A convenient three‐step synthesis of dibenzo[ a,j ]acridines is reported which relies on regioselective Pd‐catalyzed cross‐coupling reactions of 2,3,5,6‐tetrachloropyridine and subsequent Brønsted acid mediated cycloisomerization. Products are obtained in good yields and the method is broadly applicable. For selected dibenzo[ a,j ]acridines, photophysical and electrochemical properties were studied.

Two new and efficient methods for the synthesis of benzo[b] carbazolediones have been developed. Various derivatives were synthesized by either a three-component one-pot reaction or a two-component domino reaction in moderate to good yield. Moreover, inhibition studies of these compounds against nucleotide pyrophosphatases (NPPs) have been carried out. An interesting and promising inhibitory effect was observed by the influence of different substituents. Substitution with a methyl group located at the indole moiety was found sensitive towards h-NPP1 (4b; IC50 +/- SEM = 0.57 +/- 0.05 mu M), while the unsubstituted derivative exhibited a higher sensitivity towards h-NPP3 (4a; IC50 +/- SEM = 0.16 +/- 0.06 mu M). Both derivatives presented non-selective inhibition of both isozymes. Among all the derivatives, two derivatives with anisyl groups showed the highest selectivity towards h-NPP3 and no interaction with h-NPP1. Finally, the free binding energies were calculated and molecular docking studies were performed in order to provide an insight into putative binding modes of these inhibitors.

An efficient and convenient method for the synthesis of dibenzo[c,h]acridine derivatives via electrophilic cycloisomerisation mediated by methanesulfonic acid has been developed. This method provides the desired acridines in moderate to very good yields introducing various substituents in positions 2 and 6 as well as on the dibenzo[c,h]acridine scaffold. Photophysical and electrochemical properties have been investigated for selected products by UV/Vis and CV measurements which have been verified by DFT calculations.

4-Bromo-2,3,5-trichloro-6-iodopyridine was studied as a new substrate in chemoselective Sonogashira reactions. This approach provides an efficient access to non-symmetrical mono-, di-, tri- and pentaalkynylated pyridines in good yields. Selected pentaalkynylated pyridines were studied with regard to their UV/Vis- and emission properties showing moderate to high fluorescence quantum yields.

4‐Bromo‐2,3,5‐trichloro‐6‐iodopyridine has been synthesized for the first time and applied in chemo‐ and site‐selective Suzuki–Miyaura cross‐coupling reactions. This novel starting material allows the selective synthesis of pentaarylpyridines with up to four different aryl substituents.

A new method for the chemoselective synthesis of alkynylpyridines from 3,5-dibromo-2,6-dichloropyridine has been developed. Optimized conditions give access to a variety of mono-, di-, tri- and tetraalkynylated pyridines in good yields. Interestingly, the employment of 3,5-dibromo-2,6-dichloropyridine as a starting material led to the opposite regioisomers of dialkynylated pyridines as compared to the application of 2,3,5,6-tetrachloropyridine.

A new and efficient two-step procedure for the preparation of 5,7-disubstituted 5,7-dihydropyrido[2,3-b:6,5-b′]diindoles, containing aryl-, benzyl- as well as alkyl-substituents has been developed. This methodology consists of a chemo-selective double Suzuki-Miyaura cross-coupling reaction followed by a fourfold Buchwald-Hartwig amination reaction. UV/VIS absorption and fluorescence measurements have been carried out for a selected series of compounds. The results are summarized and compared with those of the isomeric 5,7-disubstituted 5-7-dihydropyrido[3,2-b:5,6-b′]diindoles.

A palladium-catalyzed one-pot reaction for the synthesis of benzo[b]carbazolediones is described which proceeds by amination of 2,3-dibromonaphthoquinone, Suzuki cross-coupling with (2-bromophenyl)boronic acid, and subsequent intramolecular C-N Buchwald-Hartwig cyclization with amines.