Synthesis of N-Sulfonyl Arylaldimines Developed by Retesting an Old Process

Eco-friendly and efficient catalyst-free synthesis of N-sulfonylimines from sulfonamides and aldehydes: crucial role of Al2O3 as a reusable dehydrating agent

A green synthetic method for the synthesis of N-sulfonylimines was developed involving the straightforward condensation of sulfonamides with aldehydes under green and catalyst-free conditions, mediated by neutral Al₂O₃ as an efficient and reusable dehydrating agent. N-Sulfonylimines were produced in high yields and purity under simple experimental procedures.

Palladium-Catalyzed Chemodivergent Carbonylation of ortho-Bromoarylimine to Biisoindolinones and Spiroisoindolinones

We herein report a palladium-catalyzed carbonylative cyclization reaction of ortho-bromoarylimines that allows for the chemodivergent synthesis of functionalized biisoindolinones and spirocyclic isoindolinones. Either product could be selectively obtained by switching the reaction temperatures and ligands, and the biisoindolinone products could be afforded facilely with catalyst loadings as low as 0.05 mol %. Further transformation of the biisoindolinone product is also described, which represents a novel and concise approach to the biisoindoline diamine ligand.

Reversed-Polarity Synthesis of N-Sulfonyl Ketimines with Imidoylsilanes and Diaryliodonium Salts via Palladium-Catalyzed Reactions

Imines are important building blocks in organic chemistry. Iminines, aldimines and ketimines, have been traditionally synthesized by the condensation reaction of the corresponding carbonyl compound with an amine moiety. More recently, palladium-catalyzed synthesis of ketimines using imidoyl chlorides has been reported. As an alternative, we report the reversed-polarity synthesis of N-sulfonyl ketimines using an anion equivalent imidoylsilane as a new nucleophilic coupling partner in the presence of a palladium catalyst. To the best of our knowledge, this is the first report of the use of imidoylsilanes in transition-metal-catalyzed coupling reactions. Diaryliodonium salt as an electrophile, various aryl-aryl or heteroaryl-aryl N-sulfonyl ketimines were successfully prepared in up to 99% isolated yields.

PhI(OAc)2 and iodine-mediated synthesis of N-alkyl sulfonamides derived from polycyclic aromatic hydrocarbon scaffolds and determination of their antibacterial and cytotoxic activities

The development of new approaches toward chemo- and regioselective functionalization of polycyclic aromatic hydrocarbon (PAH) scaffolds will provide opportunities for the synthesis of novel biologically active small molecules that exploit the high degree of lipophilicity imparted by the PAH unit. Herein, we report a new synthetic method for C-X bond substitution that is speculated to operate via a N-centered radical (NCR) mechanism according to experimental observations. A series of PAH sulfonamides have been synthesized and their biological activity has been evaluated against Gram-negative and Gram-positive bacterial strains (using a BacTiter-Glo assay) along with a series of mammalian cell lines (using CellTiter-Blue and CellTiter-Glo assays). The viability assays have resulted in the discovery of a number of bactericidal compounds that exhibit potency similar to other well-known antibacterials such as kanamycin and tetracycline, along with the discovery of a luciferase inhibitor. Additionally, the physicochemical and drug-likeness properties of the compounds were determined experimentally and using in silico approaches and the results are presented and discussed within.

Synthesis and identification of heteroaromatic N-benzyl sulfonamides as potential anticancer agents

Sulfonamides are a crucial class of bioisosteres that are prevalent in a wide range of pharmaceuticals, however, the available methods for their production directly from heteroaryl aldehyde reagents remains surprisingly limited. A new approach for regioselective incorporation of a sulfonamide unit to heteroarene scaffolds has been developed and is reported within. As a result, a variety of primary benzylic N-alkylsulfonamides have been prepared via a two-step (one pot) formation from the in situ reduction of an intermediate N-sulfonyl imine under mild, practical conditions. The compounds have been screened against a variety of cell lines for cytotoxicity effects using a Cell Titer Blue assay. The cell viability investigation identifies a subset of N-benzylic sulfonamides derived from the indole scaffold to be targeted for further development into novel molecules with potential therapeutic value. The most cytotoxic of the compounds prepared, AAL-030, exhibited higher potency than other well-known anticancer agents Indisulam and ABT-751.

Rhodium-Catalyzed Asymmetric Addition of Organoboronic Acids to Aldimines Using Chiral Spiro Monophosphite-Olefin Ligands: Method Development and Mechanistic Studies

The synthesis of a novel type of chiral spiro monophosphite-olefin (SMPO) ligands based on a hexamethyl-1,1'-spirobiindane scaffold was accomplished starting from Bisphenol C. The optimal ligand could serve as an elegant chiral bidentate ligand in the Rh-catalyzed asymmetric 1,2-addition of organoboronic acids to various acyclic/cyclic aldimines, leading to chiral amines with high yields and excellent enantioselectivities. Detailed stereochemical models for enantioselective induction were elucidated through DFT calculations and postulated the origins of the higher enantioselectivity of phosphite-olefin ligands.

Visible-Light, Iodine-Promoted Formation of N-Sulfonyl Imines and N-Alkylsulfonamides from Aldehydes and Hypervalent Iodine Reagents

Alternative synthetic methodology for the direct installation of sulfonamide functionality is a highly desirable goal within the domain of drug discovery and development. The formation of synthetically valuable N-sulfonyl imines from a range of aldehydes, sulfonamides, and PhI(OAc)₂ under practical and mild reaction conditions has been developed. According to mechanistic studies described within, the reaction proceeds through an initial step involving a radical initiator (generated either by visible-light or heat) to activate the reacting substrates. The reaction provides a synthetically useful and operationally simple, relatively mild alternative to the traditional formation of N-sulfonyl imines that utilizes stable, widely available reagents.

Recent advances in reactions of aryl sulfonyl isocyanates

Aryl sulfonyl isocyanates are important intermediates in organic synthesis. They are used as electrophilic reagents and easily react with nucleophiles to form amides, sulfonyl ureas, pyrrolidine derivatives, lactams, oxazolidinones, and so on. Although there are some reviews on the applications of isocyanates in chemistry, few are concerned about aryl sulfonyl isocyanates. This review focuses on recent advances related to aryl sulfonyl isocyanates in organic synthesis, mainly including three special characteristics. The mechanisms of the typical reactions are also discussed.

Ni-Pd Catalyzed Cyclization of Sulfanyl 1,6-Diynes: Synthesis of 1'-Homonucleoside Analogues

The Ni-Pd catalyzed addition-cyclization of sulfanyl 1,6-diynes 2-9 with nucleobases is described. The reactions of N-tethered 1,6-diynes with N³-benzoylthymine, N⁴,N⁴-bis(Boc)cytosine, N³-benzoyluracil and N⁶,N⁶-bis(Boc)adenine exclusively afforded the pyrrolylmethyl and furylmethyl nucleotides in good yields. Deprotection of nucleobases was completed by treatment with acids or bases. Furthermore, the reactions of pyrroles and furans with nucleophiles such as alkoxides and amines underwent detosylation and conversion to the alkoxymethyl- and arylaminomethyl-pyrroles and furans in good yields.

Formation of N-sulfonyl imines from iminoiodinanes by iodine-promoted, N-centered radical sulfonamidation of aldehydes

A light-promoted, non-traditional carbonyl activation via a N-centered radical (NCR) species to produce activated imines using iminoiodinanes is reported.

Facile synthesis of nonsymmetrical heteroaryl-substituted triarylmethanes via the FeCl3·6H2O-catalyzed two-step Friedel–Crafts-type reaction

A mild, facile, atom economical and efficient method was described for the synthesis of functionalized nonsymmetrical heteroaryl-substituted triarylmethanes via the two step Friedel–Crafts-type reaction catalyzed by FeCl₃·6H₂O under “open-flask” at room temperature.