Potent antitumor activity of anti-HER2 antibody-topoisomerase I inhibitor conjugate based on self-immolative dendritic dimeric-linker.

Antibody-drug conjugates (ADCs) are a rapidly expanding class of anticancer therapeutics, with 14 ADCs already approved worldwide. We developed unique linker technologies for the bioconjugation of drug molecules with controlled-release applications. We synthesized cathepsin-cleavable ADCs using a dimeric prodrug system based on a self-immolative dendritic scaffold, resulting in a high drug-antibody ratio (DAR) with the potential to reach 16 payloads due to its dendritic structure, increased stability in the circulation and efficient release profile of a highly cytotoxic payload at the targeted site.

Stable and Storable N(CF ) Transfer Reagents.

Fluorinated groups are essential for drug design, agrochemicals, and materials science. The bis(trifluoromethyl)amino group is an example of a stable group that has a high potential. While the number of molecules containing perfluoroalkyl, perfluoroalkoxy, and other fluorinated groups is steadily increasing, examples with the N(CF ) group are rare.

Spontaneous Isopeptide Bond Formation as a Powerful Tool for Engineering Site-Specific Antibody-Drug Conjugates.

Spontaneous isopeptide bond formation, a stabilizing posttranslational modification that can be found in gram-positive bacterial cell surface proteins, has previously been used to develop a peptide-peptide ligation technology that enables the polymerization of tagged-proteins catalyzed by SpyLigase. Here we adapted this technology to establish a novel modular antibody labeling approach which is based on isopeptide bond formation between two recognition peptides, SpyTag and KTag. Our labeling strategy allows the attachment of a reporting cargo of interest to an antibody scaffold by fusing it chemically to KTag, available via semi-automated solid-phase peptide synthesis (SPPS), while equipping the antibody with SpyTag.

One-Pot Synthesis of Substituted Trifluoromethylated 2,3-Dihydro-1H-imidazoles.

An operationally simple one-pot reaction for the preparation of a novel class of racemic trifluoromethylated 2,3-dihydro-1H-imidazoles derived from electron-poor N,O-acetals and aryl Grignard reagents is described. In addition, access to highly functionalized 2-trifluoromethyl-2,3-dihydro-1H-imidazoles was accomplished by reaction of N-aryl hemiaminal ethers and N-aryl trifluoroethylamines in the presence of an excess of n-butyllithium.

Combined coinage metal catalysis in natural product synthesis: total synthesis of (+)-varitriol and seven analogs.

A modular total synthesis of the natural product (+)-varitriol (1) and seven analogs was achieved by using combined coinage metal catalysis. Starting from enynol 13, reagent-controlled introduction of stereogenic centers and efficient center-to-axis-to-center chirality transfer viaα-hydroxyallene 5 afforded (+)-varitriol with 6.4% yield over 10 steps.

(NHC)CuH-catalyzed entry to allenes via propargylic carbonate S(N)2'-reductions.

The copper hydride-catalyzed S(N)2'-reduction of propargylic carbonates provides an efficient route to functionalized allenes. The method takes advantage of the stabilizing effect of NHC ligands on CuH and combines high reactivity and stereoselectivity with excellent tolerance toward reactive functionalities.

Stereoselective synthesis of syn-configured alpha-allenols by rhodium-catalyzed reaction of alkynyl oxiranes with arylboronic acids.

A rhodium-catalyzed reaction of alkynyl oxiranes with arylboronic acids affords syn-configured alpha-allenols with high diastereoselectivity. The reaction is initiated by addition of an arylrhodium(I) species onto the alkyne moiety of the alkynyl oxirane. The resulting alkenylrhodium(I) intermediate undergoes beta-oxygen elimination to open the oxirane ring in a syn-selective fashion.

Synthesis of covalent DNA-protein conjugates by expressed protein ligation.

Semisynthetic DNA-protein conjugates are versatile tools for many applications in bioanalytics and nanobiotechnology. We here report a method based on expressed protein ligation (EPL) for the site-specific coupling of cysteine-modified DNA oligomers with recombinant intein-fusion proteins. The latter contain a C-terminal thioester, enabling the mild and highly specific reaction with N-terminal cysteine compounds.