Abed Saady

Bar Ilan University | BIU · Department of Chemistry

In 1971, Schill recognized that a prochiral macrocycle encircling an oriented axle led to geometric isomerism in rotaxanes. More recently, we identified an overlooked chiral stereogenic unit in rotaxanes that arises when a prochiral macrocycle encircles a prochiral axle. Here, we show that both stereogenic units can be accessed using equivalent str...

Mechanical stereochemistry arises when the interlocking of stereochemically trivial covalent subcomponents results in a stereochemically complex object. Although this general concept was identified in 1961, the stereochemical description of these molecules is still under development to the extent that new forms of mechanical stereochemistry are sti...

Inspired by interlocked oligonucleotides, peptides and knotted proteins, synthetic systems where a macrocycle cages a bioactive species that is “switched on” by breaking the mechanical bond have been reported. However, to date, each example uses a bespoke chemical design. Here we present a platform approach to mechanically caged structures wherein...

Inspired by interlocked oligonucleotides, peptides and knotted proteins, synthetic systems where a macrocycle cages a bioactive species that is “switched on” by breaking the mechanical bond have been reported. However, to date, each example uses a bespoke chemical design. Here we present a platform approach to mechanically caged structures wherein...

Inspired by interlocked oligonucleotides, peptides and knotted proteins, synthetic systems where a macrocycle cages a bioactive species that is “switched on” by breaking the mechanical bond have been reported. However, to date, each example uses a bespoke chemical design. Here we present a platform approach to mechanically caged structures wherein...

These authors contributed equally. ABSTRACT: Mechanical stereochemistry arises when the interlocking of stereochemically trivial covalent subcomponents results in a stereochemical complex object. Although this general concept was identified in 1961, the stereochemical description of these molecules is still under development, with new mechanical st...

In 1971, Schill recognized that a prochiral macrocycle encircling an oriented axle led to geometric isomerism in rotaxanes. More recently, we identified an overlooked chiral stereogenic unit in rotaxanes that arises when a prochiral macrocycle encircles a prochiral axle. Here we show that both stereogenic units can be accessed using equivalent stra...

Mechanical geometric isomerism, which arises when bilaterally dissymmetric components are interlocked such that their internal mirror planes can be made congruent, is under-explored using simple prochiral components. Here we demonstrate that a single intercomponent H-bond appears sufficient to control the formation of rotaxanes and catenanes contai...

Magnetic resonance imaging (MRI) is a powerful imaging modality, widely employed in research and clinical settings. However, MRI images suffer from low signals and a lack of target specificity. We aimed to develop a multimodal imaging probe to detect targeted cells by MRI and fluorescence microscopy. We synthesized a trifunctional imaging probe con...

Active-template auxiliary methodologies have previously been developed for the stereoselective synthesis of chiral interlocked molecules in which the mechanical bond provides the sole stereogenic unit. To date however, the covalent auxiliary has been included in the half-axle components (rotaxanes) or pre-macrocycle components (catenanes), and thus...

Active-template auxiliary methodologies have previously been developed for the stereoselective synthesis of chiral interlocked molecules in which the mechanical bond provides the sole stereogenic unit. To date however, the covalent auxiliary has been included in the half-axle components (rotaxanes) or pre-macrocycle components (catenanes), and thus...

Active-template auxiliary methodologies have previously been developed for the stereoselective synthesis of chiral interlocked molecules in which the mechanical bond provides the sole stereogenic unit. To date however, the covalent auxiliary has been included in the half-axle components (rotaxanes) or pre-macrocycle components (catenanes), and thus...

This article presents a new method for the rapid, stereoselective and regioselective synthesis of nucleoside 2′,3′‐ O , O ‐phosphorothioate and 2′,3′‐ O , O ‐phosphoroselenoate molecules. The method avoids the use of protection groups, chiral reagents, and chiral metal catalysts, as well as complicated chiral separations. This synthetic method has...

Two kinds of Bovine Serum Albumin (BSA)-loaded microspheres were prepared in water-organic bilayer systems using ultrasonic irradiation. The first method included an aqueous solution of BSA and water-soluble dye together, mixed with dodecane, that upon sonication formed a matrix system where the dye is concentrated in the protein shell. The other s...

Chiral crystals of ϵ‐Zn(OH)2 were crystallized from supersaturated aqueous solutions in the presence of l‐ or d‐arginine and chiral discrimination was observed during the crystallization. A new method for identifying chirality in crystals by using electron paramagnetic resonance (EPR) has also been developed. Abstract Many inorganic materials can...

Today, the development of innovative methods for production of organic compounds from natural resources is essential topic for many research groups in the worldwide. Levulinic acid is a platform for many important organic processes in the synthesis of natural products, pharmaceuticals, plasticizers, drugs and various other additives. In addition, 1...

Many inorganic materials can form crystals, but little is known about their enantioselective crystallization. Herein, we report on the enantioselective crystallization of ϵ‐Zn(OH)2 (Wulfingite) chiral crystals by using amino acids. Crystals of ϵ‐Zn(OH)2 were crystallized from supersaturated sodium hydroxide and zinc nitrate aqueous solutions in the...

The ultrasonic technique has received considerable attention in several fields; in particular, it gained rapid momentum in organic synthesis due to the larger reaction rates, milder reaction conditions, and better yields. We report herein a facile synthesis of a series of styrylpyridinium based dyes under ultrasonic irradiation. Within short reacti...

Currently, there is demand for fluorescent oligonucleotide probes for diagnostic purposes. To address this necessity, we developed nucleosides containing a flexible spacer with an intercalating moiety at its end (NIC molecules). The intercalator is based on 4-hydroxybenzylidene imidazolinone (HBI), found in the Green Fluorescent Protein. We synthes...

Nucleoside intercalator conjugates (NICs) describe an innovative methodology developed in our research group for preparation of fluorescence turn‐on DNA hybridization probes targeting specific mRNA sequences (e.g., breast cancer markers). In this methodology, we conjugate a non‐fluorescent intercalator to the base of a nucleic acid (e.g., uracil) v...

The detection of subcellular domains in cells can be obtained by specific fluorescent markers. Here we report the use of styryl quinolinium dyes that selectively stain ribosomal RNA (rRNA) in nucleoli and in the cytoplasm of mammalian cells. Specifically, we synthesized a series of 1-methyl-4-(substituted) styryl-quinolinium derivatives, 12a–l. We...

Fluorescent probes with high signal/background ratio are needed for hybridization assays. Hence, the chromophore of green fluorescent protein (GFP), 4-hydroxybenzylidene-imidazolinone (HBI), was targeted as a potential fluorescent intercalator. For producing a building block for fluorescent oligonucleotide probes, 2'-deoxyuridine (dU) was conjugate...

As part of our efforts to develop a new method for chiral resolution of amino acids with sonochemically modified proteins, we present result that indicates how ovalbumin microspheres (OAMS) interact specifically with l-amino acids from a racemate in solution, leaving an excess of d-enantiomer in the permeate solution. Among different amino acids th...

Diagnosis and treatment of breast cancer can be greatly enhanced and personalized based on the quantitative detection of mRNA markers. Here, we targeted the development of a fluorescent oligonucleotide probe to detect specifically the HER-2 mRNA breast cancer marker. We have selected the chromophore of the Green Fluorescent Protein (GFP), 4-hydroxy...

This preliminary study describes a one-step sonochemical formation of Bovine Serum Albumin (BSA) microspheres and their chiral interaction with several amino acids. Partial separation between enantiomers of various amino acids was accomplished by the interaction of these microspheres with solutions of racemic amino acids. The highest rate of enanti...