Delayed release singlet oxygen sensitizers based on pyridone-appended porphyrins

Abstract

A new type of porphyrin photosensitizer capable of generating singlet oxygen upon irradiation, storing it through binding to pyridone subunits, followed by slow release at 20-40 °C, is reported. The timescale of singlet oxygen release can be varied depending on the pyridone group substitution pattern, forming endoperoxides of different stabilities. Modified tetra- and octa-substituted pyridone-porphyrins showed solubility in water, allowing for straightforward delivery into cells. The effect of delayed singlet oxygen formation due to endoperoxide decomposition was demonstrated on cancer cells in vitro.

Visible‐Light‐Mediated Synthesis of β‐Chloro Ketones from Aryl Cyclopropanes

“…While the ciprofibrate derivative 2 w could only be obtained in low yield, which was probably due to facile decarboxylation of the alkyl carboxylic acid, the corresponding methyl ester as well as the tramadol derivative gave the products in high yields ( 2 x – 2 y ). Unfortunately, since 2‐pyridones are known to react with oxygen under irradiation, only low yields were obtained in the case of ring‐fused 2‐pyridones ( 2 z – 2 aa ) . To illustrate the utility of the method, a gram‐scale reaction (10 mmol) was performed, giving 2 a in 79 % yield of isolated product.…”

“…Unfortunately,s ince 2-pyridones are known to react with oxygen under irradiation, only low yields were obtained in the case of ring-fused 2-pyridones (2z-2aa). [11] To illustrate the utility of the method, ag ram-scale reaction (10 mmol) was performed, giving 2a in 79 %y ield of isolated product. In addition, when SAS was used as ap hotosensitizer, it was possible to employ other nucleophiles,for example,bromide, water, or methanol, providing 3a-3i in moderate to excellent yields.…”

Trends and targets in antiviral phototherapy

“…20). 393 This 'storage' and thermal release of 1 O 2 has also been investigated for the PDI of viruses. 394, 395 Dewilde et al used a water-soluble naphthalene derivative (55) to effectively inactivate the enveloped viruses HIV 1, HSV type 1, cytomegalovirus, and VSV, evidencing that 1 O 2 plays an important role in the inactivation of these viruses, as the thermally generated 1 O 2 excludes Type I photoreactions.…”

Durch sichtbares Licht vermittelte Synthese von β‐Chlorketonen aus Arylcyclopropanen

“…Daher begannen wir unsere Untersuchungen mit Cyclopropylbenzol (1a)a ls Modellsubstrat, Natriumchlorid als Chloridquelle,N atriumanthrachinon-2-sulfonat (SAS) als stark oxidierendem Photokatalysator und Tr ifluoressigsäure (TFA) zur Aktivierung von SAS. [11] Um die Anwendbarkeit des Verfahrens zu veranschaulichen, wurde eine Reaktion im Gramm-Maßstab (10 mmol) durchgeführt, die 2a in einer isolierten Ausbeute von 79 %e rgab.W enn SAS als Photokatalysator verwendet wurde,w ar es außerdem mçglich, andere Nucleophile,z .B. Die Verwendung von Schwefelsäure anstelle von TFAoder einer Kombination von HCl und HNO 3 veränderte die Ausbeute nicht signifikant (Eintrag 2, 3).…”