First example of a diazepinoporphyrazine with dendrimeric substituents

Article abstract of DOI:10.1016/j.tetlet.2017.01.027

The synthesis and physicochemical properties of a novel diazepinoporphyrazine possessing G1-dendrimeric substituents are presented. Initially, diaminomaleonitrile was condensed with 1,3-bis-(4-hydroxyphenyl)-1,3-propanedione to give a novel 1,4-diazepine-

Full text of DOI:10.1016/j.tetlet.2017.01.027

Accepted Manuscript
First Example of a Diazepinoporphyrazine with Dendrimeric Substituents
Ewelina Wieczorek, Jaroslaw Piskorz, Lukasz Popenda, Stefan Jurga, Jadwiga
Mielcarek, Tomasz Goslinski
PII:
S0040-4039(17)30049-7
DOI:
http://dx.doi.org/10.1016/j.tetlet.2017.01.027
TETL 48530
Reference:
Tetrahedron Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
17 November 2016
23 December 2016
10 January 2017
Please cite this article as: Wieczorek, E., Piskorz, J., Popenda, L., Jurga, S., Mielcarek, J., Goslinski, T., First
Example of a Diazepinoporphyrazine with Dendrimeric Substituents, Tetrahedron Letters (2017), doi: http://
dx.doi.org/10.1016/j.tetlet.2017.01.027
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2
Graphical Abstract
First Example of a Diazepinoporphyrazine
with Dendrimeric Substituents
Leave this area blank for abstract info.
Ewelina Wieczorek, Jaroslaw Piskorz, Lukasz Popenda, Stefan Jurga, Jadwiga Mielcarek and Tomasz Goslinski
* Corresponding author. Fax: +48 61 854 6631.
E-mail address: tomasz.goslinski@ump.edu.pl (T. Goslinski).

1
Tetrahedron Letters
First Example of a Diazepinoporphyrazine with Dendrimeric Substituents
Ewelina Wieczoreka, Jaroslaw Piskorzb, Lukasz Popendac, Stefan Jurgac,d, Jadwiga Mielcarekb and Tomasz
Goslinskia,*
a Department of Chemical Technology of Drugs, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland
b Department of Inorganic and Analytical Chemistry, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland
c NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
d Department of Macromolecular Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
ARTICLE INFO
ABSTRACT
Article history:
Received
The synthesis and physicochemical properties of a novel diazepinoporphyrazine possessing G1-
dendrimeric substituents are presented. Initially, diaminomaleonitrile was condensed with 1,3-
Received in revised form
Accepted
Available online
bis-(4-hydroxyphenyl)-1,3-propanedione to give a novel 1,4-diazepine-2,3-dicarbonitrile
derivative which was subjected to an alkylation reaction with 3,5-bis(benzyloxy)benzylbromide
furnishing a 1,4-diazepine-2,3-dicarbonitrile derivative with bulky substituents. Subsequent
macrocyclization led to the desired diazepinoporphyrazine with conjugated, hyperbranched G1-
dendrimeric substituents, which was characterized by MS MALDI and NMR. The potential
photosensitizing activity of the novel porphyrazine was evaluated by measuring its ability to
generate singlet oxygen. This measurement was performed with and without addition of the anti-
aggregation agent tetramethylamonium fluoride to determine the role of the monomeric form in
singlet oxygen generation.
Keywords:
Diazepine
Porphyrazine
Dendrimers
Linstead macrocyclization
Singlet oxygen
2016 Elsevier Ltd. All rights reserved.
1. Introduction
substituents at the C5 and C7 positions 1 (Fig. 1) was synthesized
and characterized.
Derivatives
of
1,4-diazepine-2,3-dicarbonitrile
were
discovered by Begland,1,2 Ohtsuka3 and their co-workers. These
compounds in their parent form or after further modifications
have been studied in various aspects, especially as dyes4-9 and/or
intermediates for macrocyclization reactions to give
porphyrazines
with
annulated
diazepine,10-13
tetrahydrodiazepine,14,15 and styryldiazepine,15-18 rings. Initially,
Ercolani, Stuzhin and their co-workers applied 5,7-diphenyl- and
5,7-di(4-tert-butylphenyl)-2,3-dicyano-6H-1,4-diazepines in the
synthesis of porphyrazines and tribenzoporphyrazines with
annulated diazepine rings and investigated their electronic
properties.10-13,19,20 More recently, novel homoleptic double-
decker sandwich-type complexes with rare earth metal ions (La,
Nd, Ce) have been electrochemically studied.21,22
Previously, we reported the synthesis of porphyrazines
bearing styryldiazepine and bis(styryl)diazepine substituents, and
evaluated their electronic properties, tendency for aggregation
and photodegradation, singlet oxygen generation efficiency, and
in vitro photodynamic activity at a nanomolar level using two
oral squamous cell carcinoma cell lines.15,17,18
Herein, we report the synthesis, characterization and
Figure 1. Magnesium diazepinoporphyrazine with G1-
dendrimeric substituents 1.
photochemical
properties
of
dendrimer-substituted
diazepinoporphyrazine 1.
Following the procedure of Begland and co-workers,2
diaminomaleonitrile 2 was subjected to a condensation reaction
in the presence of phosphorus pentoxide with the known
2. Result and discussion
Novel magnesium diazepinoporphyrazine with bulky and
hyperbranched 4-[3,5-bis(benzyloxy)benzyloxy]phenyl
compound
1,3-bis-(4-hydroxyphenyl)-1,3-propanedione
423
* Corresponding author. Fax: +48 61 854 6631.
E-mail address: tomasz.goslinski@ump.edu.pl (T. Goslinski).

2
(obtained following the literature procedure24) to give the
corresponding 1,4-diazepine-2,3-dicarbonitrile derivative with 4-
hydroxyphenyl substituents 525 (Fig. 2). Then, compound 5 was
alkylated with 3,5-bis(benzyloxy)benzylbromide 7 to give the
1,4-diazepine-2,3-dicarbonitrile
derivative
with
bulky
substituents 8.26 The alkylating agent 727 was prepared from 3,5-
bis[(phenylmethoxy)phenyl]methanol 6 using the conditions
reported by Hawker and co-workers.28 Derivative 8 was used for
the Linstead macrocyclization with magnesium n-butanolate in n-
butanol to give novel diazepinoporphyrazine 129 in 39% yield.30
Porphyrazine
1
was carefully purified by column
chromatography and further analyzed using HPLC (see ESI).
1
Figure 3. H NMR spectrum of 1 in DMSO-d6 at 353 K. Variable
1
temperature H NMR spectra expansions of the regions: 4.94–5.05
ppm, 5.10-5.18 ppm and 5.85–6.00 ppm are presented in the insets.
The tendency of porphyrazine 1 to aggregate was evaluated in
DMSO following the procedure of Stuzhin and co-workers.16
Figure 4 presents the changes in the UV-Vis spectra of 1 in
DMSO
after
the
addition
of
10%
water
and
tetramethylammonium fluoride (TMAF), which is a known anti-
aggregation agent. It can be seen that the addition of water
increased the intensity of the short wavelength sub-band with
λmax at ~640 nm and decreased the intensity of the long
wavelength band with λmax at ~675 nm. Moreover, the addition of
TMAF caused the disappearance of the short wavelength band
and only the single intensive band with λmax at ~675 nm was
observed. It was found that the long wavelength band
corresponded to the monomeric form of 1, whereas the short
wavelength band results from the presence of the aggregated
form.
Figure 2. Synthesis of porphyrazine 1.
1
The H NMR spectrum of 1 revealed three signals at 7.39,
7.33 and 7.28 ppm from eighty protons belonging to the outer,
peripheral phenyl rings, two signals at 6.83, 6.68 ppm from
twenty four protons of the middle phenyl rings and two signals at
7.05, 8.16 ppm from thirty two protons belonging to the inner
phenyl rings directly attached to the diazepine rings (Fig. 3).
Aliphatic protons from the outer and inner methyleneoxy bridges
were found at 5.04 and 5.14-5.20 ppm, respectively.
Additionally, two characteristic broad signals resonating at 5.96
and 5.13 ppm from C6-CH2 eight geminal protons were observed
(ESI). Moreover, variable-temperature NMR experiments
showed that the pseudoquartet signal of the outer methyleneoxy
bridges in the range of 4.94-4.99 ppm at 298K was shifted
downfield when the temperature was raised to 353 K and
appeared as a sharp singlet at 5.04 ppm (Fig. 3). The broad, flat,
Figure 4. Aggregation studies of 1 in DMSO.
The potential photosensitizing activity of the obtained
porphyrazine, which is crucial for application in photodynamic
therapy, was evaluated by measuring its ability for singlet oxygen
generation, which is the result of interaction between the
activated photosensitizer and oxygen. 1,3-Diphenylisobenzofuran
(DPBF) was used as a chemical quencher, which undergoes a
cycloaddition reaction with singlet oxygen to produce
endoperoxide.15,31 DMSO solutions containing porphyrazine 1, or
a reference zinc(II) phthalocyanine, with DPBF were irradiated
with monochromatic light at wavelengths corresponding to their
monomeric forms Q-band maxima (Fig. 5). The kinetics of
DPBF decomposition by photogenerated singlet oxygen was
studied in the UV-Vis spectra as a decrease of the absorbance at
417 nm, and was further used to calculate the singlet oxygen
eq
unresolved signal of the equatorial protons from C6-CH2 of the
diazepine rings at 5.96 ppm (298K) appeared as a doublet with an
2
estimated J value of 12 Hz when the temperature was raised to
353K. The C6-CH2ax protons were overlapped by 5.14-5.20 ppm
signals of protons from the inner sphere methyleneoxy bridges of
the G1-dendritic moieties according to 2D-NMR spectra. It is
worth noting that the presence of these signals from C6-CH2
indicates that all diazepine rings are in the 6H tautomeric form.11
* Corresponding author. Fax: +48 61 854 6631.
E-mail address: tomasz.goslinski@ump.edu.pl (T. Goslinski).

3
generation yield (ФΔ). Measurements of singlet oxygen
generation efficacy were performed with and without the addition
of TMAF to determine the role of the monomeric form of 1. The
calculated value of singlet oxygen quantum yield for 1 in the
presence of TMAF was 0.295 ± 0.024 (ΦΔ ± ΔΦΔ*), whereas in
its absence it was 0.090 ± 0.007 (ΦΔ ± ΔΦΔ*). The ФΔ values of 1
in DMSO were higher after the addition of TMAF, indicating
that a decreased generation of singlet oxygen is the result of
aggregation.
Acknowledgments
This study was supported by the Polish National Science Centre
under Grant No. 2012/05/E/NZ7/01204. SJ and LP acknowledge
financial support from the National Centre for Research and
Development, contract number PBS1/A9/13/2012.
References and notes
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2. Begland R .W., Hartter D. R., Jones F. N., Sam D. J., Sheppard W. A.,
Webster O. W., Weigert F. J. J. Org. Chem. 1974, 39, 2341-2350.
3. Ohtsuka Y. J. Org. Chem. 1976, 41, 629-633.
4. Horiguchi E., Shirai K., Jaung J., Furusyo M., Takagi K., Matsuoka M.
Dyes Pigm. 2001, 50, 99-107.
5. Horiguchi E., Shirai K., Matsuoka M., Matsui, M. Dyes Pigments
2002, 53, 45-55.
6. Horiguchi E., Matsumoto S., Funabiki K., Matsui M. Bull. Chem. Soc.
Jpn. 2005, 78, 1167-1173.
7. Horiguchi E., Funabiki K., Matsui M. Bull. Chem. Soc. Jpn. 2005, 78,
316-322.
8. Wieczorek E., Gierszewski M., Popenda L., Tykarska E., Gdaniec M.,
Jurga S., Sikorski M., Mielcarek J., Piskorz J., Goslinski T. J. Mol.
Struct. 2016, 1110, 208-214.
9. Tarakanov P. A., Simakov A. O., Dzuban A. V., Shestov V. I.,
Tarakanova E. N., V. Pushkarev, Tomilova L. G. Org. Biomol. Chem.
2016, 14, 1138-1146.
10. Donzello M. P., Ercolani C., Stuzhin P. A., Chiesi-Villa A., Rizzoli C.
Eur. J. Inorg. Chem. 1999, 2075-2084.
11. Angeloni S., Ercolani C. J. Porphyr. Phthalocya 2000, 4, 474-483.
12. Donzello M. P., Dini D., D’Arcangelo G., Ercolani C., Zhan R., Ou Z.,
Stuzhin P. A., Kadish K. M. J. Am. Chem. Soc. 2003, 125, 14190-
14204.
13. Donzello M. P., Ercolani C., Mannina L., Viola E., Bubnova A.,
Khelevina O., Stuzhin P. A. Aust. J. Chem. 2008, 61, 262-272.
14. Baum S. M., Tabanco A. A., Montalban A. G., Micallef A. S., Zhong
C., Meunier H. G., Suhling K., Phillips D., Wite A. J. P., Williams D.
J., Barret A. G. M., Hoffman B. M. J. Org. Chem. 2003, 68, 1664-
1670.
15. Goslinski T., Piskorz J., Brudnicki D., White A. J. P., Gdaniec M.,
Szczolko W., Tykarska E. Polyhedron 2011, 30, 1004-1011.
16. Stuzhin P. A., Tarakanov P., Shiryaeva S., Zimenkova A., Koifman O.
I., Viola E., Donzello M. P., Ercolani C. J. Porphyr. Phthalocya. 2012,
16, 968–976.
17. Piskorz J., Tykarska E., Gdaniec M., Gośliński T., Mielcarek J. Inorg.
Chem. Commun. 2012, 20, 13-17.
18. Piskorz J., Konopka K., Düzgüneş N., Gdaniec Z., Mielcarek J.,
Goslinski T. ChemMedChem 2014, 9 1775-1782.
19. Tarakanov P. A., Donzello M. P., Koifman O. I., Stuzhin P. A.
Macroheterocycles 2011, 4, 177-183.
20. Tarakanov P. A., Simakov A. O., Tolbin A. Y., Balashova I. O.,
Shestov V. I., Tomilova L. G. Spectrochim Acta A 2015, 139, 464–
470.
Figure 5. Changes in the UV–Vis spectra during irradiation of 1 and
DPBF in DMSO without (a) or with TMAF (b) and first-order plots
of DPBF degradation by photosensitized 1.
Conclusion
21. Tarakanova E. N., Trashin S. A., Tarakanov P. A., Pushkarev V. E.,
Tomilova L. G., Dyes Pigments 2015, 117, 61-63.
The first example of a diazepinoporphyrazine possessing G1-
dendrimeric substituents was presented. The novel macrocycle
was characterized using UV-Vis, MS MALDI and various NMR
techniques. The potential photosensitizing activity of the novel
porphyrazine was evaluated by measuring its ability to generate
singlet oxygen in DMSO, with and without addition of the anti-
aggregation agent TMAF. The obtained value of singlet oxygen
quantum yield of 0.295 makes it a potential photosensitizer for
application in photodynamic therapy. Considering the successful
results obtained within our group for dendrimeric sulfanyl
porphyrazines,32 the direction of this research for
diazepinoporphyrazines will be continued and reported in due
course.
22. Tarakanova E. N., Levitskiy O. A., Magdesieva T. V., Tarakanov P.
A., Pushkareva V. E., Tomilova L. G., New J Chem 2015, 39, 5797-
5804.
23. Ayabe S-I., Kobayashi M., Hikichi M., Matsumoto K., Furaya T.
Phytochemistry 1980, 19, 2179-2183.
24. Secondo P., Fages F. Org. Lett. 2006, 8, 1311–1314.
25. 5,7-Bis(4-hydroxyphenyl)-6H-1,4-diazepine-2,3-dicarbonitrile
(5)
Diketone 4 (0.8 g, 3.12 mmol), diaminomaleonitrile 1 (0.337 g, 3.12
mmol) and P2O5 (0.15 g, 1.56 mmol) in anhydrous MeOH (40 mL)
were stirred for 1 h at room temp. After the addition of further P2O5
(0.15 g, 1.56 mmol), the reaction mixture was heated at reflux for 20 h.
The solvent was evaporated and the residual solid purified by column
chromatography (dichloromethane-methanol, 20:1) to give a yellow
solid (0.525 g, 52%). mp 140 °C dec. Rf (dichloromethane:methanol
20:1) 0.54. UV-Vis (dichloromethane): λmax, nm (log ε) 388 (4.77), 313
* Corresponding author. Fax: +48 61 854 6631.
E-mail address: tomasz.goslinski@ump.edu.pl (T. Goslinski).

4
(5.03). MS (ES pos) m/z 329 [M+H]+, 351 [M+Na]+, 367 [M+K]+, (ES
neg) m/z 327 [M-H]-. HRMS (ES pos) found: 329.1016 [M+H]+,
requires 329.1038 [M+H]+. HRMS (ES neg) found: 327.0877 [M-H]-,
requires 327.0882 [M-H]-. Limited solubility of compound in organic
solvents and water effectively hampered purification by column
chromatography and identification (NMR, combustion analysis)
leading to the use of the crude product in the next step.
29. Tetrakis[5,7-bis-[4-[3,5-bis(benzyloxy)benzyloxy]phenyl]-6H-1,4-
diazepino][2,3-b;2’,3’-g;2’’,3’’-l;2’’’,3’’’-q]porphyrazinato
magnesium(II) (1) Magnesium turnings (10.0 mg, 0.4 mmol) and a
small crystal of iodine were heated at reflux in n-butanol (15 mL) for 4
h. After cooling to room temperature, 8 (400 g, 0.4 mmol) was added.
The reaction mixture was then heated at reflux for 20 h. The reaction
mixture was cooled to room temp., filtered through Celite, then washed
with toluene and dichloromethane. The filtrates were evaporated to
dryness, and the solid residue purified by column chromatography
(dichloromethane, dichloromethane-methanol, 20:1; then reversed-
phase silica gel, methanol to dichloromethane-methanol, 2:1) (0.148 g,
39% yield). mp > 300 °C. Rf (dichloromethane-methanol 20:1) 0.57.
UV-Vis (dichloromethane): λmax, nm (log ε) 276 (5.14), 348 (5.25), 652
26. 5,7-Bis-[4-[3,5-bis(benzyloxy)benzyloxy]phenyl]-6H-1,4-diazepine-
2,3-dicarbonitrile (8) The reaction mixture of 7 (397 mg, 1.20 mmol),
5 (1.38 g, 3.60 mmol), and K2CO3 (663 mg, 4.80 mmol) in DMF (10
mL) was stirred for 48 h at room temp. The solvent was evaporated
and the residual solid diluted with water (20 mL) then extracted with
dichloromethane (total amount 150 mL). The organic layers were
combined and evaporated to give a yellow oil, which was purified by
column chromatography (dichloromethane) to give a yellow solid 8
(0.850 g, 76% yield). mp 105-108 °C. Rf (dichloromethane) 0.66. UV-
Vis (dichloromethane): λmax, nm (log ε) 380 (4.73), 314 (5.01) 230
1
(5.02), 672 (4.95). H NMR (799.926 MHz, DMSO-d6): δH, ppm 8.16
3
3
(d, 16H, J=8.1 Hz, C2, C6 ArH), 7.39 (d, 32H, J=7 Hz, C2``, C6``,
ArH), 7.33 (t, 32H, 3J=7.6 Hz, C3``, C5``, ArH), 7.28 (t, 16H, 3J=8 Hz,
3
C4``, ArH), 7.05 (d, 16H, J=8 Hz, C3, C5 ArH), 6.83 (d, 16H, J=2
1
3
(4.9). H NMR (799.926 MHz, DMSO-d6); δH, ppm 8.08 (d, 4H, J=9
Hz, C3, C5 ArH), 7.40 (d, 8H, 3J=7 Hz, C2``, C6``, ArH ), 7.36 (t, 8H,
3J=7.3 Hz, C3``, C5``, ArH), 7.30 (t, 4H, 3J=7 Hz, C4``, ArH), 7.06 (d,
Hz, C2`, C6`, ArH), 6.68 (t, 8H, J=2 Hz, C4` ArH), 5.96 (d, 4H, 2J=12
Hz, N=C-CHeq), 5.14-5.20 (m, 16H, O-CH2), 5.13 (overlapped, 4H,
N=C-CHax), 5.04 (s, 32H, O-CH2). 13C NMR (201.162 MHz, DMSO-
d6): δC, ppm 159.6 (C4, ArC), 159.5 (C3`, C5`, ArC), 152.4, 143.7 (C1,
ArC), 140.6, 138.8 (C1`, ArC), 136.6 (C1``, ArC), 130.4 (C2, C6,
ArC), 129.4, 127.9 (C3``, C5``, ArC), 127.3 (C4``, ArC), 127.0 (C2``,
C6``, ArC), 114.3 (C3``, C5``, ArC), 106.8 (C2`, C6`, ArC), 101.6
(C4`, ArC), 69.3 (O-CH2), 69.4 (O-CH2), 35.8 (N=C-CH2). HRMS
(MALDI) m/z found: [M+H]+ 3754,4053 requires 3754,4219.
30. Linstead R. P.; Whalley M. J. Chem. Soc. 1952, 4839-4846
31. Durmuş M., Ahsen V., Nyokong T. J. Photochem. Photobiol. Chem.
2007, 186, 323-329.
3
4H, J=9 Hz, C2, C6 ArH), 6.67 (s, 4H, C2`, C6`, ArH), 6.62 (s, 2H,
C4` ArH), 5.99 (s, 1H, N=C-CHeq), 5.09 (s, 4H, O-CH2), 5.06 (s, 8H,
O-CH2), 2.21 (s, 1H, N=C-CHax). 13C NMR (201.162 MHz, DMSO-
d6): δC, ppm 162.1 (C1`, ArC), 159.5 (C3`, C5`, ArC), 150.0 (C1,
ArC), 138.4 (C4, ArC), 136.7 (C1``, ArC), 132.3 (C3, C5, ArC), 128.1
(C3``, C5``, ArC), 127.5 (C4``, ArC), 127.3 (C2``, C6``, ArC), 125.8
(N=C), 122.5 (C-C≡N), 115.8 (C≡N), 115.1 (C2, C6, ArC), 106.6
(C2`, C6`, ArC), 101.5 (C4`, ArC), 69.3 (O-CH2), 38.5 (N=C-CH2).
MS (ES pos) m/z 956 [M+Na]+, (ES neg) m/z [M-H]- 932. HRMS
(MALDI) found: 933.3730 [M+H]+, requires 933.3652 [M+H]+. Anal.
calcd for C61H48N4O6: C, 78.52; H, 5.19; N, 6.00, O, 10.29. Found: C,
78.45; H, 5.24; N, 6.15; O, 10.15.
32. Młynarczyk D. T., Lijewski S., Falkowski M., Piskorz J., Szczołko W.,
Sobotta Ł., Stolarska M., Popenda Ł., Jurga S., Konopka K., Düzgüneş
N., Mielcarek J., Goślińsi T. ChemPlusChem 2016, 81, 460-470.
27. Reimann E., Chem. Ber. 1969, 102, 2881–2888.
28. Hawker C. J., Frkchet M. J. J. Am. Chem. Soc. 1990, 112, 7638-7647.
* Corresponding author. Fax: +48 61 854 6631.
E-mail address: tomasz.goslinski@ump.edu.pl (T. Goslinski).

5
Highlights
Diazepinoporphyrazine possessing G1-dendrimeric
substituents is presented
The potential photosensitizing activity of novel
porphyrazine was evaluated
The aggregation study for diazepinoporphyrazine
was performed
* Corresponding author. Fax: +48 61 854 6631.
E-mail address: tomasz.goslinski@ump.edu.pl (T. Goslinski).