Dr. Tanay Kesharwani

Benzo[b]thiophene scaffolds form the backbone of many pharmaceutical products. Their uses in medicinal chemistry include antidepressants, anti-inflammatories, and anti-tumor among other possibilities. In the traditional multi-step synthesis, the product needs purification after each step1,2 . This can lead to increased chemical waste and loss of product. Further exploration into this field could yield more efficient synthesis, as well as create a foundation capable of being altered with different substituents for varied applications.

Benzofuran is an important backbone for molecules that make up several pharmaceuticals, herbicides/pesticides, and organo-electronics. An environmentally benign dimethyl(methylthio)sulfonium tetrafluoroborate salt was used as an electrophile to induce cyclization of o-alkynyl anisoles to form 2,3-disubstituted benzofurans. The cyclization is performed at ambient reaction conditions, only takes 12 hours to get excellent yields, and shows a high tolerance for various substituted alkynes. Also, a trimethyl group obtained after the cyclization reactions allows for a cascade cyclization, and an alkyne is used in the reaction to create a thieno[3,2-b]benzofuran core structure.

Electrostatic interactions between oppositely charged entities play a key role in pre-organizing substrates and stabilizing transition states of reactions in enzymes. The use of electrostatic interactions to pre-organize ions in nanoconfined pores, however, has not been investigated to its full potential. Herein, we describe how carboxylate anions can be pre-organized at the behest of their electrostatic interactions with K+ cations in nanoconfined tunnels present in γ-cyclodextrin metal-organic frameworks, i.e., CD-MOFs. Several carboxylate anions, which are all much smaller than the cavities of the tunnels, were visualized by X-ray crystallography when nanoconfined in CD-MOFs, despite the large voids present in the tunnels. These anions were found to be aligned within a planar array defined by four K+ cations, positioned around the periphery of the tunnels. The strong electrostatic interactions between the carboxylate anions and the K+ cations dictate the orientation of the anions and override the influence of other possible noncovalent bonding interactions between them and the tunnels. Consequently, the aligned pairs of γ-cyclodextrin rings constituting the tunnels become distorted, resulting in their lower symmetry and fewer disordered carboxylate anions in the solid-state. Our findings offer a transformative strategy for controlling the packing and orientation of ions in nanoconfined environments.

Studying the energy of a band gap in molecules has valuable applications in semiconductor physics. The energy of a band gap refers to the energy difference between the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) or the top of the valence band and the bottom of the conduction band. A lower band gap energy corresponds to higher efficiency or lower wavelength. Studying the conductivity of organic molecules is a very useful field since organic compounds are more versatile and cheaper to produce than regular silicon semiconductors. This has a wide array of applications, especially in LEDs and micro processing units.

Molecular machines combine the fundamentals of physics and chemistry to progress a variety of fields from medicine to material science.1 These specific arrangements of molecules carry out mechanical processes on the molecular level, enabling precise movements and control at the nanoscale. One concept for a molecular machine is the Nanocar–a vehicle scaled down to the molecular level, as shown in Figure 1.3 The development of Nanocars through the manipulation of individual atoms and molecules pushes the realm of possibilities of mechanical miniaturization and nanotechnology. In this poster, we explore the synthesis of Nanocars with simple organic reactions to further expand the possibilities of molecular machinery.

Antimicrobial Resistance (AMR) is the next impending health crisis knocking at our doors and the biggest challenge in fighting AMR infections is the scarcity of novel and effective antibiotics. The objective of this study is to evaluate novel class of compounds called benzothiophenes for their potential antimicrobial activity. Previous studies have indicated great promise of benzothiophene derivatives as an important biological core structure. Benzo[b]thiophene core structure is present in several FDA-approved drugs, such as raloxifene, zileuton, and sertaconazole. In this study, the novel benzothiophene derivatives were synthesized using common organic synthesis methods such as Sonogashira coupling and electrophilic cyclization reactions. Proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), gas chromatography-mass spectroscopy (GC-MS), and high-performance liquid chromatography (HPLC) were used to determine compound identity and purity. The compounds were tested against gram positive bacteria (S. aureus, M. luteus, and E. faecalis), gram-negative bacteria (E. coli, and P. aeruginosa) and fungi such as C. albicans and C. tropicalis, via a broth microdilution susceptibility assay in a 96-well plate. Briefly, varying concentrations of the compound were incubated with the cells. After incubation, the plates were read using a plate reader to determine the absorbance and minimum inhibitory concentration (MIC) values. The low MIC values for the benzo[b]thiophene derivative compounds signify a promising antimicrobial activity. Further biological studies were performed to determine the toxicity of the compounds to human cell lines. Preliminary results showed that addition of some groups increased the antibacterial activity of the benzo[b]thiophene derivatives while addition of other groups decreased the activity of the compounds. In conclusion, this project will help to identify more potent benzo[b]thiophene derivatives with broader efficacy against both bacteria and fungi. This research accomplishes crucial steps toward developing potent benzo[b]thiophenes as a possible clinical candidate as an antimicrobial drug.

Billions of years of evolution have honed nature’s extraordinary capacity in promoting site-selective functionalization of C(sp3)–H bonds in complex molecules. Central to this incredible proficiency is the effect of confinement incurred by enzymes’ active sites, which pre-organize substrates in desired co-conformations prior to their selective transformations. The fact that C(sp3)–H bonds with negligible stereoelectronic differences can be differentiated at an Ångström level during enzymatic catalysis means that precise control of site selectivities in C(sp3)–H functionalization can in principle be achieved by tailoring the cavity sizes, geometries, and stereoelectronic environments of artificial receptors. Given the importance of late-stage functionalization in drug development, there is every reason to believe that confinement, among other strategies, will become an increasingly important tool for tackling challenges in the selective editing of C(sp3)–H bonds in complex settings.

Covalent organic frameworks (COFs) have unique features, including intrinsic porosity, crystallinity, and tunability, making them desirable materials for diverse applications ranging from environmental remediation to energy harvesting. Among these applications, COFs are extensively studied for their photocatalytic hydrogen evolution by converting solar energy into clean and renewable fuel via water splitting. COFs have several advantages over conventional inorganic catalysts, such as tunable band structures, high surface areas, and low cost. However, the research in this field is still in the early stages, and COFs still face some challenges, such as low charge carrier mobility, high exciton binding energy, and poor stability. To overcome these challenges, various design strategies relying on a mechanistic approach have been developed to design and modify COFs for enhanced photocatalytic performance. These include extending the p-conjugation, incorporating heteroatoms or metal complexes, and donor-acceptor (D-A) configuration, which ultimately improves the light absorption charge separation of COFs. Additionally, blending COFs with other functional materials, such as inorganic-organic semiconductors, can create synergistic effects to boost photocatalytic activity. In this review, the design aspects of the fabrication of COFs as effective photocatalysts have been reported.