DPPD-Q (Synonyms: C.I. 56000,2,5-Dianilino-1,4-benzoquinone,2,5-Dianilino-p-benzoquinone,2,5-Dianilino-para-benzoquinone,N,N′-Diphenyl-1,4-phenylenediamine quinone,N,N′-Diphenyl-p-phenylenediamine quinone,N,N′-Diphenyl-para-phenylenediamine quinone,NSC 11)

DPPD-Q is an oxidized derivative of the antioxidant and substituted p-phenylenediamine DPPD.^1,2,3 It inhibits jack bean urease by 91.4% when used at a concentration of 5 µM.^[4] DPPD-Q is less toxic to the aquatic bacterium V. fischeri than DPPD (EC₅₀ = 1.76 mg/ml).^[5] It has been found in tire wear particles and crumb rubber, particulate matter 2.5 (PM_2.5), and wastewater influent and effluent.^1,2,3

References:
[1].Zhao, H.N., Hu, X., Gonzalez, M., et al.Screening p-phenylenediamine antioxidants, their transformation products, and industrial chemical additives in crumb rubber and elastomeric consumer productsEnviron. Sci. Technol.57(7)2779-2791(2023).
[2].Wang, W., Cao, G., Zhang, J., et al.Beyond substituted p-phenylenediamine antioxidants: Prevalence of their quinone derivatives in PM[2].5Environ. Sci. Technol.56(15)10629-10637(2022).
[3].Cao, G., Wang, W., Zhang, J., et al.Occurrence and fate of substituted p-phenylenediamine-derived quinones in Hong Kong wastewater treatment plantsEnviron. Sci. Technol.57(41)15635-15643(2023).
[4].Nain-Perez, A., Barbosa, L.C.A., Rodríguez-Hernández, D., et al.Antiureolytic activity of substituted 2,5-diaminobenzoquinonesChem. Biodivers.16(12)e1900503(2019).
[5].Wang, W., Chen, Y., Fang, J., et al.Toxicity of substituted p-phenylenediamine antioxidants and their derived novel quinones on aquatic bacterium: Acute effects and mechanistic insightsJ. Hazard. Mater.469:133900(2024).