Solvent-dependent ambident nucleophilicity of phenoxide ion towards nitroporphyrins: Synthesis of 2-hydroxyaryl- and 2-aryloxy-5,10,15,20-tetraphenylporphyrins by displacement of a nitro group

Article abstract of DOI:10.1039/a701673e

The reaction of phenoxide ion with the copper(II), nickel(II) and free-base 2-nitro-5,10,15,20-tetraphenylporphyrins, 1-3 respectively, has been investigated as a means of introducing inwards-directed functionality to the periphery of pre-existing porphyrin systems. It has been found that phenoxide ion shows highly selective solvent-dependent ambident nucleophilicity towards the nitroporphyrin system. Porphyrins 1-3 react with phenoxide ion in refluxing phenol to afford the corresponding 2-(o-hydroxyphenyl)- and 2-(p-hydroxyphenyl)-5,10,15,20-tetraphenylporphyrins in good yields; in each case the ortho isomer is the major product and none of the meta isomer is detected. The scope of the reaction has been extended by the use of the substituted phenols which are blocked from reaction para to the hydroxy (p-cresol and 2,4-dimethylphenol) or blocked from reaction in the ortho-positions (2,6-dimethylphenol). In this way the copper(II) 2-(2-hydroxy-5-methylphenyl)porphyrin 14 (86%), 2-(2-hydroxy-5-methylphenyl)-porphyrin 15 (65%), copper(II) 2-(2-hydroxy-3,5-dimethylphenyl)porphyrin 16 (77%), 2-(2-hydroxy-3,5-dimethylphenyl)porphyrin 17 (69%) and 2-(4-hydroxy-3,5-dimethylphenyl)porphyrin 19 (63%) have all been obtained in good yields by reaction of the appropriate 2-nitroporphyrin 1 or 3 with the requisite substituted phenolate in the corresponding phenol. Reaction of the metalloporphyrins 1 and 2 with phenoxide ion in refluxing HCONMe₂ in contrast gives the corresponding 2-phenoxy-metalloporphyrins 10 and 11 in good yield. The results of mechanistic studies using the deuteriated compound, nickel(II) 2-nitro-5,10,15,20-tetraphenyl[3-²H]porphyrin, 37, suggest that both sets of products (from phenoxide as a C-nucleophile and as an O-nucleophile) can arise from ipso-substitution of the nitro group.

Full text of DOI:10.1039/a701673e

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Solvent-dependent ambident nucleophilicity of phenoxide ion towards
nitroporphyrins: synthesis of 2-hydroxyaryl- and 2-aryloxy-
5,10,15,20-tetraphenylporphyrins by displacement of a nitro group
Maxwell J. Crossley,* Lionel G. King and Janelle L. Simpson
School of Chemistry, The University of Sydney, NSW 2006, Australia
The reaction of phenoxide ion with the copper(II), nickel(II) and free-base 2-nitro-5,10,15,20-
tetraphenylporphyrins, 1–3 respectively, has been investigated as a means of introducing inwards-directed
functionality to the periphery of pre-existing porphyrin systems. It has been found that phenoxide ion
shows highly selective solvent-dependent ambident nucleophilicity towards the nitroporphyrin system.
Porphyrins 1–3 react with phenoxide ion in refluxing phenol to afford the corresponding 2-(o-hydroxy-
phenyl)- and 2-(p-hydroxyphenyl)-5,10,15,20-tetraphenylporphyrins in good yields; in each case the ortho
isomer is the major product and none of the meta isomer is detected. The scope of the reaction has been
extended by the use of the substituted phenols which are blocked from reaction para to the hydroxy
(p-cresol and 2,4-dimethylphenol) or blocked from reaction in the ortho-positions (2,6-dimethylphenol).
In this way the copper(II) 2-(2-hydroxy-5-methylphenyl)porphyrin 14 (86%), 2-(2-hydroxy-5-methylphenyl)-
porphyrin 15 (65%), copper(II) 2-(2-hydroxy-3,5-dimethylphenyl)porphyrin 16 (77%), 2-(2-hydroxy-3,5-
dimethylphenyl)porphyrin 17 (69%) and 2-(4-hydroxy-3,5-dimethylphenyl)porphyrin 19 (63%) have all been
obtained in good yields by reaction of the appropriate 2-nitroporphyrin 1 or 3 with the requisite substituted
phenolate in the corresponding phenol. Reaction of the metalloporphyrins 1 and 2 with phenoxide ion in
refluxing HCONMe2 in contrast gives the corresponding 2-phenoxy-metalloporphyrins 10 and 11 in good
yield. The results of mechanistic studies using the deuteriated compound, nickel(II) 2-nitro-5,10,15,20-
tetraphenyl[3-2H]porphyrin, 37, suggest that both sets of products (from phenoxide as a C-nucleophile
and as an O-nucleophile) can arise from ipso-substitution of the nitro group.
In the course of work on synthetic porphyrin-based model
systems for cytochrome P450 and other haemoproteins, we
required a means of introducing inwards-directed functionality
X
L
to the periphery of pre-existing 5,10,15,20-tetraarylporphyrin
systems. Substituents (ligands or substrates L) subsequently
attached to the new functionality would thereby be directed
M
towards the porphyrin centre (metal-ion binding site M) where
the proximity of the attached groups was required (Fig. 1).
Collman et al. have shown that ligands attached by a short
porphyrin plane
Fig. 1 Design for covalent attachment of an inward-directed ligand
L to the porphyrin periphery
chain to a meso o-aminophenyl substituent complex effectively
with an appropriate central metal ion in metalloporphyrin
chemical models for haemoproteins,1 but the possibility of
functionalising a meso-aryl ring regioselectively in a pre-
existing porphyrin was not attractive. Accordingly, our atten-
tion focused on the introduction of a substituent at a β-pyrrolic
position. Use of a flexible substituent would not impose the
required inwards orientation of an attached substrate or ligand.
As the initial bond with a β-pyrrolic carbon is directed away
from the porphyrin centre, the introduced substituent needs to
have a rigid framework of bonds that loops back towards the
porphyrin centre.
aryloxide nucleophiles with 2-nitroporphyrins that lead to the
development of conditions which afford corresponding 2-
(o-hydroxyaryl)porphyrins efficiently;7 this hydroxy group
thereby provides a site for attachment of an inwards-directed
side-chain with an appended ligand, substrate or substrate
recognition site.
Results and discussion
In order to reduce the degrees of freedom of the bonds link-
ing the functional group to the porphyrin, we sought to append
an ortho-substituted ring to the β-pyrrolic position on the por-
phyrin periphery. Buttressing of this substituent by a nearby
meso-aryl group and biphenyl-like interactions with the por-
phyrin ring were both expected to orient such a substituted ring
in an orthogonal plane to the porphyrin. Further elaboration of
the ring substituent by attachment of a ligand or substrate
would provide a means to direct such groups towards the metal
site (M).
Nucleophilic substitution reactions at the β-pyrrolic positions
of porphyrins are most efficient when the porphyrin inner
periphery is metallated with a relatively electron-withdrawing
metal ion.2–14 In this work, the reactions of the copper(),
nickel() and free-base 2-nitro-5,10,15,20-tetraphenylpor-
phyrins,15 1–3 respectively, were investigated.
Synthesis of 2-(hydroxyaryl)-5,10,15,20-tetraphenylporphyrins
Reaction of (2-nitro-5,10,15,20-tetraphenylporphyrinato)-
copper() 1 with sodium phenoxide (8–12 equiv.) in refluxing
phenol for 4 to 7 h afforded the isomeric (hydroxyaryl)por-
phyrins, [2-(o-hydroxyphenyl)-5,10,15,20-tetraphenylporphyri-
nato]copper() 4 (52–54%) and [2-(p-hydroxyphenyl)-5,10,15,
Nitroporphyrins have proved to be versatile starting materials
for the synthesis of porphyrins with other functionalities.2–14
In this paper we report in full our studies of the reaction of
J. Chem. Soc., Perkin Trans. 1, 1997
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proton AAЈXXЈ pattern (δ 6.50 and 7.04) of a para-disubsti-
tuted phenyl, together with one-proton hydroxy (δ 4.83) and
seven-proton β-pyrrolic resonances (δ 8.41–8.74). Both isomers
showed a parent peak in the mass spectrum [m/z 762 (M, 100)].
The structures of the two copper() 2-hydroxyphenylpor-
phyrins, 4 and 7, [m/z 767 (M, 100)] were definitively established
by metallation of each of the free-base porphyrin isomers 6 and
9 which were prepared and characterised subsequently, as
described below. The 2-phenoxyporphyrins 10 and 11 can be
prepared in high yield by the route outlined later and their
characterisation is discussed then.
Ph
M
OH
Ph
N
N
N
N
Ph
Ph
O
Na
The reaction of nitroporphyrins with phenoxide ion in
phenol provides non-basic conditions for nucleophilic attack on
the porphyrin. Under these conditions the free-base 2-nitro-
5,10,15,20-tetraphenylporphyrin 3 can also be used as a sub-
strate for nucleophilic reaction without the formation of a
deactivated porphyrin anion, which has been observed for the
reaction of 3 with alkoxides in neutral solvents.3,12 Thus, treat-
ment of 2-nitro-5,10,15,20-tetraphenylporphyrin 3 with sodium
phenoxide (1.2 equiv.) in refluxing phenol for 4.5 h afforded
free-base 2-(o-hydroxyphenyl)-5,10,15,20-tetraphenylporphyrin
6 in 38% yield and 2-(p-hydroxyphenyl)-5,10,15,20-tetraphenyl-
porphyrin 9 in 20% yield (Scheme 1). These yields are not opti-
mised and might be improved by the use of a larger excess of
nucleophile.
Ph
M
4 M = CuII
5 M = NiII
6 M = 2H
NO2
N
N
N
N
+
Ph
Ph
phenol
OH
Ph
Ph
1 M = CuII
2 M = NiII
3 M = 2H
N
N
N
Ph
M
Ph
N
As was found for the nickel() 2-hydroxyphenylporphyrins, 5
and 8, the less polar of these two free-base porphyrins proved
to be the 2-(o-hydroxyphenyl)porphyrin isomer 6 [ortho-
disubstituted phenyl proton resonances (δ 6.63–7.17)] and the
more polar isomer proved to be 2-(p-hydroxyphenyl)-5,10,15,20-
tetraphenylporphyrin 9 [AAЈXXЈ system (δ 6.50 and 7.17)].
Metallation of 6 with cupric acetate afforded [2-(o-hydroxy-
phenyl)-5,10,15,20-tetraphenylporphyrinato]copper() 4 and
similar metallation of 9 afforded [2-(p-hydroxyphenyl)-5,10,
15,20-tetraphenylporphyrinato)copper() 7, each identical with
the respective products isolated from the reaction between
(2-nitro-5,10,15,20-tetraphenylporphyrinato)copper() 1 and
phenoxide ion in phenol (Scheme 1).
An (o-hydroxyaryl)-5,10,15,20-tetraphenylporphyrin was
prepared regiospecifically by blocking the para-position of the
aryloxide nucleophile. Thus, the reaction of (2-nitro-5,10,15,20-
tetraphenylporphyrinato)copper() 1 with sodium p-cresolate
12 (7 equiv.) in refluxing p-cresol afforded after 6 h [2-(2-
hydroxy-5-methylphenyl)-5,10,15,20-tetraphenylporphyrinato]-
copper() 14 [m/z 781 (M, 100)] in 86% yield (Scheme 2).
Demetallation of 14 using strong acid gave the corresponding
free-base porphyrin 15 in 54% yield; porphyrin 15 was also pre-
pared in 65% yield by direct reaction of the free-base 2-
nitroporphyrin 3 with sodium p-cresolate (Scheme 2).
O
Li
Ph
7 M = CuII
8 M = NiII
9 M = 2H
HCONMe2
O
Ph
M
N
N
N
N
Ph
Ph
Ph
10 M = CuII
11 M = NiII
Scheme 1
20-tetraphenylporphyrinato]copper() 7 (31–35%) along with a
2% yield of (2-phenoxy-5,10,15,20-tetraphenylporphyrinato)-
copper() 10 (Scheme 1). Similar treatment of (2-nitro-
5,10,15,20-tetraphenylporphyrinato)nickel() 2 afforded [2-(o-
hydroxyphenyl)-5,10,15,20-tetraphenylporphyrinato]nickel() 5
(66%) and [2-(p-hydroxyphenyl)-5,10,15,20-tetraphenylpor-
phyrinato]nickel() 8 (24%) along with (2-phenoxy-5,10,15,20-
tetraphenylporphyrinato)nickel() 11 (5%) (Scheme 1). The
generation of a new C᎐C bond in these products requires the
phenoxide ion to have acted as a carbon-centred nucleophile.
The ambident nucleophilicity of phenoxide has been known for
some time;16 carbon-centred rather than oxygen-centred reac-
tions have been found to be favoured in polar, protic solvents.
The structures of the two nickel() hydroxyphenylporphy-
rins, 5 and 8 were assigned on the basis of 400 MHz 1H NMR
spectral data. The less polar and major of these two nickel()
porphyrin products, 5, was established as the 2-(o-hydroxy-
phenyl)porphyrin on the basis of the four-proton resonances
(δ 6.61–7.08) of an ortho-disubstituted phenyl, together with
the seven-proton β-pyrrolic resonances (δ 8.47–8.76) and the
one-proton singlet at δ 5.00 corresponding to the hydroxy. The
1H NMR spectrum of the more polar isomer, 8, showed a four-
We also sought to prepare a 2-(2-hydroxy-3-substituted-
aryl)porphyrin. A substrate or ligand attached through the
hydroxy site would be further limited in degree of freedom, and
should be constrained to be directed towards the porphyrin
centre, because of the vicinal substituent which should prevent
conformations that allow the attached group to turn outwards
again. Such porphyrins were readily prepared by reaction of a
nitroporphyrin with sodium 2,4-dimethylphenoxide 13 in 2,4-
dimethylphenol. In this way [2-(2-hydroxy-3,5-dimethyl-
phenyl)-5,10,15,20-tetraphenylporphyrinato]copper() 16 was
obtained in 77% yield from the copper() 2-nitroporphyrin 1,
and the corresponding free-base porphyrin 17 was obtained in
69% yield from 2-nitroporphyrin 3 (Scheme 2). Free-base por-
phyrin 17 was also prepared in 57% yield by demetallation of
the copper() porphyrin 16 under acidic conditions (Scheme 2)
thereby providing additional evidence for the structure of
the paramagnetic copper() compound. Extension of this idea
to include reactions of even more hindered phenols and naph-
thols with more encumbered porphyrins will be described
elsewhere.
A p-hydroxyaryl substituent could be introduced regio-
3088
J. Chem. Soc., Perkin Trans. 1, 1997

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OH
OMe
Me
Ph
R
OH
Ph
Ph
O
Na
R
N
N
N
N
N
N
N
N
N
N
N
N
i
Ph
M
Ph
+
i
1, 3
Ph
Ph
Cu
Ph
Cu
Ph
1.5 d
Me
12 R = H
13 R = Me
Ph
Ph
Ph
14 M = CuII, R = H
15 M = 2H, R = H
16 M = CuII, R = Me
17 M = 2H, R = Me
7
20
ii
ii
Ph
Ph
OH
Ph
OMe
Ph
OH
Me
N
N
N
N
N
N
N
N
i
Ph
Ph
Cu
Cu
Me
3.5 d
Ph
O
Na
Ph
Ph
Me
Me
N
N
N
N
4
21
iii
H
Ph
Ph
+
3
H
Me
Me
Me
Me
18
Ph
Ph
OH
Ph
OMe
Ph
19
N
N
N
N
N
N
N
N
Scheme 2 Reagents and conditions: i, p-cresol, reflux; ii, H2SO4 (18 mol
i
dmϪ3), CH2Cl2, stir, 5 min; iii, 2,6-dimethylphenol, reflux, 2 h
Ph
Ph
Cu
Cu
Ph
14 d
selectively to the porphyrin periphery by using a phenol in
which both the positions vicinal to the hydroxy group were
blocked from reaction. Treatment of the free-base 2-nitro-
porphyrin 3 with sodium 2,6-dimethylphenoxide 18 in 2,6-
dimethylphenol gave 2-(4-hydroxy-3,5-dimethylphenyl)-5,10,
15,20-tetraphenylporphyrin 19 in 63% yield (Scheme 2).
It is evident that o-hydroxyaryl substituents potentially repre-
sent an excellent solution to the problem of producing an
appropriately directed attachment point for the connection of
chains bearing ligands or substrates for porphyrin-based model
haemoprotein systems. An alkyl chain attached to the aryl
hydroxy group would be expected to be directed toward the
porphyrin centre at a well-defined angle and from a well-defined
distance due to the rigidity of the sp2 bonds connecting the
linking oxygen atom back to the porphyrin periphery, and to
the restricted rotation of the aryl substituent (Fig. 1).
Ph
Ph
16
22
Me
Ph
Me
Ph
Me
Me
OH
Ph
OMe
N
N
N
N
N
N
N
N
i
H
H
Ph
Ph
Ph
H
H
14 d
Ph
Ph
17
23
The feasibility of attaching an alkyl chain to the aryl hydroxy
groups in these molecules was demonstrated by the methylation
of the phenolic hydroxys of copper() 2-(hydroxyaryl)-tetra-
phenylporphyrins 4, 7 and 16 and free-base compound 17
(Scheme 3). The relative rate of the methylation parallels the
degree of crowding about the hydroxy site. Thus, treatment of a
solution of [2-(p-hydroxyphenyl)-5,10,15,20-tetraphenylpor-
phyrinato]copper() 7 in acetone with methyl iodide and potas-
sium carbonate afforded [2-(p-methoxyphenyl)-5,10,15,20-
tetraphenylporphyrinato]copper() 20 [m/z 781 (M, 100)] after
1.5 days in 98% yield. Under identical conditions the more
hindered [2-(o-hydroxyphenyl)-5,10,15,20-tetraphenylporph-
yrinato]copper() 4 afforded [2-(o-methoxyphenyl)-5,10,15,20-
tetraphenylporphyrinato]copper() 21 in 84% yield after 3.5
days (Scheme 3). Reaction of the even more hindered [2-(2-
hydroxy-3,5-dimethylphenyl)-5,10,15,20-tetraphenylporphyrin-
ato]copper() 16 was only partially completed after 14 days to
give the methylation product 22 in 59% yield and the corre-
sponding free-base porphyrin 17 yielded a 44% yield of 2-(2-
Scheme 3 Reagents and conditions: i, acetone, anhydrous K2CO3, MeI
methoxy-3,5-dimethylphenyl)-5,10,15,20-tetraphenylporphyrin
23 after 14 days reaction time.
Synthesis of 2-phenoxy-5,10,15,20-tetraphenylporphyrins
An efficient synthesis of 2-phenoxyporphyrins was also sought.
It was envisaged that metallo-2-aryloxy-5,10,15,20-tetraphenyl-
porphyrins might be prepared by reaction of a metallo-2-nitro-
5,10,15,20-tetraphenylporphyrin with aryloxide ion at room
temperature using solvents other than the corresponding
phenol. By analogy to the reaction with alkoxides,3,12 it was
expected that the reaction of 2-nitroporphyrin with phenoxide
would initially afford
a metallo-2,2-diaryloxy-3-nitro-2,3-
dihydroporphyrin which could then undergo reductive radical
denitration and subsequent elimination of 1 equiv. of phenol.
Copper() and nickel() 2-nitro-5,10,15,20-tetraphenylpor-
phyrin, 1 and 2, were each treated with phenoxide ion under
J. Chem. Soc., Perkin Trans. 1, 1997
3089

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similar conditions to those used for alkoxide addition. This
reaction, however, did not follow this course and 2-phenoxy-
porphyrins were obtained directly.
uct 27 by loss of nitrite from the intermediate 25; the overall
process is similar to that of an SNAr reaction.5 While such an
intermediate has not yet been isolated, protonation of the σ-
anionic adduct 25 to give the chlorin 26, which would afford 27
on elimination of nitrous acid, is also possible by analogy to
processes that occur following α-attack of the nucleophile.
With ‘hard’ nucleophiles (such as hydride,9 alkoxides,12 hydrox-
ide,9 acylamide ions13 and carbanion equivalents from Grig-
nard reagents and organolithium reagents10) α-attack occurs to
initially afford the σ-anionic adduct 28. Protonation of 28 gives
the chlorin 29 which can eliminate nitrous acid to give the
product of cine-substitution 30 or undergo oxidation to the α-
substitution product 31 which is formally the vicarious nucleo-
philic substitution of hydrogen.16 Subsequent nucleophilic add-
ition to 31 affords the second σ-adduct 32 which can be trapped
as the chlorin 33 by protonation.12 Chlorins 33 have been
exploited in a step-wise synthesis of 30 by denitration and elim-
ination steps.3,12 The products 27 and 30 are equivalent but the
hydrogen at the 3-position of the starting porphyrin 24 has
also been replaced in compound 30, the product of cine-
substitution. Without labelling a position on the porphyrin or
isolating an intermediate compound, the two paths cannot be
distinguished.
Reactions involving radical intermediates are also possible.
Single electron transfer (SET) would give the nitroporphyrin
radical anion 34 and then the porphyrinyl radical 35 by loss of
nitrite (Scheme 5). The radical 35 can then be trapped by
hydrogen abstraction to give 36 or possibly by reaction with
another radical to give a substitution product 27. Radical deni-
tration occurs in reactions with single electron donors in the
presence of an extractable hydrogen atom; these reactions are
seen in reactions of nitroporphyrins with a 2-aminobenzene-
thiolate–2-aminobenzenethiol system18 and with methoxide at
elevated temperature.12 The operation of a radical mechanism
giving rise to either set of reaction products was considered
unlikely as the highly reactive porphyrinyl radical 35 putatively
generated in these mechanisms might be anticipated to abstract
a hydrogen atom from the solvent (especially in the case of
phenol) in competition with reaction leading to the phenoxy or
hydroxyphenylporphyrin products. No denitrated product was
observed, however, in any of these reactions.
Initial experiments led to the formation of only trace
amounts (<1%) of copper() and nickel() 2-phenoxy-
5,10,15,20-tetraphenylporphyrin, 10 and 11, and the return of
the corresponding unreacted starting porphyrin 1 or 2. These
experiments involved the use of sodium phenoxide in N,N-
dimethylformamide and in dimethyl sulfoxide at room temper-
ature for periods of 1 to 4 days, and also involved the same
experiments with lithium phenoxide. Phenoxide ion thus
appeared to be much less reactive than alkoxide ions in this
reaction.
Increasing the reaction temperature further increased the
yield of 2-phenoxyporphyrins. Thus addition of lithium
phenoxide (3 equiv.) to a refluxing solution of (2-nitro-5,10,15,
20-tetraphenylporphyrinato)copper() 1 in HCONMe2 (10
mmol dmϪ3) afforded the required (2-phenoxy-5,10,15,20-
tetraphenylporphyrinato)copper() 10 in 71% yield after
4 h. Similar treatment of (2-nitro-5,10,15,20-tetraphenyl-
porphyrinato)nickel()
2
afforded (2-phenoxy-5,10,15,20-
tetraphenylporphyrinato)nickel() 11 in 52% yield (Scheme 1).
In each case, at elevated temperature, the formation of many
minor products were also observed; similar side-products arose
in the reactions of alkoxides with the porphyrins in these solv-
ents at elevated temperature. It seemed likely that a number of
these minor products arose from the reaction of the metallo-2-
nitro-5,10,15,20-tetraphenylporphyrin 1 or 2 with decom-
position products from the solvent. N,N-Dimethylformamide
in particular is known to be unstable at reflux, especially in the
presence of base, such as phenoxide.17
The structure of (2-phenoxy-5,10,15,20-tetraphenylpor-
phyrinato)nickel() 11 was evident from the 400 MHz 1H NMR
spectrum [δ 6.88–6.93 (2 H, m, o-PhO), 7.04 (1 H, m, p-PhO),
7.20–7.26 (2 H, m, m-PhO)] and the mass spectrum [m/z 762
(M, 100)]. The structure of the paramagnetic copper() com-
plex 10 is supported by the mass spectrum [m/z 767 (M, 100)],
elemental analysis and by TLC analysis [which showed 10 and
11 to have similar polarity and to be much less polar than the
corresponding starting 2-nitroporphyrins and the 2-(hydroxy-
phenyl)porphyrin products] and visible spectrum comparison
with 11.
The direct introduction of a phenoxy group to the porphyrin
ring is thus achieved in good yield by this elevated temperature
reaction. In this respect the behaviour of phenoxide ion is simi-
lar to that of alkoxide ions12 in that both types of nucleophile
display increased tendency to effect apparent direct displace-
ment of the porphyrin nitro group with increased reaction tem-
perature in N,N-dimethylformamide solutions. Unlike alkoxide
ions,12 however, phenoxide does not undergo Michael addition
with 2-nitroporphyrins at room temperature nor does it appear
to effect significant porphyrin denitration in refluxing N,N-
dimethylformamide.
This reaction represents the only synthesis of 2-aryloxy-
porphyrins currently available and is applicable, in principle, to
the synthesis of other 2-aryloxyporphyrins. The application of
this method to the preparation of aryloxyporphyrins with a free
hydroxy group on the aryloxy substituent, however, was not
pursued as the 2-hydroxyphenylporphyrins provide a more rigid
anchor for attaching inwards-directed substituents.
The possibility that both phenoxyporphyrin and hydroxy-
phenylporphyrin products arise from nucleophilic reactions is
supported by the known ability of phenoxide ion to act as an
ambident nucleophile toward nitroaromatic systems. Thus
phenoxide ion has been shown to form C-bonded Meisen-
heimer complexes with trinitrobenzene and the ‘superelectro-
philes’ 4,6-dinitrobenzofuran and 4,6-dinitro-2-(2Ј,4Ј,6Ј-tri-
nitrophenyl)benzotriazole 1-oxide through both the ortho- and
para-carbons.19–21 Further, 2,6-di-tert-butylphenoxide has been
reported to react with nitrobenzenes, via C-4 attack, to give 4-
hydroxy-4Ј-nitrobiphenyls.22 The closely related anilines have
also been reported to form C-bonded Meisenheimer complexes
through both ortho- and para-carbons.23–25
In order to distinguish between the two mechanisms involv-
ing nucleophilic substitution, the reactions of phenoxide in
phenol and in N,N-dimethylformamide were repeated with
the vicinally deuteriated (2-nitro-5,10,15,20-tetraphenyl[3-2H]-
porphyrinato)nickel()9 37 as the substrate.
A
solution of (2-nitro-5,10,15,20-tetraphenyl[3-2H]por-
phyrinato)nickel() 37 in refluxing phenol (11 mmol dmϪ3) was
reacted with sodium phenoxide (11 equiv.) for 1 h and afforded
{2-(o-hydroxyphenyl)-5,10,15,20-tetraphenyl[3-2H]porphyrin-
ato}nickel() 38 (34%), {2-(p-hydroxyphenyl)-5,10,15,20-
tetraphenyl[3-2H]porphyrinato}nickel() 39 (12%) and unre-
acted starting material 37 (13%) (Scheme 6). The deuterium
content of the two hydroxyphenylporphyrins, 38 and 39, was
found to be 40 5%. The recovered starting material 37
retained 100% deuterium content.
Mechanistic considerations
A number of mechanisms can operate in reactions of nitro-
porphyrins. Attack of a nucleophile on metallo-2-nitro-
porphyrins 24 can occur either at the carbon bearing the
nitro group (ipso-attack) to give the σ-anionic adduct 25 (Path
a, Scheme 4), or at the adjacent β-pyrrolic position (α-attack) to
give the alternate σ-anionic adduct 28 (Path b, Scheme 4). Reac-
tion of 24 with ‘soft’ aldoximate and thiolate nucleophiles
results in ipso-substitution of the nitro group to give the prod-
Treatment
of
(2-nitro-5,10,15,20-tetraphenyl[3-2H]por-
3090
J. Chem. Soc., Perkin Trans. 1, 1997

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Ph
M
Ph
M
Ph
R
R
R
NO2
NO2
H
H
H
H
N
N
N
N
N
N
N
N
N
N
" H +
"
– HNO2
Ph
Ph
Ph
Ph
Ph
Ph
M
N
N
Path a
Ph
Ph
Ph
27
25
26
NO2
Ph
M
H
– NO2
N
N
N
N
Ph
Ph
+
R
Ph
O
O
24
N
NO2
Ph
Ph
M
Ph
H
Path b
H
H
R
R
R
N
N
N
N
N
N
N
N
" H +
"
– HNO2
Ph
Ph
Ph
Ph
Ph
Ph
M
M
N
N
N
N
Ph
Ph
Ph
28
29
30
O
O
NO2
H
NO2
Ph
M
Ph
M
Ph
M
N
R'
R'
R
R
N
N
N
R
N
N
N
N
N
R' –
" H +
"
Ph
Ph
Ph
Ph
Ph
Ph
N
N
N
N
Ph
Ph
32
Ph
31
33
– RH
Scheme 4
phyrinato)nickel() 37 in refluxing N,N-dimethylformamide
with lithium phenoxide afforded deuterium labelled (2-
phenoxy-5,10,15,20-tetraphenyl[3-2H]porphyrinato)nickel()
40 (33%). The deuterium content of 40 was determined by 400
MHz 1H NMR and mass spectrometry to be 80 5%.
It is clear from the retention of some deuterium label in the
products of both these reactions that each reaction proceeds, at
least to a significant extent, by an ipso-substitution mechanism.
The source of the variation in the products formed is therefore
not simply the adoption of an ipso mechanism in one solvent
and a cine mechanism, with different requirements for attack of
the nucleophile, in the other.
The loss of deuterium label in the products (approximately
20% in the formation of 40 and 60% in the formation of 38 and
39) from the reactions in N,N-dimethylformamide and phenol,
respectively, could simply indicate that some reaction also
occurs by a cine-substitution mechanism. Alternately, the loss
of label could arise from protonation of the σ-anionic adduct
25 (Scheme 4). Protonation from either face of the porphyrin
would give a diastereomeric mixture of chlorins 26 which then
undergo syn-elimination of nitrous or [2H]nitrous acid, the
latter process affording non-deuteriated product. The trapping
of the alternate σ-anionic adduct (arising from α-attack) is
commonplace in the reaction of 2-nitroporphyrins with ‘hard’
nucleophiles such as alkoxide, hydride and the carbanions
derived from Grignard reagents and organometallics.3,9,10 The
low amount of deuterium loss in the formation of phenoxy-
porphyrin 40 would then reflect a small amount of protonation
of the σ-anionic adduct 25, presumably from the water present
even in rigorously dried N,N-dimethylformamide.26 A much
higher degree of protonation of the σ-anionic adduct 25 would
be expected for the reaction carried out in phenol; complete,
non-diastereoselective protonation of the anion 25, however,
and subsequent nitrous or [2H]nitrous acid elimination can
only account for a maximum 50% loss of label in hydroxy-
phenylporphyrins 38 and 39, as [2H]nitrous acid is lost by a syn-
elimination process.10,12 The reason for the 60% label loss in 38
and 39 is not known but may involve an extent of diastereo-
selective protonation of σ-anionic adduct resulting from
intramolecular proton transfer from the adjacent hydroxy-
phenyl group in the initially formed dienone tautomer or may
indicate competing cine-substitution. Labelling of the 2-, 4- and
6-positions of phenol with deuterium would unravel the detail
of the mechanism. The alternate possible source of label loss
J. Chem. Soc., Perkin Trans. 1, 1997
3091

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Similarly, the fact that recovered nitroporphyrin 37 was still
fully labelled ruled out loss of the label from intermediates in
equilibrium with the starting nitroporphyrin.
24
SET
Conclusions
– •
NO2
Ph
Ph
M
The products arising from reaction of 2-nitroporphyrins with
phenoxide ion can be controlled by choice of solvent. Reaction
in phenol as solvent affords 2-(o- and p-hydroxyphenyl)-
porphyrins while reaction in N,N-dimethylformamide yields 2-
phenoxyporphyrins. Blocking the para-position of a phenol
with a substituent forces the reaction of the corresponding
phenoxide in the phenol to yield only the 2-(o-hydroxyaryl)-
porphyrin. The products from both sets of reactions arise
mainly, if not wholly, from ipso-substitution of the nitro group,
a process seen in the reactions of 2-nitroporphyrins with other
‘soft’ nucleophiles such as aldoximate and thiolate. Compared
with simple nitroarenes, the ease with which 2-nitroporphyrins
react with nucleophiles is probably because of the fact the
aromaticity is maintained in the macrocycle by a chlorin-like
delocalisation pathway in all of the intermediates in the
reaction.
In ongoing work we have found that the reaction of 2-nitro-
porphyrins with aryloxide ions to yield 2-(hydroxyaryl)-
porphyrins to be a general one which may find useful appli-
cation in the design of haemoprotein model systems. The
synthesis, study of conformation and epoxidation reactions of
arachidonic and oleic acid adducts of 2-(hydroxyaryl)por-
phyrins which illustrate this point will be reported in full
shortly.
H
H
–
N
N
N
N
N
N
N
– NO2
Ph
Ph
Ph
Ph
M
N
Ph
Ph
34
35
RH
RH
R
Ph
M
H
Ph
H
H
N
N
N
N
N
N
Ph
Ph
Ph
Ph
M
N
N
Ph
Ph
27
This work is a further illustration of the fact that 2-nitro-
porphyrins are versatile starting materials for introduction of
other functionality to the porphyrin periphery.2–14
36
Scheme 5
Experimental
O
Na
Ph
Ph
Ni
NO2
OH
Melting points were recorded on a Kofler hot-stage microscope
and are uncorrected. Elemental analyses were performed by the
Australian Microanalytical Service, Melbourne, Australia.
Infrared spectra were recorded on a Perkin-Elmer 221 spec-
trometer. Visible spectra were recorded on a Hitachi 150-20
[2H]
[2H]
Ph
N
N
N
N
N
Ph
Ni
Ph
Ph
phenol
N
N
1
N
spectrophotometer. H NMR spectra were recorded at 300 K
on a Bruker WM400 (400 MHz) spectrometer with tetra-
methylsilane as the internal standard. J Values are given in Hz.
Electron impact (EI) mass spectra were recorded on an AEI MS
902 spectrometer at 70 eV which was attached to a DS 30 data
handling system for high-resolution mass spectra. Matrix-
assisted laser desorption ionisation time-of-flight (MALDI-
TOF) mass spectra were recorded on a VG TofSpec spec-
trometer. Mass spectra recorded using this instrument are
obtained as an envelope of the isotope peaks of the molecular
ion. The mass corresponding to the envelope’s maxima is
reported and was compared with the maxima of a simulated
Ph
38
Ph
37
(100 atom% deuterium)
(40 atom% deuterium)
+
O
Li
OH
HCONMe2
Ph
[2H]
Ph
spectrum. The MALDI-TOF mass spectra were accurate to
1
O
Ph
Ni
N
N
N
N
amu (ca. 0.10%).
Ph
Ni
[2H]
Ph
Flash chromatography was performed on Merck Type 9385
silica gel. Zinc-free silica gel refers to Merck Type 7754 (70–230
mesh) and was used for gravity-feed column chromatography.
The chromatotron is a preparative, thin layer, centrifugally
accelerated, chromatograph supplied by Harrison Research.
Chromatotron separations were carried out on 4 mm thick
plates prepared with Merck silica gel 60 PF254. All reagents were
purchased from commercial sources and used as received unless
otherwise noted. All solvents were redistilled prior to use. N,N-
Dimethylformamide (HCONMe2) was dried over calcium
hydride and distilled under reduced pressure.
N
N
N
Ph
N
Ph
39
(40 atom% deuterium)
Ph
40
(80 atom% deuterium)
Scheme 6
from 38 and 39, exchange under the reaction conditions after
formation of the product, was discounted since no further label
was lost when 38 was heated at reflux in phenol for 3 h.
The reaction between (2-nitro-5,10,15,20-tetraphenylporphyrin-
ato)copper(II) 1 and sodium phenoxide in phenol
A mixture of (2-nitro-5,10,15,20-tetraphenylporphyrinato)-
3092
J. Chem. Soc., Perkin Trans. 1, 1997

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copper()15,27 1 (265 mg, 0.368 mmol), sodium phenoxide (500
mg, 4.31 mmol) and phenol (10 g) was heated under reflux for 7
h. Upon cooling, the mixture was poured into aqueous sodium
hydroxide (2 mol dmϪ3; 100 cm3). The aqueous suspension was
extracted with dichloromethane (100 cm3, 2 × 50 cm3) and the
combined extracts were washed with aqueous sodium hydrox-
ide (2 mol dmϪ3; 50 cm3) and water (100 cm3), dried over
anhydrous sodium sulfate, filtered and evaporated to dryness.
The residue was chromatographed on a silica column (4 cm
diameter, 200 g) eluted with dichloromethane to yield three red
fractions. The front running, non-polar band on evaporation
C50H32N460NiO requires m/z 764.1908) (Found: m/z 766.1942.
C50H32N462NiO requires m/z 766.1859) (Found: m/z 768.1919.
C50H32N464NiO requires m/z 768.1856); νmax(Nujol)/cmϪ1
3450br (OH), 1245, 1155, 1060 and 955; λmax(CHCl3)/nm 421
(log ε 5.30), 536 (4.17) and 570 sh (3.66); δH(400 MHz; CD2Cl2)
4.83 (1 H, s, OH), 6.50 (2 H, m, spacing 1.5 and 8, 2-Hm), 7.04 (2
H, m, spacing 1.5 and 8, 2-Ho), 7.19 (2 H, m, 20-Ho), 7.30 (1 H,
m, 20-Hp), 7.60 (2 H, m, 20-Ho), 7.64–7.76 (9 H, m, 5-, 10- and
15-Hm,p), 7.95–8.05 (6 H, m, 5-, 10- and 15-Ho), 8.41 and 8.62 (2
H, ABq, JAB 5, β-pyrrolic H), 8.61 (1 H, s, 3-H), 8.70 and 8.74 (2
H, ABq, JAB 5, β-pyrrolic H), 8.71 and 8.73 (2 H, ABq, JAB 5,
β-pyrrolic H); m/z (EI) 766 (15%), 765 (29), 764 (57), 763 (58)
and 762 (M, 100).
afforded
(2-phenoxy-5,10,15,20-tetraphenylporphyrinato)-
copper() 10 (6.5 mg, 2%) which was identical with material
prepared and fully characterised in an experiment described
below.
The reaction between 2-nitro-5,10,15,20-tetraphenylporphyrin 3
and sodium phenoxide in phenol
The second fraction, on evaporation afforded [2-(o-hydroxy-
phenyl)-5,10,15,20-tetraphenylporphyrinato]copper()
4
(147
A mixture of 2-nitro-5,10,15,20-tetraphenylporphyrin2 3 (64
mg, 0.097 mmol), sodium phenoxide (12 mg, 0.10 mmol) and
phenol (5 g) was heated under reflux for 4.5 h. Upon cooling,
the mixture was taken up in dichloromethane (60 cm3), washed
with aqueous sodium hydroxide (3 mol dmϪ3; 2 × 50 cm3), and
water (100 cm3), dried over anhydrous sodium sulfate, filtered
and evaporated to dryness. The residue was chromatographed
on zinc-free silica, eluted with dichloromethane–light petrol-
eum (7:3) until the first band eluted, thence with dichloro-
methane. The first band afforded 2-nitro-5,10,15,20-tetra-
phenylporphyrin 3 (5 mg, 8%).
The second band afforded 2-(o-hydroxyphenyl)-5,10,15,20-
tetraphenylporphyrin 6 (26 mg, 38%) as an amorphous brown
solid, mp 205–210 ЊC (from dichloromethane and hexane)
(Found: C, 84.6; H, 4.7; N, 8.1. C50H34N4O requires C, 85.0; H,
4.9; N, 7.9%); νmax(Nujol)/cmϪ1 3500br, 3300br, 1600, 1180 and
970; λmax(CHCl3)/nm 403 sh (log ε 4.04), 422 (5.55), 487 (3.59),
519 (3.59), 554 (4.23), 594 (3.82) and 650 (3.56); δH(400 MHz;
CD2Cl2) Ϫ2.67 (2 H, br s, NH), 6.63 (1 H, dd, J 1 and 8, 2Ј-H),
6.74 (1 H, dt, J 1 and 7.5, 5Ј-H), 7.03 (1 H, ddd, J 2, 7.5 and 8,
4Ј-H), 7.17 (1 H, dd, J 2 and 7.5, 6Ј-H), 7.19–7.30 (3 H, m,
20-Hm,p), 7.68–7.81 (10 H, m, 5-, 10-, 15-Hm,p and 20-Ho), 7.98
(1 H, m, 20-Ho), 8.18–8.25 (6 H, m, 5-, 10- and 15-Ho), 8.66 and
8.78 (2 H, ABq, JAB 5, β-pyrrolic H), 8.81 (1 H, s, 3-H), 8.83
and 8.85 (2 H, ABq, JAB 5, β-pyrrolic H), 8.87 and 8.88
(2 H, ABq, JAB 5, β-pyrrolic H); m/z (EI) 770 (15%), 769 (31),
768 (27), 767 (M ϩ [63Cu], 43), 708 (24), 707 (67) and 706
(M, 100).
The third band yielded 2-(p-hydroxyphenyl)-5,10,15,20-tetra-
phenylporphyrin 9 (14 mg, 20%) as a brown amorphous solid,
mp 191–195 ЊC (from dichloromethane and hexane) (Found: C,
84.8; H, 5.2; N, 7.7. C50H34N4O requires C, 85.0; H, 4.9; N,
7.9%); νmax(Nujol)/cmϪ1 3300br, 1590, 1260, 1170 and 960;
λmax(CHCl3)/nm 402 sh (log ε 4.90), 422 (5.52), 488 (3.58), 520
(4.23), 555 (3.83), 594 (3.73) and 649 (3.47); δH(400 MHz;
CD2Cl2) Ϫ2.70 (2 H, br s, NH), 6.50 (2 H, m, spacing 1.5 and
8, 2-Hm), 7.17 (2 H, m, spacing 1.5 and 8, 2-Ho), 7.25 (2 H, m,
20-Hm), 7.33 (1 H, m, 20-Hp), 7.69–7.81 (9 H, m, 5-, 10- and
15-Hm,p), 7.84–7.89 (2 H, m, 20-Ho), 8.19–8.25 (6 H, m, 5-,
10- and 15-Ho), 8.67 and 8.73 (2 H, ABq, JAB 4.5, β-pyrrolic H),
8.81 and 8.84 (2 H, ABq, JAB 4.5, β-pyrrolic H), 8.86 and 8.88 (2
H, ABq, JAB 4.5, β-pyrrolic H); m/z (EI) 770 (29%), 769 (54),
768 (58), 767 (M ϩ [63Cu], 86), 708 (18), 707 (58) and 706 (M,
100).
mg, 52%), mp 239–242 ЊC (from dichloromethane and light pet-
roleum) (Found: C, 78.3; H, 4.3; N, 7.4. C50H32CuN4O requires
C, 78.2; H, 4.2; N, 7.3%); νmax(KBr)/cmϪ1 3450br (OH), 1580,
1435, 1330, 1165, 1070 and 990; λmax(CHCl3)/nm 419 (log ε
5.65), 505 (3.56), 542 (4.29) and 576 sh (3.53); m/z (EI) 770
(30%), 769 (67), 768 (60) and 767 (M, 100).
The third fraction yielded, on evaporation [2-(p-hydroxy-
phenyl)-5,10,15,20-tetraphenylporphyrinato]copper()
7 (100
mg, 35%), mp 295–298 ЊC (from dichloromethane and light
petroleum) (Found: C, 78.7; H, 4.2; N, 7.2. C50H32CuN4O
requires C, 78.2; H, 4.2; N, 7.3%); νmax(Nujol)/cmϪ1 3450br
(OH), 1595, 1260, 1160, 1065 and 995; λmax(CHCl3)/nm 419 (log
ε 5.64), 504 (3.61), 543 (4.33) and 578 sh (3.53); m/z (EI) 770
(30%), 769 (67), 768 (60) and 767 (M, 100).
The reaction between (2-nitro-5,10,15,20-tetraphenylporphyri-
nato)nickel(II) 2 and sodium phenoxide in phenol
A mixture of (2-nitro-5,10,15,20-tetraphenylporphyrinato)-
nickel()9,15 2 (110 mg, 0.154 mmol), sodium phenoxide (110
mg, 0.948 mmol) and phenol (5 g) was heated at reflux for 3.5 h.
Upon cooling, the mixture was diluted with dichloromethane
(80 cm3), washed with aqueous sodium hydroxide (3 mol dmϪ3;
3 × 100 cm3) and water (100 cm3), dried over anhydrous sodium
sulfate, filtered and evaporated to dryness. The residue was
chromatographed on a silica column (2 cm diameter, 100 g)
eluted with dichloromethane–light petroleum (1:1) until the
first red band was eluted, thence with dichloromethane–light
petroleum (4:1) to yield three fractions. The first band afforded
on evaporation (2-phenoxy-5,10,15,20-tetraphenylporphyri-
nato)nickel() 11 (6 mg, 5%) as a red solid which was identical
with material prepared and fully characterised in an experiment
described below.
The second, major, red band on evaporation yielded [2-(o-
hydroxyphenyl)-5,10,15,20-tetraphenylporphyrinato]nickel() 5
(78 mg, 66%) as a red powder, mp 315–317 ЊC (from dichlo-
romethane and light petroleum) (Found: C, 79.2; H, 4.3; N, 7.5.
C50H32N4NiO requires C, 78.7; H, 4.2; N, 7.3%); νmax(Nujol)/
cmϪ1 3350br (OH), 1580 and 1000; λmax(CHCl3)/nm 420 (log ε
5.38), 496 sh (3.62), 534 (4.24) and 567 sh (3.68); δH(400 MHz;
CD2Cl2) 5.00 (1 H, s, OH), 6.61 (1 H, dd, J 1 and 8, 3Ј-H), 6.72
(1 H, dt, J 1 and 7.5, 5Ј-H), 7.03 (1 H, ddd, J 1.5, 7.5 and 8, 4Ј-
H), 7.08 (1 H, dd, J 1.5 and 7.5, 6Ј-H), 7.17 (2 H, m, 20-Hm),
7.22 (1 H, m, 20-Hp), 7.56–7.78 (11 H, m, 5-, 10-, 15-Hm,p and
20-Ho), 7.96–8.05 (6 H, m, 5-, 10- and 15-Ho), 8.47 and 8.63 (2
H, ABq, JAB 5, β-pyrrolic H), 8.72–8.76 (4 H, m, β-pyrrolic H)
and 8.73 (1 H, s, 3-H); m/z (EI) 766 (18%), 765 (29), 764 (56),
763 (60) and 762 (M, 100).
The reaction between (2-nitro-5,10,15,20-tetraphenylporphyrin-
ato)copper(II) 1 and sodium p-cresolate 12
A mixture of (2-nitro-5,10,15,20-tetraphenylporphyrinato)-
copper() 1 (246 mg, 0.342 mmol), sodium p-cresolate 12 (300
mg, 2.31 mmol) and p-cresol (7 g) was heated at reflux for 6 h.
Upon cooling, the mixture was diluted with dichloromethane
(100 cm3), washed with aqueous sodium hydroxide (3 mol
dmϪ3; 2 × 50 cm3) and water (100 cm3), dried over anhydrous
sodium sulfate, filtered and evaporated to dryness. The residue
The third, red fraction afforded on evaporation [2-(p-
hydroxyphenyl)-5,10,15,20-tetraphenylporphyrinato]nickel() 8
(28 mg, 24%) as an amorphous red solid, mp 278–285 ЊC (from
dichloromethane and light petroleum) (Found: H, 4.2; N, 7.5.
C50H32N4NiO requires H, 4.2; N, 7.3%) (Found: m/z 762.1942.
C50H32N458NiO requires m/z 762.1930) (Found: m/z 764.1935.
J. Chem. Soc., Perkin Trans. 1, 1997
3093

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was chromatographed on a chromatotron eluted with dichloro-
methane to afford [2-(2-hydroxy-5-methylphenyl)-5,10,15,20-
tetraphenylporphyrinato]copper() 14 (230 mg, 86%) as a red
amorphous solid, mp 260–270 ЊC (from dichloromethane and
hexane) (Found: C, 78.3; H, 4.5; N, 7.5. C51H34CuN4O requires
C, 78.3; H, 4.4; N, 7.2%); νmax(Nujol)/cmϪ1 3400br (OH), 1585,
1335 and 985; λmax(CHCl3)/nm 394 sh (log ε 4.56), 419 (5.66), 477
sh (3.66), 506 (3.61), 542 (4.33) and 578 sh (3.58); m/z (EI) 784
(32%), 783 (62), 782 (59) and 781 (M, 100).
methane and methanol) (Found: C, 78.2; H, 4.5; N, 7.1.
C52H36CuN4O requires C, 78.4; H, 4.6; N, 7.0%); νmax(CHCl3)/
cmϪ1 3548m (OH), 3014s, 1600s, 1491m, 1480m, 1442s, 1344s,
1073m, 1005s and 996s; λmax(CHCl3)/nm 418 (log ε 5.58), 505 sh
(3.50) and 542 (4.23); m/z (EI) 799 (6%), 798 (18), 797 (65), 796
(75) and 795 (M, 100).
The reaction between porphyrin 3 and sodium 2,4-dimethyl-
phenoxide 13 to give 2-(2-hydroxy-3,5-dimethylphenyl)-5,10,
15,20-tetraphenylporphyrin 17
The reaction between porphyrin 3 and sodium p-cresolate 12 to
give 2-(2-hydroxy-5-methylphenyl)-5,10,15,20-tetraphenylpor-
phyrin 15
Method 1. A mixture of 2-nitro-5,10,15,20-tetraphenyl-
porphyrin 3 (160 mg, 0.24 mmol), sodium 2,4-dimethyl-
phenoxide 13 (200 mg, 1.39 mmol) and 2,4-dimethylphenol (14
g) was heated at reflux for 10 h and cooled. It was then extracted
into dichloromethane (100 cm3), washed with aqueous sodium
hydroxide (3 mol dmϪ3; 2 × 100 cm3), water (2 × 100 cm3), dried
over anhydrous sodium sulfate and evaporated to dryness. The
residue was chromatographed on a silica column, eluted with
dichloromethane–light petroleum (1:1). The major band was
collected and evaporated to dryness to afford 2-(2-hydroxy-3,5-
dimethylphenyl)-5,10,15,20-tetraphenylporphyrin 17 (126 mg,
69%), mp 220–224 ЊC (from dichloromethane and methanol)
(Found: C, 85.2; H, 5.5; N, 7.7. C52H38N4O requires C, 85.0; H,
5.2; N, 7.6%); νmax(CHCl3)/cmϪ1 3550w br (OH), 3331w (NH),
1599w, 1475m, 1442w, 1350w, 1074w, 1003w and 966s;
λmax(CHCl3)/nm 420 (log ε 4.61), 486 sh (3.59), 517 (4.29), 552
(3.83), 592 (3.74) and 647 (3.56); δH(400 MHz; CDCl3) Ϫ2.64 (2
H, br s, inner NH), 2.14 (3 H, s, CH3), 2.18 (3 H, s, CH3), 4.94 (1
H, br s, OH), 6.72 (1 H, d, J 2.5, 4Ј-H), 6.80 (1 H, d, J 2.5,
6Ј-H), 7.22–7.27 (3 H, m, 20-Hm,p), 7.67–7.77 (9 H, m, 5-,
10- and 15-Hm,p), 7.82 (1 H, br m, 20-Ho), 7.95 (1 H, br m, 20-
Ho), 8.18–8.22 (6 H, m, 5-, 10- and 15-Ho), 8.67 and 8.76 (2 H,
ABq, JAB 7.4, 12- and 13-H), 8.83 (1 H, s, 3-H), 8.81 and 8.84 (2
H, ABq, JAB 6.3, 7- and 8-H) and 8.85 (2 H, ABq, JAB 6.3, 17-
and 18-H); m/z (EI) 736 (4%), 735 (30), 734 (M, 52), 659 (12),
658 (57) and 657 (100).
Method 2. To a stirred solution of [2-(2-hydroxy-3,5-
dimethylphenyl)-5,10,15,20-tetraphenylporphyrinato]copper()
16 (129 mg, 0.16 mmol) in dichloromethane (50 cm3) was added
concentrated sulfuric acid (98%; 10 cm3). The mixture was
stirred for 5 min, then poured onto ice (50 g). The organic
layer was separated and the aqueous layer was extracted with
dichloromethane (2 × 50 cm3). The combined organic layers
were washed with aqueous sodium hydroxide (3 mol dmϪ3; 75
cm3), water (100 cm3), dried over anhydrous sodium sulfate,
filtered and evaporated to dryness. The residue was chromato-
graphed on a silica column, eluted with dichloromethane–light
petroleum (1:2) to afford 2-(2-hydroxy-3,5-dimethylphenyl)-
5,10,15,20-tetraphenylporphyrin 17 (68 mg, 57%). This product
was identical in all respects with the sample prepared by
Method 1.
Method 1. To a refluxing mixture of sodium p-cresolate 12
(200 mg, 1.54 mmol) and p-cresol (15 g) was added 2-nitro-
5,10,15,20-tetraphenylporphyrin 3 (317 mg, 0.48 mmol). The
mixture was heated at reflux for 3.5 h and upon cooling it was
diluted with dichloromethane (150 cm3), washed with aqueous
sodium hydroxide (3 mol dmϪ3; 2 × 50 cm3) and water (100
cm3). It was then dried over anhydrous sodium sulfate, filtered
and evaporated to dryness. The residue was chromatographed
on a silica column, eluted with dichloromethane–light petrol-
eum (1:2), and the major band was collected and evaporated to
dryness to afford 2-(2-hydroxy-5-methylphenyl)-5,10,15,20-
tetraphenylporphyrin 15 (226 mg, 65%), mp 225–230 ЊC (from
dichloromethane and methanol) (Found: C, 84.7; H, 5.3; N, 7.4.
C51H36N4O requires C, 85.0; H, 5.0; N, 7.8%); νmax(CHCl3)/cmϪ1
3547m br (OH), 3062m, 3011m, 1599m, 1495s, 1474s, 1442m,
1350m, 1074w, 1032w, 1003m and 984m; λmax(CHCl3)/nm 420
(log ε 5.63), 484 sh (3.59), 517 (4.28), 552 (3.84), 592 (3.45) and
648 (3.58); δH(400 MHz; CDCl3) Ϫ2.63 (2 H, br s, inner NH),
2.21 (3 H, s, CH3), 5.04 (1 H, s, OH), 6.66 (1 H, d, J 7.3, 3Ј-H),
6.85 (1 H, d, J 7.3, 4Ј-H), 6.87 (1 H, s, 6Ј-H), 7.19–7.36 (3 H, m,
20-Hm,p), 7.68–7.80 (9 H, m, 5-, 10- and 15-Hm,p), 7.85 (1 H, d,
J 7, 20-Ho), 7.96 (1 H, d, J 7, 20-Ho), 8.20–8.23 (6 H, m, 5-,
10- and 15-Ho), 8.68 and 8.80 (2 H, ABq, JAB 5, 12- and 13-H),
8.82 (1 H, s, 3-H), 8.81 and 8.83 (2 H, ABq, JAB 5, 7- and 8-H),
8.85 and 8.87 (2 H, ABq, JAB 5, 17- and 18-H); m/z (MALDI-
TOF) 722 (M ϩ H requires 722).
Method 2. [2-(2-Hydroxy-5-methylphenyl)-5,10,15,20-tetra-
phenylporphyrinato]copper() 14 (100 mg, 0.13 mmol) was dis-
solved in dichloromethane (50 cm3) and concentrated sulfuric
acid (98%; 10 cm3) was added. The mixture was stirred for 5
min and then poured onto ice (150 g). The organic layer was
separated and the aqueous layer was extracted with dichloro-
methane (2 × 50 cm3). The combined organic layers were
washed with aqueous sodium hydroxide (3 mol dmϪ3; 50 cm3),
water (50 cm3) and then dried over anhydrous sodium sulfate,
filtered and evaporated to dryness. The residue was chromato-
graphed on a silica column, eluted with dichloromethane–light
petroleum (1:3) to yield 2-(2-hydroxy-5-methylphenyl)-
5,10,15,20-tetraphenylporphyrin 15 (48 mg, 54%). This prod-
uct was identical in all respects with the sample prepared by
Method 1.
The reaction between porphyrin 3 and sodium 2,6-dimethylphen-
oxide 18 to give 2-(4-hydroxy-3,5-dimethylphenyl)-5,10,
15,20-tetraphenylporphyrin 19
The reaction between porphyrin 1 and sodium 2,4-dimethyl-
phenoxide 13 to give [2-(2-hydroxy-3,5-dimethylphenyl)-5,10,
15,20-tetraphenylporphyrinato]copper(II) 16
To a refluxing mixture of 2,6-dimethylphenol (15 g) and sodium
hydroxide (200 mg) was added 2-nitro-5,10,15,20-tetraphenyl-
porphyrin 3 (200 mg, 0.30 mmol). The mixture was heated at
reflux for 2 h, cooled, then extracted into dichloromethane (100
cm3). This was washed with aqueous sodium hydroxide (3 mol
dmϪ3; 150 cm3), water (100 cm3) and dried over sodium sulfate,
filtered and evaporated to dryness. The residue was chromato-
graphed on a silica column, eluted with dichloromethane–light
petroleum (1:3). The major band gave 2-(4-hydroxy-3,5-
dimethylphenyl)-5,10,15,20-tetraphenylporphyrin 19 (140 mg,
63%) as purple crystals, mp >300 ЊC (Found: C, 84.6; H, 5.4;
N, 7.3. C52H38N4O requires C, 84.5; H, 5.2; N, 7.0%);
νmax(CHCl3)/cmϪ1 3610w br (OH), 3310w br (NH), 3062w,
3009m, 2924w, 2382w, 1598m, 1484s, 1442m, 1350w, 1196w and
1165s; λmax(CHCl3)/nm 412 (log ε 5.60), 486 sh (3.61), 517
To a refluxing mixture of sodium 2,4-dimethylphenoxide 13
(400 mg, 2.78 mmol) and 2,4-dimethylphenol (20 g) was added
(2-nitro-5,10,15,20-tetraphenylporphyrinato)copper() 1 (614
mg, 0.852 mmol). The mixture was heated at reflux for 2.5 h,
cooled, then extracted into dichloromethane (100 cm3). This
was washed with aqueous sodium hydroxide (3 mol dmϪ3; 150
cm3), water (100 cm3) and dried over anhydrous sodium sulfate,
filtered and evaporated to dryness. The residue was chromato-
graphed on a silica column, eluted with dichloromethane–light
petroleum (1:3). The red band on evaporation yielded [2-(2-
hydroxy-3,5-dimethylphenyl)-5,10,15,20-tetraphenylporphyrin-
ato]copper() 16 (521 mg, 77%), mp > 320 ЊC (from dichloro-
3094
J. Chem. Soc., Perkin Trans. 1, 1997

View Article Online
(4.32), 553 (3.86), 592 (3.77) and 647 (3.49); δH(400 MHz;
CDCl3) Ϫ2.64 (2 H, br s, inner NH), 2.17 (6 H, s, 2 × CH3), 4.55
(1 H, br s, OH), 6.94 (2 H, s, 2Ј- and 6Ј-H), 7.23 (3 H, m,
20-Hm,p), 7.68–7.78 (9 H, m, 5-, 10- and 15-Hm,p), 7.87 (1 H, d,
J 2.5, 20-Ho), 7.89 (1 H, d, J 2.5, 20-Ho), 8.19–8.25 (6 H, m,
5-, 10- and 15-Ho), 8.67 and 8.72 (2 H, ABq, JAB 4.9, β-pyrrolic
H), 8.74 (1 H, s, 3-H), 8.78 and 8.81 (2 H, ABq, JAB 4.7, β-
pyrrolic H), 8.84 and 8.86 (2 H, ABq, JAB 4.8, β-pyrrolic H); m/z
(MALDI-TOF) 735 (M ϩ H requires 736).
H, 4.7; N, 6.9%); νmax(CHCl3)/cmϪ1 3014s, 1600m, 1491m,
1442m, 1344s, 1151m, 1073m, 1006s and 997s; λmax(CHCl3)/nm
417 (log ε 5.63), 504 sh (3.58) and 540 (4.30); m/z (EI) 812 (26%),
811 (73), 810 (60) and 809 (M, 100).
Methylation of porphyrin 17 to give 2-(2-methoxy-3,5-dimethyl-
phenyl)-5,10,15,20-tetraphenylporphyrin 23
A solution of 2-(2-hydroxy-3,5-dimethylphenyl)-5,10,15,20-
tetraphenylporphyrin 17 (104 mg, 0.14 mmol) in acetone (20
cm3) was stirred with methyl iodide (3 cm3, 48 mmol) and
anhydrous potassium carbonate (150 mg) for 7 days. Further
methyl iodide (5 cm3, 80 mmol) was added and the mixture was
stirred for a further 7 days. The solvent was removed by rotary
evaporation and the residue was extracted into dichloro-
methane (100 cm3), washed with water (100 cm3), dried over
anhydrous sodium sulfate, filtered and evaporated to dryness.
The residue was then chromatographed on a silica column,
eluted with dichloromethane–light petroleum (1:2) to yield
2-(2-methoxy-3,5-dimethylphenyl)-5,10,15,20-tetraphenylpor-
phyrin 23 (47 mg, 44%), mp 201–205 ЊC (from dichloro-
methane and light petroleum) (Found: C, 84.7; H, 5.5; N, 7.3.
C53H40N4O requires C, 85.0; H, 5.4; N, 7.5%); νmax(CHCl3)/cmϪ1
3314m (NH), 3061m, 3009s, 1598s, 1474s, 1442s, 1349m,
1073m, 1015m, 1003s, 981m and 966s; λmax(CHCl3)/nm 420 (log
ε 5.64), 516 (4.29), 552 (3.84), 591 (3.74) and 647 (3.47); δH(400
MHz; CDCl3) Ϫ2.64 (2 H, br s, inner NH), 2.12 (3 H, s, CH3),
2.28 (3 H, s, CH3), 3.04 (3 H, s, OCH3), 6.78 (1 H, d, J 2, 4Ј-H),
7.05 (1 H, d, J 2, 6Ј-H), 7.16–7.31 (3 H, m, 20-Hm,p), 7.71–7.77
(6 H, m, 5-, 10- and 15-Hm,p), 8.06 (1 H, d, J 7, 20-Ho), 8.18–8.25
(7 H, m, 5-, 10-, 15- and 20-Ho), 8.63 and 8.72 (2 H, ABq, JAB
5, 12- and 13-H) and 8.80–8.85 (5 H, m, 3-, 7-, 8-, 17- and 18-
H); m/z (EI) 752 (3%), 751 (16), 750 (61), 749 (M, 100) and 748
(3).
Methylation of porphyrin 7 to give [2-(p-methoxyphenyl)-5,10,
15,20-tetraphenylporphyrinato]copper(II) 20
[2-(p-Hydroxyphenyl)-5,10,15,20-tetraphenylporphyrinato]-
copper() 7 (51 mg, 0.066 mmol) in acetone (10 cm3) was stirred
with anhydrous potassium carbonate (48 mg, 0.35 mmol) and
methyl iodide (0.5 cm3, 8.0 mmol) for 1.5 days, by which time the
product had precipitated from solution. The solvent was
removed by rotary evaporation. The residue was taken up in
chloroform (30 cm3), washed with water (50 cm3), dried over
anhydrous sodium sulfate, filtered and evaporated to dryness.
The residue was chromatographed on a silica column (1 cm
diameter, 50 g) eluted with dichloromethane–light petroleum
(1:1) to yield [2-(p-methoxyphenyl)-5,10,15,20-tetraphenylpor-
phyrinato]copper() 20 (51 mg, 98%) as a red powder, mp >
350 ЊC (from dichloromethane and methanol) (Found: C, 78.5;
H, 4.2; N, 6.9. C51H34CuN4O requires C, 78.3; H, 4.4; N, 7.2%);
νmax(KBr)/cmϪ1 1595, 1480, 1420, 1335, 1230, 1165, 1060 and
985; λmax(CHCl3)/nm 389 sh (log ε 3.94), 418 (5.55), 504 (3.56),
542 (4.27) and 574 sh (3.49); m/z (EI) 785 (15%), 784 (38), 783
(68), 782 (68) and 781 (M, 100).
Methylation of porphyrin 4 to give [2-(o-methoxyphenyl)-5,10,
15,20-tetraphenylporphyrinato]copper(II) 21
A
solution of [2-(o-hydroxyphenyl)-5,10,15,20-tetraphenyl-
The reaction between (2-nitro-5,10,15,20-tetraphenylporphyrin-
ato)copper(II) 1 and lithium phenoxide in N,N-dimethyl-
formamide
porphyrinato]copper() 4 (54 mg, 0.070 mmol) in acetone (10
cm3) was stirred with anhydrous potassium carbonate (48 mg,
0.35 mmol) and methyl iodide (0.5 cm3, 8.0 mmol) for 3.5 days,
by which time the product had precipitated from solution. The
solvent was removed by rotary evaporation. The residue was
taken up in chloroform (30 cm3), washed with water (50 cm3),
dried over anhydrous sodium sulfate, filtered and evaporated to
dryness. The residue was chromatographed on a silica column
(1 cm diameter, 50 g) eluted with dichloromethane–light pet-
roleum (1:1) to yield [2-(o-methoxyphenyl)-5,10,15,20-tetra-
phenylporphyrinato]copper() 21 (46 mg, 84%) as a red pow-
der, mp 298–303 ЊC (from dichloromethane and methanol)
(Found: C, 78.3; H, 4.5; N, 7.1. C51H34CuN4O requires C,
78.3; H, 4.4; N, 7.2%); νmax(KBr)/cmϪ1 1590, 1425, 1335, 1240
and 985; λmax(CHCl3)/nm 396 sh (log ε 4.49), 417 (5.50), 474 sh
(3.60), 504 (3.55), 541 (4.28) and 575 sh (3.45); m/z (EI) 785
(13%), 784 (36), 783 (61), 781 (M, 100), 691 (14), 690 (13)
and 689 (21).
To a refluxing solution of (2-nitro-5,10,15,20-tetraphenyl-
porphyrinato)copper() 1 (53 mg, 0.074 mmol) in dry HCON-
Me2 (7 cm3), under nitrogen, was added solid lithium phenoxide
(20 mg, 0.20 mmol) and the mixture was heated at reflux under
nitrogen for 4 h. On cooling, the mixture was diluted with
dichloromethane (30 cm3), washed with water (6 × 50 cm3),
dried over anhydrous sodium sulfate, filtered and evaporated to
dryness. The residue was chromatographed on a silica column
(1 cm diameter, 50 g), eluted with dichloromethane–light petrol-
eum (1:1). The front running red band was collected and evap-
orated to dryness to yield (2-phenoxy-5,10,15,20-tetraphenyl-
porphyrinato)copper() 10 (37 mg, 65%, 71% based on con-
sumed starting material) as an amorphous red solid, mp 316–
318 ЊC (from benzene and methanol) (Found: C, 78.6; H, 4.1;
N, 7.3. C50H32CuN4O requires C, 78.2; H, 4.2; N, 7.3%);
νmax(Nujol)/cmϪ1 1585, 1545, 1205, 1160, 1060 and 985;
λmax(CHCl3)/nm 394 sh (log ε 4.59), 416 (5.68), 472 sh (3.64),
502 (4.34), 540 (3.54) and 604 sh (2.97); m/z (EI) 770 (30%), 769
(64), 768 (63), 767 (M, 100) and 675 (10). A second, reddish-
green band contained starting porphyrin 1 (4 mg, 8%).
Methylation of porphyrin 16 to give [2-(2-methoxy-3,5-dimethyl-
phenyl)-5,10,15,20-tetraphenylporphyrinato]copper(II) 22
A solution of [2-(2-hydroxy-3,5-dimethylphenyl)-5,10,15,20-
tetraphenylporphyrinato]copper() 16 (106 mg, 0.13 mmol) in
acetone (20 cm3) was stirred with methyl iodide (1 cm3, 16 mmol)
and anhydrous potassium carbonate (220 mg) for 7 days.
Further methyl iodide (2 cm3, 32 mmol) was added and the
mixture was stirred for a further 7 days. The solvent was
removed by rotary evaporation and the residue was dissolved in
dichloromethane (50 cm3), washed with water (50 cm3), dried
over anhydrous sodium sulfate, filtered and evaporated to dry-
ness. The residue was then chromatographed on a silica
column, eluted with dichloromethane–light petroleum (1:2)
to yield [2-(2-methoxy-3,5-dimethylphenyl)-5,10,15,20-tetra-
phenylporphyrinato]copper() 22 (64 mg, 59%), mp >320 ЊC
(Found: C, 78.9; H, 4.5; N, 7.2. C53H38CuN4O requires C, 78.6;
The reaction between (2-nitro-5,10,15,20-tetraphenylporphyrin-
ato)nickel(II) 2 and lithium phenoxide in N,N-dimethyl-
formamide
To a refluxing solution of (2-nitro-5,10,15,20-tetraphenyl-
porphyrinato)nickel() 2 (53 mg, 0.074 mmol) in dry HCON-
Me2 (30 cm3) under nitrogen was added lithium phenoxide (48
mg, 0.48 mmol) and the mixture was heated at reflux for 3.5 h.
On cooling, the mixture was diluted with dichloromethane (50
cm3), washed with water (6 × 100 cm3), dried over anhydrous
sodium sulfate, filtered and evaporated to dryness. The resi-
due was chromatographed on a chromatotron eluted with
dichloromethane–light petroleum (3:2) to yield two major frac-
J. Chem. Soc., Perkin Trans. 1, 1997
3095

View Article Online
tions. The first, red fraction afforded on evaporation (2-
phenoxy-5,10,15,20-tetraphenylporphyrinato)nickel() 11 (26
mg, 44%, 52% based on consumed starting material), mp 174–
176 ЊC (Found: m/z 762.1927. C50H32N4NiO requires M,
762.1929); νmax(Nujol)/cmϪ1 1596, 1579, 1485, 1220 and 1070;
λmax(CHCl3)/nm 417 (log ε 5.35), 491 (3.72), 531 (4.21) and
565 sh (3.69); δH(400 MHz; CD2Cl2) 6.88–6.93 (2 H, m, 2-Ho),
7.04 (1 H, m, 2-Hp), 7.20–7.26 (2 H, m, 2-Hm), 7.44–7.54 (3 H,
m, 20-Hm,p), 7.58–7.75 (9 H, m, 5-, 10- and 15-Hm,p), 7.79–7.83 (2
H, m, 20-Ho), 7.91–7.98 (2 H, m, 5-Ho), 7.99–8.04 (4 H, m, 10-
and 15-Ho), 8.06 (1 H, s, 3-H), 8.64 and 8.69 (2 H, ABq, JAB 5,
β-pyrrolic H), 8.66 and 8.73 (2 H, ABq, JAB 5, β-pyrrolic H) and
8.73 (2 H, ABq, JAB 5, β-pyrrolic H); m/z (EI) 766 (16%), 765
(30), 764 (61), 763 (61), 762 (M, 100), 673 (12), 672 (25), 671
(26) and 670 (52). A more polar, reddish-green fraction yielded
starting porphyrin 2 (6 mg, 11%).
major, red fraction of (2-phenoxy-5,10,15,20-tetraphenyl-
[3-2H]porphyrinato)nickel() 40 (80 atom% deuterium, 14 mg,
33%), δH(400 MHz; CD2Cl2) 6.88–6.93 (2 H, m, 2-Ho), 7.04 (1
H, m, 2-Hp), 7.20–7.26 (2 H, m, 2-Hm), 7.44–7.54 (3 H, m,
20-Hm,p), 7.58–7.75 (9 H, m, 5-, 10- and 15-Hm,p), 7.79–7.83 (2
H, m, 20-Ho), 7.91–7.98 (2 H, m, 5-Ho), 7.79–8.04 (4 H, m,
10- and 15-Ho), 8.06 (0.2 H, s, 3-H), 8.64 and 8.69 (2 H, ABq,
JAB 5, β-pyrrolic H), 8.66 and 8.73 (2 H, ABq, JAB 5, β-pyrrolic
H) and 8.73 (2 H, ABq, JAB 5, β-pyrrolic H); m/z (EI) 767
(14%), 766 (28), 765 (50), 764 (63), 763 ([2H]M, 100), 762
([1H]M, 29), 674 (14), 673 (27), 672 (24) and 671 (49).
Acknowledgements
This research was funded by an Australian Research Council
research grant to M. J. C. We thank the Australian Government
for the award of a Postgraduate research scholarship to
L. G. K.
The reaction between (2-nitro-5,10,15,20-tetraphenyl[3-2H]-
porphyrinato)nickel(II) 37 and sodium phenoxide
A
mixture of
(2-nitro-5,10,15,20-tetraphenyl[3-2H]por-
References
phyrinato)nickel() 37 (100 atom% deuterium, 39 mg, 0.054
mmol), sodium phenoxide (70 mg, 0.60 mmol) and phenol (5 g)
was heated at reflux for 1 h. Upon cooling, the mixture was
diluted with dichloromethane (50 cm3), washed with aqueous
sodium hydroxide (3 mol dmϪ3; 2 × 80 cm3) and water (100
cm3), dried over anhydrous sodium sulfate, filtered and evapor-
ated to dryness. The residue was chromatographed on a chro-
matotron eluted with dichloromethane–light petroleum (1:1)
until the major red band was eluted thence with dichloro-
methane–light petroleum (3:1) to yield three major fractions.
The first, reddish-green band on evaporation yielded (2-nitro-
5,10,15,20-tetraphenyl[3-2H]porphyrinato)nickel() 37 (100
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1
atom% deuterium, 5 mg, 13%), identical H NMR and EI
mass spectrum with authentic starting material and co-
chromatographed with authentic unlabelled compound 2.
The second, red fraction afforded {2-(o-hydroxyphenyl)-
5,10,15,20-tetraphenyl[3-2H]porphyrinato}nickel() 38 (40
atom% deuterium, 14 mg, 34%), δH(400 MHz; CD2Cl2) 5.00 (1
H, s, OH), 6.61 (1 H, dd, J 1 and 8, 3Ј-H), 6.72 (1 H, dt, J 1 and
7.5, 5Ј-H), 7.03 (1 H, ddd, J 1.5, 7.5 and 8.0, 4Ј-H), 7.08 (1 H,
dd, J 1.5 and 7.5, 6Ј-H), 7.17 (2 H, m, 20-Hm), 7.22 (1 H, m,
20-Hp), 7.56–7.78 (11 H, m, 5-, 10-, 15-Hm,p and 20-Ho), 7.96–
8.05 (6 H, m, 5-, 10- and 15-Ho), 8.47 and 8.63 (2 H, ABq, JAB
5, β-pyrrolic H), 8.72–8.76 (4 H, m, β-pyrrolic H) and 8.73 (0.6
H, s, 3-H); m/z (EI) 767 (12%), 766 (28), 765 (52), 764 (80), 763
([2H]M, 100) and 762 ([1H]M, 92).
The third, red fraction afforded {2-(p-hydroxyphenyl)-5,10,
15,20-tetraphenyl[3-2H]porphyrinato}nickel() 39 (40 atom%
deuterium, 5 mg, 12%), δH(400 MHz; CD2Cl2) 4.83 (1 H, s,
OH), 6.50 (2 H, m, spacing 1.5 and 8, 2-Hm), 7.04 (2 H, m,
spacing 1.5 and 8, 2-Ho), 7.19 (2 H, m, 20-Hm), 7.30 (1 H, m,
20-Hp), 7.60 (2 H, m, 20-Ho), 7.64–7.76 (9 H, m, 5-, 10- and
15-Hm,p), 7.95–8.05 (6 H, m, 5-, 10- and 15-Ho), 8.41 and 8.62 (2
H, ABq, JAB 5, β-pyrrolic H), 8.61 (0.6 H, s, 3-H), 8.70 and 8.74
(2 H, ABq, JAB 5, β-pyrrolic H), 8.71 and 8.73 (2 H, ABq, JAB 5,
β-pyrrolic H); m/z (EI) 767 (15%), 766 (31), 765 (58), 764 (84),
763 ([2H]M, 100) and 762 ([1H]M, 86).
21 E. Buncel, R. A. Renfrow and M. J. Strauss, J. Org. Chem., 1987, 52,
488.
22 G. P. Stahly, J. Org. Chem., 1985, 50, 3091.
23 R. J. Spear, W. P. Norris and R. W. Read, Tetrahedron Lett., 1983,
24, 1555.
24 M. J. Strauss, R. A. Renfrow and E. Buncel, J. Am. Chem. Soc., 1983,
105, 2473.
The reaction between (2-nitro-5,10,15,20-tetraphenyl[3-2H]-
porphyrinato)nickel(II) 37 and lithium phenoxide
To a refluxing solution of (2-nitro-5,10,15,20-tetraphenyl[3-
2H]porphyrinato)nickel() 37 (40 mg, 0.056 mmol) in dry, dis-
tilled HCONMe2 (20 cm3) under nitrogen was added lithium
phenoxide (35 mg, 0.35 mmol) and the mixture was heated at
reflux for 2 h. Upon cooling, the mixture was diluted with
dichloromethane (50 cm3), washed with water (6 × 200 cm3),
dried over anhydrous sodium sulfate, filtered and evaporated to
dryness. The residue was chromatographed on a chromatotron
eluted with dichloromethane–light petroleum (1:1) to yield a
25 R. W. Read, R. J. Spear and W. P. Norris, Aust. J. Chem., 1984, 37,
985.
26 G. Peychal-Heiling and G. S. Wilson, Anal. Chem., 1971, 43, 545.
27 A. Giradeau, H. J. Callot, J. Jordan, I. Ezhar and M. Gross, J. Am.
Chem. Soc., 1979, 101, 3857.
Paper 7/01673E
Received 10th March 1997
Accepted 24th June 1997
3096
J. Chem. Soc., Perkin Trans. 1, 1997