Bioconjugation of Small Molecules to RNA Impedes Its Recognition by Toll-Like Receptor 7

2017

A fundamental mechanism of the innate immune system is the recognition, via extra- and intracellular pattern recognition receptors, of pathogen-associated molecular patterns. A prominent example is represented by foreign nucleic acids, triggering the activation of several signaling pathways. Among these, the endosomal toll-like receptor 7 (TLR7) is known to be activated by single stranded RNA (ssRNA), which can be specifically influenced through elements of sequence structure and posttranscriptional modifications. Furthermore, small molecules TLR7 agonists (smTLRa) are applied as boosting adjuvants in vaccination processes. In this context, covalent conjugations between adjuvant and vaccine…

Targeting of immune cells with trimannosylated liposomes

2020

A Photoredox-Catalyzed Four Component Reaction for the Atom-Efficient Synthesis of Complex Secondary Amines

2020

The one-pot sulfonylation/aminoalkylation of styrene derivatives furnishing highly substituted gamma-sulfonylamines was accomplished through a photoredox-catalyzed four-component reaction. Apart from one molecule of water and the sodium counterion of the sulfinate, all atoms of the starting materials are transferred to the final product, rendering this process highly atom-efficient. The operationally simple protocol allows for the simultaneous formation of three new single bonds (C–S, C–N, and C–C) and therefore grants rapid access to structurally diverse products. The reaction proceeds under mild conditions in aqueous acetonitrile and shows a broad scope, including natural products and dru…

HPMA-Based Nanocarriers for Effective Immune System Stimulation.

2019

The selective activation of the immune system using nanoparticles as a drug delivery system is a promising field in cancer therapy. Block copolymers from HPMA and laurylmethacrylate-co-hymecromone-methacrylate allow the preparation of multifunctionalized core-crosslinked micelles of variable size. To activate dendritic cells (DCs) as antigen presenting cells, the carbohydrates mannose and trimannose are introduced into the hydrophilic corona as DC targeting units. To activate DCs, a lipophilic adjuvant (L18-MDP) is incorporated into the core of the micelles. To elicit an immune response, a model antigen peptide (SIINFEKL) is attached to the polymeric nanoparticle-in addition-via a click rea…

Visible Light Enables Aerobic Iodine Catalyzed Glycosylation

2019

Front Cover: Visible‐Light‐Induced Cleavage of C−S Bonds in Thioacetals and Thioketals with Iodine as a Photocatalyst (ChemPhotoChem 2/2020)

2020

Neo-clerodane diterpenoids from Conyza pyrrhopappa Sch.Bip. ex A.Rich

2019

Two hitherto unknown neo-clerodane-type diterpenoids along with twelve known compounds have been isolated from Conyza pyrrhopappa Sch.Bip. ex A.Rich, a medicinal plant traditionally used across tropical Africa to relieve fever. The structures of isolates have been elucidated by a combination of spectroscopic techniques. The crude extract and the isolated compounds were evaluated in the Hela-S3 cell line and in a panel of microorganisms (bacteria and fungi) at concentrations up to 50 µg/mL. The new compounds were inactive while the pentamethylated flavonoids showed low to significant activity against the cancer cell line used. However, none of the samples showed any activity against the test…

Photoredox-Catalyzed Four-Component Reaction for the Synthesis of Complex Secondary Amines.

2020

The one-pot sulfonylation/aminoalkylation of styrene derivatives furnishing substituted γ-sulfonylamines was accomplished through a photoredox-catalyzed four-component reaction. Besides one molecule of water and the sodium counterion of the sulfinate, all atoms of the starting materials are transferred to the final product, rendering this process highly atom-efficient. The operationally simple protocol allows for the simultaneous formation of three new single bonds (C-S, C-N, and C-C) and therefore grants rapid access to structurally diverse products.

Front Cover: Visible Light Enables Aerobic Iodine Catalyzed Glycosylation (Eur. J. Org. Chem. 28/2019)

2019

Total Synthesis of a Partial Structure from Arabinogalactan and Its Application for Allergy Prevention

2020

Abstract Arabinogalactan, a microheterogeneous polysaccharide occurring in plants, is known for its allergy‐protective activity, which could potentially be used for preventive allergy treatment. New treatment options are highly desirable, especially in a preventive manner, due to the constant rise of atopic diseases worldwide. The structural origin of the allergy‐protective activity of arabinogalactan is, however, still unclear and isolation of the polysaccharide is not feasible for pharmaceutical applications due to a variation of the activity of the natural product and contaminations with endotoxins. Therefore, a pentasaccharide partial structure was selected for total synthesis and subse…

Multivalency Beats Complexity: A Study on the Cell Uptake of Carbohydrate Functionalized Nanocarriers to Dendritic Cells.

2020

Herein, we report the synthesis of carbohydrate and glycodendron structures for dendritic cell targeting, which were subsequently bound to hydroxyethyl starch (HES) nanocapsules prepared by the inverse miniemulsion technique. The uptake of the carbohydrate-functionalized HES nanocapsules into immature human dendritic cells (hDCs) revealed a strong dependence on the used carbohydrate. A multivalent mannose-terminated dendron was found to be far superior in uptake compared to the structurally more complex oligosaccharides used.

Visible‐Light‐Induced Cleavage of C−S Bonds in Thioacetals and Thioketals with Iodine as a Photocatalyst

2020

Cover Feature: Total Synthesis of a Partial Structure from Arabinogalactan and Its Application for Allergy Prevention (Chem. Eur. J. 3/2021)

2020

Neo-clerodane diterpenoids from Conyza pyrrhopappa Sch.Bip. ex A.Rich

2019

Two hitherto unknown neo-clerodane-type diterpenoids along with twelve known compounds have been isolated from Conyza pyrrhopappa Sch.Bip. ex A.Rich, a medicinal plant traditionally used across tropical Africa to relieve fever. The structures of isolates have been elucidated by a combination of spectroscopic techniques. The crude extract and the isolated compounds were evaluated in the Hela-S3 cell line and in a panel of microorganisms (bacteria and fungi) at concentrations up to 50 ��g/mL. The new compounds were inactive while the pentamethylated flavonoids showed low to significant activity against the cancer cell line used. However, none of the samples showed any activity against the tes…