scholarly journals Competing photochemical reactions of bis-naphthols and their photoinduced antiproliferative activity

2019 ◽  
Vol 18 (5) ◽  
pp. 1197-1211 ◽  
Author(s):  
Matija Sambol ◽  
Katja Ester ◽  
Stephan Landgraf ◽  
Branka Mihaljević ◽  
Mario Cindrić ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Symmetry Breaking ◽  
Proton Transfer ◽  
Antiproliferative Activity ◽  
Charge Separation ◽  
Photochemical Reactions ◽  
Quinone Methides ◽  
Excited State Proton Transfer

Bis-naphthols 4 in aqueous solution undergo three competing photochemical reactions: photodehydration delivering quinone methides, symmetry breaking charge separation and excited state proton transfer.

Photogeneration of 1,5-naphthoquinone methides via excited-state (formal) intramolecular proton transfer (ESIPT) and photodehydration of 1-naphthol derivatives in aqueous solution

2004 ◽  
Vol 82 (2) ◽  
pp. 240-253 ◽  
Author(s):  
Matthew Lukeman ◽  
Duane Veale ◽  
Peter Wan ◽  
V Ranjit N. Munasinghe ◽  
John ET Corrie
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Proton Transfer ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Intramolecular Proton Transfer ◽  
Photochemical Reactions ◽  
Quinone Methide ◽  
Phenol Derivatives ◽  
Naphthol Derivatives

The photochemistry of naphthols 1, 2, 4, 5 and 9, and phenol 10 has been studied in aqueous solution with the primary aim of exploring the viability of such compounds for naphthoquinone and quinone methide photogeneration, along the lines already demonstrated by our group for phenol derivatives. 1-Naphthol (1) is known to be substantially more acidic than 2-naphthol (2) in the singlet excited state (pKa* = 0.4 and 2.8, respectively) and it was expected that this difference in excited-state acidity might be manifested in higher reactivity of 1-naphthol derivatives for photochemical reactions requiring excited-state naphtholate ions, such as quinone methide formation. Our results show that three types of naphthoquinone methides (26a, 26b, and 27) are readily photogenerated in aqueous solution by irradiation of 1-naphthols. Photolysis of the parent 1-naphthol (1) in neutral aqueous solution gave 1,5-naphthoquinone methide 26a as well as the non-Kekulé 1,8-naphthoquinone methide 26b, both via the process of excited-state (formal) intramolecular proton transfer (ESIPT), based on the observation of deuterium exchange at the 5- and 8-positions, respectively, on photolysis in D2O–CH3CN. A transient assignable to the 1,5-naphthoquinone methide 26a was observed in laser flash photolysis experiments. The isomeric 2-naphthol (2) was unreactive under similar conditions. The more conjugated 1,5-naphthoquinone methide 27 was formed efficiently via photodehydroxylation of 4; isomeric 5 was unreactive. The efficient photosolvolytic reaction observed for 4 opens the way to design related naphthol systems for application as photoreleasable protecting groups by virtue of the long-wavelength absorption of the naphthalene chromophore.Key words: photosolvolysis, excited-state intramolecular proton transfer, quinone methide, photorelease, photoprotonation.

Observation of excited state proton transfer reactions in 2-phenylphenol and 2-phenyl-1-naphthol and formation of quinone methide species

2015 ◽  
Vol 17 (14) ◽  
pp. 9205-9211 ◽  
Author(s):  
Jiani Ma ◽  
Xiting Zhang ◽  
Nikola Basarić ◽  
Peter Wan ◽  
David Lee Phillips
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Transient Absorption ◽  
Intramolecular Proton Transfer ◽  
Quinone Methide ◽  
Transfer Reactions ◽  
Quinone Methides ◽  
Time Resolved ◽  
Excited State Proton Transfer ◽  
Proton Transfer Reactions

Excited state intramolecular proton transfer from a phenol (naphthol) to a carbon atom of the adjacent aromatic ring and formation of quinone methides was studied by femtosecond time-resolved transient absorption.

Excited-State Proton Transfer in 3-Cyano-7-azaindole: From Aqueous Solution to Ice

2018 ◽  
Vol 122 (9) ◽  
pp. 2479-2484 ◽  
Author(s):  
Ting-Husn Tu ◽  
Yi-Ting Chen ◽  
Jiun-Yi Shen ◽  
Ta-Chun Lin ◽  
Pi-Tai Chou
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Proton Transfer ◽  
Excited State Proton Transfer
Sign in / Sign up

Export Citation Format

Share Document