Coordination-Driven Self-Assembly of a Discrete Molecular Cage and an Infinite Chain of Coordination Cages Based on <i>ortho</i>-Linked Oxacalix[2]benzene[2]pyrazine and Oxacalix[2]arene[2]pyrazine

Coordination-Driven Self-Assembly of a Discrete Molecular Cage and an Infinite Chain of Coordination Cages Based on ortho-Linked Oxacalix[2]benzene[2]pyrazine and Oxacalix[2]arene[2]pyrazin

Coordination-Driven Self-Assembly of a Discrete Molecular Cage and an Infinite Chain of Coordination Cages Based on <i>ortho</i>-Linked Oxacalix[2]benzene[2]pyrazine and Oxacalix[2]arene[2]pyrazine

Coordination-Driven Self-Assembly of a Discrete Molecular Cage and an Infinite Chain of Coordination Cages Based on ortho-Linked Oxacalix[2]benzene[2]pyrazine and Oxacalix[2]arene[2]pyrazin

Coordination-Driven Self-Assembly of a Discrete Molecular Cage and an Infinite Chain of Coordination Cages Based on <i>ortho</i>-Linked Oxacalix[2]benzene[2]pyrazine and Oxacalix[2]arene[2]pyrazine

Coordination-Driven Self-Assembly of a Discrete Molecular Cage and an Infinite Chain of Coordination Cages Based on ortho-Linked Oxacalix[2]benzene[2]pyrazine and Oxacalix[2]arene[2]pyrazin

Synthesis of 2‘-<i>O</i>-Methoxyethylguanosine Using a Novel Silicon-Based Protecting Group

A short and efficient synthesis of 2‘-O-methoxyethylguanosine (8) is described. Central to this strategy is the development of a novel silicon-based protecting group (MDPSCl2, 2) used to protect the 3‘,5‘-hydroxyl groups of the ribose. Silylation of guanosine with 2 proceeded with excellent regioselectivity and in 79% yield. Alkylation of the 2‘-hydroxyl group of 6 proceeded with methoxyethyl bromide and NaHMDS and afforded compound 7 in 85% yield, without any noticeable cleavage of the silyl protecting group and without the need to protect the guanine base moiety. Finally, deprotection of 7 was achieved using TBAF and produced 8 in 97% yield

Synthesis of 2‘-<i>O</i>-Methoxyethylguanosine Using a Novel Silicon-Based Protecting Group

A short and efficient synthesis of 2‘-O-methoxyethylguanosine (8) is described. Central to this strategy is the development of a novel silicon-based protecting group (MDPSCl2, 2) used to protect the 3‘,5‘-hydroxyl groups of the ribose. Silylation of guanosine with 2 proceeded with excellent regioselectivity and in 79% yield. Alkylation of the 2‘-hydroxyl group of 6 proceeded with methoxyethyl bromide and NaHMDS and afforded compound 7 in 85% yield, without any noticeable cleavage of the silyl protecting group and without the need to protect the guanine base moiety. Finally, deprotection of 7 was achieved using TBAF and produced 8 in 97% yield

<i>ortho</i>-Functionalization of Pillar[5]arene: An Approach to Mono-<i>ortho</i>-Alkyl/Aryl-Substituted A1/A2-Dihydroxypillar[5]arene

Despite the fact that the rim and lateral functionalizations of pillar­[n]­arenes have been well explored, ortho-functionalization has rarely been realized. In this work, we report a facile method of introducing a single functionality ortho to the hydroxyl group in A1/A2-dihydroxypillar[5]­arene via a Grignard addition to pillar[4]­arene[1]­quinone followed by a dienone–phenol rearrangement. The described ortho-alkylation/arylation method allowed formation of various mono ortho-alkyl/aryl-substituted A1/A2-dihydroxypillar[5]­arenes previously difficult to obtain

Tetranitro-oxacalix[4]crown-Based Host–Guest Recognition Motif and a Related [2]Rotaxane-Based Molecular Switch

Different from so far reported oxacalix[4]­crown-based host–guest motifs in which oxacalix[4]­crowns act only as hydrogen bond acceptors, a [2]­pseudorotaxane-type tetranitro-oxacalix[4]­crown/urea host–guest recognition motif was developed in which tetranitro-oxacalix[4]­crown played a role as both a hydrogen bond donor and an acceptor to stabilize the resulting supramolecular complex. Furthermore, on the basis of a [2]­pseudorotaxane complex formed from a tetranitro-oxacalix[4]­crown and an axle containing a secondary ammonium ion and a urea group, a [2]­rotaxane-based molecular switch was created, in which the oxacalix[4]­crown wheel was able to reversibly translocate between the secondary ammonium binding site and the urea binding site of the axle under acid–base stimulation

DataSheet1_Endothelial glycocalyx sensitivity to chemical and mechanical sub-endothelial substrate properties.PDF

Glycocalyx (GCX) is a carbohydrate-rich structure that coats the surface of endothelial cells (ECs) and lines the blood vessel lumen. Mechanical perturbations in the vascular environment, such as blood vessel stiffness, can be transduced and sent to ECs through mechanosensors such as GCX. Adverse stiffness alters GCX-mediated mechanotransduction and leads to EC dysfunction and eventually atherosclerotic cardiovascular diseases. To understand GCX-regulated mechanotransduction events, an in vitro model emulating in vivo vessel conditions is needed. To this end, we investigated the impact of matrix chemical and mechanical properties on GCX expression via fabricating a tunable non-swelling matrix based on the collagen-derived polypeptide, gelatin. To study the effect of matrix composition, we conducted a comparative analysis of GCX expression using different concentrations (60–25,000 μg/mL) of gelatin and gelatin methacrylate (GelMA) in comparison to fibronectin (60 μg/mL), a standard coating material for GCX-related studies. Using immunocytochemistry analysis, we showed for the first time that different substrate compositions and concentrations altered the overall GCX expression on human umbilical vein ECs (HUVECs). Subsequently, GelMA hydrogels were fabricated with stiffnesses of 2.5 and 5 kPa, representing healthy vessel tissues, and 10 kPa, corresponding to diseased vessel tissues. Immunocytochemistry analysis showed that on hydrogels with different levels of stiffness, the GCX expression in HUVECs remained unchanged, while its major polysaccharide components exhibited dysregulation in distinct patterns. For example, there was a significant decrease in heparan sulfate expression on pathological substrates (10 kPa), while sialic acid expression increased with increased matrix stiffness. This study suggests the specific mechanisms through which GCX may influence ECs in modulating barrier function, immune cell adhesion, and mechanotransduction function under distinct chemical and mechanical conditions of both healthy and diseased substrates.</p