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The reactivity of complexes [Fe2(μ‐S2)(CO)4L2] (L=CO (1), PPh3 (2)), with lithium alkynylide reagents generated in situ, was investigated. The behavior of the S2‐bridge in these compounds depends on the substitution at the diiron core. The reaction with the hexacarbonyl derivative 1 leads to the formation of the 1,2‐dithiolene bridged complex [Fe2(μ‐SCH=C(R)S)(CO)6] (3R) while the molecule [Fe2(μ‐SH)(μ‐SC≡CR)(CO)4(PPh3)2] (5R), with an open butterfly structure, is isolated when reacting the disubstituted derivative 2. The disubstituted dithiolene complex [Fe2(μ‐SCH=C(Ph)S)(CO)4(PPh3)2] (4Ph) can only be obtained by substitution of carbonyls with PPh3 in 3R. In the presence of piperidine, 5R isomerizes into the 1,1'‐dithiolene bridged derivative 6Ph. The novel compounds 4–6 were synthesized and characterized by IR and NMR spectroscopies. X‐ray crystallographic studies of the dithiolene complexes 3Ph–4Ph allowed their structural analysis. [ABSTRACT FROM AUTHOR]

Two series of novel hybrid heterocyclic compounds that combine the imidazole ring with bioactive piperidine, morpholine or piperazine heterosystems, through a hydrazone unit, were easily obtained by two competitive pathways. Starting from 5‐amino‐4‐cyanoformimidoyl imidazoles and 1‐aminopiperidine, 4‐aminomorpholine or 1‐amino‐4‐methylpiperazine under mild acidic media led to the selective synthesis of 5‐aminoimidazole 4‐carboxamidrazones, whereas the corresponding 4‐hydrazonoyl cyanide derivatives were obtained under stronger acidic conditions. These highly functionalized imidazoles provide convenient synthetic precursors to a vast array of heterocycles with potential pharmaceutical applications. The reaction mechanisms were elucidated on the basis of experimental assays and in silico calculations. The compounds were screened against colorectal cancer HCT116‐p53 wt cell line, and significant IC50 values of 3.69 μM and 4.83 μM were obtained. [ABSTRACT FROM AUTHOR]

In previous works, we demonstrated that tertiary 3‐chloropiperidines are potent chemotherapeutics, alkylating the DNA through the formation of bicyclic aziridinium ions. Herein, we report the synthesis of novel secondary 3‐chloropiperidine analogues. The synthesis incorporates a new procedure to monochlorinate unsaturated primary amines utilizing N‐chlorosuccinimide, while carefully monitoring the temperature to prevent dichlorination. Furthermore, we successfully isolated highly strained bicyclic aziridines by treating the secondary 3‐chloropiperidines with a sufficient amount of base. We conclude this work with a DNA cleavage assay as a proof of principle, comparing our previously known substrates to the novel compounds. In this, the secondary 3‐chloropiperidine as well as the isolated bicyclic aziridine, proved to be more effective than their tertiary counterpart. [ABSTRACT FROM AUTHOR]

Stable boroxine-amine adducts comprising dative B←N bond(s) were prepared by mechanochemically-induced reactions of phenylboronic acid (PBA) and amines (pyridine, DMAP, 1Hpyrazole, piperidine, DABCO, hexamethylenetetramine, or 4,4'-bipyridine). In-situ Raman monitoring, ex-situ PXRD and DFT calculations were used for product identification. Stoichiometry of the product (3: 1, 3:2 or 6:1 adduct) was controlled by the amine structure and the molar ratio of the reactants. The 1:2 Hbonded assembly of PBA and 4,4'-bipyridine (bpy) was confirmed as an intermediate in the adduct formation for bpy. Competitive binding experiments indicated that the exchange of the amines in the 3:1 adducts follows the computed adduct stabilities that increase with the amine basicity. Following the DFT prediction, the first adduct with two different amines, DMAP and pip, bound to one boroxine moiety was isolated and structurally characterized. Results show that calculations can be used to predict possible and preferred product(s) and their spectral characteristics. [ABSTRACT FROM AUTHOR]

Linearly fused polycyclic piperidines represent common substructures in natural products and biologically active small molecules. We have devised a Pd‐catalyzed annulation strategy to these compounds that converts readily available 2‐tetralones and indanones into these scaffolds with the potential for control of both enantio‐ and diastereoselectivity. Importantly, these compounds can be chemoselectively functionalized, providing an efficient and robust methodology to these important nitrogen‐containing molecules. [ABSTRACT FROM AUTHOR]

Novel rhodium‐catalyzed [3+3] annulations of diazoenals and α‐amino ketones has been disclosed here. The reactivity of diazoenals has been switched from carbenoid to vinylogous NH‐insertion by altering acyclic to cyclic α‐amino ketones. In this direction, we report an efficient strategy to synthesize 1,2‐dihydropyridines (DHPs) and fused 1,4‐oxazines. Mechanistic investigation revealed that the formyl group is necessary for carbenoid [3+3] annulation and the cyclohexyl group is the dictating factor for vinylogous NH‐ insertion. The synthetic utility of 1,2‐dihydropyridines was demonstrated by synthesizing piperidine, pyrido[1,2‐a]indole, and 2‐pyridone scaffolds. Further, structural diversification of fused 1,4‐oxazines resulted in the short synthesis of hexahydroquinolin‐2(1H)‐ones, hexahydro quinolines and tetrahydroquinolinones via ring opening rearrangement and a new oxidative deformylation, respectively. [ABSTRACT FROM AUTHOR]

New derivatives of crown compounds were successfully prepared via multicomponent reactions of a thia‐podand, an β‐keto ester and ammonium acetate based on modifications of the Petrenko‐Kritschenko reaction. The structure of the synthesized compounds was identified by physical‐chemical methods of analysis including IR, NMR, HRMS, and single‐crystal X‐ray diffraction. In addition, an in vitro assay against the α‐glucosidase of synthetic compounds was first evaluated and showed positive results. The most active compound exhibited an IC50 value of 5.69±0.27 μM, which is 37 fold more potent than the standard drug of acarbose (IC50 208.42±4.68 μM). Furthermore, prediction of ADMET parameters revealed that almost all synthesized trithiacrown ether derivatives expressed drug‐like characteristics. Our results provide useful evidence that crown ether compounds are not only good chelators with metal ions but also scaffolds for developing lead candidates in the treatment of diabetic disease. [ABSTRACT FROM AUTHOR]

An approach to gem‐difluoro‐3‐azabicyclo[3.n.1]alkane‐ derived building blocks through double‐Mannich addition– deoxofluorination sequence is described. The scope of the method was demonstrated for a series of saturated (hetero)cyclic ketones or ketoesters (including five‐ to seven‐membered cycloalkane derivatives and N‐, O‐, S‐containing saturated heterocycles). Further transformations of functional groups produced various bifunctionalized difluorinated building blocks, namely, N‐protected aminoacids, mono‐N‐Boc‐protected diamines, and unprotected aminoalcohols in good to excellent overall yields. For the azabicyclo[3.3.1]alkane series, a potential for isosteric replacements is demonstrated by evaluation of the key physicochemical properties (i. e., pKa(H) and LogP). [ABSTRACT FROM AUTHOR]

The possibility of stratifying patients according to differences in ROS proto‐oncogene 1 (ROS1) fusion partners has been discussed. This study aimed to clarify the clinicopathological differences between two SDC4::ROS1 positive NSCLC cases who had different responses to crizotinib. Cytology and pathology samples from two NSCLC cases with SDC4::ROS1 who were diagnosed and treated with crizotinib at Nihon University Itabashi Hospital were obtained. Case 1 has been well‐controlled with crizotinib for over 5 years, but case 2 was worse and overall survival was 19 months. Sequencing analysis of ROS1 fusion genes was performed by reverse‐transcription‐PCR and Sanger's sequencing methods. In addition, thyroid transcription factor (TTF)‐1, ROS‐1, Ki67, and phosphorylated extracellular signal‐regulated kinase (pERK)1/2 expression were investigated using immunohistochemistry. Sequencing analysis showed SDC4 exon2::ROS1 exon 32 (exon33 deleted) in case 1, and coexistence of SDC4 exon2::ROS1 exon 34 and SDC4 exon2::ROS1 exon35 in case 2. The Ki67 index was not different, but ROS1 and pERK1/2 expression levels tended to be higher in the tumor cells of case 2 than in case 1. Therapeutic response to crizotinib and patients' prognosis in ROS1 rearranged NSCLC may be related to the activation of ROS1 signaling, depending on ROS1 and pERK1/2 overexpression status, even if the ROS1 fusion partner is the same. [ABSTRACT FROM AUTHOR]

The article titled "Front Cover: gem-Difluoro-3-azabicyclo[3.n.1]alkanes and Their Derivatives - Bicyclic Fluorinated Piperidine Isosteres for Drug Discovery" highlights the potential of 9,9-difluoro-3-azabicyclo[3.3.1]alkane as a novel fluorinated three-dimensional piperidine isostere in drug discovery. The compound, synthesized by Ukrainian chemists, is depicted on the front cover as a peaceful night sky above Kyїv city, symbolizing its position in the medicinally relevant chemical space. The article provides more information on this topic and is authored by Serhii Kihakh, Kostiantyn P. Melnykov, Vitalii Bilenko, Serhii Trofymchuk, Oleksandr S. Liashuk, and Oleksandr O. Grygorenko. [Extracted from the article]