Photoredox chemistry of p-nitrophenylalanine and p-nitrophenethyl amine in basic aqueous solution: formation of an observable long-lived intermediate

Decarboxylation is a significant reaction pathway for photolabile calcium chelators and related compounds

“…On irradiation, this compound lost CO 2 and formed 4-nitrosophenylacetaldehyde as the primary product, although this was transformed to 4-aminobenzaldehyde by secondary dark reactions. 25 The decarboxylation was proposed to be initiated by single electron transfer from the amino group to the triplet excited state of the nitroaryl group. A similar process had been described earlier to explain photodecarboxylation of N-(2,4dinitrophenyl)amino acids, albeit with a less plausible mechanistic interpretation.…”

“…Efficient decarboxylation of aminium radicals, as present in 11, has been reported previously. 27 In the compounds studied here, the presence of the nitro radical anion within 11 permits a rearrangement of electrons 25 to return to the fully electron-paired species 12. Hydrolysis of the Schiff base and loss of water from the nitroso hydrate would then be expected to give 2-nitrosobenzylamine 13 as the primary photochemical product from 4.…”