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Efforts Toward Difunctionalization of (Hetero)Arenes Enabled by Visible Light
No full textFunctionalized arenes and heteroarenes are ubiquitous motifs in natural products, pharmaceuticals, and functional materials. As such, methods to place multiple functionalities on (hetero)arenes in one synthetic step create molecular complexity quickly and are highly valued. The vast majority of current strategies are metal-mediated, although others such as utilizing aryne intermediates and cycloadditions have also been reported. The premier challenge in this research area is the difficulty in controlling regioselectivity. Strategies of controlling regioselectivity have included tuning the electronic nature of the substrate, the use of directing groups (DGs), steric influences, ligand control, and photochemically initiated methods. Certain strategies tend to bias particular regioselectivity outcomes. The use of direction groups in difunctionalization, for example, tend to give ortho/ortho selectivity due to the proximity of the C-H bond to the directing group. Some advancements have emerged in expanding the scope of particular regioselectivity patterns, but many challenges still exist in this relatively underdeveloped area. Our research aims to develop difunctionalization protocols of high synthetic utility using both photochemical and ligand influences to effect uncommon selectivity patterns without the need for excessive prefunctionalization of the substrate. Our model system and proof-of-concept used [Ir(ppy)2(Cl)2]PF6 as a substrate, with the goal of difunctionalizing and isolating the coordinated phenylpyridine ligand. A mixed electrophile method combining diphenyl disulfide and N-chlorosuccinimide was used, which we hypothesized may add to the phenylpyridine ligands of the iridium complex with useful regioselectivity patterns. Visibile light (390 nm) was used to generate reactive thiophenyl and chloryl radicals which we hypothesized could difunctionalize the phenylpyridine ligand through a tandem SRAr-reductive elimination sequence. Mass spectrometry (ESI) evidence showed significant amounts of several organic products including dithiolated, thiolated plus chlorinated, and dithiolated plus chlorinated phenylpyridine products. Isolation of the products proved difficult and was ultimately unsuccessful. Further isolation techniques will be needed to isolate and fully characterize these compounds. Another reaction developed towards difunctionalization of (hetero)arenes uses Co(bpy)2Cl2 combined with activated zinc powder, a supporting N-donor ligand, an aryl bromide, DMF, and visible light irradiation (390 nm) to yield 6-phenyl – 2,2 – bipyridine. This method gives the product as the sole regioisomer. The reaction protocol provides a new aryl radical generation method that is both convenient and mild. Further optimization is needed to improve yields and expand the scope of this initial step. We envision that a rollover cyclometallation and reductive elimination sequence could give a difunctionalized bipyridine product with reliable regioselectivity
Comprehensive Behavioral Intervention for Tics Specialty Clinic Outcomes
Get PDFTics are abrupt, repetitive, and non-rhythmic movements (motor tics) and vocalizations (vocal tics). Persistent (Chronic) Tic Disorders (PTDs), which include conditions such as Tourette Disorder (TD), are characterized by involuntary motor and vocal tics. PTDs are associated with a myriad of adverse social repercussions, reduced quality of life, and concurrent psychiatric diagnoses, and occur in approximately 1.1% to 4.8% of the global population. Comprehensive Behavioral Intervention for Tics (CBIT) stands as the primary nonpharmacological therapeutic approach for tics. Although the efficacy of CBIT has been established in multiple large-scale randomized control trials (RCTs), there is a paucity of research scrutinizing the effectiveness of CBIT within standard outpatient settings. Consequently, the current study involved a chart review in a university-based clinic to elucidate the effectiveness of CBIT in a psychology training clinic that specializes in tic treatment. Objective 1 sought to use preexisting data on tic severity and self-reported distress to assess the outcomes of a CBIT specialty training clinic. Patients who receive CBIT in this setting were hypothesized to experience a significant reduction in tic severity and tic-related perceived distress from first to last visit. Objective 2 aimed to investigate potential differences in the duration of administration between a naturalistic context of CBIT and the standardized CBIT protocol. It was hypothesized that the average number of CBIT sessions delivered to patients in a real-world community clinic would be notably lower than the predetermined quantity outlined in the standard CBIT protocol. Objective 3 aimed to investigate whether patient sex at birth and age predicted change in tic severity over the course of CBT. It was hypothesized that greater tic severity would be reduced more significantly for males and older patients compared to females and younger patients
Zuckerberg Facebook video about Meta AI image generation and an imaginary meat shop
No full texthttps://epublications.marquette.edu/zuckerberg_files_videos/1436/thumbnail.jp
