Chemistry

20 pages, 8093 KiB

Open AccessArticle

Reaction of β-Nitrostyrene with Diethyl Malonate in the Presence of Bispidines: The Unusual Role of the Organocatalyst

by Alexander I. Dalinger, Sabina F. Mamedova, Julia V. Burykina, Evgeniy O. Pentsak and Sergey Z. Vatsadze

Chemistry 2024, 6(3), 387-406; https://doi.org/10.3390/chemistry6030023 (registering DOI) - 10 May 2024

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Abstract

The aim of this work was the investigation of novel organocatalysts for the Michael addition of diethyl malonate to β-nitrostyrene. The methodology of the study included NMR titration, reaction monitoring by NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS), product characterization by [...] Read more.

The aim of this work was the investigation of novel organocatalysts for the Michael addition of diethyl malonate to β-nitrostyrene. The methodology of the study included NMR titration, reaction monitoring by NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS), product characterization by MALDI, IR spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and elemental analysis. As a result, evidence of supramolecular interactions between two pairs of components of the reaction was found. In addition to the supramolecular complexes, an unusual reaction, i.e., the Michael addition of NH-bispidines to β-nitrostyrene, was found, which led to previously unknown oligomers of β-nitrostyrene. A new mechanism for the catalytic action of NH-bispidine was proposed, which involved catalysis not by the initial organocatalyst but rather by its adduct with β-nitrostyrene. Thus, in this reaction, N-benzylbispidine acted as an initiator, and the real catalyst was the betaine formed during the initiation stage. Full article

(This article belongs to the Special Issue Future Trends in Catalytic Organic Synthesis)

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11 pages, 2815 KiB

Open AccessCommunication

Anxiolytic-Like and Antidepressant Effects of a 13H-indolo[2,3-a]thiopyrano[2,3-g]quinolizine Derivative

by Carlos E. Castillo-Espinoza, María Leonor González-Rivera, Alberto Medina-Ortiz, Juan Carlos Barragan-Galvez, Sergio Hidalgo-Figueroa, David Cruz Cruz, Martha Alicia Deveze-Alvarez, Gerardo González-García, Clarisa Villegas Gómez and Angel Josabad Alonso-Castro

Chemistry 2024, 6(3), 376-386; https://doi.org/10.3390/chemistry6030022 - 9 May 2024

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Abstract

Depressive and anxiety disorders constitute some of the most prevalent mental disorders around the world. For years, the development of new lead compounds for drug discovery in this field has been an area of great attention. Recently, a series of tetrahydrocarbazole derivatives have [...] Read more.

Depressive and anxiety disorders constitute some of the most prevalent mental disorders around the world. For years, the development of new lead compounds for drug discovery in this field has been an area of great attention. Recently, a series of tetrahydrocarbazole derivatives have demonstrated important anxiolytic-like activity, associated with their structures and stereochemistry. Here, we present a study of the antidepressant effect and anxiolytic-like activity of a fused thiopyrano-piperidone-tetrahydrocarboline (compound 4). The antidepressant and anxiolytic-like effects of 4 (1–50 mg/kg p.o.) were assessed with the tail suspension test and the hole-board test, respectively. This study determined the possible mechanisms involved in the anxiolytic-like actions of 4 using inhibitors or neurotransmission and evaluated its interaction with 5HT_2A receptors using a molecular docking study. As an analog to the tetrahydrocarbazole core, the tetrahydrocarboline derivative showed anxiolytic-like activity (ED₅₀ = 13 mg/kg p.o.) in the hole-board test, with a comparable effect to the reference drug, 1.5 mg/kg clonazepam, with the possible participation of the serotonergic system. Full article

(This article belongs to the Section Medicinal Chemistry)

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16 pages, 5346 KiB

Open AccessArticle

One-Step Ethanol Conversion for 1,3-Butadiene Synthesis over Two-Dimensional VMT-SiO₂ Nanomesh Loaded with Magnesium and Copper Oxide

by Yaqi Qin, Kegong Fang, Wenbin Li and Hongfang Jiu

Chemistry 2024, 6(3), 361-375; https://doi.org/10.3390/chemistry6030021 - 26 Apr 2024

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Abstract

A two-dimensional porous silica nanomesh (VMT-SiO₂) was used as a carrier to prepare MgO-CuO-based catalysts and tested for one-step ethanol conversion to 1,3-butadiene. The effects of catalyst composition and different calcination temperatures on the reaction performances of the catalysts were mainly [...] Read more.

A two-dimensional porous silica nanomesh (VMT-SiO₂) was used as a carrier to prepare MgO-CuO-based catalysts and tested for one-step ethanol conversion to 1,3-butadiene. The effects of catalyst composition and different calcination temperatures on the reaction performances of the catalysts were mainly investigated. Combining various characterization techniques, such as HRTEM, XRD, FT-IR, and TPD, it was found that the dispersion state of MgO and CuO on the catalyst surface was related to the calcination temperature, which further induced changes in the acid–base properties. A small number of acidic centers and a proper proportion of medium–strong alkaline centers maintained a subtle balance, affecting catalytic performance. A lower total acid/base ratio is more conducive to ethanol conversion and 1,3-butadiene formation. At the same time, the synergistic effect of CuO and MgO promotes the transformation of the intermediate acetaldehyde product, which is the key to ensuring the subsequent aldol condensation and then 1,3-butadiene formation. Among the investigated samples, the CuO/MgO-VMT-SiO₂ catalyst calcined at 500 °C exhibited the best catalytic performance, with an impressive ethanol conversion of 47.8% and 1,3-butadiene formation (42.6% selectivity and a space-time yield of 182.0 g_C4H6·kg_cat⁻¹·h⁻¹). Full article

(This article belongs to the Section Catalysis)

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16 pages, 5385 KiB

Open AccessArticle

The Conjugate of Rhein–Artesunate for Inducing Immunogenic Cell Death to Prepare Cancer Vaccine and Suppress Tumor Growth

by Zi-Jian Xu, Wei Wang and Shi-Wen Huang

Chemistry 2024, 6(3), 345-360; https://doi.org/10.3390/chemistry6030020 - 25 Apr 2024

Viewed by 282

Abstract

The conjugate of rhein and artesunate have shown promising effects in inducing immunogenic cell death (ICD) and inhibiting tumor growth. Rhein, a natural anthraquinone derivative found in various medicinal plants such as Rheum palmatum, possesses diverse pharmacological properties including anti-inflammatory and anticancer [...] Read more.

The conjugate of rhein and artesunate have shown promising effects in inducing immunogenic cell death (ICD) and inhibiting tumor growth. Rhein, a natural anthraquinone derivative found in various medicinal plants such as Rheum palmatum, possesses diverse pharmacological properties including anti-inflammatory and anticancer activities. Artesunate, a sesquiterpene lactone extracted from Artemisia annua, exhibits potent antimalarial efficacy and has garnered attention for its potential anticancer properties. Through rational drug design, the conjugation of rhein with artesunate has yielded compounds capable of selectively targeting mitochondria of cancer cells, inducing oxidative stress-mediated ICD, and enhancing the immunogenicity of tumor cells. The conjugate leverages the inherent cytotoxicity of artesunate while incorporating the capability to selectively target the mitochondria of rhein, thereby fostering a special approach to immunotherapy for cancer. Upon accumulation in the mitochondria, these compounds induce the generation of reactive oxygen species (ROS), leading to mitochondrial membrane potential (ΔΨm) reduction and endoplasmic reticulum (ER) stress. Notably, the conjugate exhibits far more potent ICD-inducing properties than their parent compounds. In vivo studies have demonstrated that the vaccine, when treated with the conjugate, effectively suppresses tumor growth. Full article

(This article belongs to the Section Medicinal Chemistry)

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Chemistry, Volume 6, Issue 3 (June 2024) – 4 articles

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