Diverging Rh(I)-catalyzed carbocylization strategy to prepare a library of unique cyclic ethers

Rhodium(i)-catalysed “ene-type” cycloisomerization of N-[2-(2-alkyn-1-yl)phenyl]carbodiimides leading to 3-(cis-alken-1-yl)-2-aminoquinolines

cis-Selective 3-(1-alkenyl)quinoline synthesis via rhodium catalyzed cycloisomerization has been developed.

Synthesis of skeletally diverse and stereochemically complex library templates derived from isosteviol and steviol

We have applied a diversity-oriented approach for the synthesis of skeletally diverse and stereochemically complex templates for small-molecule library production by performing Beckmann rearrangement and Beckmann fragmentation reactions on the bicyclo[3.2.1]octane rings of steviol and isosteviol, aglycones derived from the diterpene natural product stevioside. The optimization of these two reaction pathways is presented along with the successful application of a photo-Beckmann rearrangement. This work also led to the discovery of cyano-Prins-type and Thorpe-Ziegler-type cyclization reactions.

Exploiting PubChem for Virtual Screening

IMPORTANCE OF THE FIELD: PubChem is a public molecular information repository, a scientific showcase of the NIH Roadmap Initiative. The PubChem database holds over 27 million records of unique chemical structures of compounds (CID) derived from nearly 70 million substance depositions (SID), and contains more than 449,000 bioassay records with over thousands of in vitro biochemical and cell-based screening bioassays established, with targeting more than 7000 proteins and genes linking to over 1.8 million of substances. AREAS COVERED IN THIS REVIEW: This review builds on recent PubChem-related computational chemistry research reported by other authors while providing readers with an overview of the PubChem database, focusing on its increasing role in cheminformatics, virtual screening and toxicity prediction modeling. WHAT THE READER WILL GAIN: These publicly available datasets in PubChem provide great opportunities for scientists to perform cheminformatics and virtual screening research for computer-aided drug design. However, the high volume and complexity of the datasets, in particular the bioassay-associated false positives/negatives and highly imbalanced datasets in PubChem, also creates major challenges. Several approaches regarding the modeling of PubChem datasets and development of virtual screening models for bioactivity and toxicity predictions are also reviewed. TAKE HOME MESSAGE: Novel data-mining cheminformatics tools and virtual screening algorithms are being developed and used to retrieve, annotate and analyze the large-scale and highly complex PubChem biological screening data for drug design.

Design and synthesis of a library of tetracyclic hydroazulenoisoindoles

Forty-four tetracyclic hydroazulenoisoindoles were synthesized via a tandem cyclopropanation/Cope rearrangement, followed by a Diels-Alder sequence from easily available five-membered cyclic cross-conjugated trienones. These trienones were obtained from two different routes depending upon whether R(1) and R(2) are alkyl or amino acid derived functional groups, via a rhodium(I)-catalyzed cycloisomerization reaction. To increase diversity, four maleimides and two 1,2,4-triazoline-3,5-diones were used as dienophiles in the Diels-Alder step. Several Diels-Alder adducts were further reacted under palladium-catalyzed hydrogenation conditions, leading to a diastereoselective reduction of the trisubstituted double bond. This library has demonstrated rapid access to a variety of structurally complex natural product-like compounds via stereochemical diversity and building block diversity approaches.

"Click, click, cyclize": a DOS approach to sultams utilizing vinyl sulfonamide linchpins

A diversity-oriented synthesis (DOS) strategy termed "Click, Click, Cyclize" is reported. This approach relies on functional group (FG) pairing between a vinyl sulfonamide and an array of functional groups to synthesize skeletally diverse sultams. Several FG pairing pathways on central tertiary vinyl sulfonamide linchpins have been developed including intramolecular Heck, aza-Michael, ring-closing enyne metathesis, Pauson-Khand, and chemoselective oxidation/Baylis-Hillman reactions.