Mechanism of Photochemical O-Atom Exchange in Nitrosamines with Molecular Oxygen

Visible-Light-Promoted Photoaddition of N-Nitrosopiperidines to Alkynes: Continuous Flow Chemistry Approach to Tetrahydroimidazo[1,2-a]pyridine 1-Oxides

The photoaddition of N-nitrosopiperidines to terminal alkynes was effected under visible-light irradiation, in which a novel synthetic access to tetrahydroimidazo[1,2-a]pyridine 1-oxides was achieved via the dehydrogenative cycloisomerization of β-nitroso enamine intermediates. The decomposition pathways of N-nitrosamines, alkynes, and β-nitroso enamine intermediates were better handled in a continuous flow setting through the diffusion control of chemical species that negatively affected the formation of tetrahydroimidazo[1,2-a]pyridine 1-oxides under batch reaction conditions.

Visible-Light-Induced Photoaddition of N-Nitrosoalkylamines to Alkenes: One-Pot Tandem Approach to 1,2-Diamination of Alkenes from Secondary Amines

The generation of aminium radical cation species from N-nitrosoamines is disclosed for the first time through visible-light excitation at 453 nm. The developed visible-light-promoted photoaddition reaction of N-nitrosoamines to alkenes was combined with the o-NQ-catalyzed aerobic oxidation protocol of amines to telescope the direct handling of harmful N-nitroso compounds, where the desired α-amino oxime derivatives were obtained in a one-pot tandem N-nitrosation and photoaddition sequence.

An Organic Chemist's Guide to N-Nitrosamines: Their Structure, Reactivity, and Role as Contaminants

N-Nitrosamines are a class of compounds notorious both for the potent carcinogenicity of many of its members and for their widespread occurrence throughout the human environment, from air and water to our diets and drugs. Considerable effort has been dedicated to understanding N-nitrosamines as contaminants, and methods for their prevention, remediation, and detection are ongoing challenges. Understanding the chemistry of N-nitrosamines will be key to addressing these challenges. To facilitate such understanding, we focus in this Perspective on the structure, reactivity, and synthetic applications of N-nitrosamines with an emphasis on alkyl N-nitrosamines. The role of N-nitrosamines as water contaminants and the methods for their detection are also discussed.

Cyanine Modification Tuned for Amine Photorelease

Cyanines are emerging as useful agents for photoreleasing biological compounds because of their capability of utilizing near-infrared (NIR) light. Another benefit is their ability to self-sensitize to produce singlet oxygen for the release of aryl amines, a process that has not been as feasible in the past. Here, we highlight the paper by Schnermann et al. (https://doi.org/10.1111/php.13090), which reports on a cyanine conjugate for heterolytic photocleavage of aryl amines. This paper is timely-delving into a photorelease mechanism involving a domino rearrangement and β-elimination triggered by NIR light.