Die Dimroth-Umlagerung - Platzwechsel zwischen Ring- und Seitenkettenatomen von Heteroaromaten oder ihren Dihydrostufen unter intermediärer Ringöffnung

Facile Synthesis of 2-Methylnicotinonitrile through Degenerate Ring Transformation of Pyridinium Salts

Nucleophilic recyclization of pyridinium salts involving a CCN interchange ring transformation for the synthesis of 2-methylnicotinonitrile derivatives was herein developed. 3-Aminocrotononitrile (3-ACN) produced in situ from CH₃CN acted as a C-nucleophile, as well as the source of CH₃ and CN groups, which was supported by isotope-labeling and control experiments.

Synthesis and biological evaluation of selenogefitinib for reducing bleomycin-induced pulmonary fibrosis

Selenium has demonstrated effectiveness in the reduction of oxidative stress and inflammation in vitro and in vivo, both of which are key indicators of the pathogenesis of pulmonary fibrosis. Gefitinib, an FDA-approved EGFR inhibitor, effectively reverses the deterioration of bleomycin-induced pulmonary fibrosis. Based on this, we proposed introducing a selenium atom into the structure of gefitinib, resulting in the generation of selenogefitinib. Compared to gefitinib, selenogefitinib was significantly less hepatotoxic and cytotoxic in cells. The results of the H&E staining of lung tissue validated that Selenogefitinib effectively protected the structure of the alveolar tissue and mitigated the infiltration of inflammatory cells in bleomycin-induced pulmonary fibrosis models. The reduction in the deposition of collagen fibers in lung tissue determined by Masson staining and hydroxyproline (HYP) content also corroborated the efficacy of selenogefitinib in the treatment of pulmonary fibrosis. Furthermore, Selenogefitinib decreased the levels of pro-inflammatory markers IL-4, IL-6, and TNF-α more significantly than gefitinib, which indicated that it exhibited a higher anti-inflammatory activity. In addition, the presence of selenium manifested a greater reduction in oxidative stress based on the decrease in the levels of MDA in mice blood. These results suggested that Selenogefitinib may be a potential candidate for the treatment of IPF.

Nucleolipids of Canonical Purine ß-d-Ribo-Nucleosides: Synthesis and Cytostatic/Cytotoxic Activities Toward Human and Rat Glioblastoma Cells

We report on the synthesis of two series of canonical purine ß‐d‐ribonucleoside nucleolipids derived from inosine and adenosine, which have been characterized by elemental analyses, electrospray ionization mass spectrometry (ESI MS) as well as by ¹H and ¹³C NMR, and pH‐dependent UV/Vis spectroscopy. A selection of the novel nucleolipids with different lipophilic moieties were first tested on their cytotoxic effect toward human macrophages. Compounds without a significant inhibitory effect on the viability of the macrophages were tested on their cytostatic/cytotoxic effect toward human astrocytoma/oligodendroglioma GOS‐3 cells as well as against the rat malignant neuroectodermal BT4Ca cell line. In order to additionally investigate the potential molecular mechanisms involved in the cytotoxic effects of the derivatives on GOS‐3 or BT4Ca cells, we evaluated the induction of apoptosis and observed the particular activity of the nucleolipid ethyl 3‐{4‐hydroxymethyl‐2‐methyl‐6‐[6‐oxo‐1‐(3,7,11‐trimethyl‐dodeca‐2,6,10‐trienyl)‐1,6‐dihydro‐purin‐9‐yl]‐tetrahydro‐furo[3,4‐d][1,3]dioxol‐2‐yl}propionate (8 c) toward both human and rat glioblastoma cell lines in vitro.

Formylnitroenamines: useful building blocks for nitrated pyridones and aminopyridines with functional groups

beta-formyl-beta-nitroenamines possess both an electrophilic formyl group and a nucleophilic amino group and, therefore, serve as C3N1 building blocks having a nitro group to afford nitropyridones and aminonitropyridines with a functional group at the 3-position. Upon treatment with malonic acid derivatives or beta-keto esters, nitropyridones were obtained, whereas reactions with functionalized acetonitriles afford aminonitropyridines, via a formal transfer of an alkyl group from the ring nitrogen to the imino group. These procedures provide practical and useful methods for preparation of heterocycles with a nitro group.

Multicomponent Synthesis of Dihydropyrimidines and Thiazines

A broad range of differently substituted dihydropyrimidines and thiazines can be efficiently prepared by using a four-component reaction between phosphonates, nitriles, aldehydes, and iso(thio)cyanates. The scope and limitations of this multicomponent reaction are fully described. Variation of all four components has been investigated. The nitrile and aldehyde inputs can be varied extensively, but variation of the phosphonate input remains limited. An interesting rearrangement leading to phosphoramidates has been observed. Furthermore, the multicomponent reaction seems to be restricted to the use of isocyanates with strongly electron-withdrawing substituents, but an interesting additional exchange reaction under microwave conditions leads to dihydropyrimidines with less electron-withdrawing substituents at N3. In addition, a diastereoselective formation of dihydropyrimidines has been observed when using a chiral aldehyde as the input. Finally, by changing the isocyanate component to an isothiocyanate, thiazines are efficiently formed instead of the corresponding thio-dihydropyrimidines.