A Proline-Squaraine Ligand Framework (Pro-SqEB) for Stereoselective Rhodium(II)-Catalyzed Cyclopropanations.

A proline-squaraine ligand (Pro-SqEB) that demonstrates high levels of stereoselectivity in olefin cyclopropanations when anchored to a Rh2II scaffold is introduced. High yields and enantioselectivities were achieved in the cyclopropanation of alkenes with diazo compounds in the presence of Rh2(Pro-SqEB)4. Notably, the unique electronic and steric design of this catalyst enabled the use of polar solvents that are otherwise incompatible with most RhII complexes.

Rational Design and Identification of Harmine-Inspired, N-Heterocyclic DYRK1A Inhibitors Employing a Functional Genomic In Vivo Drosophila Model System.

Deregulation of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) plays a significant role in developmental brain defects, early-onset neurodegeneration, neuronal cell loss, dementia, and several types of cancer. Herein, we report the discovery of three new classes of N-heterocyclic DYRK1A inhibitors based on the potent, yet toxic kinase inhibitors, harmine and harmol. An initial in vitro evaluation of the small molecule library assembled revealed that the core heterocyclic motifs benzofuranones, oxindoles, and pyrrolones, showed statistically significant DYRK1A inhibition. Further, the utilization of a low cost, high-throughput functional genomic in vivo model system to identify small molecule inhibitors that normalize DYRK1A overexpression phenotypes is described. This in vivo assay substantiated the in vitro results, and the resulting correspondence validates generated classes as architectural motifs that serve as potential DYRK1A inhibitors. Further expansion and analysis of these core compound structures will allow discovery of safe, more effective chemical inhibitors of DYRK1A to ameliorate phenotypes caused by DYRK1A overexpression.

A Phosphine-Mediated Dearomative Skeletal Rearrangement of Dianiline Squaraine Dyes.

A phosphorus(III)-mediated dearomatization of ortho-substituted dianiline squaraine dyes results in an unusual skeletal rearrangement to provide exotic, highly conjugated benzofuranone and oxindole scaffolds bearing a C3 side chain comprised of a linear conflagration of an enol, a phosphorus ylide, and 2,4-disubstituted aniline. Employing experimental and computational analysis, a mechanistic evaluation revealed a striking dependence on the acidity of the aniline ortho substituent. Notably, the rearrangement adducts underwent rapid and complete reversion to the parent squaraine in the presence of a Brønsted acid.

Combined Scaffold Evaluation and Systems-Level Transcriptome-Based Analysis for Accelerated Lead Optimization Reveals Ribosomal Targeting Spirooxindole Cyclopropanes.

With evolutionary drug resistance impacting efforts to treat disease, the need for small molecules that exhibit novel molecular mechanisms of action is paramount. In this study, we combined scaffold-directed synthesis with a hybrid experimental and transcriptome analysis to identify bis-spirooxindole cyclopropanes that inhibit cancer cell proliferation through disruption of ribosomal function. These findings demonstrate the value of an integrated, biologically inspired synthesis and assay strategy for the accelerated identification of first-in-class cancer therapeutic candidates.

Nucleophilic addition of phosphorus(iii) derivatives to squaraines: colorimetric detection of transition metal-mediated or thermal reversion.

Nucleophilic addition of phosphorus(iii) agents to the electrophilic core of intensely colored squaraine dyes gives a bleached zwitterionic adduct in good to excellent yields (up to 99%) at room temperature. The process can be reversed by adding specific transition metal complexes with high phosphorous(iii) affinity.