The synthesis of 2-nitroaryl-1,2,3,4-tetrahydroisoquinolines, nitro-substituted 5,6-dihydrobenzimidazo[2,1-a]isoquinoline N-oxides and related heterocycles as potential bioreducible substrates for the enzymes NAD(P)H: quinone oxidoreductase 1 and E. coli nitroreductase

Intramolecular Reductive Cyclization of o-Nitroarenes via Biradical Recombination

A visible-light-induced/thiourea-mediated intramolecular cyclization of o-nitroarenes under mild conditions is realized for the first time, which provides an efficient and environmentally friendly way to access pharmaceutical relevant quinazolinone derivatives. The reaction can be easily extended to gram level by using a continuous-flow setup with high efficiency. Mechanistic investigation including control experiments, transient fluorescence, UV-vis spectra, and DFT calculations suggests that the formation of active biradical intermediates via intramolecular single electron transfer (SET) is key stage in the catalytic cycle.

Studies on the interactions of 5-R-3-(2-pyridyl)-1,2,4-triazines with arynes: inverse demand aza-Diels–Alder reaction versus aryne-mediated domino process

The interactions between substituted 5-R-3-(pyridyl-2)-1,2,4-triazines with in situ generated substituted aryne intermediates have been studied.

One-Pot Synthesis of Benzo[4,5]imidazo[2,1-a]isoquinolines and Isoquinolino[3,4-b]quinoxalines via Tandem Cyclization Strategies

Two operationally simple one-pot protocols have been developed for the synthesis of amino-functionalized benzo[4,5]imidazo[2,1-a]isoquinolines and isoquinolino[3,4-b]quinoxalines. Optimization data and substrate scope for these atom-economical transformations, which engage commercially available o-phenylenediamines and o-cyanobenzaldehydes, are discussed.