Nucleobase-Functionalized 7-Deazaisoguanine and 7-Deazapurin-2,6-diamine Nucleosides: Halogenation, Cross-Coupling, and Cycloaddition.

The functionalization in position-7 of 7-deazaisoguanine and 7-deazapurin-2,6-diamine ribo- and 2'-deoxyribonucleosides by halogen atoms (chloro, bromo, iodo), and clickable alkynyl and vinyl side chains for copper-catalyzed and copper-free cycloadditions is described. Problems arising during the synthesis of the 7-iodinated isoguanine ribo- and 2'-deoxyribonucleosides were solved by the action of acetone. The impact of side chains and halogen atoms on the p values and hydrophobicity of nucleosides was investigated.

Purine DNA Constructs Designed to Expand the Genetic Code: Functionalization, Impact of Ionic Forms, and Molecular Recognition of 7-Deazaxanthine-7-Deazapurine-2,6-diamine Base Pairs and Their Purine Counterparts.

Purine DNA represents an alternative pairing system formed by two purines in the base pair with the recognition elements of Watson-Crick DNA. Base functionalization of 7-deaza-2'-deoxyxanthosine with ethynyl and octadiynyl residues led to clickable side chain derivatives with short and long linker arms. As complementary bases, purine-2,6-diamine or 7-deazapurine-2,6-diamine 2'-deoxyribonucleosides were used.

Stereoselective Synthesis of Dysoxylactam A.

The first report on the stereoselective synthesis of dysoxylactam A is disclosed. The five stereogenic centers of the fatty acid chain are created by utilizing Merck-Carreira and Marshall's propargylation reaction, Evans' alkylation methodology, and Noyori's transfer hydrogenation protocol.

Stereoselective Synthesis of the C1-C22 Carbon Framework of (-)-Amphidinolide K.

Two stereoselective routes to the C7-C22 subunit of amphidinolide K are disclosed. Jacobsen's hydrolytic kinetic resolution and Sharpless' asymmetric dihydroxylation reactions have been employed for the construction of the tetrahydrofuran ring. The C10-C11, C16-C17, C9-O, and C18-O bonds have been created using α-chloro sulfide intermediates and [2,3] sigmatropic rearrangement.