The document summarizes research on synthesizing phenazine ligands through metal templation. Key points: 1) Phenazine ligands like phendione, DPQ and DPPZ were synthesized through both literature methods and metal templation with cobalt. Metal templation produced higher yields for DPQ and lower impurities for all ligands. 2) PDT was successfully synthesized through cobalt templation for the first time, in just one hour compared to 20 hours for literature methods. 3) The metal templation method overcomes difficult syntheses and is an excellent approach for synthesizing ligands like PDT. Future work will aim to increase PDT yield and purity.

1. Synthetic Optimization of Phenazine
Ligands Through Metal Templation.
Student Number: 12506443
CS454

2. Kellett Research Group
• Three worldwide clinically approved PtII drugs – Cisplatin, Carboplatin and Oxaliplatin.
• Commonly used in anti-cancer treatment crosslinks with DNA resulting in cell apoptosis.
• Major drawbacks: Not selective, resistance and side – effects (nephrotoxicity, ototoxicity, hematologic, and
gastrointestinal toxicity.1
• 90% cisplatin excreted in the urine.2
• Phenazine complexes are non-mutagenic and have better selectivity compared to cisplatin, which makes them an
excellent potential anti-cancer drug.
Image adapted from Todd, R.C. and Lippard, S.J. J. Inorg. Biochem. (104) 2010, 902-908.
1) Loehrer, P.; EIinhorn, L. Drugs 5 Years Later - Cisplatin. Ann. Intern. Med. 1984, 100, 704-713.
2) Jahromi, E. Z.; Divsalar, A.; Saboury, A. A.; Khaleghizadeh, S.; Mansouri-Torshizi, H.; Kostova, I. Palladium complexes: new candidates for anti-cancer drugs. J. Iran Chem. Soc. 2016, 13, 967-989.
Introduction

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Phenazine Ligands – Novel DNA interaction
Phenazine ligands (Phendione, DPQ, DPPZ and PDT) coordinated to a metal centres (Cu, Ru) interact with DNA by three
interactions;
• Hydrophobic interaction – Minor groove
• Intercalation –Intercalation in the major groove.
• π-stacking by metallo-intercalators.3
• [Ru(DPPZ)(Phen)2] 2+ has excellent DNA recognition properties.
• [Cu(Phen)2]2+, is an effective chemical nuclease.4
3) eglis, B. M.; Pierre, V. C.; Barton, J. K. Metallo-intercalators and metallo-insertors. Chemical Communications 2007, 4565-4579.
4) Molphy, Z.; Prisecaru, A.; Slator, C.; Barron, N.; McCann, M.; Colleran, J.; Chandran, D.; Gathergood, N.; Kellett, A. Copper
Phenanthrene Oxidative Chemical Nucleases. Inorg. Chem. 2014, 53, 5392-5404.

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Optimisation – Template Reaction
• Reactivity of organic molecule change when coordinated to a metal.
• Metal templation can help stabilze intermediates formed.5
• Previous metal templation synthesis of phendione proved successful.
• Metal template adapted for synthesis of phenazine ligands:
5) Microscale Inorganic Chemistry – A comprehensive laboratory experience. Zvi Szafran, Ronald M.Pike, Mono M.Singh
Optically Active Co-ordination Compounds. Part XX.Reactions of 1,10-Phenanthroline co-ordinated to Cobalt(II) By D. Gillard,E. Hill, and R. Maskill, Inorganic Chemistry
Laboratories, The University of Kent, Canterbury, Kent

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Optimisation
• Procedure of metal templation for the synthesis of phendione:
• Aim 1 of this project is to synthesis phenazine ligands by current literature methods6 and compare results with metal
templation synthesis for phenazine ligands.
• Aim 2 attempted synthesis of PDT through metal templation pending results from aim 1.
6) Molphy, Z.; Prisecaru, A.; Slator, C.; Barron, N.; McCann, M.; Colleran, J.; Chandran, D.; Gathergood, N.; Kellett, A. Copper Phenanthrene Oxidative Chemical Nucleases. Inorg. Chem. 2014, 53, 5392-5404

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Synthesising Phendione, DPQ, DPPZ and PDT from literature method.

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Synthesising Phendione, DPQ, and DPPZ by Template reaction.

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Analysis of Phendione synthesised by Literature method.
Multiplicity Chemical Shift (ppm) Proton Integration
Singlet 7.25 CDCl3 n/a
Doublet of Doublets 7.6 B 1
Doublet of Doublets 8.5 C 1
Doublet of Doublets 9.15 A 1

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Analysis of DPQ synthesised by literature method.
Multiplicity Chemical Shift (ppm) Proton Integration
Doublet of doublets 9.4 D 1
Doublet of doublets 9.3 B 1
Singlet 8.9 A 1
Doublet of doublets 7.7 C 1

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Analysis of DPPZ synthesised by literature method. Multiplicity Chemical Shift (ppm) Proton Integration
Doublet of doublets 9.6 E 1
Doublet of doublets 9.2 C 1
Doublet of doublets 8.3 D 1
Doublet of doublets 7.9 B 1
Doublet of doublets 7.7 A 1

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Multiplicity Chemical Shift (ppm) Proton Integration
Doublet of doublets 9.45 Hd 1
Doublet of doublets 9.25 Hb 1
Singlet 8.95 Ha 1
Doublet of doublets 7.75 Hc 1
Solvent 7.2 CDCl3 n/a
Multiplicity Chemical Shift (ppm) Proton Integration
Doublet of doublets 9.05 Ha 1
Doublet of doublets 8.45 Hc 1
Doublet of doublets 7.55 Hb 1
Singlet 7.2 Solvent CDCl3
Analysis of Phendione and DPQ synthesised by template reaction.
Phendione DPQ
NMR spectrum the same as Phendione from previous NMR spectrum the same as DPQ from previous
synthesis – Less Impurities from previous synthesis – Less Impurities
Lower yield 24% Higher yield 61%

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Analysis of DPPZ from Template Method
• No product formed.
• Colour change from orange to black on addition of phenylenediamine.
• Side reaction: Phenylenediamine added to Cobalt – Solution immediately turned black
• Conclusion:

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Analysis of DPPZ synthesised by Template Method
• Cobalt oxidised from Co(II) to Co(III) using iodine.
• Again upon addition of phenyldiamine solution turned black.
• Refluxed and EDTA added – Black precipitate.
• Couldn’t be isolated.

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Comparison of Results following literature method and template reaction.
• Higher yields achieved by the literature method for phendione and DPPZ.
• Higher yield achieved for DPQ by template reaction.
• Higher melting range for template reaction ligands – Possibly higher grade of purity achieve as confirmed by NMRs.
• Aim 1 successful in applying cobalt template reaction to obtain product. Methodology applied to synthesis PDT.
Literature Method Template Reaction Literature Method Template Reaction
Yield (%) Yield (%) Melting Range (OC) Melting Range (OC) Literature Value(OC)
Phendione 88 24 225 – 230 240 – 244 258 - 260
DPQ 42 61 298 – 302 315 – 318 330 - 335
DPPZ 62 n/a 240 – 242 n/a 248 - 253

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Synthesising PDT – Template reaction.
• Synthesis of PDT difficult – No PDT forming and large amounts of phendiol forming.
• Proposed mechanism for formation of phendiol7:
7) McCann, M.; McGinley, J.; Ni, K.; O'Connor, M.; Kavanagh, K.; Mckee, V.; Colleran, J.; Devereux, M.; Gathergood, N.; Barron, N.; Prisecaru, A.; Kellett, A. A new phenanthroline-oxazine ligand:
synthesis, coordination chemistry and atypical DNA binding interaction. Chemical Communications 2013, 49, 2341-2343

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Synthesising PDT – Template Reaction
• Reaction Scheme for PDT synthesis by template reaction.
• Difficult due to intermediate reacting with phendione – Phendiol forming

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Synthesising PDT – Template Reaction
• Template reaction will stabilize the intermediate allowing reaction to form PDT.

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Synthesis of PDT by template reaction
• Literature method requires 20 hr reflux and results in little or no product with large amount phendiol synthesised.
• Experiments carried out in parallel synthesiser.
• Triethylamine (TEA) neutralize HCl.
• Reactions 1-3 and the control all failed to synthesis PDT.
Reaction Temperature
(OC)
Time Phendione
(mg) (mmol)
L-tyrosine methyl ester
(mg)(mmol)
Triethyl-
amine
Cobalt
1 70 15 m 100 (0.44) 93 (0.48) Yes Yes
2 70 3 h 100 (0.44) 93 (0.48) Yes Yes
3 70 24 h 100 (0.44) 93 (0.48) Yes Yes
Reaction Temperature
(OC)
Time Phendione
(mg)(mmol)
L-tyrosine methyl ester
(mg)(mmol)
Triethyl-
amine
Cobalt
Control 70 24 h 100(0.44) 93 (0.48) No No

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Synthesis of PDT by template reaction
• Reaction A produced red / brown crystals.
• 0.198 g crude yield.
• Product peaks : Impurity peaks 1:5
• 0. 040 g (40 mg) PDT Present.
• Product purified using flask chromatography – 90/10 DCM/MeOH
Reaction Temperature
(OC)
Time Phendione
(mg)(mmol)
L-tyrosine methyl ester
(mg)(mmol)
Triethyl-
amine
Cobalt
A 70 1 h 100 (0.44) 93 (0.48) No Yes
B 70 3 h 100 (0.44) 93 (0.48) No Yes
C 70 20 h 100(0.44) 93 (0.48) No Yes
D 70 24 h 100 (0.44) 93 (0.48) No Yes

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Synthesising PDT by Template reaction.

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Analysis PDT synthesised by Template Method
PDT
Red Line – Previously synthesised PDT.
Blue line – PDT synthesised through template reaction.

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Analysis PDT synthesised by Template Method – Flash Chromatography

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Conclusion:
The metal template reaction is an excellent method to overcome difficult synthesis – PDT.
PDT synthesised in one hour in moderate yield compared to 20 hr literature method.
DPQ synthesised in higher yield compared to literature method.
Aim 1: Successfully synthesis phenazine ligands by template reaction.
Aim 2: Successfully synthesis PDT by template reaction in shorter reaction time.
Future Work
• Increasing the yield of PDT by carrying out reaction for 2 hours and every 15 minutes analysing reaction flask.
• Increasing the purity of PDT.
• Applying this template reaction for future synthesis of novel ligands.

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Acknowledgement:
I would like to thank project director Dr.Andrew Kellett for providing guidance and allowing me to work as part of his
research team for the duration of this project.
I’d also like to thank Natasha McStay whose knowledge, guidance and patience was a huge help throughout my project.
Also to Damian, Nicolo, Tadhg and Sean who helped throughout the project.