Experimental and Theoretical Study of Phosphine-Catalyzed Reaction Modes in the Reaction of α-Substituted Allenes with Aryl Imines.

A new phosphine-catalyzed reaction of α-substituted allenes with aryl imines, in stark contrast to classic cycloaddition reactions, has been developed. This reaction delivers valuable highly functionalized itaconimides with excellent stereoselectivities by a new «un-cyclizing¼ reaction mode involving ß'-carbon of α-substituted allenes. Moreover, the present «un-cyclizing¼ reaction can also be carried out in a one-pot fashion and scaled up to the gram scale by using aryl aldehydes, without the need to isolate the aryl imines. Mechanistic studies and control experiments reveal the crucial role of H2 CO3 for the present reaction mode. In addition, density functional theory (DFT) calculations were performed to understand the possible mechanism.

Metal-Free Regioselective Hydrophosphorodithioation of Spirovinylcyclopropyl Oxindoles: Rapid Access to Allyl Dialkylphosphorodithioates.

Phosphorodithioates are important substructures due to their great use in bioactive compounds and functional materials. A metal-free 1,5-addition of spirovinylcyclopropyl oxindoles have been developed by choosing P4S10 and alcohol as nucleophiles through the regioselective ring-opening of spirovinylcyclopropyl oxindoles. This method provides access to allylic organothiophosphates with high efficiency, wide functional group tolerance, good chemo- and regioselectivity, and E-selectivity. 1,3-Addition products were also prepared in high yield. Furthermore, the resulting organothiophosphates could be readily transformed into other allylic derivatives.

An FGFR1-Binding Peptide Modified Liposome for siRNA Delivery in Lung Cancer.

Liposome modification by targeting ligands has been used to mediate specific interactions and drug delivery to target cells. In this study, a new peptide ligand, CP7, was found to be able to effectively bind to FGFR1 through reverse molecular docking and could cooperate with VEGFR3 to achieve targeting of A549 cells. CP7 was modified on the surface of the liposome to construct a targeted and safe nanovehicle for the delivery of a therapeutic gene, Mcl-1 siRNA. Due to the specific binding between CP7 and A549 cells, siRNA-loaded liposome-PEG-CP7 showed increased cellular uptake in vitro, resulting in significant apoptosis of tumor cells through silencing of the Mcl-1 gene, which is associated with apoptosis and angiogenesis. This gene delivery system also showed significantly better antitumor activity in tumor-bearing mice in vivo. All of these suggested that siRNA-loaded liposome-PEG-CP7 could be a promising gene drug delivery system with good bioavailability and minimal side effects for treatment.

Iodine-Catalyzed Aerobic Oxidation of Spirovinylcyclopropyl Oxindoles to Form Spiro-1,2-dioxolanes Diastereoselectively.

A novel method of iodine-catalyzed aerobic oxidation with spirovinylcyclopropyl oxindoles under mild conditions has been described. A series of spiro-1,2-dioxolanes were prepared in good to excellent yields and considerable diastereoselectivities. The new approach is operationally simple, scalable, and tolerant of various functional groups.

Synthesis of functionalized 2,5-dihydropyrrole derivatives via a convenient [3 + 2] annulation of azomethine ylides with allenoates.

A convenient [3 + 2] annulation of azomethine ylides with allenoates promoted by triethylamine produced highly functionalized 2,5-dihydropyrrole derivatives in moderate to excellent yields under mild conditions. The potential utility of this reaction indicates that this reaction could be performed on the gram scale and the synthesized functionalized 2,5-dihydropyrrole derivatives could be further transformed into other interesting heterocycles. The mechanism for the transformation is a tandem ß-addition/Mannich cyclization process.

Hydroxy-Assisted Regio- and Stereoselective Synthesis of Functionalized 4-Methylenepyrrolidine Derivatives via Phosphine-Catalyzed [3 + 2] Cycloaddition of Allenoates with o-Hydroxyaryl Azomethine Ylides.

In this work, we present a new strategy for the chemo-, regio-, and stereoselective synthesis of functionalized pyrrolidine derivatives via a hydroxy-assisted phosphine-catalyzed reaction of allenoates or substituted allenoates with o-hydroxyaryl azomethine ylides that offers a wide variety of 4-methylenepyrrolidine derivatives in synthetically useful yields with high stereoselctivities under mild conditions. Remarkably, it is the first example of highly regio- and stereoselective phosphine-catalyzed [3 + 2] cycloaddition of allenoates with o-hydroxyaryl azomethine ylides.

Stereoselective synthesis of 3-methyleneisoindolin-1-ones via base-catalyzed intermolecular reactions of electron-deficient alkynes with N-hydroxyphthalimides.

Highly stereoselective intermolecular reactions of electron-deficient alkynes with N-hydroxyphthalimides for efficient construction of N-unprotected 3-methyleneisoindolin-1-ones have been developed through base catalytic strategies. The reaction of alkynoates with N-hydroxyphthalimides catalyzed by Bu3P in DMF at 150 °C gave the corresponding 3-methyleneisoindolin-1-ones with a (Z)-configuration, while the reaction of alkynoates with N-hydroxyphthalimides catalyzed by K2CO3 in DMF at 60 °C gave the corresponding 3-methyleneisoindolin-1-ones with an (E)-configuration, and (Z)-3-methyleneisoindolin-1-ones were obtained when alkyne ketones reacted with N-hydroxyphthalimide.

Stereoselective Syntheses of α,ß-Unsaturated γ-Amino Esters Through Phosphine-Catalyzed γ-Umpolung Additions of Sulfonamides to γ-Substituted Allenoates.

α,ß-Unsaturated γ-amino esters can be synthesized efficiently and stereoselectively through phosphine-catalyzed γ-umpolung additions of sulfonamides to γ-substituted allenoates. The structures of the sulfonamide and γ-substituted allenoate partners can be varied to achieve a range of α,ß-unsaturated γ-amino esters with potentially interesting chemical and biological properties.

Small molecule modulators of cystic fibrosis transmembrane conductance regulator (CFTR): Structure, classification, and mechanisms.

The advent of small molecule modulators targeting the cystic fibrosis transmembrane conductance regulator (CFTR) has revolutionized the treatment of persons with cystic fibrosis (CF) (pwCF). Presently, these small molecule CFTR modulators have gained approval for usage in approximately 90 % of adult pwCF. Ongoing drug development endeavors are focused on optimizing the therapeutic benefits while mitigating potential adverse effects associated with this treatment approach. Based on their mode of interaction with CFTR, these drugs can be classified into two distinct categories: specific CFTR modulators and non-specific CFTR modulators. Specific CFTR modulators encompass potentiators and correctors, whereas non-specific CFTR modulators encompass activators, proteostasis modulators, stabilizers, reader-through agents, and amplifiers. Currently, four small molecule modulators, all classified as potentiators and correctors, have obtained marketing approval. Furthermore, numerous novel small molecule modulators, exhibiting diverse mechanisms of action, are currently undergoing development. This review aims to explore the classification, mechanisms of action, molecular structures, developmental processes, and interrelationships among small molecule CFTR modulators.

Discovery of Indolo[3,2-c]isoquinoline Derivatives as Novel Top1/2 Dual Inhibitors with Orally Efficacious Antitumor Activity and Low Toxicity.

Topoisomerase (Top) inhibitors used in clinical cancer treatments are limited because of their toxicity and severe side effects. Noteworthily, Top1/2 dual inhibitors overcome the compensatory effect between Top1 and 2 inhibitors to exhibit stronger antitumor efficacies. In this study, a series of indolo[3,2-c]isoquinoline derivatives were designed as Top1/2 dual inhibitors possessing apparent antiproliferative activities. Mechanistic studies indicated that the optimal compounds 23 and 31 with increasing reactive oxygen species levels damage DNA, inducing both cancer cell apoptosis and cycle arrest. Importantly, the results of the toxicity studies showed that compounds 23 and 31 possessed good oral safety profiles. In xenograft models, compound 23 exhibited remarkable antitumor potency, which was superior to the clinical Top inhibitors irinotecan and etoposide. Overall, this work highlights the therapeutic potential and safety profile of compound 23 as a Top1/2 dual inhibitor in tumor therapy and provides valuable lead compounds for further development of Top inhibitors.

Discovery of novel itaconimide-based derivatives as potent HDAC inhibitors for the efficient treatment of prostate cancer.

Histone deacetylases (HDACs) are a family of enzymes that play important roles in the development and progression of cancers. Inhibition of HDACs has been widely studied as a therapeutic strategy in the development of anticancer drugs. However, developing HDAC inhibitors that are effective for solid tumors remains a great challenge. In this work, we designed and synthesized a series of itaconimide-based derivatives as potent HDAC inhibitors. Among them, compound 17q exhibited potent inhibition of HDAC1/2/3/6, with good antiproliferative activity in vitro and an excellent pharmacokinetic profile. Compound 17q significantly inhibited tumor growth in a DU145 xenograft tumor model and showed no obvious toxicity. Moreover, when 17q was combined with other prostate cancer therapeutics, outstanding synergistic effects were observed and the toxic side effects of DTX were reduced. Overall, based on the data, these inhibitors may offer promising new targeted therapies for prostate cancer.

Indolo[3,2-c]isoquinoline Hydroxamic Acid Derivatives as Novel Orally Topoisomerase-Histone Deacetylase Dual Inhibitors for NSCLC Therapy.

Based on the synergistic effects of topoisomerase (Top) inhibitors and histone deacetylase (HDAC) inhibitors in cancer therapy, a series of novel Top/HDAC dual inhibitors were designed and synthesized herein. The optimal compound 31 was identified to simultaneously inhibit both Tops and HDACs with potent antiproliferative activity against nonsmall cell lung cancer (NSCLC). Mechanistic studies indicated that compound 31 with increasing reactive oxygen species levels damages DNA, inhibiting cancer cell colony formation and migration and inducing both cancer cell apoptosis and cycle arrest. Noteworthily, compound 31 was orally active in the NSCLC xenograft model, and its antitumor efficacy (TGI = 77.5%, 100 mg/kg) was superior to that of HDAC inhibitor SAHA and SAHA in combination with the Top inhibitor irinotecan. Consequently, this work highlights the therapeutic potential of compound 31 as the Top/HDAC dual inhibitor in NSCLC therapy and provides valuable lead compounds for the further development of antitumor agents in solid tumor therapy.

Stereoselective syntheses of functionalized spirocyclopenteneoxindoles via triphenylphosphine-catalyzed [3+2] cycloaddition reactions.

Spirocyclopenteneoxindole derivatives were obtained by stereoselective triphenylphosphine-catalyzed [3+2] cycloadditions of ynones and alkylidene oxindole derivatives. This approach is based on the Michael addition of ynones to alkylidene oxindole derivatives, followed by intermolecular [Formula: see text]-addition using 50 mol% triphenylphosphine as catalyst.

A facile synthesis of 3-substituted 9H-pyrido[3,4-b]indol-1(2H)-one derivatives from 3-substituted beta-carbolines.

A mild and efficient two-step synthesis of 3-substituted beta-carbolinone derivatives from 3-substituted beta-carboline in good yields is described. A possible reaction mechanism for the formation of the skeleton of beta-carbolin-1-one is proposed. The structures of these compounds were established by IR, 1H-NMR, 13C-NMR, mass spectrometry and elemental analysis, as well as X-ray crystallographic analysis of 4-2 and 6-2.

Catalyst-Free [3+2] Cycloaddition of Electron-Deficient Alkynes and o-Hydroxyaryl Azomethine Ylides in Water.

A catalyst-free [3 + 2] cycloaddition reaction of electron-deficient alkynes and o-hydroxyaryl azomethine ylides in water was developed, affording pyrroline derivatives in moderate to high yields (up to 90%).

Phosphine-Catalyzed Stereoselective Tandem Annulation Reaction for the Synthesis of Chromeno[4,3-b]pyrroles.

A phosphine-catalyzed tandem cyclization reaction has been developed to provide a series of chromeno[4,3-b]pyrrole derivatives, which contain three consecutive asymmetric centers. The reaction has a good yield, excellent stereoselectivity, and Z/E selectivity. The new method is simple, requires only mild conditions, and shows tolerance for various functional groups. Similarly, this reaction can be catalyzed by a chiral phosphine catalyst to achieve asymmetric synthesis.

Stereoselective Synthesis of Functionalized Benzooxazepino[5,4- a]isoindolone Derivatives via Cesium Carbonate Catalyzed Formal [5 + 2] Annulation of 2-(2-Hydroxyphenyl)isoindoline-1,3-dione with Allenoates.

In this work, we present a strategy for the stereoselective synthesis of functionalized benzooxazepino[5,4- a]isoindolone derivatives via a Cs2CO3-catalyzed domino ß-addition and γ-aldol reaction of 2-(2-hydroxyphenyl)isoindoline-1,3-dione derivatives with allenoates, which offers an avenue for a combination of the structural unity between benzooxazepine and isoindolone motifs in synthetically useful yields with high stereoselectivities under mild conditions. Remarkably, it is the first example of highly stereoselective Cs2CO3-catalyzed formal [5 + 2] annulation of 2-(2-hydroxyphenyl)isoindoline-1,3-dione with allenoates.

Iodine-Promoted Deoxygenative Iodization/Olefination/Sulfenylation of Ketones with Sulfonyl Hydrazides: Access to ß-Iodoalkenyl Sulfides.

A highly regio- and stereoselective synthesis of ß-haloalkenyl sulfides using commercially available ketones and sulfonyl hydrazides as starting materials has been developed. This protocol obviates the need for alkynes and traditional sulfenylating agents and therefore opens up a new door to construct ß-iodoalkenyl sulfides in a highly simple manner. This study reveals that ketones could be used as vinyl iodide precursors in organic synthesis.

Umpolung of o-Hydroxyaryl Azomethine Ylides: Entry to Functionalized γ-Aminobutyric Acid under Phosphine Catalysis.

A phosphine-catalyzed reaction between o-hydroxyaryl azomethine ylides and MBH carbonates provides access to highly functionalized γ-aminobutyric acid derivatives in moderate to good yields. Mechanistically, the reaction involves a phosphine-catalyzed tandem SN2'/2-aza-Cope rearrangement/intramolecular addition process.

Physiologically stable F127-GO supramolecular hydrogel with sustained drug release characteristic for chemotherapy and photothermal therapy.

A synthetic method for preparing a Pluronic F127 (F127)-stabilized graphene (GO) supramolecular hydrogel as a safe nanovehicle for combination treatment has been studied. Doxorubicin (DOX) as a model drug is non-covalently bound on the great surface area of GO due to strong π-π interaction, hydrophobic interaction, and the strongest hydrogen bonding. In vitro drug release experiments revealed that this F127-stabilized GO supramolecular hydrogel has a sustained drug release characteristic. Furthermore, the supramolecular hydrogel showed better in vitro antitumor ability under NIR (near infrared) laser irradiation because of the excellent photothermal effect of GO. Moreover, we evaluated its antitumor ability in vivo and the results show that the hydrogel system can also markedly inhibit the growth of a tumor when administered individually, especially under laser irradiation. All these findings make the supramolecular hydrogel system promising for combination therapy with good bioavailability and minimal side effects.