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Following our quest for N-heterocyclic Hammick silylenes, we have to probe the electronegative and electropositive substitutions on the singlet (s) and triplet (t) silapyridine-4-ylidene fused by two furan rings compared to the synthesized silylenes by West (I-s), Denk (II-s), and Kira (III-s). In all cases, s silapyridine-4-ylidenes emerge as ground state, revealing more stability than their corresponding t analogous. All species seem to have a minimum on their energy surfaces, demonstrating the positive force constant and the positive frequency. The optimized s silylenes show bond length, divalent and dihedral bond angles, somewhat similar to their corresponding t congeners. Irrespective of how substituent groups are arranged in either the "W (ortho)" or "chair (para)" positions of the silylenic center, the most stability is verified by the substitution of more electronegative NH and O groups (as electron withdrawing groups; EWGs) in the corresponding furan rings, while the least stability is respected by III-s. In contradiction to previous reports on the N-heterocyclic Hammick carbenes, silylenes, and germylenes (NHCs, NHSis, and NHGes) that size, type, and orientation, in addition to the number of fused rings, formulated influence on ΔΕs-t, ΔΕHOMO-LUMO, and reactivity of the corresponding divalent species, now PH, AsH, S, and Se (as σ and π- electron donating groups; EDGs) similar to EWGs stabilize their silylenic derivatives. In going from second row to third row and from third row to forth row of every group in the periodic table, stability is decreased. As a result, the stability and electronic properties of s and t NHSis are considerably dependent on the electronegativity and radius of the substituted dopants. [ABSTRACT FROM AUTHOR]

A new ligand, 4-(4-carboxyphenyl)-6-(pyrazin-2-yl)picolinic acid (H2L1), was used to construct four isostructural one-dimensional (1 D) zig-zag chain coordination polymers ([M(L1)(H2O)2]·3H2O, M = Mn (1), Co (2), Cd (3) and Zn (4)). Moreover, when changing the ligand substituent group from pyrazine ring to furan ring, another new ligand, 4-(4-carboxyphenyl)-6-(furan-2-yl)picolinic acid (H2L2), was synthesized. Based on H2L2, different structural 1 D coordination polymers, ([Mn(L2)(H2O)2] (5) and [Ni(L2)(H2O)2]·H2O (6)), have been obtained under the same solvothermal conditions as for the syntheses of isostructural 1–4. Interestingly, only through changing the ligand substituent group, the 1 D isostructural zig-zag chain (1–4) was adjusted to a 1 D molecular box chain (5) and 1 D linear chain (6), which should be ascribed to ligand substituent group effects. The various 1 D chain structures originate from the types of ligand substituent group: the substituent group with a pyrazine ring only yields isostructural coordination polymers 1–4, whereas the substituent group with a furan ring can construct different structural coordination polymers, such as a 1 D molecular box chain (5) or a 1 D linear chain (6). The photoluminescent properties of all coordination polymers were also examined. [ABSTRACT FROM AUTHOR]

Nimbolide is a major furanoid compound isolated from Azadirachta indica. The aim of this study was to characterize the metabolites of nimbolide in rats and to propose the metabolic pathways. The metabolites were generated by incubating nimbolide (10 μM) with rat liver microsomes, nicotinamide adenine dinucleotide phosphate (NADPH), and nucleophiles (glutathione [GSH] or N-acetyl-lysine [NAL]) at 37°C for 60 min. For the in vivo study, nimbolide was intravenously administered to rats at a single dose of 10 mg/kg, and the bile and urine were collected. The metabolites were identified by ultra-high-performance liquid chromatography-quadrupole/orbitrap mass spectrometry (UPLC-Q/Orbitrap-MS) using electrospray ionization in positive ion mode. Totally, nine metabolites were detected, and their identities were characterized by accurate MS and MS/MS data. In GSH-supplemented liver microsomes, GSH conjugation was the primary elimination pathway. The furan ring was bioactivated into cis-butene-1,4-dial that can be trapped by GSH. In NAL-supplemented liver microsomes, two NAL conjugates (M4 and M5) derived from cis-butene-1,4-dial were observed. In rat bile and urine, N-acetyl-cysteine, cysteine-glycine, and GSH conjugate were also found. The current study provides an overview of the metabolism and the bioactivation profiles of nimbolide in rats, which aids in understanding its safety and activity., (© 2024 John Wiley & Sons, Ltd.)

In the title compound, C20H19NO5, the central six-membered ring has a slightly distorted half-chair conformation, with puckering parameters of QT = 0.3387 (11) Å, θ = 49.11 (19)° and φ = 167.3 (2)°. The conformation of the fused pyrrolidine ring is that of an envelope. Molecules are connected by intermolecular C—H...O hydrogen bonds, C—H...π interactions and π–π stacking interactions [centroid-to-centroid distance = 3.9536 (11) Å, with a slippage of 2.047 Å], forming a three-dimensional network. The most important contributions to the surface contacts are from H...H (46.3%), O...H/H...O (31.5%) and C...H/H...C (17.3%) interactions, as concluded from a Hirshfeld surface analysis.

Although 1H‐benzo[d]imidazole‐4‐carboxamide derivatives have been explored for a long time, the structure–activity relationship of the substituents in the hydrophobic pocket (AD binding sites) has not thoroughly discovered. Here in, a series of 2‐(4‐[4‐acetylpiperazine‐1‐carbonyl]phenyl)‐1H‐benzo[d]imidazole‐4‐carboxamide derivatives have been designed, synthesized, and successful characterization as novel and effective poly ADP‐ribose polymerases (PARP)‐1 inhibitors to improve the structure–activity relationships about the substituents in the hydrophobic pocket. These derivatives were evaluated for their PARP‐1 inhibitory activity and cellular inhibitory against BRCA‐1 deficient cells (MDA‐MB‐436) and wild cells (MCF‐7) using PARP kit assay and MTT method. The results indicated that compared with other heterocyclic compounds, furan ring‐substituted derivatives 14n‐14q showed better PARP‐1 inhibitory activity. Among this derivatives, compound 14p displayed the strongest inhibitory effects on PARP‐1 enzyme (IC50 = 0.023 μM), which was close to that of Olaparib. 14p (IC50 = 43.56 ± 0.69 μM) and 14q (IC50 = 36.69 ± 0.83 μM) displayed good antiproliferation activity on MDA‐MB‐436 cells and inactivity on MCF‐7 cells, indicating that 14p and 14q have high selectivity and targeting. The molecular docking method was used to explore the binding mode of compound 14p and PARP‐1, and implied that the formation of hydrogen bond was essential for PARP‐1 inhibition activities. This study also showed that in the hydrophobic pocket (AD binding sites), the introduction of strong electronegative groups (furan ring, e.g.) or halogen atoms in the side chain of benzimidazole might improve its inhibitory activity and this strategy could be applied in further research. [ABSTRACT FROM AUTHOR]

A di‐substituted quinone (5), having two amido‐groups at opposite positions, was reacted with tertiary, secondary, or primary amines via a one‐pot reaction in the presence of palladium salt. Crystal structures of some of the products, 7b‐7c, from these reactions reveal that two new pyrrole rings are formed and linked to quinone framework of 5 by taking advantage of the in situ generated alkenyl moiety, which is from the reaction of amine with palladium salt. Furthermore, the reaction of di‐amido substituted diquinone (8a) with tertiary amines led to the formations of 9a‐9d with new pyrrole and benzene rings to the moiety of 8a. Similar procedures for the reaction of 8b with tertiary amines provides an alternated route to make notable 1,4,5,8‐phenanthrenetetraone derivatives, 9e and 9f. Moreover, the reaction of diquinone (8a) with tricyclohexylphosphine led to two products, 11 and 13, with new formation of furan ring as well as PC bond. Further reaction of 11 with NBu3 yielded 14 with newly formed pyrrole ring. Crystal structures of these newly‐formed compounds revealed by single‐crystal X‐ray diffraction methods substantiate the claim. [ABSTRACT FROM AUTHOR]

In the title compound, C20H19NO5, the central six-membered ring has a slightly distorted half-chair conformation, with puckering parameters of QT = 0.3387 (11) Å, Φ = 49.11 (19)° and Φ = 167.3 (2)°. The conformation of the fused pyrrolidine ring is that of an envelope. Molecules are connected by intermolecular C-H...O hydrogen bonds, C-H...π interactions and π-π stacking interactions [centroid-to-centroid distance = 3.9536 (11) Å, with a slippage of 2.047 Å], forming a three-dimensional network. The most important contributions to the surface contacts are from H...H (46.3%), O...H/H...O (31.5%) and C...H/H...C (17.3%) interactions, as concluded from a Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

Three new epoxy-clerodanes bearing a furan ring hypoleins A–C , were isolated from the aerial parts of Croton hypoleucus , along with the known compounds crotonpenes A and B. The structure of all compounds was elucidated on the basis of extensive ID and 2D NMR and mass (HR-ESIMS) spectroscopic data analyses. All of them possess an epoxy ring at C-3/C-4, and one furan ring at C-12. The absolute configuration of hypolein A was established by X-ray diffraction analysis. The crystal packing of hypolein A showed two types of intermolecular contacts such as C H⋯O and C H⋯π (Furan ring) interactions. [ABSTRACT FROM AUTHOR]

Four new and rare iridoid glucosides, cornusfuroside A–D ( 1 – 4 ), containing the furan ring were identified from water extract of the fruit of Cornus officinalis . These new chemical structures were determined through extensive spectroscopic analysis, including 1D and 2D NMR, IR, HRESIMS, experimental and calculated electronic circular dichroism (ECD). Notably, this study is the first report on the isolation of four iridoid glucoside structures with acetal functions in the sugar moiety. The neuroprotective effects of these compounds were also evaluated in vitro . [ABSTRACT FROM AUTHOR]

[Display omitted] • Pd nanoparticles encapsulated in MOF-303 was designed and synthesized. • The adjacent pair of N atoms in MOF-303 facilitated the stabilization of Pd species. • The Pd nanoparticles exhibited excellent performance for HMF conversion to DHMTHF under mild conditions. • Pd in Pd@MOF-303 could expose more defective sites that were highly selective for the hydrogenation reaction. Catalytic conversion of biomass-derived compounds into value-added chemicals or liquid fuels is of significant importance for the valorization of sustainable biomass. Currently, selective hydrogenation of typical biomass-derived 5‑hydroxymethylfurfural (HMF) to the valuable 2,5-dihydroxymethyl-tetrahydrofuran (DHMTHF) has attracted considerable interest, but still suffers from the low efficiency and harsh H 2 pressure (usually 4 ∼ 8 MPa) in this process. Therefore, developing more efficient catalysts for the facile synthesis of DHMTHF from HMF under mild conditions is highly desired. Herein, small Pd nanoparticles were encapsulated in a metal–organic framework (Pd@MOF-303), and highly stabilized by the adjacent pair of N atoms of organic linkers of MOF-303. The small Pd nanoparticles were significantly efficient for HMF conversion to DHMTHF, and exhibited a yield of 95.8 % with a production rate of 85.1 h−1 under 1 MPa H 2. The excellent catalytic performance was attributed to the small Pd nanoparticles which could expose more stable defective sites that were highly active and selective for this reaction. [ABSTRACT FROM AUTHOR]

3-(2-Furanyl)-4-amino-5-mercapto-1,2,4-triazole (1) was prepared from 2-furoic acid through a multi-step reaction sequence. Compound 1 reacted with aromatic acids in the presence of phosphorus oxychloride to give 3-(2-furanyl)-6-aryl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles (2). The structures of all the newly synthesized compounds have been confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectra. The bioassay indicated most of the title compounds possess significant growth promoting effects on mung bean radicles.

[Display omitted] Sarglafuran A (1), a new [4 + 2] type lindenane sesquiterpene dimer with an unique furan ring moiety, and a pair of new [2 + 2] type dimeric lindenane epimers, sarglalactones N and O (2 and 3), were isolated from the leaves of Sarcandra glabra. Their structures were elucidated by comprehensive spectroscopic analyses, and the absolute configurations of these compounds were determined by single crystal X-ray diffraction or CD exciton chirality method. In addition, a possible biosynthetic pathway of the unique furan ring moiety in 1 had been proposed. Their cytotoxicity against MCF-7 and MDA-MB-231, together with the inhibitory activity against nitric oxide (NO) production of LPS-induced RAW264.7 macrophages were evaluated. [ABSTRACT FROM AUTHOR]

new method is proposed for the production of derivatives of thieno[2,3-b]pyrrole on the basis of acid-catalyzed recyclization of the furan ring in 2-R-amino-3-furfurylthiophenes. It was established that the direction of the transformations occurring under the influence of a mixture of hydrochloric and acetic acids and also the structure of the obtained compounds depend on the nature of the protecting group. [ABSTRACT FROM AUTHOR]

A substituted polyacetylene bearing a furan ring, poly(2-propynyl 2-furoate) (PPF), was synthesized for the first time with palladium acetylide complex catalysts in CHCI3 at 60°C to give a soluble and stable polymer with a yield of ca. 75%. Some features for polymerization of 2-propynyl 2-furoate are described and discussed. The resulting polymer was characterized by IR, GPC and ¹H-NMR analysis. [ABSTRACT FROM AUTHOR]

Stereoselective synthesis of C1–C9 subunit of macrocyclic lactone—tylonolide is presented. Starting from 2-methylfuran and crotyl alcohol, a 2,5-disubstituted furan derivative was synthesized. Its oxidation leads to α,β-unsaturated dicarbonyl intermediate which has been transformed into acyclic fragment bearing five consecutive asymmetric centers. [Copyright &y& Elsevier]

[Display omitted] • Synthesis of enantiomerically pure oxa[9]helicenes by cyclodehydration reaction. • P 2 O 5 was optimal among several cyclodehydration reaction conditions. • Chiroptical properties of oxa[9]helicene were shown by ECD measurement. • Oxa[9]helicenes with several substituents were synthesized. A new one-step cyclization reaction has been established for the synthesis of oxa[9]helicene derivatives, containing eight ortho-condensed benzene rings and one furan ring. 1,1′-Bibenzo[ c ]phenanthrene-2,2′-diols (HEBPOLs) afforded the corresponding oxa[9]helicenes by refluxing with phosphorous pentoxide (P 2 O 5) in o -dichlorobenzene. Enantiomerically pure oxa[9]helicenes were also synthesized with retention of the configuration and enantiopurity (>98% ee) from the corresponding enantiomerically pure HEBPOLs. [ABSTRACT FROM AUTHOR]

Psoralen or furocoumarin is a linear three ring heterocyclic compound. Psoralens are planar, tricyclic compounds, consisting of a furan ring fused to a coumarin moiety. Psoralen has been known for a wide spectrum of biological activities, spanning from cytotoxic, photosensitizing, insecticidal, antibacterial to antifungal effect. Thus, several structural changes were introduced to explore the role of specific positions with respect to the biological activity. Convenient approaches utilized for the synthesis of psoralen skeleton can be categorized into two parts: (i) the preparation of the tricyclic ring system from resorcinol, (ii) the exocyclic modification of the intact ring system. Furthermore, although psoralens have been used in diverse ways, we mainly focus in this work on their clinical utility for the treatment of psioraisis, vitiligo and skin-related disorder., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

A rapid and efficient synthesis of 5-methoxypsoralen, �furocoumarin commonly used in dermatology for the treatment by PUVA therapy of skin diseases, is described using cheap and easily available starting materials. An alternative method to synthesize 7-(2-oxoethoxy)coumarin, the key step to generate the furan ring, is suggested. [ABSTRACT FROM AUTHOR]