Coumarin Ring System Research Articles

Synthesis, structure and Hirshfeld surface analysis of 2-oxo-2H-chromen-4-yl penta-noate.

In the title compound, C14H14O4, the dihedral angle between the coumarin ring system (r.m.s deviation = 0.016 Å) and the penta-noate ring is 36.26 (8)°. A short intra-molecular C-H⋯O contact of 2.40 Å is observed. Hirshfeld surface analysis reveals that 46.1% of the inter-molecular inter-actions are from H⋯H contacts, 28.6% are from H⋯O/O⋯H contacts and 14.7% are from H⋯C/C⋯H.

Neuroprotective Potential of Pyranocoumarins from Angelica gigas Nakai on Glutamate-Induced Hippocampal Cell Death.

Chronic neurodegenerative diseases are typically associated with oxidative stress conditions leading to neuronal cell death. We aimed to investigate the neuroprotective effect of three pyranocoumarins (decursin, decursinol angelate, and decursinol) targeting oxidative stress factors. Decursin (also known as dehydro-8-prenylnaringenin) is a prenylated coumarin compound consisting of a coumarin ring system with a prenyl group attached to one of the carbons in the ring. As a secondary metabolite of plants, pyranocoumarin decursin from Angelica gigas Nakai presented protective effects against glutamate-induced oxidative stress in HT22, a murine hippocampal neuronal cell line. Decursinol (DOH) is a metabolite of decursin, sharing same coumarin ring system but a slightly different chemical structure with the prenyl group replaced by a hydroxyl group (-OH). In our findings, DOH was ineffective while decursin was, suggesting that this prenyl structure may be important for compound absorption and neuroprotection. By diminishing the accumulation of intracellular reactive oxygen species as well as stimulating the expression of HO-1, decursin triggers the self-protection system in neuronal cells. Additionally, decursin also revealed an anti-apoptotic effect by inhibiting chromatin condensation and reducing the forming of annexin-V-positive cells.

Chemical library design, QSAR modeling and molecular dynamics simulations of naturally occurring coumarins as dual inhibitors of MAO-B and AChE

Coumarins are a highly privileged scaffold in medicinal chemistry. It is present in many natural products and is reported to display various pharmacological properties. A large plethora of compounds based on the coumarin ring system have been synthesized and were found to possess biological activities such as anticonvulsant, antiviral, anti-inflammatory, antibacterial, antioxidant as well as neuroprotective properties. Despite the wide activity spectrum of coumarins, its naturally occurring derivatives are yet to be investigated in detail. In the current study, a chemical library was created to assemble all chemical information related to naturally occurring coumarins from the literature. Additionally, a multi-stage virtual screening combining QSAR modeling, molecular docking, and ADMET prediction was conducted against monoamine oxidase B and acetylcholinesterase, two relevant targets known for their neuroprotective properties and ‘disease-modifying’ potential in Parkinson’s and Alzheimer’s disease. Our findings revealed ten coumarin derivatives that may act as dual-target drugs against MAO-B and AChE. Two coumarin candidates were selected from the molecular docking study: CDB0738 and CDB0046 displayed favorable interactions for both proteins as well as suitable ADMET profiles. The stability of the selected coumarins was assessed through 100 ns molecular dynamics simulations which revealed promising stability through key molecular interactions for CDB0738 to act as dual inhibitor of MAO-B and AChE. However, experimental studies are necessary to evaluate the bioactivity of the proposed candidate. The current results may generate an increasing interest in bioprospecting naturally occurring coumarins as potential candidates against relevant macromolecular targets by encouraging virtual screening studies against our chemical library. Communicated by Ramaswamy H. Sarma

Synthesis of a Coumarin-Based Analogue of Schweinfurthin F.

The natural schweinfurthins are stilbenes with significant antiproliferative activity and an uncertain mechanism of action. To obtain a fluorescent analogue with minimal deviation from the natural structure, a coumarin ring system was annulated to the D-ring, creating a new analogue of schweinfurthin F. This stilbene was prepared through a convergent synthesis, with a Horner–Wadsworth–Emmons condensation employed to form the central stilbene olefin. After preparation of a tricyclic phosphonate via a recent and more efficient modification of the classic Arbuzov reaction, condensation was attempted with an appropriately substituted bicyclic aldehyde but the coumarin system did not survive the reaction conditions. When olefin formation preceded generation of the coumarin, the stilbene formation proceeded smoothly and ultimately allowed access to the targeted coumarin-based schweinfurthin analogue. This analogue displayed the desired fluorescence properties along with significant biological activity in the National Cancer Institute’s 60-cell line bioassay, and the pattern of this biological activity mirrored that of the natural product schweinfurthin F. This approach gives facile access to new fluorescent analogues of the natural schweinfurthins and should be applicable to other natural stilbenes as well.

Recent Developments in Coumarin Derivatives for Breast Cancer Therapy

The coumarin ring system (benzopyran-2-one, or chromen-2-one), gift in natural shown fascinating medical specialty properties, has intrigued chemists to explore the natural coumarins or artificial analogs for his or her relevance as medication. uncountable molecules supported the coumarin ring system are synthesized within the laboratories utilizing completely different artificial techniques. the variety orientating artificial routes have crystal rectifier to fascinating derivatives together with the furanocoumarins, pyranocoumarins, and coumarin sulfamates, that are found to be helpful in photochemotherapy, antitumour and anti-HIV medical care, and conjointly as stimulants for central systema nervosum, anti-inflammatory drug, anti-coagulants, medicament and dyes. In carcinoma therapy, some coumarins and their active matter 7-hydroxycoumarin derivatives have shown sulfatase and aromatase restrictive activities. Coumarin primarily based selective oestrogen receptor modulators (SERMs) and coumarin oestrogen conjugates have conjointly been expressed as an excellent potential antibreast cancer agent. carcinoma is leading reason behind death in ladies, there's a powerful focus to spot potential new drug treatments for carcinoma. Therefore, the most objective of this review is to specialise in vital coumarin analogs with antibreast cancer activities, highlight their mechanisms of action and structure-activity relationships on elect receptors in breast tissues.

6-Methyl-4-{[4-(tri-methyl-sil-yl)-1H-1,2,3-triazol-1-yl]meth-yl}-2H-chromen-2-one.

In the title compound, C16H19N3O2Si, the dihedral angle between the coumarin ring system (r.m.s. deviation = 0.031 Å) and the triazole ring is 73.81 (8)°. In the crystal, mol-ecules are linked into [010] chains by weak C-H⋯O inter-actions.

Synthesis, Spectrometric Characterization (ESI-MS, NMR, IRTF), X-Ray Study and Quantum Chemical Calculations of 2-oxo-2H-chromen-7-yl Benzoate

The paper presents a combined experimental and computational study of 7-substituted coumarin derivative, the 2-oxo-2H-chromen-7-yl benzoate (I). The compound was prepared in the laboratory by linking the coumarin system (7-hydroxycoumarin) to benzoyl chloride and crystallized in the monoclinic space group P2 1 with = 3.86010(10), = 27.7876(9), = 5.7453(2) A, = = 90, =91.063(3)° and = 2. The compound has been characterized structurally by spectroscopy and by single-crystal X-Ray diffraction. In the latter, the structure of (I) was solved by direct methods and refined to a final R value of 0.038 for 2260 independent reflections. Its structure is stabilized by intramolecular C-H•••O and intermolecular C-H•••O hydrogen bonds that extended as infinite 1D chain along [001]. Stabilization is also ensured by oxygen-π stacking interaction between the aromatic ring and oxygen of the benzoate moiety. The analysis of intermolecular interactions through the mapping of d norm and shape-index revel that the most significant contributions to the Hirshfeld surface 36.2 and 27.9% are from H•••H and O•••H contacts, respectively. Besides, the molecular geometry of (I) was also optimized using density functional theory (DFT/RB3LYP), the basic ab initio model i.e the restricted Hartree-Fock (RHF) methods with the 6-311 ++ G(d, p) basis set in ground state and frequency calculations with RB3LYP method using 6-31G(d,p) basis set. The theoretical data resulting from these quantum chemical calculations are generally in good agreement with the observed structure. The only significant observed difference is in the torsion angles between the coumarin ring system and the benzoate ring, where the observed CO -CC value (59.6 (4)°) is slightly lower than the DFT/RB3LYP calculated value (54.32°) and the frequency calculations (41.23°) value and larger than that of the RHF computed value (110.63°). The non-linear optical effects (NLO), molecular electrostatic potential (MEP), frontier molecular orbitals (FMO), and the Mulliken charge distribution were also investigated theoretically. The theoretical HOMO-LUMO energy gap values originating from these calculations are 4.465 eV (DFT/RB3LYP/6-311++G(d,p)) and 4.434 eV (FREQ/ RB3LYP/6-31G(d,p)).

Crystal structure of a new polymorph of 3-acetyl-8-meth-oxy-2H-chromen-2-one.

A new polymorphic form of the title compound, C12H10O4, is described in the ortho-rhom-bic space group Pbca and Z = 8, as compared to polymorph I, which crystallizes in the monoclinic space group C2/c and Z = 8 [Li et al. (2012). Chin. J. Struct. Chem. 31, 1003-1007.]. In polymorph II, the coumarin ring system is almost planar (r.m.s. deviation = 0.00129 Å). In the crystal, mol-ecules are connected by Csp 3-H⋯O and Car-H⋯O hydrogen bonds, forming mol-ecular sheets linked into zigzag shaped layers along the b-axis direction. The three-dimensional lattice is assembled through stacking of the zigzag layers by π-π inter-actions with a centroid-to-centroid distance of 3.600 (9) Å and anti-parallel C=O⋯C=O inter-actions with a distance of 3.1986 (17) Å, which give rise to a helical supra-molecular architecture.

Synthesis, Spectrometric Characterization, X-Ray Crystallography and Quantum Chemical Calculations of 2-oxo-2H-chromen-7-yl Propionate

The title compound, (I), has been solved by direct methods and refined to a final R value of 0.038 for 1835 independent reflections. In the structure, the planar [r.m.s deviation = 0.014 Å] chromen-2-one ring and the 7-propionate side chain are inclined to one another at an acute angle of 65.34(9)°. The molecules form R₄⁴ (30) tetrameric units via C—H···O interactions which extend into layers approximately parallel to the <i>ab</i> plane. Furthermore, the crystal structure is supported by π–π stacking interactions between neighbouring benzene and pyrone or coumarin rings [centroid–centroid distances in the range 3.6097(8)–3.6475(9)Å], as well as C–H···π interactions [H···centroid distances in the range 2.95–3.00Å]. The molecular geometry of (I) was also optimized using density functional theory (DFT/RB3LYP), RMP2 and RHF methods with the 6-311⁺⁺G(<i>d</i>, <i>p</i>) basis set in ground state. The theoretical data resulting from these quantum chemical calculations are in good agreement with the observed structure, although the observed C—O—C—C torsion angle between the coumarin ring system and the 7-propionate side chain (121.49 (16)°) is somewhat lower than the DFT/RB3LYP calculated value (132.32°) and larger than the RMP2 (114.65°) and the RHF (69.19°) values. Hirshfeld surface analysis has been used to confirm and quantify the supramolecular interactions.

2-Oxo-2H-chromen-7-yl 4-tert-butyl-benzoate.

In the title compound, C20H18O4, the benzoate ring is oriented at an acute angle of 33.10 (12)° with respect to the planar (r.m.s deviation = 0.016 Å) coumarin ring system. An intra-molecular C-H⋯O hydrogen bond closes an S(6) ring motif. In the crystal, C-H⋯O contacts generate infinite C(6) chains along the b-axis direction. Also present are π-π stacking inter-actions between neighbouring pyrone and benzene rings [centroid-centroid distance = 3.7034 (18) Å] and C=O⋯π inter-actions [O⋯centroid = 3.760 (3) Å]. The data obtained from quantum chemical calculations performed on the title compound are in good agreement with the observed structure, although the calculated C-O-C-C torsion angle between the coumarin ring system and the benzoate ring (129.1°) is somewhat lower than the observed value [141.3 (3)°]. Hirshfeld surface analysis has been used to confirm and qu-antify the supra-molecular inter-actions.

3-Benzoyl-4-methyl-2-oxo-2H-chromen-7-yl acetate

In the title compound, C19H14O5, the dihedral angle between the coumarin ring system (r.m.s. deviation = 0.026 Å) and the pendant benzoyl group is 81.91 (7)°. In the crystal, weak C—H...O interactions link the molecules into a three-dimensional network.

A Review on Pharmacological Properties of Coumarins.

The coumarin (benzopyran-2-one, or chromen-2-one) ring system, present in many natural products, displays diverse pharmacological properties. It has attracted the attention of chemists and medicinal chemists for decades. Many molecules based on the coumarin ring system have been described utilizing innovative synthetic methods. These synthetic routes have led to interesting analogues of coumarins which possess pharmacological activities like anti-HIV, antimicrobial, antiinflammatory, anticancer, anti-TB, anticonvulsant and MAO inhibitory properties. Details of these studies, correlating structure with biological activity are described in this review.

Development of Phenyl Cyclohexylcarboxamides as a Novel Class of Hsp90 C-terminal Inhibitors.

Inhibition of the heat shock protein 90 (Hsp90) C-terminus represents a promising therapeutic strategy for the treatment of cancer. Novobiocin, a coumarin antibiotic, was the first Hsp90 C-terminal inhibitor identified, however, it manifested poor anti-proliferative activity (SKBr3, IC50 ≈700 μm). Subsequent structure-activity relationship (SAR) studies on novobiocin led to development of several analogues that exhibited improved anti-proliferative activity against several cancer cell lines. Recent studies demonstrate that the biphenyl core could be used in lieu of the coumarin ring system, which resulted in more efficacious analogues. In continuation of previous efforts, the work described herein has identified the phenyl cyclohexyl core as a novel scaffold for Hsp90 C-terminal inhibition. Structure-activity relationship (SAR) studies on this scaffold led to the development of compounds that manifest mid-nanomolar activity against SKBr3 and MCF-7 breast cancer cell lines through Hsp90 inhibition.

Dimethyl (7-hydroxy-4-methyl-2-oxo-2H-chromen-3-yl)phosphonate

In the title compound, C12H13O6P, the coumarin ring system is essentially planar [dihedral angle between the rings = 1.32 (16)°] and the methoxy groups and double-bonded O atom of the phosphonate group are disordered over two sets of sites [occupancy ratio 0.537 (2):0.463 (2)]. In the crystal, C—H...O hydrogen bonds involving the disordered phosphonate O atom as acceptor occur, which generate [100] chains. Weak C—H...O and aromatic π–π stacking interactions [minimum centroid–centroid separation = 3.713 (2) Å] are also observed.

Mechanism and properties of positive allosteric modulation of N-methyl-d-aspartate receptors by 6-alkyl 2-naphthoic acid derivatives

The theory that N-methyl-d-aspartate receptor (NMDAR) hypofunction is responsible for the symptoms of schizophrenia is well supported by many pharmacological and genetic studies. Accordingly, positive allosteric modulators (PAMs) that augment NMDAR signaling may be useful for treating schizophrenia. Previously we have identified several NMDAR PAMs containing a carboxylic acid attached to naphthalene, phenanthrene, or coumarin ring systems. In this study, we describe several functional and mechanistic properties of UBP684, a 2-naphthoic acid derivative, which robustly potentiates agonist responses at each of the four GluN1a/GluN2 receptors and at neuronal NMDARs. UBP684 increases the maximal l-glutamate/glycine response while having minor subunit-specific effects on agonist potency. PAM binding is independent of agonist binding, and PAM activity is independent of membrane voltage, redox state, and the GluN1 exon 5 N-terminal insert. UBP684 activity is, however, markedly pH-dependent, with greater potentiation occurring at lower pHs and inhibitory activity at pH 8.4. UBP684 increases channel open probability (Po) and slows receptor deactivation time upon removal of l-glutamate, but not glycine. The structurally related PAM, UBP753, reproduced most of these findings, but did not prolong agonist removal deactivation time. Studies using cysteine mutants to lock the GluN1 and GluN2 ligand-binding domains (LBDs) in the agonist-bound states indicate that PAM potentiation requires GluN2 LBD conformational flexibility. Together, these findings suggest that UBP684 and UBP753 stabilize the GluN2 LBD in an active conformation and thereby increase Po. Thus, UBP684 and UBP753 may serve as lead compounds for developing agents to enhance NMDAR activity in disorders associated with NMDAR hypofunction.

2-Oxo-2H-chromen-3-yl benzoate

In the title compound, C16H10O4, the dihedral angle between the coumarin ring system (r.m.s. deviation = 0.015 Å) and the benzoate group is 83.58 (9)°, which compares to a value of 81.8° obtained from a DFT calculation at the B3LYP/6–311 G(d,p) level. In the crystal, C—O...π and C—H...π interactions and aromatic π–π [Cg...Cg= 3.7214 (14) and 3.7059 (14) Å] stacking generate a three-dimensional network.

2-Oxo-2H-chromen-3-yl 4-fluorobenzoate

In the title compound, C16H9FO4, the dihedral angle between the planar coumarin ring system [maximum deviation = 0.027 (1) Å] and the benzene ring is 70.18 (6)°. In the crystal, π–π interactions [shortest centroid–centroid separation = 3.5338 (8) Å] link the molecules into a three-dimensional framework.

3-Benzoyl-7-methoxy-2H-chromen-2-one

In the title compound, C17H12O4, the dihedral angle between the coumarin ring system (r.m.s. deviation = 0.018 Å) and the phenyl ring is 55.96 (8)°. In the crystal, weak C—H...O interactions connect the molecules into a three-dimensional network and aromatic π–π stacking interactions are also observed [shortest centroid–centroid separation = 3.6692 (9) Å].

Crystal structure of 2-oxo-2H-chromen-3-yl 4-chloro-benzoate and Hirshfeld surface analysis.

In the title compound, C16H9ClO4 the dihedral angle between the coumarin ring system [maximum deviation = 0.023 (1) Å] and the benzene ring is 73.95 (8)°. In the crystal, π-π inter-actions link the dimers into a three-dimensional framework. A quantum chemical calculation is in generally good agreement with the observed structure, although the calculated dihedral angle between the ring systems (85.7%) is somewhat larger than the observed value [73.95 (8)°]. Hirshfeld surface analysis has been used to confirm and qu-antify the supra-molecular inter-actions.

Crystal structure of 4-(4b,8a-di-hydro-9H-pyrido[3,4-b]indol-1-yl)-7-methyl-2H-chromen-2-one.

The title compound, C21H14N2O2, was prepared by Pictet-Spengler cyclization of tryptamine and 4-formyl coumarin. In the mol-ecule, the dihedral angle between the mean planes of the coumarin and β-carboline ring systems is 63.8 (2)°. In the crystal, mol-ecules are linked via N-H⋯N hydrogen bonds, forming chains along the b-axis direction. Within the chains, there are a number of offset π-π inter-actions present [shortest inter-centroid distance = 3.457 (2) Å].