A series of aza-5[H]-phenanthridin-6-ones were synthesized and evaluated as inhibitors of poly ADP-ribose polymerase-1 (PARP-1). Inhibitory potency of the unsubstituted aza-5[H]-phenanthridin-6-ones (i.e., benzonaphthyridones) was dependent on the position of the nitrogen atom within the core structure. The A ring nitrogen analogues (7-, 8-, and 10-aza-5[H]-phenanthridin-6-ones) were an order of magnitude less potent than C ring nitrogen analogues (1-, 2-, 3-, and 4-aza-5[H]-phenanthridin-6-ones). Preliminary stroke results from 1- and 2-aza-5[H]-phenanthridin-6-one prompted structure-activity relationships to be established for several 2- and 3-substituted 1-aza-5[H]-phenanthridin-6-ones. The 2-substituted 1-aza-5[H]-phenanthridin-6-ones were designed to improve the solubility and pharmacokinetic profiles for this series of PARP-1 inhibitors. Most importantly, three compounds from this series demonstrated statistically significant protective effects in rat models of stroke and heart ischemia.

A wide variety of benzotriazolyl-stabilized anions 2, obtained by the lithiation of 1-(alpha-alkoxyalkyl)-, 1-[alpha-(alkylthio)alkyl]-, and 1-[alpha-(carbazol-9-yl)alkyl]benzotriazoles 1, on reaction with aliphatic and aromatic aldehydes and ketones, followed by rearrangement induced by heating in the presence of zinc bromide, furnish one-carbon-homologated alpha-alkoxyalkyl, alpha-(alkylthio)alkyl, and alpha-(carbazol-9-yl)alkyl ketones 4 in simple one-pot operations in good yields with excellent regioselectivity. In several alkoxymethylene insertions, intermediate 2-alkoxyoxiranes were separated in good yields, demonstrating the epoxide mechanism for the rearrangements and providing a facile approach to polysubstituted 2-alkoxyoxiranes, another class of important compounds.

Several substituted 2- and 4-hydroxyacetophenones are linked to Wang resin via a modified Mitsunobu protocol. These resin-bound acetophenones are condensed with aromatic aldehydes, and the resulting chalcones 5 are used for the synthesis of 2-dialkylamino- (9a-d) and 2-alkylamino-4,6-diarylpyridines (11a-f), and 2-alkyl-4,6-diaryl- (14a) and 2,4,6-triarylpyrimidines (14b,c) in a manner suitable for combinatorial applications.

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