Marc Y. Stevens

Sulfonyl Azides as Precursors in Ligand-Free Palladium-Catalyzed Synthesis of Sulfonyl Carbamates and Sulfonyl Ureas and Synthesis of Sulfonamides.

An efficient synthesis of sulfonyl carbamates and sulfonyl ureas from sulfonyl azides employing a palladium-catalyzed carbonylation protocol has been developed. Using a two-chamber system, sulfonyl azides, PdCl2, and CO gas, released ex situ from Mo(CO)6, were assembled to generate sulfonyl isocyanates in situ, and alcohols and aryl amines were exploited as nucleophiles to afford a broad range of sulfonyl carbamates and sulfonyl ureas. A protocol for the direct formation of substituted sulfonamides from sulfonyl azides and amines via nucleophilic substitution was also developed.

Synthesis of Sulfonyl Azides via Diazotransfer using an Imidazole-1-sulfonyl Azide Salt: Scope and 15N NMR Labeling Experiments

Imidazole-1-sulfonyl azide hydrogen sulfate is presented as an efficient reagent for the synthesis of sulfonyl azides from primary sulfonamides. The described method is experimentally simple and high-yielding and does not require the addition of Cu salts. Furthermore, (15)N NMR mechanistic studies show the reaction proceeds via a diazo transfer mechanism. Imidazole-1-sulfonyl azide hydrogen sulfate provides a considerable advantage over existing diazo transfer reagents in terms of impact stability, cost, and ease of use.

Mild and Low-Pressure fac-Ir(ppy)3 -Mediated Radical Aminocarbonylation of Unactivated Alkyl Iodides through Visible-Light Photoredox Catalysis.

A novel, mild and facile preparation of alkyl amides from unactivated alkyl iodides employing a fac-Ir(ppy)3 -catalyzed radical aminocarbonylation protocol has been developed. Using a two-chambered system, alkyl iodides, fac-Ir(ppy)3 , amines, reductants, and CO gas (released ex situ from Mo(CO)6 ), were combined and subjected to an initial radical reductive dehalogenation generating alkyl radicals, and a subsequent aminocarbonylation with amines affording a wide range of alkyl amides in moderate to excellent yields.

A microwave-assisted multicomponent synthesis of substituted 3,4-dihydroquinazolinones

A microwave-assisted, multicomponent protocol for the synthesis of substituted 3,4-dihydroquinazolinones via a novel cascade imine/cyclization/aza-Henry reaction sequence is reported. Starting from o-formyl carbamates, a series of structurally diverse 3,4-dihydroquinazolinones was synthesized via a cyclic iminium ion intermediate in moderate to excellent yields. Notably, the reaction is fast, flexible, simple to perform and tolerates a variety of functional groups.

Synthesis of 11C-labeled Sulfonyl Carbamates through a Multicomponent Reaction Employing Sulfonyl Azides, Alcohols, and [11C]CO

Abstract We describe the development of a new methodology focusing on 11C‐labeling of sulfonyl carbamates in a multicomponent reaction comprised of a sulfonyl azide, an alkyl alcohol, and [11C]CO. A number of 11C‐labeled sulfonyl carbamates were synthesized and isolated, and the developed methodology was then applied in the preparation of a biologically active molecule. The target compound was obtained in 24±10 % isolated radiochemical yield and was evaluated for binding properties in a tumor cell assay; in vivo biodistribution and imaging studies were also performed. This represents the first successful radiolabeling of a non‐peptide angiotensin II receptor subtype 2 agonist, C21, currently in clinical trials for the treatment of idiopathic pulmonary fibrosis.

3,4-Dihydro-3-(2-hydroxyethyl)-4-(nitromethyl)quinazolin-2(1H)-one

A one-pot, direct synthesis of 3,4-dihydro-3-(2-hydroxyethyl)-4-(nitromethyl)quinazolin-2(1H)-one from methyl (2-formylphenyl)carbamate, ethanolamine and nitromethane in AcOH is reported. The reaction proceeds via a cascade three-component aza-Henry reaction under microwave irradiation and the title compound was characterized by 1H NMR, 13C NMR and ESI/MS analysis.

Microwave-Assisted Branching Cascades: A Route to Diverse 3,4-Dihydroquinazolinone-Embedded Polyheterocyclic Scaffolds

A novel metal-free microwave-assisted branching cascades strategy for the efficient synthesis of 3,4-dihydroquinazolinone-embedded polyheterocyclic scaffolds is reported. Starting from in situ generated key N-acyliminium ion precursors, 12 distinct and skeletally diverse polycyclic frameworks were accessed in a single step/pot via adjustment of the nucleophile(s) and reaction conditions. Postcascade functionalization of these compounds was also demonstrated, proving the utility of this method in accessing structurally diverse chemical entities.