One-pot synthesis of N-methylindoles from N-methylanilines and of benzofurans from phenols using transition-metal carbene X–H insertion reactions

Pharmacophore Identification and Structure-Activity Relationship Analysis of a Series of Substituted Azaindoles as Inhibitors of Trypanosoma brucei

Human African trypanosomiasis is among the World Health Organization's designated neglected tropical diseases. Repurposing strategies are often employed in academic drug discovery programs due to financial limitations, and in this instance, we used human kinase inhibitor chemotypes to identify substituted 4-aminoazaindoles, exemplified by 1. Structure-activity and structure-property relationship analysis, informed by cheminformatics, identified 4s as a potent inhibitor of Trypanosoma brucei growth. While 4s appeared to be fast acting and cidal in the in vitro assays, it failed to cure a murine model of infection. Preliminary efforts to identify the potential mechanism of action of the series pointed to arginine kinase, though, as we demonstrate, this does not appear to be the sole target of our compounds. This comprehensive approach to drug discovery, encompassing cheminformatics, structure-potency and structure-property analysis, and pharmacophore identification, highlights our multipronged efforts to identify novel lead compounds for this deadly disease.

Pd-Catalyzed Functionalization of Aryl Amines on a Soluble Polymer Support

Herein we report the use of a soluble polymer support PEG-2000 on Pd-catalyzed reactions to improve the functionalization of aromatic amines and the synthesis of N-heterocycles. Compatibility of metal-catalyzed reactions for assembling privileged structures such as functionalized anilines were studied. PEG-supported anilines were found to be suitable substrates for Pd-catalyzed N-arylation, Sonogashira and Heck reactions. PEGylated substrates were prepared in yields up to 94%. This work consists on a proof of concept on the use of PEGylated anilines on Pd-catalyzed cross-coupling reactions. Indole core was attained in 82% and 62% yields, via two different routes.

Last Decade of Unconventional Methodologies for the Synthesis of Substituted Benzofurans

This review describes the progress of the last decade on the synthesis of substituted benzofurans, which are useful scaffolds for the synthesis of numerous natural products and pharmaceuticals. In particular, new intramolecular and intermolecular C-C and/or C-O bond-forming processes, with transition-metal catalysis or metal-free are summarized. (1) Introduction. (2) Ring generation via intramolecular cyclization. (2.1) C7a-O bond formation: (route a). (2.2) O-C2 bond formation: (route b). (2.3) C2-C3 bond formation: (route c). (2.4) C3-C3a bond formation: (route d). (3) Ring generation via intermolecular cyclization. (3.1) C7a-O and C3-C3a bond formation (route a + d). (3.2) O-C2 and C2-C3 bond formation: (route b + c). (3.3) O-C2 and C3-C3a bond formation: (route b + d). (4) Benzannulation. (5) Conclusion.

Synthesis of poly-functionalized benzofurans via one-pot domino oxidation/[3+2] cyclization reactions of a hydroquinone ester and ynamides

Densely substituted amino-functionalized benzofurans were concisely accessed via the first one-pot domino oxidation/[3+2] cyclization of a hydroquinone ester and easily accessible ynamides under mild conditions in a short time. The complex benzofurans were able to be efficiently synthesized all from simple and inexpensive starting materials in two steps.

Efficient method for the construction of poly-functionalized benzofurans has been developed via one-pot domino oxidation/[3+2] cyclization reactions.

Rhodium-Catalyzed Synthesis of Sulfur Ylides via in Situ Generated Iodonium Ylides

A convenient strategy for the synthesis of sulfur ylides via rhodium-catalyzed coupling of in situ generated iodonium ylides with sulfides or sulfoxides has been developed. A wide range of sulfur ylides were obtained in moderate to good yields from inexpensive sulfur compounds and active methylene compounds with a short reaction time (MW, 5-10 min) or 12-16 h at rt. Furthermore, these sulfoxonium ylides were used as novel acceptor/acceptor carbenes for N-H insertion reactions.

Modular construction of multifunctional ligands for the enantioselective ruthenium-catalyzed carbenoid N–H insertion reaction: an enzyme-like and substrate-sensitive catalyst system

It was found for the first time that BINOL-derived multifunctional ligands bearing a silicon-based bulky group exhibited promising enantioselective control in the ruthenium-catalysed carbenoid N–H insertion reaction.

Synthesis of Indoxylic Acid Esters by Rhodium-catalyzed Carbene N–H Insertion and Thermal Cyclization

Reaction between diethyl diazomalonate and a range of N-alkylanilines in the presence of a catalytic amount of rhodium(ii) acetate dimer afforded carbene N–H insertion to produce anilinomalonates in modest-to-good yields. Upon heating to a high temperature for a short time, the anilinomalonates underwent thermal cyclization to indoxylic acid esters.

Copper-catalyzed annulation of α-substituted diazoacetates with 2-ethynylanilines: the direct synthesis of C2-functionalized indoles

Copper-catalyzed direct annulation of α-substituted diazoacetates with 2-ethynylanilines leading to C2-functionalized indoles was achieved under mild reaction conditions. The C2-(carboxylate methyl) substituted indoles were obtained in moderate to high yields.

Benzofuran-, benzothiophene-, indazole- and benzisoxazole-quinones: excellent substrates for NAD(P)H:quinone oxidoreductase 1

A series of heterocyclic quinones based on benzofuran, benzothiophene, indazole and benzisoxazole has been synthesized, and evaluated for their ability to function as substrates for recombinant human NAD(P)H:quinone oxidoreductase (NQO1), a two-electron reductase upregulated in tumor cells. Overall, the quinones are excellent substrates for NQO1, approaching the reduction rates observed for menadione.

A mild and efficient direct α-amination of β-dicarbonyl compounds using iodosobenzene and p-toluenesulfonamide catalyzed by perchlorate zinc hexahydrate

A direct α-amination of β-dicarbonyl compounds has been achieved by using iodosobenzene (PhIO) as an oxidant and p-toluenesulfonamide (TsNH(2)) as an aminating reagent in the presence of a catalytic amount of perchlorate zinc hexahydrate. The present amination reaction proceeds quickly at rt (<30 min needed for most tested substrates) to provide the corresponding α-N-tosylamido β-dicarbonyl compounds in high to excellent yields.