Photochemistry and Photophysics of Papaverine N‐Oxide

Abstract

The photochemistry and photophysics of papaverine N‐oxide in polar aprotic and protic solvents has been studied in detail. Complex energy and charge‐transfer phenomena between chromophores occur in papaverine. New photochemistry for the papaverine N‐oxide system is reported. Irradiation in protic media results in the formation of an emissive charge‐transfer state with ensuing intramolecular hydroxylation in high isolated yields (75–80%).

The Excited-State Interaction of Resazurin and Resorufin with Aminesin Aqueous Solutions. Photophysics and Photochemical Reaction¶

“…The photoinduced deoxygenation of N-oxides has been reported previously for other molecules (10) and was found to proceed on irradiation of N-oxide alone or in the presence of suitable acceptors such as amines (11,12). But in most cases the reaction is accompanied by side reactions and rearrangements of the N-oxide (13). More recently, we found that the two related dyes, resazurin and resorufin, in the presence of triethanolamine (TEOHA) produce radicals that are efficient photoinitiators of aqueous acrylamide polymerization (14).…”

Naturally occurring plant isoquinoline N-oxide alkaloids: Their pharmacological and SAR activities

“…2) (El Sayed 2000). oxidation products that were papaverinol, papaveraldine, and papaverine N-oxide (106) under the influence of UV light, was reported (Girreser et al 2003;Souto-Bachiller et al 1999;Bremner and Wiriyachitra 1973). Papaverine hydrochloride, papaverinol, and papaveraldine chloroform solutions were exposed to UV light of 254 nm in atmospheric, aerobic and anaerobic (helium) condition, their photooxidation in chloroform solutions was studied (Piotrowska et al 2002;Muller and Dorfman 1934).…”

β-Phenylethylamines and the isoquinoline alkaloids (July 1999 to June 2000)

“…56 The photolysis of papaverine N-oxide in polar solvents has been studied. 57 An X-ray crystallographic study of the solvation of O-tetraethyl-1,2-dehydronorlaudanosoline in ethanol, benzene and hydrochloric acid has been reported. 58 The trimethyl ether of imbricatine, derived from the star fish Dermasteria imbricata, 59 has been synthesised.…”