I. Saltsman et al. / Tetrahedron Letters 48 (2007) 239–244
243
tively. The former option also exists when the condensa-
tion of 1 is performed with 3, and accordingly, this could
be the apparent source of compound 2 in that reaction.
gawa, H.; Yanagiya, S.; Tabeta, Y.; Nakano, Y.;
Takahashi, M. Tetrahedron 2001, 57, 2103–2108.
. For most recent reviews, see: (a) Gross, Z.; Gray, H. B.
Adv. Synth. Cat. 2004, 346, 165–170; (b) Gryko, D. T.;
Fox, J. P.; Goldberg, D. P. J. Porphyrins Phthalocyanines
5
In summary, the condensation of tripyrrane and 2-formyl-
pyrrole did not lead to the desired parent corrole, the
effective synthesis of which remains a considerable
challenge, but rather to a mixture containing porphine
and a new porphyrin substituted at one of its meso-
carbon atoms by pyrrole. Both products were fully
characterized by NMR spectroscopic methods and
X-ray crystallography. The formation of pentapyrranes
and their cyclization to substituted tetrapyrrolic rather
than pentapyrrolic macrocycles appears to be quite gen-
eral. Recent examples include the dipyrrine-substituted
2
004, 8, 1091–1105; (c) Nardis, S.; Monti, D.; Paolesse, R.
Mini-Rev. Org. Chem. 2005, 2, 355–372.
. Lin, V. S.-Y.; Iovine, P. M.; DiMagno, S. G.; Therien, M.
J. Inorg. Synth. 2002, 33, 55–61.
7. Tripyrromethane (1, 202 mg, 0.9 mmol) and 2-(hydroxy-
methyl)pyrrole (3, 87 mg, 0.9 mmol) were dissolved in
6
200 mL of dry dichloromethane and stirred under N
min. TFA (0.07 mL, 0.9 mmol) was added and stirring
was continued for another 90 min at rt. Chloranil (224 mg,
.9 mmol) was added and the reaction mixture was
2
for
5
0
refluxed for 1 h. The solvent was evaporated under
vacuum and the residue was purified by column chroma-
tography on basic alumina (Merck, grade I). The first pink
band was eluted with ethyl acetate–n-hexane (1:6), pro-
viding porphine 2 as purple crystals (28 mg, 10%). All
1
5
16
17
chlorins isolated by Gryko, Lee, and Callot and
pyrrole-substituted porphyrins were also obtained by
1
8
Maravin et al. from linear hexapyrrolic compounds.
8
The isolation of the pyrrole-substituted porphyrin 6
physicochemical properties coincided with literature data.
from a synthesis devised for rational synthesis of corrole
X-ray quality crystals were obtained by crystallization
from dichloromethane and n-hexane. A second light-pink
band was eluted with ethyl acetate–n-hexane (1:4) and
provided trace amounts of 5-(pyrrole-2 -yl)-porphine 6.
Replacing 2-(hydroxymethyl)pyrrole 3 by 2-formylpyrrole
1
9
also possesses a historical perspective, as a similar
structure was considered by Woodward and co-workers
for the compound obtained during their attempted
synthesis of corroles. This compound was later identified
as being the first isolated member of the sapphyrin
0
4
under otherwise identical reaction conditions and work-
up procedures yielded 28 mg of 2 (10%) and 24 mg of 6
7%). X-ray quality crystals of 6 were obtained by
recrystallization from dichloromethane and n-hexane
2
0
family, which are nowadays best known for their
(
2
1
anion binding capabilities.
1
during 12 h at 4 ꢁC.
6 6
H NMR (500 MHz, C D ):
Crystallographic data of the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 609953 and 609954 for 2
and 6, respectively. Copies of this information can be
obtained free of charge from The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (fax: +44
d = 9.94 (s, 2H-meso), 9.83 (s, 1H-meso), 9.23 (d,
3
3
J(H,H) = 4.5 Hz, 2H), 9.15 (d, J(H,H) = 4.5 Hz, 2H),
3
3
9.12 (d, J(H,H) = 4.5 Hz, 2H), 9.07 (d, J(H,H) = 4.8 Hz,
2
6
H), 8.03 (br s, 1H-N-pyrrole), 7.40 (m, 1H), 6.90 (m, 1H),
.79 (m, 1H), ꢀ3.02 (s, 2H); C NMR (125 MHz, tol-d8):
13
d = 105.0 (s, 2C-meso), 104.0 (s, 1C-meso); UV–vis
ꢀ
3
(
CH
2 2
Cl ): kmax, nm (e · 10 ) 402 (188), 500 (18.5), 572
+
(
8.5). MS (MALDI-TOF): m/z (%): 375.1 [M , 100%].
8
9
. Neya, S.; Funasaki, N. Tetrahedron Lett. 2002, 43, 1057–
058.
1
. (a) Paolesse, R.; Sagone, F.; Macagnano, A.; Boschi, T.;
Prodi, L.; Montalti, M.; Zaccheroni, N.; Bolletta, F.;
Smith, K. M. J. Porphyrins Phthalocyanines 1999, 3,
Acknowledgements
This research was supported by the Israel Science Foun-
dation, Grant Nos. 254/04 (I.G.) and 330/04 (Z.G.). The
funding of I.S. by the Center for Absorption in Science,
Ministry of Immigration, is also acknowledged.
3
64–370; (b) Gross, Z.; Galili, N.; Saltsman, I. Angew.
Chem., Int. Ed. 1999, 38, 1427–1429; (c) Bendix, J.;
Dmochowski, I. J.; Gray, H. B.; Mahammed, A.; Sim-
khovich, L.; Gross, Z. Angew. Chem., Int. Ed. 2000, 39,
4
048–4051; (d) Stavitski, E.; Berg, A.; Ganguly, T.;
Mahammed, A.; Gross, Z.; Levanon, H. J. Am. Chem.
Soc. 2004, 126, 6886–6890; (e) Ventura, B.; Degli Esposti,
A.; Koszarna, B.; Gryko, D. T.; Flamigni, L. New J.
Chem. 2005, 29, 1559–1566; (f) Ding, T.; Aleman, E. A.;
Modarelli, D. A.; Ziegler, C. J. J. Phys. Chem. A 2005,
109, 7411–7417.
References and notes
1
. (a) Sessler, J. L.; Gebauer, A.; Weghorn, S. J. In The
Porphyrin Handbook; Kadish, K. M., Smith, K. M.,
Guilard, R., Eds.; Academic Press: San Diego, CA, 2000;
Vol. 2, pp 55–124; (b) Lash, T. D. In The Porphyrin
Handbook; Kadish, K. M., Smith, K. M., Guilard, R.,
Eds.; Academic Press: San Diego, CA, 2000; Vol. 2, pp
10. Balazs, Y. S.; Saltsman, I.; Mahammed, A.; Tkachenko,
E.; Golubkov, G.; Levine, J.; Gross, Z. Magn. Reson.
Chem. 2004, 42, 624–635.
1
25–199; (c) Arsenault, G. P.; Bullock, E.; MacDonald, S.
11. Crystal data for porphine (2) at 110(2) K. C20
H N : M =
14 4 w
˚
F. J. Am. Chem. Soc. 1960, 82, 4384–4389.
310.35, a = 10.2262(3), b = 11.9060(5), c = 12.3853(4) A,
˚
3
2
. (a) Johnson, A. W.; Overend, W. R. J. Chem. Soc., Perkin
Trans. 1. 1972, 2681–2691; (b) Jonson, A. W.; Kay, I. T. J.
Chem. Soc. 1965, 1620–1629.
. (a) Sankar, J. S.; Anand, V. G.; Venkataman, S.; Rath, H.;
Chandrashekar, T. K. Org. Lett. 2002, 4, 4233–4235; (b)
Sankar, J.; Rath, H.; PrabhuRaja, V.; Chandrashekar, T.
K.; Vittal, J. J. J. Org. Chem. 2004, 69, 5135–5138.
. (a) Taniguchi, S.; Hasegawa, H.; Nishimura, M.; Taka-
hashi, M. Synlett 1999, 73–74; (b) Taniguchi, S.; Hase-
b = 101.711(3)ꢁ, V = 1476.56(9) A , monoclinic, space
ꢀ
3
group P2 /c, Z = 4, Dcalc = 1.396 g cm , l(Mo Ka) =
1
1
ꢀ
0.09 mm
,
3492
unique
reflections,
R = 0.057
> 2r(F ),
3
(wR = 0.113) for 2284 reflections with
F
o
o
R = 0.099 (wR = 0.129) for all unique data.
0
12. Crystal data for 5-(pyrrole-2 -yl)-porphine (6) at 110(2) K.
24 17 5 w
C H N : M = 375.43, a = 7.7315(3), b = 11.3844(5),
˚
4
c = 11.4494(5) A, a = 65.034(2), b = 76.394(3), c =
˚
3
76.414(2)ꢁ, V = 877.37(6) A , triclinic, space group P-1,