Naslov
Methods of pyridylporphyrin oxidation and synthesis

Autori
Pavletić, Pegi

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, diplomski rad, diplomski

Fakultet
Odjel za biotehnologiju

Mjesto
Rijeka

Datum
12.09

Godina
2019

Stranica
66

Mentor
Malatesti, Nela

Ključne riječi
Porphyrin ; m-CPBA ; Dimethyldioxirane ; PDT ; Synthesis

Sažetak
Porphyrins are organic compounds that can be used as photosensitizers in photodynamic therapy (PDT). PDT involves photosensitizer (PS) administration into the body, where they penetrate tumour tissues and, once illuminated, cause tumour degradation. Most common way of porphyrin synthesis in our laboratory includes modified Adler-Longo method, since it is relatively easy to conduct, it is fast and gives us products with impurities separable with a column chromatography. Recently we have found that zwitterionic N-oxidised pyridylporphyrins as PSs in PDT exhibit low “dark” toxicity, as opposed to their cationic analogues, N- methylated pyridylporphyrins, thus we decided to focus our research on this perspective group of porphyrin PSs. One of the requirements for porphyrins to be used in PDT efficiently, is their high uptake into targeted cells. Therefore, N-oxidised pyridylporphyrins we are particularly interested in have lipophilic component, and their synthesis in this work includes adding long alkyl chains derived from dodecanoyl and hexadecanoyl chlorides. In this work different methods of pyridylporphyrin N-oxidation were analysed to investigate which method is the best in terms of yields and ease of purification for preparation of new potential photosensitisers for the use in PDT. Four methods were assessed for N-oxidations of porphyrins using: meta- chloroperoxybenzoic acid (m-CPBA), dimethyldioxirane (DMD) ; hydrogen peroxide, sodium hydroxide and meta-chloroperoxybenzoic acid ; or acetic acid. Only methods using m-CPBA and DMD showed promising results, providing high yields of oxidised pyridylporphyrins (65 % for m-CPBA and 70 % for DMD) in the reactions that were easy to optimize and conduct. Method including H2O2, NaOH and m-CPBA gave a yield of (oxydo)pyridylporphyrin of 3, 92 % and the reaction using CH3COOH did not occur. UV/ Vis spectroscopic analysis showed no difference between the spectra of symmetric porphyrin oxidised by the different methods. We are concluding from this work that both methods 1 (m-CPBA) and 2 (DMD) provide good yields. Although method 2 is more complicated to perform due to constant pH adjustments, the product contains less impurities, needs less additional purification and the yield is up to 5 % higher in comparison to the method 1.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Interdisciplinarne prirodne znanosti, Biotehnologija u biomedicini (prirodno područje, biomedicina i zdravstvo, biotehničko područje)

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