Direct β-amination reaction in porphyrin systems - A simple route to compounds containing two nitrogen substituents at both β-positions of the same pyrrole unit

Article abstract of DOI:10.1016/j.tetlet.2012.09.024

The direct β-amination of porphyrin derivatives is described. 2-Nitro-meso-tetraarylporphyrins (zinc and copper complexes) react with N,N,N-trimethylhydrazinium iodide (TMHI) in the presence of a base (KOH/DMSO system, ca 70-80 °C) to give products of nucleophilic aromatic substitution of hydrogen. In this process, the nucleophilic replacement of a H-atom by an NH₂ group takes place. The products obtained, bearing two neighbouring nitrogen substituents on the same pyrrole ring, are valuable intermediates for various synthetic uses.

Full text of DOI:10.1016/j.tetlet.2012.09.024

Tetrahedron Letters 53 (2012) 6355–6357
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Direct b-amination reaction in porphyrin systems—a simple route to compounds
containing two nitrogen substituents at both b-positions of the same
pyrrole unit
⇑
Stanisław Ostrowski , Sebastian Grzyb
Institute of Chemistry, Uniwersytet Przyrodniczo–Humanistyczny w Siedlcach (formerly University of Podlasie), ul. 3 Maja 54, 08-110 Siedlce, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 June 2012
Revised 25 August 2012
Accepted 6 September 2012
Available online 14 September 2012
The direct b-amination of porphyrin derivatives is described. 2-Nitro-meso-tetraarylporphyrins (zinc and
copper complexes) react with N,N,N-trimethylhydrazinium iodide (TMHI) in the presence of a base (KOH/
DMSO system, ca 70–80 °C) to give products of nucleophilic aromatic substitution of hydrogen. In this
process, the nucleophilic replacement of a H-atom by an NH2 group takes place. The products obtained,
bearing two neighbouring nitrogen substituents on the same pyrrole ring, are valuable intermediates for
various synthetic uses.
Keywords:
Porphyrins
Ó 2012 Elsevier Ltd. All rights reserved.
b-Amination
N,N,N-Trimethylhydrazinium iodide
Aromatic nucleophilic substitution of
hydrogen
b-Functionalized porphyrins are very useful and versatile inter-
mediates for the synthesis of more complex moieties (e.g., Lacerda
et al.;1 Alonso et al.;2 Silva et al.;3 Silva et al.;4 Wang et al.;5
Ostrowski and Wyre˛bek6). Among others, b-amino derivatives ap-
pear to be very attractive starting materials.7 They were used for
the preparation of N-linked bis-porphyrins (e.g., Tröger’s base ana-
cessfully applied this methodology for the amination of porphyrins
in meso-aryl rings.10
Herein, electrophilic b-nitroporphyrins were used as the start-
ing materials, which can be easily prepared according to literature
methods (Scheme 1).11 Some are known compounds and they were
previously used in our laboratory.
Initially, the NH groups inside the core ring were protected to
avoid N-anion generation under the strong basic conditions em-
ployed.10,12 N,N,N-Trimethylhydrazinium iodide ([Me3N+ÀNH2]IÀ)
logues7a), new porphyrins with extended
p
-system (pyrazine- and
quinoxaline-fused porphyrins,7b pyridine-fused porphyrins,2,7c,7d
imidazole-fused porphyrins,7e,7f etc.), or porphyrins conjugated
with a fused peripheral N-heterocyclic carbene moiety (NHC).7e,7f
b-Amino functionalization also offers the possibilities for modula-
tion of physico-chemical properties of the parent compounds (e.g.,
sensitivity to oxidation and very interesting electrochemical
properties7b).
Ar
Ar
Zn(OAc)2·2H2O
or Cu(OAc)2·H2O
NH
N
N
N
N
N
Ar
Ar
M
Ar
Ar
CHCl3/MeOH, reflux
N
HN
Simple b-aminoporphyrins are usually prepared by reduction of
the corresponding nitro-derivatives. Their synthesis could be pos-
sible, as well, by the aromatic nucleophilic substitution of hydro-
gen in appropriate electrophilic porphyrin systems. However, in
the literature there are only occasional known examples of this
type of nucleophilic substitution in b-positions of porphyrins by
nitrogen nucleophiles.7b,7e,7f,8
In continuation of our ongoing research, investigations towards
the synthesis of b-amino-porphyrins via vicarious nucleophilic
substitution of hydrogen9 were undertaken. We have already suc-
Ar
Ar
1
2
NO2
Ar
M
N
N
N
N
HNO3/CHCl3
Ar
Ar
Ar
3
a: M = Zn, Ar = Ph; b: M = Cu, Ar = 3-F-C6H4; c: M = Cu, Ar = 3-Cl-C6H4;
d: M = Cu, Ar = 3-Me-C6H4; e: M = Cu, Ar = 3-MeO-C6H4
⇑
Corresponding author. Tel.: +48 25 643 1113; fax: +48 25 644 2045.
E-mail address: stan@uph.edu.pl (S. Ostrowski).
Scheme 1.
0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tetlet.2012.09.024

6356
S. Ostrowski, S. Grzyb / Tetrahedron Letters 53 (2012) 6355–6357
was chosen as the aminating agent, which has been previously suc-
cessfully applied in several reactions. We also used other aminat-
ing reagents (sulfenamides, hydroxylamine, and 4-amino-4H-
1,2,4-triazole) which were tested for various porphyrin systems
in our laboratory, but only with moderate success.13 Similarly, in
the present case, when using the above listed reagents, we did
not observe promising results. It should be mentioned, however,
that for 4-amino-4H-1,2,4-triazole Richeter et al. reported good
yields of the b-amination of two similar porphyrinates.7e,7f
In the first experiment, b-nitroporphyrin-zinc(II) 3a was reacted
with TMHI to give the expected 2-amino-3-nitro-substituted prod-
uct 4a (KOH/DMSO, 70–80 °C, 1.5 h).14 The yield of this product
was very high (89%). In its 1H NMR spectrum the characteristic sig-
nal of the b-proton neighbouring the NO2 group had disappeared.
This provided clear evidence that the substitution occurred on
the same pyrrole ring containing the NO2 group. Additionally, a
broad singlet was observed at 6.54 ppm (NH2) and three doublets:
8.98 ppm (J = 4.9 Hz, 1H), 8.84 ppm (J = 4.9 Hz, 1H), and 8.54 ppm
(J = 4.9 Hz, 1H) due to three of the remaining b-protons. The other
three b-protons appeared as a multiplet at 8.75–8.81 ppm. These
signals confirmed the structure of product 4a. Three similar com-
pounds were obtained by Crossley et al.7b and Richeter et al.7e, 7f
They used other N-nucleophiles, generated from amides and from
4-amino-4H-1,2,4-triazole.
Amination of several other porphyrin complexes with the use of
TMHI gave good yields of the expected products:14 [2-amino-
3-nitro-5,10,15,20-tetrakis(3-fluorophenyl)porphyrinato]copper(II)
(4b, 64%), [2-amino-3-nitro-5,10,15,20-tetrakis(3-chlorophenyl)-
porphyrinato]copper(II) (4c, 65%), [2-amino-3-nitro-5,10,15,20-
tetrakis(3-methylphenyl)porphyrinato]copper(II) (4d, 79%), and
[2-amino-3-nitro-5,10,15,20-tetrakis(3-methoxyphenyl)porphyri-
nato]copper(II) (4e, 70%) (Scheme 2). It is worth noting that labile
groups such as F or Cl in meso-aryl rings did not enter into an SNAr
substitution reaction with the hydrazinium anion.
NO2
NH2
NO2
NH2
Ar
Ar
Ar
CF3CO2H / H2SO4 / CHCl3
room temp.
NH N
N
N
N
Ar
M
Ar
Ar
N
N
HN
Ar
Ar
4a,b,d,e
6a,b,d,e
a: Ar = Ph; 84%
b: Ar = 3-F-C6H4; 67%
d: Ar = 3-Me-C6H4; 80%
e: Ar = 3-MeO-C6H4; 88%
Scheme 3.
the yields of the decomplexation were very good (67–88%). The
structures of the final products were confirmed by 1H NMR, UV–
vis, and MS methods. Interestingly, in the 1H NMR spectra, diag-
nostic signals originating from the b-protons, situated at the oppo-
site side to the substituted pyrrole ring, appeared as AB systems in
all cases in the region 8.61–8.66 ppm.
In conclusion, the described amination represents an important
tool in porphyrin chemistry. This method is of high utility because
the corresponding amino-/nitro–moieties allow for various syn-
thetic transformations. Currently, we are investigating the utility
of these compounds and results concerning the synthesis of new
attractive porphyrin hybrids will be reported in due course.
Acknowledgments
This work was financially supported by the Ministry of Science
and Higher Education, Grant N N204 218535 (2008–2012).
References and notes
In the reaction of 3e, the desired product 4e was accompanied
by small amounts of [2-hydroxy-3-nitro-5,10,15,20-tetrakis(3-
methoxyphenyl)porphyrinato]copper(II) (5e, 6%). Probably, this is
due to an OHÀaddition to the nitroporphyrin complex and subse-
1. Lacerda, P. S. S.; Silva, A. M. G.; Tomé, 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, 5487–5491.
2. Alonso, C. M. A.; Neves, M. G. P. M. S.; Tomé, A. C.; Silva, A. M. S.; Cavaleiro, J. A.
S. Eur. J. Org. Chem. 2004, 3233–3239.
3. Silva, A. M. G.; Tomé, A. C.; Neves, M. G. P. M. S.; Cavaleiro, J. A. S. Synlett 2002,
1155–1157.
4. Silva, A. M. G.; Tomé, A. C.; Neves, M. G. P. M. S.; Silva, A. M. S.; Cavaleiro, J. A. S.
J. Org. Chem. 2005, 70, 2306–2314.
5. Wang, H. J. H.; Jaquinod, L.; Nurco, D. J.; Vicente, M. G. H.; Smith, K. M. Chem.
Commun. 2001, 2646–2647.
6. Ostrowski, S.; Wyre˛bek, P. Tetrahedron Lett. 2006, 47, 8437–8440.
7. (a) Crossley, M. J.; Hambley, T. W.; Mackay, L. G.; Try, A. C.; Walton, R. J. Chem.
Soc., Chem. Commun. 1995, 1077–1079; (b) Crossley, M. J.; King, L. G.; Newsom,
I. A.; Sheehan, C. S. J. Chem. Soc., Perkin Trans. 1 1996, 2675–2684; (c) Alonso, C.
M. A.; Neves, M. G. P. M. S.; Tomé, A. C.; Silva, A. M. S.; Cavaleiro, J. A. S.
Tetrahedron Lett. 2001, 42, 8307–8309; (d) Alonso, C. M. A.; Serra, V. I. V.; Neves,
M. G. P. M. S.; Tomé, A. C.; Silva, A. M. S.; Paz, F. A.; Cavaleiro, J. A. S. Org. Lett.
2007, 9, 2305–2308; (e) Richeter, S.; Hadj-Aïssa, A.; Taffin, C.; van der Lee, A.;
Leclercq, D. Chem. Commun. 2007, 2148–2150; (f) Lefebvre, J.-F.; Leclercq, D.;
Gisselbrecht, J.-P.; Richeter, S. Eur. J. Org. Chem. 2010, 1912–1920; (g) Crossley,
M. J.; Govenlock, L. J.; Prashar, J. K. J. Chem. Soc., Chem. Commun. 1995, 2379–
2380; (h) Johnston, M. R.; Gunter, M. J.; Warrener, R. N. Tetrahedron 2002, 58,
3445–3451.
8. (a) Richeter, S.; Jeandon, Ch.; Ruppert, R.; Callot, H. J. Tetrahedron Lett. 2001, 42,
2103–2106; (b) Richeter, S.; Jeandon, Ch.; Ruppert, R.; Callot, H. J. Chem.
Commun. 2002, 266–267; (c) Richeter, S.; Jeandon, Ch.; Gisselbrecht, J.-P.;
Ruppert, R.; Callot, H. J. J. Am. Chem. Soc. 2002, 124, 6168–6179; (d) Richeter, S.;
Jeandon, Ch.; Gisselbrecht, J.-P.; Graff, R.; Ruppert, R.; Callot, H. J. Inorg. Chem.
2004, 43, 251–263.
quent oxidation of the
r
H-adduct formed, according to the oxida-
tive nucleophilic substitution mechanism (ONSH).10b,15,16
The products described in this communication represent
valuable intermediates for further syntheses, which sometimes
can be realized under acidic conditions. To avoid potential
problems in these transformations, we decided to convert the
above chelates into the free porphyrin bases. Therefore, the synthe-
sized compounds were demetallated in reactions carried out in
H2SO4/CF3COOH/CHCl3 mixture at room temperature (Scheme 3).17
Thus, a new set of valuable products (6a,b,d,e) was obtained and
NO2
NH2
Ar
M
NO2
Ar
M
N
N
N
N
N
N
N
N
TMHI
Ar
Ar
Ar
Ar
KOH/DMSO, 70-80 °C
Ar
Ar
3a-e
4a-e
9. Ma˛kosza, M.; Białecki, M. J. Org. Chem. 1998, 63, 4878–4888.
10. (a) Ostrowski, S.; Grzyb, S. Jordan J. Chem. 2007, 2, 297–299; (b) Ostrowski, S.;
Grzyb, S.; Mikus, A. Helv. Chim. Acta 2007, 90, 2000–2008.
11. Substrates:[2-Nitro-5,10,15,20-tetrakis(3-chlorophenyl)porphyrinato]copper(II)
(3c) and [2-nitro-5,10,15,20-tetrakis(3-methylphenyl)porphyrinato]-copper(II)
(3d) were obtained according to known procedures18 (yields: 80% and 85%,
respectively). (2-Nitro-5,10,15,20-tetraphenylporphyrinato)zinc(II) (3a) was
prepared according to a modified literature procedure19 (0.13 mmol of 2a in
180 ml of CHCl3; addition of 32.5 ml of 50% HNO3; 0.5 min); yield—35%.
Synthesis of 3b: 5,10,15,20-Tetrakis(3-fluorophenyl)porphyrin (1b)20 was
Ar NO2
OH
a: M = Zn, Ar = Ph; 89%
N
N
N
b: M = Cu, Ar = 3-F-C6H4; 64%
c: M = Cu, Ar = 3-Cl-C6H4; 65%
d: M = Cu, Ar = 3-Me-C6H4; 79%
e: M = Cu, Ar = 3-MeO-C6H4; 70%
Cu
Ar
Ar
N
5e
Ar
converted into complex 2b according to
a procedure applied for similar
Scheme 2.

S. Ostrowski, S. Grzyb / Tetrahedron Letters 53 (2012) 6355–6357
6357
compounds21 (with the use of Cu(OAc)2ÁH2O); yield—97%. Then, the above
complex was nitrated (also according to a procedure described for similar
compounds:18 30% HNO3, rt, 15 min) to give [2-nitro-5,10,15,20-tetrakis(3-
fluorophenyl)porphyrinato]copper(II) (3b); yield—93%. Synthesis of 3e:
5,10,15,20-Tetrakis(3-methoxyphenyl)porphyrin (1e)22 was converted into
complex 2e according to a procedure applied for similar compounds21 (with
the use of Cu(OAc)2ÁH2O); yield—75%. Then, the above complex was nitrated
(also according to a procedure described for similar compounds:18 20% HNO3, rt,
5 min) to give [2-nitro-5,10,15,20-tetrakis(3-methoxyphenyl)porphyrinato]-
copper(II) (3e); yield—89%. Data for new compounds: [5,10,15,20-Tetrakis(3-
fluorophenyl)porphyrinato]copper(II) (2b): mp >300 °C. UV–vis (CHCl3), kmax
(CHCl3), kmax (loge): 604.5 (3.84), 561.5 (4.00), 440 nm (5.06, Soret band). MS
(ESI) m/z (% rel int.): 881 (4), 880 (7), 879 (6.5), 878 (11) [isotope (M+Na)+]; 860
(6), 859 (16), 858 (43), 857 (74), 856 (71), 855 (100) [isotope M+]. HR-MS (ESI)
calculated for C48H36N6O6Cu [M+]: 855.1992; Found: 855.1946. [2-Hydroxy-3-
nitro-5,10,15,20-tetrakis(3-methoxyphenyl)porphyrinato]copper(II) (5e): mp
>300 °C. UV–vis (CHCl3), kmax (loge): 605 (3.88), 557.5 (3.95), 430.5 nm (4.97,
Soret band). MS (ESI) m/z (% rel int.): 861 (17), 860 (28), 859 (62), 858 (94), 857
(100), 856 (97) [isotope M+ and (M+H)+]. HR-MS (ESI) calculated for
C48H35N5O7Cu [M+]: 856.1832; Found: 856.1821.
15. Ma˛kosza, M.; Stalin´ ski, K. Tetrahedron 1998, 54, 8797–8810.
16. Ma˛kosza, M.; Stalin´ ski, K. Polish J. Chem. 1999, 73, 151–161.
17. General procedure for the demetallation of 2-amino-3-nitro-5,10,15,20-
(loge): 570 (3.13), 537.5 (4.06), 499.5 (3.28), 413.5 nm (5.34, Soret band). MS
(FD) m/z (% rel int.): 751 (4), 750 (20), 749 (56), 748 (44), 747 (100) [isotope M+].
HR-MS (FD) calculated for C44H24N4F4Cu [M+]: 747.1233; Found: 747.1275.
[5,10,15,20-Tetrakis(3-methoxyphenyl)porphyrinato]copper(II) (2e): mp >300 °C.
tetraarylporphyrinates. To
tetraarylporphyrinate (4a,b,d,e; 0.03 mmol) in 1 ml of CHCl3 in
a
stirred solution of 2-amino-3-nitro-5,10,15,20-
round-
a
bottomed flask, concentrated H2SO4 (1 ml) and CF3COOH (1.5 ml) were added
dropwise. The reaction was continued with stirring at room temperature for
10–15 min. Then, the mixture was poured into H2O (20 ml). The aqueous phase
was extracted with CHCl3 (3 Â 10 ml), the combined organic layers were
washed with H2O (3 Â 50 ml), and dried over MgSO4/Na2CO3. After evaporating
the solvent, the residue was chromatographed (silica gel, 230–400 mesh;
eluent: CHCl3/n-hexane, 2:1) to yield the respective 2-amino-3-nitro-
5,10,15,20-tetraarylporphyrins: (a) 17 mg of 6a, 84%; (b) 15 mg of 6b, 67%;
(c) 17.5 mg of 6d, 80%; (d) 21 mg of 6e, 88%. Data for new compounds: 2-Amino-
3-nitro-5,10,15,20-tetraphenylporphyrin (6a): This compound has been already
described in the literature;7b the additional data are given below for more
detailed and accurate characterizarion of the product. mp >300 °C. 1H NMR
(400 MHz, CDCl3): 8.96 (d, J = 5.2 Hz, 1H, Hb-pyrrole), 8.78 (d, J = 5.2 Hz, 1H, Hb-
pyrrole), 8.76 (d, J = 4.8 Hz, 1H, Hb-pyrrole), 8.63 and 8.61 (AB, J = 4.6 Hz, 2H, Hb-
pyrrole), 8.59 (d, J = 4.8 Hz, 1H, Hb-pyrrole), 8.36 (d, J = 7.2 Hz, 2H, H-Ph), 8.24–
8.15 (m, 6H, H-Ph), 7.94–7.89 (m, 3H, H-Ph), 7.81–7.63 (m, 9H, H-Ph), 6.81 (br s,
UV–vis (CHCl3), kmax (loge): 591.5 (3.76), 549 (3.96), 514 (3.43), 424.5 nm (5.11,
Soret band). MS (APPI) m/z (% rel int.): 800 (9), 799 (30), 798 (66), 797 (58), 796
(100) [isotope (M+H)+]. HR-MS (FD) calculated for C48H36N4O4Cu [M+]:
795.2033; Found: 795.1981. [2-Nitro-5,10,15,20-tetrakis(3-fluorophenyl)
porphyrinato]copper(II) (3b): mp >300 °C. UV–vis (CHCl3), kmax (loge): 589.5
(4.04), 547 (4.27), 513 (3.79), 419.5 nm (5.36, Soret band). MS (FD) m/z (% rel
int.): 796 (7), 795 (28), 794 (65), 793 (45), 792 (100) [isotope M+]. HR-MS (FD)
calculated for C44H23N5O2F4Cu [M+]: 792.1084; Found: 792.1108. [2-Nitro-
5,10,15,20-tetrakis(3-methoxyphenyl)porphyrinato]-copper(II) (3e): mp >300 °C.
UV–vis (CHCl3), kmax (loge): 591.5 (3.99), 548.5 (4.18), 511 (3.64), 422.5 nm
(5.32, Soret band). MS (APPI) m/z (% rel int.): 845 (8), 844 (26), 843 (57), 842 (58),
841 (100) [isotope (M+H)+]. MS (FD) m/z (% rel int.): 844 (1), 843 (15), 842 (54),
841 (52), 840 (100) [isotope M+]. HR-MS (FD) calculated for C48H35N5O6Cu [M+]:
840.1883; Found: 840.1852.
12. Ostrowski, S.; Mikus, A.; Shim, Y. K.; Lee, J.-Ch.; Seo, E.-Y.; Lee, K.-I.; Olejnik, M.
Heterocycles 2002, 57, 1615–1626.
13. Grzyb, S.; Ostrowski, S. Jordan J. Chem. 2012, 7, 231–237.
14. General procedure for the amination of b-nitro-5,10,15,20-tetraarylporphyrin
2H, NH2), À2.32 and À2.54 (2 Â s, 2H, 2 Â NH). UV–vis (CHCl3), kmax (log
e): 661
(3.49), 604.5 (3.62), 568.5 (3.81), 529.5 (4.05), 431 nm (5.26, Soret band). MS
(FD) m/z (% rel int.): 677 (2), 676 (13), 675 (50), 674 (100) [isotope M+]. HR-MS
(FD) calculated for C44H30N6O2 [M+]: 674.2430; Found: 674.2405. 2-Amino-3-
nitro-5,10,15,20-tetrakis(3-fluorophenyl)porphyrin (6b): mp >300 °C. 1H NMR
(400 MHz, CDCl3): 8.97 (d, J = 5.1 Hz, 1H, Hb-pyrrole), 8.79 (d, J = 5.1 Hz, 1H, Hb-
pyrrole), 8.77 (d, J = 5.1 Hz, 1H, Hb-pyrrole), 8.63 and 8.61 (AB, J = 4.7 Hz, 2H, Hb-
pyrrole), 8.60 (d, J = 5.0 Hz, 1H, Hb-pyrrole), 8.15–7.86, 7.78–7.61, and 7.56–
7.47 (3 Â m, 15H, H-Ar(F)), 7.38 (td, J = 8.4, 2.2 Hz, 1H of H-Ar(F)), 6.88 (br s, 2H,
complexes. To
a stirred solution of zinc(II) or copper(II) complex 3a–e
(0.20 mmol) in DMSO (4 ml), N,N,N-trimethylhydrazinium iodide (TMHI;
122 mg, 0.60 mmol) [for 3a: 200 mg, 0.99 mmol] and KOH (120 mg,
2.14 mmol) [for 3a: 170 mg, 3.03 mmol] were added. The reaction was
carried out under argon in a flask equipped with a reflux condenser at 75 °C
for 45 min (for 3a—1.5 h). The reaction mixture was cooled to room
temperature and was poured into a 3% aqueous solution of HCl (50 ml) with
ice. The product was extracted with CHCl3 (3 Â 15 ml), the combined organic
layers were washed with H2O (3 Â 50 ml), and dried over MgSO4. After
evaporating the solvent, the crude residue was chromatographed (silica gel,
230–400 mesh) to give: 4a—131 mg (eluent: CHCl3), yield 89%; 4b—104 mg
(eluent: CHCl3), yield 64%; 4c—114 mg (eluent: CHCl3), yield 65%; 4d—125 mg
(eluent: CHCl3), yield 79%; 4e—120 mg (eluent: CHCl3/MeOH, 250:1), yield
70%. In the last reaction, the desired product 4e was accompanied by [2-
hydroxy-3-nitro-5,10,15,20-tetrakis(3-methoxyphenyl)porphyrinato]copper(II)
(5e), 10.5 mg (eluted with CHCl3/MeOH, 100:1), yield 6%. Data for new
compounds: [2-Amino-3-nitro-5,10,15,20-tetraphenylporphyrinato]zinc(II) (4a):
mp >300 °C. 1H NMR (200 MHz, CDCl3): 8.98 (d, J = 4.9 Hz, 1H, Hb-pyrrole), 8.84
(d, J = 4.9 Hz, 1H, Hb-pyrrole), 8.81–8.75 (m, 3H, Hb-pyrrole), 8.54 (d, J = 4.9 Hz,
1H, Hb-pyrrole), 8.27–8.09 (m, 8H, H-Ph), 7.93–7.62 (m, 12H, H-Ph), 6.54 (br s,
NH2), À2.40 and À2.63 (2 Â s, 2H, 2 Â NH). UV–vis (CHCl3), kmax (log
e): 669
(3.48), 606.5 (3.98), 571 (4.07), 532.5 (4.38), 434.5 nm (5.36, Soret band). MS
(ESI) m/z (% rel int.): 749 (16), 748 (51), 747 (100) [isotope (M+H)+]. HR-MS (ESI)
calculated for C44H27N6O2F4 [(M+H)+]: 747.2132; Found: 747.2138. 2-Amino-3-
nitro-5,10,15,20-tetrakis(3-methylphenyl)porphyrin (6d): mp >300 °C. 1H NMR
(400 MHz, CDCl3): 8.96 (d, J = 5.0 Hz, 1H, Hb-pyrrole), 8.78 (d, J = 5.0 Hz, 1H, Hb-
pyrrole), 8.76 (d, J = 5.0 Hz, 1H, Hb-pyrrole), 8.63 and 8.61 (AB, J = 4.8 Hz, 2H, Hb-
pyrrole), 8.59 (d, J = 5.0 Hz, 1H, Hb-pyrrole), 8.18–8.11 (m, 2H, H-Ar(CH3)), 8.05–
7.94 (m, 6H, H-Ar(CH3)), 7.79 (apparent t, J = 7.8 Hz, 1H, H-Ar(CH3)), 7.74–7.51
(m, 6H, H-Ar(CH3)), 7.46 (d, J = 7.8 Hz, 1H, H-Ar(CH3)), 6.83 (br s, 2H, NH2), 2.68
(s, 3H, CH3), 2.66 (s, 3H, CH3), 2.64 (s, 6H, 2 Â CH3), À2.35 and À2.58 (2 Â s, 2H,
2 Â NH). UV–vis (CHCl3), kmax (log
e): 668.5 (3.47), 609.5 (3.83), 573.5 (3.92),
534 (4.19), 437.5 nm (5.21, Soret band). MS (FD) m/z (% rel int.): 733 (3), 732
(15), 731 (55), 730 (100) [isotope M+]. HR-MS (FD) calculated for C48H38N6O2
[M+]: 730.3056; Found: 730.3042. 2-Amino-3-nitro-5,10,15,20-tetrakis(3-
methoxyphenyl)porphyrin (6e): mp >300 °C. 1H NMR (400 MHz, CDCl3): 9.01
(d, J = 5.0 Hz, 1H, Hb-pyrrole), 8.83–8.77 (m, 2H, Hb-pyrrole), 8.66 and 8.64 (AB,
J = 4.6 Hz, 2H, Hb-pyrrole), 8.63 (d, J = 5.0 Hz, 1H, Hb-pyrrole), 7.97–7.60 (m,
16H, H-Ar(OCH3)), 5.92 (br s, 2H, NH2), 4.02 (s, 3H, OCH3), 4.01 (s, 6H,
2 Â OCH3), 3.99 (s, 3H, OCH3), À2.36 and À2 60 (2 Â s, 2H, 2 Â NH). UV–vis
2H, NH2). UV–vis (CHCl3), kmax (loge): 609 (4.07), 567.5 (4.29), 531.5 (3.70),
442 nm (5.34, Soret band). MS (FD) m/z (% rel int.): 743 (2), 742 (7), 741 (21),
740 (47), 739 (39), 738 (69), 737 (50), 736 (100) [isotope M+]. HR-MS (FD)
calculated for C44H28N6O2Zn [M+]: 736.1565; Found: 736.1602. [2-Amino-3-
nitro-5,10,15,20-tetrakis(3-fluorophenyl)porphyrinato]copper(II)
(4b):
mp
>300 °C. UV–vis (CHCl3), kmax (log ): 608.5 (4.08), 561 (4.07), 521 (3.73),
e
432 nm (5.18, Soret band). MS (FD) m/z (% rel int.): 811 (4), 810 (21), 809 (53),
808 (38), 807 (100) [isotope M+]. HR-MS (FD) calculated for C44H24N6O2F4Cu
[M+]: 807.1193; Found 807.1202. [2-Amino-3-nitro-5,10,15,20-tetrakis(3-
chlorophenyl)porphyrinato]copper(II) (4c): mp >300 °C. UV–vis (CHCl3), kmax
(CHCl3), kmax (loge): 673.5 (3.67), 650.5 (3.69), 605 (3.80), 575 (3.94), 532.5
(4.19), 436 nm (5.21, Soret band). MS (FD) m/z (% rel int.): 797 (3), 796 (15), 795
(54), 794 (100) [isotope M+]. HR-MS (FD) calculated for C48H38N6O6 [M+]:
794.2853; Found: 794.2828.
(log
e
): 606 (4.15), 562.5 (4.30), 522 (3.85), 438 (5.31, Soret band), 321 nm
18. Wyre˛bek, P.; Ostrowski, S. J. Porphyrins Phthalocyanines 2007, 11, 822–828; and
references cited therein.
19. Ostrowski, S. Polish J. Chem. 2005, 79, 1169–1172.
20. Semeikin, A. S.; Koifman, O. I.; Berezin, B. D. Khim. Geterotsikl. Soedin. 1986, 6,
798–801.
(4.37). MS (FD) m/z (% rel int.): 880 (4), 879 (5), 878 (12), 877 (20), 876 (23),
875 (61), 874 (29), 873 (100), 872 (21), 871 (53) [isotope M+]. HR-MS (FD)
calculated for C44H24N6O235Cl337Cl1Cu [M+]: 872.9981; Found: 872.9976. [2-
Amino-3-nitro-5,10,15,20-tetrakis(3-methylphenyl)porphyrinato]copper(II) (4d):
mp >300 °C. UV–vis (CHCl3), kmax (log
e
): 605 (3.42), 562.5 (3.57), 524.5
21. Fuhrhop, J. H.; Smith, K. M. In ‘Porphyrins and Metalloporphyrins’. In Section H:
Laboratory methods; Smith, K. M., Ed.; Elsevier: Amsterdam, 1975; pp 757–861.
22. Lindsey, J. S.; Schreiman, I. C.; Hsu, H. C.; Kearney, P. C.; Marguerettaz, A. M.
J. Org. Chem. 1987, 52, 827–836.
(3.14), 439.5 nm (4.62, Soret band). MS (FD) m/z (% rel int.): 795 (7), 794 (28),
793 (54), 792 (48), 791 (100) [isotope M+]. HR-MS (FD) calculated for
C
48H36N6O2Cu [M+]: 791.2196; Found: 791.2238. [2-Amino-3-nitro-5,10,15,20-
tetrakis(3-methoxyphenyl)porphyrinato]copper(II) (4e): mp >300 °C. UV–vis