Synthesis and antimycotic activity of new unsymmetrical substituted zinc phthalocyanines

Article abstract of DOI:10.1016/j.tet.2003.10.031

The synthesis of new unsymmetrical substituted zinc phthalocyanines derivatives has been described; moreover the photodynamic activity of some compounds tested against Candida albicans has been reported.

Full text of DOI:10.1016/j.tet.2003.10.031

Tetrahedron 59 (2003) 10025–10030
Synthesis and antimycotic activity of new unsymmetrical
substituted zinc phthalocyanines
b
b
b
c
Barbara Cosimelli,a Gabrio Roncucci, Donata Dei, Lia Fantetti, Fiammetta Ferroni,
,
*
Micaela Riccic and Domenico Spinellic
a
`
Dipartimento di Chimica Farmaceutica e Tossicologica, Universita di Napoli ‘Federico II’. Via D. Montesano 49, I-80131 Napoli, Italy
bMolteni Farmaceutici, S.S. 67 Loc. Granatieri, I-50018 Scandicci, Firenze, Italy
cDipartimento di Chimica Organica ‘A. Mangini’, Via S. Donato 15, I-40127 Bologna, Italy
Received 12 June 2003; revised 17 September 2003; accepted 9 October 2003
Abstract—The synthesis of new unsymmetrical substituted zinc phthalocyanines derivatives has been described; moreover the
photodynamic activity of some compounds tested against Candida albicans has been reported.
q 2003 Elsevier Ltd. All rights reserved.
1. Introduction
two differently substituted precursors; (b) the sub-phthalo-
cyanine approach and, (c) the polymeric support method. As
previously reported,13 each strategy is affected by a number
of disadvantages; therefore we decided to synthesize the
described compounds, according to the statistical approach
that is the most useful method for the synthesis of A3B
structures according to our experiences.
The importance of phthalocyanine derivatives is rapidly
growing in many fields.1–4 One of these is the photo-
dynamic therapy (PDT).5 A number of substituted phtha-
locyanines are already known as effective photosensitizers
but the interest in this field and the need for new molecules
with improved characteristics is always high owing to the
large variety of therapeutic applications.
2. Results and discussion
While the synthesis of symmetrically substituted phthalo-
cyanines has been largely investigated,6–11 only minor
attention has been devoted to the synthesis of unsymme-
trical substituted phthalocyanines, owing to the problems
associated with the low reaction yields and the mixtures of
differently substituted products which render their isolation
a difficult step.8
The synthesis of substituted phthalocyanines is related to the
preparation of the corresponding phthalonitrile precursors.
Initially, with the aim at obtaining octasubstituted phthalo-
cyanines endowed with light absorption maxima above
700 nm, we synthesized the 4,5-bis(phenylsulfanyl)phtha-
lonitrile (2) as isoindole subunit A, starting from 4,5-
dichlorophthalonitrile (1) and PhSH in 90% yield by
modification (acetone, K2CO3, rt, 18 h) of a previously
described synthesis.14 The isoindole component B used, was
the 4-[4-(hydroxymethyl)phenoxy]-5-(phenylsulfanyl)-
phthalonitrile (5) obtained from 4-chloro-5-[4-(hydroxy-
methyl)phenoxy]phthalonitrile (4) which in turn was
obtained from 1 and 4-hydroxybenzylic alcohol (3)
(Scheme 1).
As part of our current work we were interested to synthesize
phthalocyanines comprising of three identical (A) and one
different (B) isoindole subunit presenting a single functional
group (A3B type) potentially useful as PDT photosensi-
tizers. The presence of a single reactive functional group
might be also particularly interesting for the perspective
possibility of a covalent binding of the phthalocyanine
moiety to a suitable carrier molecule.8–12
The derivative 5, was obtained in moderate yield (40%) by
treating 4 with thiophenol. In this case the reaction must be
carefully controlled because thiophenol is also able to
remove the aryloxy moiety giving the undesired 2.
Usually the strategies to synthesize unsymmetrical sub-
stituted phthalocyanine are: (a) statistical condensation of
Keywords: phthalocyanines; PDT; photosensitizers; phototoxicity;
microbial inactivation; Candida albicans.
The cyclotetramerization of phthalonitriles 2 and 5 was
performed in refluxing pentanol with diazabycicloundecene
(DBU), according to conditions previously reported14 for
*
Corresponding author. Tel.: þ39-081678614; fax: þ39-081678609;
e-mail: barbara.cosimelli@unina.it
0040–4020/$ - see front matter q 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2003.10.031

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B. Cosimelli et al. / Tetrahedron 59 (2003) 10025–10030
Scheme 2. (i) DMSO, K2CO3, rt, 2 d. (ii) DMSO, K2CO3, rt, 22 h.
Unfortunately also in all these cases the reactions products
resulted in a very complex mixture from which we were
unable to separate the components.
Scheme 1. (i) Acetone, K2CO3, rt, 18 h. (ii) Acetone, K2CO3, K, 24 h. (iii)
Acetone, K2CO3, Et3N, rt, 24 h.
the cyclotetramerization of compound 2 and in the presence
of zinc acetate. The reaction was performed using a 9:1 ratio
between dinitriles 2 and 5; according to a published report13
supporting this ratio to promote the A3B structure instead of
A2B2 or AB3 species. Actually, the crude product of
reaction revealed, by ESI-MS analysis, (Table 1, entry 1) a
mixture ofstructuresA4, A3B, A2B2. Unfortunately, this crude
mixture was not useful as was impossible to accomplish any
isolation of the components from this complex mixture.
On the basis of these results we decided to drastically
change the precursor of the isoindoline subunit A, from 4,5-
bis(phenylsulfanyl)phthalonitrile (2) to the structurally
simpler 1,2-dicyanobenzene (10).
By allowing the reaction of 10 with derivative 4 in the same
reaction conditions (Scheme 3) previously used for
dinitriles 2 and 4, we obtained a mixture of zinc
phthalocyanines (identified by ESI-MS spectrum) that can
be resolved (see Section 3) by atmospheric pressure silica
To obtain a more manageable mixture of products we
progressively attempted at reducing the complexity of
isoindoline subunit B by structural variation of the reacting
dinitriles (see Table 1). We then allowed the cyclotetramer-
ization of dinitrile 2 with dinitrile 4, of the dinitrile 2 with
4-[4-(hydroxymethyl)phenoxy]phthalo nitrile (7) in turn
obtained from 4-nitrophthalonitrile (6) (Scheme 2) and,
finally, we attempted at the cyclotetramerization of the
dinitrile 2 with the 4-nitroderivative 6 or the dichloroder-
ivative 1.
Table 1. ESI-MS molecular peaks and UV data in the crude of reaction
between 2 and the phthalonitriles 5, 4, 7, 6, 1
B
Mixture
components
Observed molecular
peaks m/z
Mixture’s lmax
(nm)
5
4
7
6
1
A4
1443.9
1457.8
1471.8
1444.0
1384.0
1323.9
1443.9
1349.9
1254.8
1443.9
1272.7
1101.6
1443.9
1295.8
1148.6
709
707
709
710
706
A3B
A2B2
A4
A3B
A2B2
A4
A3B
A2B2
A4
A3B
A2B2
A4
A3B
A2B2
Scheme 3. (i) n-Pentanol, Zn(OCOCH3)2, DBU, K, 48 h.

B. Cosimelli et al. / Tetrahedron 59 (2003) 10025–10030
10027
gel chromatography. We separated zinc phthalocyanine
(A4, 45%); zinc 2-chloro-3-[4-(hydroxymethyl)phenoxy]-
phthalocyanine (A3B, 11, 9%), and a very little amount of
product which was assigned to a structurally related A2B2
species by ESI-MS spectra.
As part of this study, we also attempted (results not shown)
to vary the reaction conditions to improve the reaction yield
and/or the A3B amount in the reaction products. To this
purpose the solvent was changed (neat DBU or DBU in
n-butanol), the concentration of the reagents was increased
and the refluxing time was varied with no improvements. In
fact, the only way to improve the yield of A3B was found by
changing the ratio of the dinitriles precursors of the
isoindoline subunits A/B to 3:1.
The above reported reactant ratio was then adopted for the
following experiments. From reaction between dinitriles 10
and 7 we isolated the desired compound 12 (A3B, Scheme 3)
and a mixture of A2B2 phthalocyanines (structures not
shown, indicated as 13 in Section 3). Similarly, from the
reaction between 10 and 9 we isolated the desired
compound 14 (A3B, 15%, Scheme 4) and a mixture of
A2B2 phthalocyanines (structures not shown, indicated as 15
in Section 3, 5%).
Scheme 4. (i) n-Pentanol, Zn(OCOCH3)2, DBU, K, 48 h.
Table 2. C. albicans photoinactivation by 11–17
Compound
Growth inhibition (%)
11
12
13
14
15
16
17
1
10
1
70
1
Finally, to evaluate the influence of the 4-(hydroxymethyl)-
phenoxy substituent in the phthalocyanine core on both lmax
and antimicrobial activity, we synthesized the phthalocya-
nines corresponding to B4 structures and prepared from
4-[4-(hydroxymethyl)phenoxy]phthalonitrile (7) or from
3-[4-(hydroxymethyl)phenoxy]phthalonitrile (9), as mix-
ture of constitutional isomers corresponding to 16 (31%) or
17 (43%), respectively.
1
1
findings indicate that the activity against C. albicans
presented by mono-substituted compounds may be related
to their amphiphilic character. This behavior, strongly
noticed for mono-substituted phthalocianines, was pre-
viously found during a structure activity relationship study
on phthalocyanine quaternary ammonium salt derivatives
(Roncucci, personal communication).
In conclusion, in this paper we have presented the synthesis
of some new unsymmetrical substituted phthalocyanines;
and their antimicrobial activity tested on C. albicans as a
model. These results confirm the importance of the
amphiphilic character conferred by an hydrophilic mono
substituent to the activity of this class compounds and a
further indication and stimulation in the search for new
structures with improved activity for a perspective use as
antimicrobial PDT agents.
3. Experimental
3.1. General
2.1. Antimicrobial activity
Melting points were measured using a Reichert Termovar
apparatus and are uncorrected. NMR spectra were recorded
on a Varian Inova 300 Instrument in the Fourier transform
mode at 21^0.58C. 1H (300 MHz) and 13C NMR
(75.43 MHz) chemical shifts (d) are in ppm relative to
TMS as secondary reference standard; coupling constants
are in Hz. Mass spectra were recorded on a VG70 70E
apparatus. ESI-MS spectra were obtained on a micromass
ZMD Waters instrument (4 kV and 150 V). IR spectra were
Phthalocyanines 11–17 were all tested for their photo-
inhibitory activity against Candida albicans as a model to
assess the microorganism inactivation (see Table 2). While
the B4 (16, 17) can be considered as inactive along with
compounds having the A2B2 type of structure (13, 15), one
of the mono-substituted compounds (14) exhibited some
activity, providing a 70% cell photoinactivation at 30 mM
concentration in the standard assay employed. These

10028
B. Cosimelli et al. / Tetrahedron 59 (2003) 10025–10030
obtained by a Perkin–Elmer FT-IR Spectrometer Spectrum
2000. UV spectra were performed on an Uvicon 860
Kontron instrument. Silica gel (Merck F254) and silica gel
60 (Merck 230–400 mesh) were used for analytical TLC
and flash chromatography, respectively.
7.42 (2H, AA0 part of AA0XX0 system, H-Ar); 7.40 (1H, s,
H-6); 7.24 (1H, s, H-3); 7.12 (2H, XX0 part of AA0XX0
3
system, H-Ar); 5.27 (1H, t, J¼5.6 Hz, OH); 4.53 (2H, d,
3J¼5.6 Hz, CH2). 13C NMR (DMSO-d6) d 156.1 (s, C-4);
152.4 (s, C-10); 140.0 (s, C-40); 136.8 (s, C-100); 134.5 (d,
C-200 and C-600); 131.6 (d, C-6); 130.4 (d, C-300 e C-500); 130.1
(d, C-400); 128.4 (d,0 C-30 and C-50); 127.9 (s, C-5); 120.3 (d,
C-3); 119.2 (d, C-2 and C-60); 115.4 (s, CN), 115.3 (s, CN);
112.4 (s, C-2); 109.4 (s, C-1); 62.2 (t, CH2). EI-MS m/z (%):
358 (Mþ, 54); 196 (14); 164 (10); 107 (25); 89 (10); 79 (52);
77 (100); 69 (12); 63 (18); 51 (55). HRMS: 358.07825,
C21H14N2O2 requires 358.07760.
3.1.1. 4,5-Bis(phenylsulfanyl)phthalonitrile 2. Thiophenol
(1.24 mL, 12 mmol) and K2CO3 (2.5 g, 16 mmol) were
added, under stirring, to a solution of 4,5-dichlorophthalo-
nitrile (1) (789 mg, 4 mmol) in acetone (24 mL) and the
mixture was allowed to stir at room temperature until
disappearance (by TLC) of 1 (15 h). The solvent was
removed under reduced pressure and the residue was treated
with H2O (450 mL), filtered, washed with H2O until pH 7,
dried in vacuo and crystallized from methanol. Colourless
crystals; 1.24 g (90%), mp 1958C [lit.14 mp 1598C]. IR
(KBr) cm21 3095, 3028, 2228, 1578, 1575, 1504, 1219,
3.1.4. 4-[4-(Hydroxymethyl)phenoxy]phthalonitrile 7. 4-
Hydroxybenzylic alcohol (3) (371 mg, 3 mmol) and K2CO3
(2.5 g, 16 mmol) were added, under stirring, to a solution of
4-nitrophthalonitrile (6) (346 mg, 2 mmol) in dimethylsulf-
oxide (4 mL). The mixture was allowed at room temperature
until disappearance (TLC) of 6 (48 h), poured into H2O
(250 mL) and extracted with dichloromethane (9£30 mL).
The extracts were dried over sodium sulphate and
evaporated. Compound 7 was obtained by flash chromatog-
raphy (eluant: ethyl acetate/petroleum ether 40–608C¼2:1).
White powder; 337 mg (68%), mp 85–878C. IR (KBr)
cm21 3490, 3101, 3074, 3046, 2937, 2880, 2232, 1590,
1565, 1504, 1485, 1417, 1284, 1203, 1039, 1008; 1H NMR
1
1005; H NMR (CDCl3) d 7.54 (10H, m, 2£H–SAr); 6.98
(2H, s, H-3 and H-6) [lit.14 7.55 (10H, m, 2£H–SAr); 6.99
(2H, s, H-3 and H-6)].
3.1.2. 4-Chloro-5-[4-(hydroxymethyl)phenoxy]phthalo-
nitrile 4. 4-Hydroxybenzylic alcohol (3) (496 mg,
4 mmol) and K2CO3 (2.5 g, 16 mmol) were added, under
stirring, to a solution of 4,5-dichlorophthalonitrile (1)
(789 mg, 4 mmol) in acetone (24 mL) and the mixture
was refluxed until disappearance (TLC) of 1 (24 h). After
cooling to room temperature, the solvent was removed
under reduced pressure and the residue was treated with
H2O (300 mL), filtered, washed with H2O until pH 7 and
dried in vacuo to give pure compound 4 (1.04 g, 95%). An
analytical sample was obtained by flash chromatography
(eluant: ethyl acetate/petroleum ether 40–608C¼1:2).
White powder, mp 132–1358C. IR (KBr) cm21 3269,
3092, 3029, 2917, 2853, 2233, 1580, 1485, 1383, 1302,
1273, 1164, 1048, 1006; 1H NMR (DMSO-d6) d 8.57 (1H, s,
H-6); 7.60 (1H, s, H-3); 7.43 (2H, AA0 part of0 AA0XX0
system, H-Ar); 7.15 (2H, XX0 part of AA0XX system,
H-Ar); 5.28 (1H, t, 3J¼5.6 Hz, OH); 4.53 (2H, d,
3J¼5.6 Hz, CH2). 13C NMR (DMSO-d6) d 156.6 (s, C-4);
152.5 (s, C-10); 140.1 (s, C-40); 136.1 (d, C-6); 129.0 (s,
C-5); 128.4 (d, C-30and C-50); 122.6 (d, C-3); 119.2 (d, C-20
and C-60); 115.2 (s, C-2); 114.9 (s, CN); 114.8 (s, CN);
109.7 (s, C-1); 62.2 (t, CH2). EI-MS m/z (%): 284 (Mþ, 50);
267 (10); 255 (16); 107 (100); 89 (14); 79 (80); 77 (73);
51 (47). HRMS: 284.03577, C15H9N2O2Cl requires
284.03526.
3
(DMSO-d6) d 8.09 (1H, d, J¼8.8 Hz, H-6);07.76 (1H, d,
4J¼2.5 Hz, H-3); 7.43 (2H, AA0 part of AA XX0 system,
H-Ar); 7.34 (1H, dd0, 3J¼8.8 Hz, 4J¼2.5 Hz, H-5); 7.16 (2H,
XX0 part of AA0XX system, H-Ar); 5.28 (1H, t, 3J¼5.6 Hz,
OH); 4.53 (2H, d, 3J¼5.6 Hz, CH2). 13C NMR (DMSO-d6) d
161.2 (s, C-4); 152.2 (s, C-100); 140.1 (s, C-40); 136.2 (d,
C-6); 128.5 (d, C-30 and C-5 ); 122.4 (d, C-5); 121.7 (d,
C-3); 120.0 (d, C-20 and C-60); 116.6 (s, C-2); 115.8 (s, CN);
115.3 (s, CN); 107.9 (s, C-1); 62.2 (t, CH2). EI-MS m/z (%):
250 (Mþ, 52); 221 (18); 107 (97); 100 (16); 89 (9); 79 (100);
77 (62); 64 (19); 51 (45). HRMS: 250.07449, C15H10N2O2
requires 250.07423.
3.1.5. 3-[4-(Hydroxymethyl)phenoxy]phthalonitrile 9. 4-
Hydroxybenzylic alcohol (3) (371 mg, 3 mmol) and K2CO3
(2.5 g, 16 mmol) were added, under stirring, to a solution of
3-nitrophthalonitrile (8) (346 mg, 2 mmol) in dimethylsulf-
oxide (4 mL). The mixture was allowed at room temperature
until disappearance (TLC) of 8 (22 h) and poured into H2O
(300 mL). The precipitate was collected by filtration,
washed with H2O until pH 7, dried in vacuo and purified
by flash chromatography (eluant: ethyl acetate/petroleum
ether 40–608C¼2:1). White powder; 298 mg (66%), mp
122–1238C. IR (KBr) cm21 3261, 3078, 3039, 2923, 2881,
2231, 1585, 1560, 1506, 1469, 1290, 1207, 1164, 1010; 1H
NMR (DMSO-d6) d 7.85–7.78 (2H, m, H-5 and H-6); 7.44
(2H, AA0 part of AA0XX0 system, H-Ar); 7.23 (1H, dd,
3J¼7.6 Hz, 4J¼2.4 Hz, H-4); 7.20 (2H, XX0 part of AA0XX0
3.1.3. 4-[4-(Hydroxymethyl)phenoxy]-5-(phenylsulfa-
nyl)-phthalonitrile 5. Thiophenol (0.12 mL, 1 mmol),
K2CO3 (2.5 g, 16 mmol) and triethylamine (0.15 mL,
1.1 mmol) were added, under stirring, to a solution of
4-chloro-5-[4-(hydroxymethyl)phenoxy]phthalonitrile (4)
(285 mg, 1 mmol) in acetone (12 mL) and the mixture
was allowed at room temperature until disappearance (TLC)
of 4 (24 h). The solvent was removed under reduced
pressure and the residue was treated with H2O (200 mL),
filtered, washed with H2O until pH 7, dried in vacuo and
purified by flash chromatography (eluant: ethyl acetate/
petroleum ether 40–608C¼1:2). White powder; 143 mg
(40%), mp 168–1708C. IR (KBr) cm21 3380, 3092, 3020,
2928, 2867, 2226, 1576, 1505, 1476, 1384, 1270, 1204,
3
system, H-Ar); 5.28 (1H, t, J¼5.6 Hz, OH); 4.53 (2H, d,
3J¼5.6 Hz, CH2). 13C NMR (DMSO-d6) d 159.8 (s, C-3);
152.6 (s, C-10); 140.0 (s, C-40); 135.7 (d, C-5); 128.3 (d,0C-30
and0C-50); 127.8 (d, C-6); 121.7 (d, C-4); 119.4 (d, C-2 and
C-6 ); 115.7 (s, C-1); 115.3 (s, CN); 113.0 (s, CN); 104.9 (s,
C-2); 62.1 (t, CH2). EI-MS m/z (%): 250 (Mþ, 100); 233
(14); 221 (84); 107 (18); 106 (40); 79 (13); 78 (15); 77 (43);
69 (27); 51 (20). HRMS: 250.07443, C15H10N2O2 requires
250.07423.
1
1004; H NMR (DMSO-d6) d 7.65–7.51 (5H, m, H–SAr);

B. Cosimelli et al. / Tetrahedron 59 (2003) 10025–10030
10029
3.2. General procedure for the cyclization involving
4,5-bis(phenylsulfanyl)phthalonitrile 2
the mixture showed the presence of the species A4/A3B/
A2B2/AB3.
DBU (0.15 mL, 1 mmol) was added, under stirring, to a
solution of 4,5-bis(phenylsulfanyl)phthalonitrile 2 (311 mg,
0.9 mmol) and the opportune phthalonitrile B (0.1 mmol) in
n-pentanol (50 mL) and the mixture was warmed to reflux
before addition of Zn(OAc)2 (46 mg, 0.25 mmol). The
green solution was allowed to reflux for 48 h, and then
cooled to room temperature. The precipitate was collected
by filtration and dried under vacuum (see Table 1 for B,
ESI-MS and UV data). The NMR spectra of these blue
crudes have not sufficient resolution to allow a correct
interpretation of product composition. Only by ESI-MS
spectra we obtained an indication about the mixture
components.
Spectroscopic data for zinc 2-[4-(hydroxymethyl)phenoxy]
phthalocyanine (A3B, 12). Blue powder (13%), mp .3008C
dec. IR (KBr) cm21 3358, 3081, 3050, 2922, 2829, 1602,
1503, 1485, 1403, 1333, 1286, 1232, 1165, 1085; 1H NMR
(DMSO-d6) d 9.10–9.02 (5H, m, H-phthalo); 8.92–8.89
(2H, m, H-phthalo); 8.40 (1H, m, H-phthalo); 8.17–8.04
3
4
(6H, m, H-phthalo);0 7.71 (1H, dd, J¼8.3 Hz, J¼2.2 Hz,
H-3); 7.64 (2H, AA part of AA0XX0 system, H-Ar); 7.52
(2H, XX0 part of AA0XX0 system, H-Ar); 5.38 (1H, t,
3
3J¼5.6 Hz, OH); 4.70 (2H, d, J¼5.6 Hz, CH2). UV/Vis
(DMF) lmax: 671 nm. ESI-MS (MeOH/CHCl3): 699
(12þHþ).
Spectroscopic data for zinc phthalocyanines (A2B2, 13).
Blue powder (5%), mp .3008C dec. 1H NMR (DMSO-d6) d
9.28–8.92 (6H, m, H-phthalo); 8.68–8.43 (2H, m,
H-phthalo); 8.27–8.12 (4H, m, 0 H-phthalo)0; 7.087–7.73
(2H, m, H-phthalo); 7.63 (2H, AA pa0rt of AA XX system,
H-Ar); 7.52 (2H, XX0 part of AA0XX system, H-Ar); 5.38
(1H, t, 3J¼5.2 Hz, OH); 4.70 (2H, d, 3J¼5.2 Hz, CH2). UV/
Vis (DMF): lmax: 674 nm. ESI-MS (MeOH/CHCl3): 821
(13þHþ).
3.3. General procedure for the cyclization involving
phthalonitrile 10
DBU (0.15 mL, 1 mmol), was added, under stirring, to a
solution of phthalonitrile 10 (0.3 mmol) and the oppor-
tune phthalonitrile B (0.1 mmol) in n-pentanol (50 mL)
and the mixture was warmed to reflux before to add
Zn(OAc)2 (46 mg, 0.25 mmol). The green solution was
allowed to reflux for 48 h, and then cooled to room
temperature. The solvent was removed under reduced
pressure and the residue was treated with H2O and MeOH
to give a blue precipitate that was collected by filtration
and dried under vacuum. The crude was separated by
chromatography (THF/cyclohexane¼1:1 as eluant). The
fastest running band was constituted by the zinc
phthalocyanine (A4), then was separated the structure
A3B and, finally the compounds A2B2. Washing with
methanol further purified the second fraction containing
A3B.
3.3.3. Reaction with 3-[4-(hydroxymethyl)phenoxy]
phthalonitrile 9 as partner B. The ESI-MS spectrum of
the mixture showed the presence of the species A4/A3B/
A2B2/AB3.
Spectroscopic data for zinc 1-[4-(hydroxymethyl)phenoxy]
phthalocyanine (A3B, 14). Blue powder (15%), mp .3008C
dec. IR (KBr) cm21 3357, 3380, 3043, 2958, 2927, 2871,
1697, 1600, 1329, 1252, 1201, 1115, 1091; 1H NMR
(DMSO-d6) d 9.33–9.23 (5H, m, H-phthalo); 9.20 (1H, m,
H-phthalo); 8.91 (1H, m, H-phthalo); 8.25–8.13 (7H, m,
H-phthalo); 7.80 (1H, m, H-phthalo); 7.49 (4H, AA0BB0,
H-Ar); 5.18 (1H, t, 3J¼5.4 Hz, OH); 4.53 (2H, d,
3J¼5.4 Hz, CH2). UV/Vis (DMF) lmax: 674 nm. ESI-MS
(MeOH/CHCl3): 699 (14þHþ).
3.3.1. Reaction with 4-chloro-5-[4-(hydroxymethyl)phe-
noxy]phthalonitrile 4 as partner B. The ESI-MS spectrum
of the mixture showed the presence of the species A4/A3B/
A2B2/AB3.
Spectroscopic data for zinc phthalocyanine A4. This
compound (blue powder, 40%) is commercially available.
1H NMR (DMSO-d6) d 9.22 (8H, m, H-phthalo); 8.19 (8H,
m, H-phthalo). UV/Vis (DMF) lmax: 668 nm. ESI-MS
(MeOH/CHCl3): 577 (A4þHþ).
Spectroscopic data for zinc phthalocyanines (A2B2, 15).
Blue powder (5%), mp .3008C dec. UV/Vis (DMF): lmax
673 nm. ESI-MS (MeOH/CHCl3): 821 (15þHþ).
:
3.3.4. Zinc 2,6(7),10(11),14(15)-tetrakis[4-(hydroxy-
methyl)phenoxy]phthalocyanine (16). Operating as point
3.3 by using 4-[4-(hydroxymethyl)phenoxy]phthalonitrile 7
only. Green solid (yield: 31%) mp .3008C dec.
Spectroscopic data for zinc 2-chloro-3-[4-(hydroxymethyl)-
phenoxy]phthalocyanine (A3B, 11). Blue powder (11%), mp
.3008C dec. IR (KBr) cm21 3360, 3042, 2918, 2849, 1598,
1504, 1482, 1455, 1401, 1334, 1286, 1245, 1201, 1161,
Spectroscopic data. IR (KBr) cm21 3353, 2950, 1602, 1507,
1485, 1394, 1335, 1230, 1161; 1H NMR (DMSO-d6) d
9.25–9.05 (4H, m, H-phthalo); 8.70–8.60 (4H m,
H-phthalo); 7.90–7.70 (4H, m, H-phthalo); 7.60–7.40
(16H, m, H-phenoxy); 5.35–5.20 (4H, m, OH); 4.70–4.40
(4H, m, CH2). UV/Vis (DMF) lmax: 672 nm. ESI-MS
(MeOH/CHCl3): 1067 (16þHþ).
1
1112, 1092, 1004; H NMR (DMSO-d6) d 9.10 (2H, m,
H-phthalo); 8.97–8.94 (3H, m, H-phthalo); 8.68–8.61 (2H,
m, H-phthalo); 8.25–8.22 (2H, m, H-phthalo); 8.17–8.07
(5H, m, H-phthalo); 7.67 (2H, AA0 pa0rt of AA0XX0 system,
H-Ar); 7.53 (2H, XX0 part of AA0XX system, H-Ar); 5.41
(1H, t, 3J¼5.6 Hz, OH); 4.72 (2H, d, 3J¼5.6 Hz, CH2). UV/
Vis (DMF) lmax: 672 nm. ESI-MS (MeOH/CHCl3): 733
(11þHþ, 35Cl isotope).
3.3.5. Zinc 1,5(8),9(12),13(16)-tetrakis[4-(hydroxy-
methyl)phenoxy]phthalocyanine (17). Operating as point
3.3 by using 3-[4-(hydroxymethyl)phenoxy]phthalonitrile 9
only. Green solid (yield: 43%) mp .3008C dec.
3.3.2. Reaction with 4-[4-(hydroxymethyl)phenoxy]
phthalonitrile 7 as partner B. The ESI-MS spectrum of

10030
B. Cosimelli et al. / Tetrahedron 59 (2003) 10025–10030
Spectroscopic data. IR (KBr) cm21 3355, 3083, 3040, 2930,
2885, 1605, 1505, 1483, 1330, 1238, 1163; 1H NMR
(DMSO-d6) d 9.25–8.60 (4H, m, H-phthalo); 8.25–7.95
(4H m, H-phthalo); 7.80–7.45 (4H, m, H-phthalo); 7.45–
7.15 (16H, m, H-phenoxy); 5.25–5.10 (4H, m, OH); 4.60–
4.45 (4H, m, CH2). UV/Vis (DMF) lmax: 689 nm. ESI-MS
(MeOH/CHCl3): 1067 (17þHþ).
each dilution was plated onto specific agar medium. After
incubationoftheplatesat378C for24 h,thenumberofcolony-
forming units (cfu/mL) was counted. C. albicans survival
values were corrected with controls (cells with or without
photosensitizer and no light) and reported as percentage.
3.4. Antimicrobial activity
References
3.4.1. Phthalocyanine formulation. The phthalocyanines
were solubilized in DMSO at 1 mg/mL concentration (stock
solutions), aliquoted and stored at 2208C. Fresh aliquots from
the stock solutions were diluted in PBS containing 5% DMSO
in order to obtain the final working phthalocyanine solutions.
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cans (strain 10231 ATCC) was grown in Fluid Sabouraud
Medium (Difco Laboratories, Detroit, MI) at 378C under
aerobic conditions. Cells from culture in the stationary
growth phase were harvested, washed with PBS, and diluted
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absorbance of 0.12 at 630 nm, according to a previously
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3.4.3. Phthalocyanines treatment and irradiation pro-
cedure. Irradiated and unirradiated samples were prepared
by adding suitable volumes of the phthalocyanine solutions
to the cell suspensions; the final dye concentrations were in
the 0.01–30 mM range. Samples were incubated at 378C in
the dark for 60 min, then irradiated with red light
(50 mW/cm2) for 10 min. All the irradiation studies were
performed by using a Waldmann halogen light source,
which was equipped with a set of bandpass filters to isolate
the 600–700 nm spectral interval, thus matching the
absorption maximum of the photosensitizer used.
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¨
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2000, 2821–2823.
¨
14. Wohrle, D.; Eskes, M.; Shigeara, K.; Yamada, A. Synthesis
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3.4.4. C. albicans survival assays. Irradiated and unirra-
diated cells samples were serially 10-fold diluted with PBS;
15. Merchat, M.; Spikes, J. D.; Bertoloni, G.; Jori, G.
J. Photochem. Photobiol. B: Biol. 1996, 36, 149–157.