Photodeoxygenation of phenanthro[4,5-bcd]thiophene S-oxide, triphenyleno[1,12-bcd]thiophene S-oxide and perylo[1,12-bcd]thiophene S-oxide

Identifying cysteine residues susceptible to oxidation by photoactivatable atomic oxygen precursors using a proteome-wide analysis

“…25 Synthesis of a hydrophobic DBTO derivative representing the core structure of 2 and 3 O( 3 P) produced during the photodeoxygenation of aromatic sulphoxides has been traditionally investigated through a set of common intermediate experiments with toluene. 19,[26][27][28] This is due to the transient nature of O( 3 P), which makes it difficult to detect through conventional spectroscopic methods. 8 One of the limitations of these common intermediate experiments is its incompatibility with aromatic sulphoxides with a sulphonic ester or a sulphonic acid group due to their poor solubility in toluene.…”

“…If the toluene oxidation profile of the aromatic sulphoxide is analogous to the toluene oxidation profile of a known O( 3 P)-precursor like DBTO, 10 then it is suggested that derivatives 2 and 3 generate O( 3 P) upon UV-A irradiation. 19,[26][27][28] This approach is not very robust since previous studies have found that these common intermediate experiments are sensitive to irradiation periods, headspaces in the cuvette, and dissolved molecular oxygen. 26,27 Larger headspaces and longer duration of UV-A exposure have shown to increase benzylic oxidation products.…”

“…19,[26][27][28] This approach is not very robust since previous studies have found that these common intermediate experiments are sensitive to irradiation periods, headspaces in the cuvette, and dissolved molecular oxygen. 26,27 Larger headspaces and longer duration of UV-A exposure have shown to increase benzylic oxidation products. 27 Although steps are taken to minimize the levels of dissolved oxygen through argon sparging, the benzylic oxidation products tend to increase in presence of dissolved residual molecular oxygen.…”

Visible light‐induced photodeoxygenation of polycyclic selenophene Se‐oxides

“…As shown in Figure 4, when toluene was degassed by argon sparging, the oxidation of toluene by the photodeoxygenation of DBTO yielded 1:3 CH 3 :ring ratio (Table 2, entry 1) upon 4 h of UVA irradiation. [ 29 ] However, when the freeze‐pump‐thaw technique, which is a superior technique for removing dissolved oxygen, was used to degas toluene, the amount of benzaldehyde obtained was negligible and the ratio of CH 3 :ring obtained was 1:17 (Table 2, entry 2). It should also be noted that the head space for all of the argon sparged samples was the same, which has been shown to effect the ratio of oxidized products.…”

“…[ 14,28 ] However, benzannulated DBTO derivatives displayed other photodeoxygenation mechanisms in addition to the unimolecular SO bond scission mechanism that yields O( 3 P), and none appeared to generate O( 3 P) upon visible light irradiation. [ 28,29 ] The combination of creating selenium containing analogs with π ‐extended chromophores was postulated to create O( 3 P)‐precursors that have a high quantum yield of photodeoxygenation upon irradiation with visible light. To examine this hypothesis, polycyclic aryl selenoxides 1 to 4 were synthesized, and their photodeoxygenation processes were studied (Figure 2).…”