Synthesis of 3-substituted indoles via reactive alkylideneindolenine intermediates

Ruthenium-catalyzed tandem annulation/arylation for the synthesis of unsymmetrical bis(heteroaryl)methanes

A new Ru-catalyzed tandem furan annulation/arylation strategy has been developed to afford unsymmetrical bis(heteroaryl)methanes by a reaction between propargyl amines and indoles. A series of bis(heteroaryl)methanes containing furan and indole as well as indole and imidazopyridine moieties have been synthesized in high yields. The reaction possibly proceeds through furan annulation followed by nucleophilic addition of indole.

Lewis Acid-Controlled Regioselective Phosphorylation of 2-Indolylmethanols with Diarylphosphine Oxides: Synthesis of Highly Substituted Indoles

The Lewis acid-promoted phosphorylation of 2-indolylmethanols with diarylphosphine oxides is described. The regioselectivity of the reaction can be modulated by the choice of rare earth metal Lewis acid, offering a highly selective approach to structurally diverse indole derivatives in up to 97% yield for over 50 examples. This strategy features high selectivity, good functional group tolerance, and easy scalability. The utility of this method is further highlighted by facile modification of the products to access novel indole-based phosphine ligand.

Direct C3-arylations of 2-indolylmethanols with tryptamines and tryptophols via an umpolung strategy

A Brønsted acid-catalyzed direct C3-arylation of 2-indolylmethanols with tryptamines and tryptophols has been established, leading to a series of potentially bioactive 2,3′-biindole derivatives with a broad substrate scope and generally good yields (38 examples, up to 96% yield).

A catalytic asymmetric interrupted Nazarov-type cyclization of 2-indolylmethanols with cyclic enaminones

A chiral phosphoric acid-catalyzed asymmetric interrupted Nazarov-type cyclization of C3-alkenyl-substituted 2-indolylmethanols has been established by using cyclic enaminones as nucleophiles.

Catalytic enantioselective and regioselective substitution of 2,3-indolyldimethanols with enaminones

2,3-Indolyldimethanols as a new class of indolyldimethanols have been designed, and the first catalytic asymmetric substitution of 2,3-indolyldimethanols has been established by using cyclic enaminones as nucleophiles.

Catalytic asymmetric 1,6-conjugate addition of in situ generated para-quinone methides with tritylthiol

An asymmetric phase-transfer catalyzed 1,6-conjugate addition of in situ generated para-quinone methides with tritylthiol has been developed.

Diastereo- and enantioselective construction of chiral cyclopenta[b]indole framework via a catalytic asymmetric tandem cyclization of 2-indolymethanols with 2-naphthols

The title reaction has been established in the presence of chiral phosphoric acids, which constructed chiral cyclopenta[b]indole frameworks in high stereoselectivities.

Catalytic asymmetric synthesis of spirooxindoles: recent developments

The past four years have witnessed significant developments in the field of the catalytic asymmetric synthesis of spirooxindoles, and this feature article outlines the recent progress in this area, including the contributions of our group. This article is divided into sections according to the size and type of the generated spiro-ring fused at the C3-position of the oxindole core.

Brønsted acid catalysed eco friendly synthesis of quaternary centred C-3 functionalized oxindole derivatives

A facile atom economic and eco friendly protocol for the synthesis of biologically important quaternary centered C-3 functionalized oxindole derivatives, with a novel nucleus, in high yields has been demonstrated.

Metabolite identification and pharmacokinetic profiling of PP242, an ATP-competitive inhibitor of mTOR using ultra high-performance liquid chromatography and mass spectrometry

PP242 is a second generation novel selective ATP-competitive inhibitor of mTOR that displayed promising anti-cancer activity over several cancer types by inhibiting both the complexes of mTOR (mTORC1 and mTORC2). The purpose of this study is to identify the possible metabolites and to evaluate the pharmacokinetic profile of PP242 after a single oral administration to Sprague-Dawley (SD) rats. Two metabolites, including one phase I and one phase II, were identified by in vitro and in vivo studies using rat liver microsomes (RLMs) as well as rat plasma, urine and feces, respectively, through ultra high-performance liquid chromatography-linear ion trap quadrupole-orbitrap-mass spectrometry (UHPLC-LTQ-Orbitrap-MS). The major biotransformation pathways of PP242 were hydroxylation and glucuronide conjugation. Additionally, a simple and rapid quantification method was developed and validated. The method recovery was within 79.7-84.6%, whereas the matrix effect was 78.1-96.0% in all three quality control (QC) concentrations (low, medium and high) including the LLOQ. Other parameters showed acceptable results according to the US food and drug administration (FDA) guidelines for bioanalytical method validation. Afterwards, pharmacokinetic parameters were evaluated in rat plasma by successfully applying the validated method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). After a single oral administration at a dose of 5mg/kg, the maximum plasma concentration (C_max) of PP242 was 0.17±0.08μg/mL, while the elimination was moderately fast (T_1/2: 172.18±45.54min). All of the obtained information on the metabolite identification and pharmacokinetic parameter elucidation could facilitate the further development of PP242.

Combined Di-tert-butyl Peroxide and Inorganic Base Promoted α-Alkylation of Ethers with Arenesulfonylindoles

The di-tert-butyl peroxide (DTBP) induced coupling of arenesulfonylindoles with ethers such as 1,4-dioxane, tetrahydropyran, tetrahydrofuran, and 1,2-dimethoxyethane was studied. The distinguishing feature of this strategy was characterized by capturing in situ generated vinylogous imine intermediates for the C(sp³)-H bond alkylation of ethers. This general procedure presents the major advantages of its wide substrate scope and good functional group compatibility.

Bismuth nitrate-promoted disproportionative condensation of indoles with cyclohexanone: a new-type azafulvenium reactivity of indole

The bismuth nitrate-promoted disproportionative condensation of indoles with cyclohexanone in one pot, to yield C3-cyclohexyl substituted indoles and 1,3-di(1H-indol-3-yl)benzene derivatives is reported for the first time.

Palladium-catalyzed oxidative arylacetoxylation of alkenes: synthesis of indole and indoline derivatives

A method for the oxidative arylacetoxylation of alkenes has been developed to synthesize indole and indoline derivatives from readily accessible substrates.

TBAF catalyzed one-pot synthesis of allenyl-indoles

The site selective synthesis of functionalized indoles is presented under environmentally convenient tetrabutylammonium fluoride catalysis.

Gramine Derivatives Targeting Ca(2+) Channels and Ser/Thr Phosphatases: A New Dual Strategy for the Treatment of Neurodegenerative Diseases

We describe the synthesis of gramine derivatives and their pharmacological evaluation as multipotent drugs for the treatment of Alzheimer's disease. An innovative multitarget approach is presented, targeting both voltage-gated Ca(2+) channels, classically studied for neurodegenerative diseases, and Ser/Thr phosphatases, which have been marginally aimed, even despite their key role in protein τ dephosphorylation. Twenty-five compounds were synthesized, and mostly their neuroprotective profile exceeded that offered by the head compound gramine. In general, these compounds reduced the entry of Ca(2+) through VGCC, as measured by Fluo-4/AM and patch clamp techniques, and protected in Ca(2+) overload-induced models of neurotoxicity, like glutamate or veratridine exposures. Furthermore, we hypothesize that these compounds decrease τ hyperphosphorylation based on the maintenance of the Ser/Thr phosphatase activity and their neuroprotection against the damage caused by okadaic acid. Hence, we propose this multitarget approach as a new and promising strategy for the treatment of neurodegenerative diseases.

Sulfonyl Azoles in the Synthesis of 3-Functionalized Azole Derivatives

Sulfonyl indoles, as well as related azolyl derivatives, have been recently introduced in synthesis as stable precursors of reactive indolenine intermediates. This personal account reports on the discovery of sulfonyl azoles and their practical utilization in many synthetic processes for the preparation of functionalized 3-substituted indoles, indazoles, and pyrroles. The indolenine intermediates obtained by treatment of sulfonyl azoles with Brønsted bases or Lewis acids can be considered as vinylogous imino derivatives that can be made to react with different nucleophilic reagents. These include organometallic reagents, reducing agents, stabilized carbanions, and heteronucleophiles. The controlled and mild conditions for the generation of indolenines from sulfonyl azoles make these substrates particularly useful in asymmetric synthesis, exploiting organo- or metal-catalyzed processes. Although less exploited, sulfonyl indoles can also be involved in photochemical processes for the preparation of polycyclic derivatives.

A highly enantioselective thiolation of sulfonyl indoles to access 3-sec-sulfur-substituted indoles in water

Highly enantioselective organocatalytic Michael addition of thiol to vinylogous imine intermediates generated in situ from sulfonylindoles in aqueous medium is presented.

Exploiting the σ-phylic properties of cationic gold(i) catalysts in the ring opening reactions of aziridines with indoles

Gold(i) species catalyze the ring opening reactions of aziridines with indoles as nucleophiles for the synthesis of tryptamines and pyrroloindolines.

Brønsted acid-catalyzed regioselective reactions of 2-indolylmethanols with cyclic enaminone and anhydride leading to C3-functionalized indole derivatives

An abnormal regioselective substitution of 2-indolylmethanols with nucleophiles has been established to afford C3-functionalized indole derivatives in high yield and regiospecificity (40 examples, up to 99% yield).