaction mixture was poured on top of a silica gel chromatography
colum, and the nitrobenzene was eluted with light petroleum. The
reaction products were then eluted using a 1:1 mixture of dichlo-
romethane and light petroleum. Compounds 2a-d were obtained
as dark solids, after precipitation from dichloromethane and hexane,
with 87% (17.2 mg), 81% (16.1 mg), 75% (14.9 mg), and 76%
(15.1 mg) yields, respectively.
1
one water molecule. Its H NMR spectrum shows the signals
corresponding to the resonance of six ꢀ-pyrrolic protons (δ
8.3-8.7 ppm), indicative of a disubstituted derivative, and also
the characteristic signals corresponding to resonance of the
aniline protons. The spectrum also shows three signals at δ
-1.88, 2.46, and 3.90 ppm which disappear when D2O is added
to the sample, thus being assigned to the resonances of the inner
Data for N-phenylquinolino[2,3,4-at]porphyrin, 2a: mp 230-232
1
°C; H NMR (500 MHz, CDCl3, TMS) δ -1.25 (s, 2H, NH),
3
7.64-7.90 (m, 18H, H-3, H-2′,3′,4′, H-m,p-Ph-5,10,15 and N-C6H5),
8.10-8.11, 8.16-8.18 and 8.26-8.28 (3m, 6H, H-o-Ph-5,10,15),
8.59 (d, J ) 4.8 Hz, 1H, H-ꢀ), 8.67-8.68 (m, 2H, H-12,13), 8.74
(d, J ) 4.8 Hz, 1H, H-ꢀ), 8.82 (d, J ) 4.5 Hz, 1H, H-17), 9.67 (d,
J ) 4.5 Hz, 1H, H-18), 9.68 (d, J ) 7.0 Hz, 1H, H-5′); 13C NMR
(75 MHz, CDCl3, TMS) δ 101.3 (C-3); 110.4; 115.5 (C-2′); 116.5,
117.3; 121.9 or 122.0 (C-4′); 123.3; 124.0 (C-18); 126.5 (C-17);
126.7, 126.8, 127.1, 127.37, 127.41, 127.5, 127.7, 129.1, 129.3,
130.9 (C-m,p-Ph-5,10,15 and C-3′); 128.6, 132.3 and 134.54 (C-
ꢀ); 134.0, 134.47 and 134.7 (C-o-Ph-5,10,15); 135.0 (C-5′); 136.3,
141.3, 142.2, 142.4, 145.9, 155.3. UV-vis (CH2Cl2) λmax (log ε)
412 (5.2), 451 (4.9), 594 (4.3), 610 (4.3), 663 (4.2); HRMS (ESI)
calcd for C50H34N5 (M + H)+ 704.2794, found 704.2809.
NH, OH and ꢀ-NH protons. The HMBC spectrum shows J
correlation between the doublet at δ 3.90 ppm (J ) 4.8 Hz)
and C-2′,6′ (δ 113.0 ppm), allowing its assignment to the
resonance of the ꢀ-NH proton. The broad singlet at δ 2.46 ppm
can be, therefore, assigned to the resonance of the OH proton.
In the COSY spectrum, the ꢀ-NH signal (δ 3.90 ppm) correlates
with the doublet at δ 5.90 ppm (J ) 4.8 Hz) which corresponds
to the resonance of H-2 proton, being the singlet at δ 6.21 ppm
assigned to the H-3 resonance. The same spectrum shows that
protons H-2 and H-3 do not correlate with each other, denoting
a trans configuration with a dihedral angle around 90°.
The UV-vis spectra of compounds 1a, 2a, and 3 (shown as
examples of the three structural types of compounds described
in this paper) are depicted in Figure 2. The most interesting
Data for N-(p-methylphenyl)quinolino[2,3,4-at]porphyrin, 2b:
mp >300 °C; 1H NMR (500 MHz, CDCl3, TMS) δ -1.22 (s, 2H,
NH), 2.64 (s, 3H, CH3), 7.62 (d, J ) 8.0 Hz, 1H, H-2′), 7.66-7.88
J. Org. Chem. Vol. 73, No. 18, 2008 7355

(m, 16H, H-3, H-3′,4′, H-m,p-Ph-5,10,15 and N-C6H4Me), 8.10-8.13,
8.16-8.18 and 8.26-8.28 (3m, 6H, H-o-Ph-5,10,15), 8.59 (d, J )
4.5 Hz, 1H, H-ꢀ), 8.66-8.69 (m, 2H, H-12, 13), 8.74 (d, J ) 4.5
Hz, 1H, H-ꢀ), 8.81 (d, J ) 4.8 Hz, 1H, H-17), 9.66 (d, J ) 4.8 Hz,
1H, H-18), 9.67 (d, J ) 8.0 Hz, 1H, H-5′); 13C NMR (125 MHz,
CDCl3, TMS): δ 21.6 (CH3); 101.2 (C-3); 115.6 (C-2′); 121.9 (C-
4′); 123.3; 124.1 (C-18); 126.7 (C-17); 126.8, 127.1, 127.3, 127.7
(C-m,p-Ph-5,10,15); 128.7 (C-2′′,6′′); 131.5 (C-3′′,5′′); 126.5, 128.6,
132.2 and 134.54 (C-ꢀ); 134.0, 134.47 and 134.7 (C-o-Ph-5,10,15);
135.0 (C-5′); 138.7, 139.0, 142.3, 142.4, 145.4, 149.0; UV-vis
(CH2Cl2) λmax (log ε) 413 (5.2), 452 (4.9), 595 (4.3), 611 (4.3),
663 (4.2); HRMS (ESI) calcd for C51H36N5 (M + H)+ 718.2965,
found 718.2946.
NH), 7.60 (d, J ) 8.4 Hz, 1H, H-2′), 7.69-7.98 (m, 16H, H-3,
H-3′,4′, H-m,p-Ph-5,10,15 and N-C6H4Br), 8.09-8.12, 8.15-8.19
and 8.25-8.28 (3m, 6H, H-o-Ph-5,10,15), 8.60 (d, J ) 4.7 Hz,
1H, H-ꢀ), 8.68-8.70 (m, 2H, H-12,13), 8.76 (d, J ) 4.7 Hz, 1H,
H-ꢀ), 8.83 (d, J ) 4.7 Hz, 1H, H-17), 9.66 (d, J ) 7.5 Hz, 1H,
H-5′), 9.67 (d, J ) 4.7 Hz, 1H, H-18); 13C NMR (75 MHz, CDCl3,
TMS) δ 101.3 (C-3); 110.2; 115.2 (C-2′); 116.7, 117.3; 122.1 or
122.2 (C-4′); 123.2, 123.3; 124.1 (C-18); 126.5 (C-17); 126.7,
126.77, 126.83, 127.2, 127.4, 127.6, 127.8 (C-m,p-Ph-5,10,15);
131.0 (C-2′′,3′′,5′′,6′′); 128.57, 128.63, 132.5 and 134.6 (C-ꢀ);
134.3; 133.9, 134.5 and 134.7 (C-o-Ph-5,10,15,20); 135.2 (C-5′);
136.1, 140.3, 142.2, 142.33, 142.35, 145.6; UV-vis (CH2Cl2) λmax
(log ε) 412 (4.8), 449 (4.5), 592 (3.9), 609 (3.9), 662 (3.9); HRMS
(ESI) calcd for C50H33BrN5 (M + H)+ 784.1905, found 784.1901.
Data for N-(p-chlorophenyl)quinolino[2,3,4-at]porphyrin, 2c: mp
>300 °C; 1H NMR (500 MHz, CDCl3, TMS) δ -1.33 (s, 2H, NH),
7.62 (d, J ) 8.0 Hz, 1H, H-2′), 7.68-7.86 (m, 16H, H-3, H-3′,4′,
H-m,p-Ph-5,10,15 and N-C6H4Cl), 8.10-8.12, 8.16-8.18 and
8.26-8.28 (3m, 6H, H-o-Ph-5,10,15), 8.61 (d, J ) 4.5 Hz, 1H,
H-ꢀ), 8.68-8.70 (m, 2H, H-12, 13), 8.76 (d, J ) 4.5 Hz, 1H, H-ꢀ),
8.83 (d, J ) 4.8 Hz, 1H, H-17), 9.66 (d, J ) 8.5 Hz, 1H, H-5′),
9.68 (d, J ) 4.8 Hz, 1H, H-18); 13C NMR (125 MHz, CDCl3, TMS):
δ 101.3 (C-3); 110.2; 115.2 (C-2′); 116.7, 117.3, 117.8; 122.09 or
122.15 (C-4′); 123.3, 123.5, 124.0; 124.1 (C-18); 126.5 (C-17);
126.7, 126.78, 126.84, 127.2, 127.3, 127.4, 127.6, 127.7 and 127.8
(C-m,p-Ph-5,10,15); 130.7 and 131.3 (C-2′′,3′′,5′′,6′′); 128.57,
128.64, 128.7, 132.51, 132.53 and 134.7 (C-ꢀ); 133.9, 134.5, 134.6
and 134.7 (C-o-Ph-5,10,15); 135.2 (C-5′); 140.3, 142.2, 142.35,
142.37, 145.5; UV-vis (CH2Cl2) λmax (log ε) 412 (4.7), 449 (4.5),
592 (3.8), 609 (3.8), 662 (3.8); HRMS (ESI) calcd for C50H33ClN5
(M + H)+ 738.2419, found 738.2438.
Acknowledgment. Thanks are due to Fundac¸a˜o para a
Cieˆncia e a Tecnologia (FCT, Portugal) and POCI 2010
(FEDER) for funding the Organic Chemistry Research Unit and
the purchase of the single-crystal diffractometer. A.M.V.M.P.
and C.M.A.A. also thank FCT for their SFRH/BD/22691/2005
and SFRH/BPD/8375/2002 grants, respectively.
Supporting Information Available: Experimental proce-
dures and full spectroscopic data for all new compounds. Details
on the data collection, crystal solution, and refinement for
porphyrin 2a. Additional structural drawings of 2a. Crystal
structure (CIF). This material is available free of charge via
the Internet at http://pubs.acs.org.
Data for N-(p-bromophenyl)quinolino[2,3,4-at]porphyrin, 2d:
mp >300 °C; 1H NMR (300 MHz, CDCl3, TMS) δ -1.33 (s, 2H,
JO800975C
7356 J. Org. Chem. Vol. 73, No. 18, 2008