Photochemical Fragmentation of Irgacure PAG 103

Abstract

Photoisomerization of Irgacure PAG 103 followed by photocyclization and fragmentation leads to three tricyclic thieno[2,3-b]quinoline-4-carbonitrile heterocyclic compounds. The release of acid which can catalyze polymer resist modifications is indicated by the low pH of an aqueous extract. These reactions are discussed in view of possible mechanisms and how these might influence future design strategies.

2,6-Bis(phenylamino)-4-(iminophenyl)benzoquinone

“…The reaction of o-xylyl cyanide 9 and 2-nitrothiophene 10 with KOH gives adduct 11 which can be sulfonated to produce photoacid generator 12. The photochemical decomposition, which involves an unusual 6π photocyclisation of the C=N of an oxime leading to an acridine derivative and acid, has been explored [6,7]. Heterocyclic examples with a similar synthesis to compound 11 are also known [8].…”