Chromene Research Articles

Isocyanide-based multicomponent reactions for the synthesis of benzopyran derivatives with biological scaffolds.

Benzopyrans (BZPs) are among the most privileged and influential small O-heterocycles that form the core of many natural compounds, commercial drugs, biological compositions, agrochemicals, and functional materials. BZPs are divided into six general categories including coumarins, chromans, 2H-chromenes, 4H-chromenes, chromones, and 4-chromanones, each of which is abundant in many plants and foods. These oxygenated heterocyclic compounds are fascinating motifs and have extensive applications in biology and materials science. Hence, numerous efforts have been made to develop innovative approaches for their extraction and synthesis. However, most of them are step-by-step or multi-step strategies that suffer from waste material generation and a tedious extraction process. Isocyanide-based multicomponent reactions (I-MCRs) offer a highly efficient method for overcoming these problems. The I-MCR is a simple and environmentally friendly one-pot domino procedure that does not require intermediate isolation or workup and is generally more efficient in material usage. This review covers all research articles related to I-MCRs for synthesizing BZP derivatives from the beginning to the middle of the year 2023. This strategy will be useful for organic and pharmaceutical chemists to design new drugs and optimize the synthesis steps of biological compounds and commercial drugs with benzopyran cores.

Regio- and diastereoselective synthesis of diverse spirocyclic indenes by cyclization with indene-dienes as two carbon building blocks.

We report a base-promoted cyclization with indene-dienes as two carbon building blocks toward diverse spirocyclic indene scaffolds including hexacyclic spiroindenes bearing benzo pyran motifs and pentacyclic spiroindenes containing oxindole units in high yields with excellent diastereoselectivities.

Access to Functionalized Chromanes by Asymmetric [4+2]-Cycloaddition

Access to Functionalized Chromanes by Asymmetric [4+2]-Cycloaddition

Comparative analysis of the chemical constituents from the tuberous root and stem of Pueraria candollei var. mirifica and evaluation of their estrogenic activity

Background: Pueraria candollei var.mirifica (PC) is a tuberous plant enriched with bioactive phytoestrogens. PC is currently high demanded in the global markets as dietary supplement products, which resulted in a shortage of tuberous root from the natural resource and the field cultivation. Materials and Methods: We compare phytoestrogens contents from the tuberous root and stem of PC and their estrogenic activities on MCF-7 cells proliferation. Results: The root and stem of PC accumulated different contents of phytoestrogens. The highest amount of total isoflavonoids and total chromenes was found in the root bark of PC. However, the stem bark (10 μg/mL crude extract) which contains a high level of chromenes and low amount of isoflavonoids exhibited higher growth stimulation of MCF-7 cells (127.25% ± 4.43% relative proliferative effect [RPE] as compared to estradiol [10−10 M]) than root bark at the same concentration with 116.32% ± 3.59% RPE. After the solubilization of the ethanol extract with 10% (v/v) aqueous ethanol, the soluble fraction of crude extract of stem stimulated proliferation of MCF-7 cells without cell growth suppression effect at high concentration (100 μg/mL) as observed in the insoluble fraction of the extract. Conclusion: We suggested that the soluble part of crude extract might be less toxic than the ethanolic crude extract and its non-polar components. Our study opens the possibility of using the stem of PC as a new alternative source of bioactive phytoestrogens for dietary supplement products.

Ru(II)- and Os(II)-Induced Cycloisomerization of Phenol-Tethered Alkyne for Functional Chromene and Chromone Complexes

Diphosphine-containing Ru(II)/Os(II)–chromene and −chromone complexes were synthesized from reactions between phenol ynone HC≡C(C═O)(o-C6H4OH) and cis-[Ru/Os(dppm)2Cl2] (dppm = 1,1-bis(diphenylphos...

Domino Hydroalkoxylation‐[4+2]‐Cycloaddition for Stereoselective Synthesis of 1,4‐Heterocycle‐Fused Chromenes: Rapid Access to the [6‐6‐7‐6] Tetracyclic Core of Cytorhizhins B–D

A substrate dependent regio‐ and stereoselective domino hydroalkoxylation‐formal‐[4+2] cycloaddition is described for the facile synthesis of linear as well as spirocyclic 1,4‐heterocycle‐fused chromene ketals. Enantiospecific synthesis of oxazepino chromene derivatives was successfully carried out using chiral pool amino alkynols. The developed hydroalkoxylation cascade offered rapid access to the spirocyclic [6‐6‐7‐6] tetracyclic core of cytorhizhins B–D with correct relative configuration.

Synthesis and Characterization of Pyrano[3,2-C]Chromene Derivatives: Exploring Their Optoelectronic and Charge Transport Properties By First-Principles Approach

With the aim to enhance the charge transport, optoelectronic and semiconducting properties various multifunctional pyrano[3,2-c]chromene derivatives were synthesized and characterized. To shed light on the various properties of interests, the ground state geometries were optimized by Density Functional Theory (DFT). The effect of different substituents, e.g., thiophen-2-yl, 5-bromothiophen-2-yl, 1H-indol-3-yl, pyridin-3-yl, and benzo[d][1,3]dioxol-5-yl was studied on the structural stability, electronic properties, and absorption wavelengths by DFT and Time-Domain DFT (TDDFT). The experimental excitation energies were successfully reproduced at TD-PBE/6-31G** level in DMSO. The electron injection barrier, ionization potential, electron affinity and reorganization energies for hole and electron were calculated and compared systematically. The smaller electron reorganization energies of pyrano[3,2-c]chromene derivatives except indole substituted one are illuminating that these materials would be efficient to be used in n-type semiconductor devices.

Application of Box-Behnken Design in Synthesis of 2-Amino-5-oxo-5,6,7,8-Tetrahydro-4H-Chromenes Using Tetrabutylammonium Hydrogen Sulfate (TBAHS)

Chromene heterocycles are reported to possess important activities such as antimicrobial,1 anti-viral,2 anti-inflammatory,3 antimalarial,4,5 antiproliferative,6 anti-tumor,7 anti-cancer,8 anti-estr...

Double C–H Activation Approach to Chromenes

Double C–H Activation Approach to Chromenes

Structure-activity relationships and molecular docking studies of chromene and chromene based azo chromophores: A novel series of potent antimicrobial and anticancer agents.

The design of novel materials with significant biological properties is a main target in drug design research. Chromene compounds represent an interesting medicinal scaffold in drug replacement systems. This report illustrates a successful synthesis and characterization of two novel series of chromene compounds using multi-component reactions. The synthesis of the first example of azo chromophores containing chromene moieties has also been established using the same methodology. The antimicrobial activity of the new molecules has been tested against seven human pathogens including two Gm+ve, two Gm-ve bacteria, and four fungi, and the results of the inhibition zones with minimum inhibitory concentrations were reported as compared to reference drugs. All the designed compounds showed significant potent antimicrobial activities, among of them, four potent compounds 4b, 4c, 13e, and 13i showed promising MIC from 0.007 to 3.9 µg/mL. In addition, antiproliferative analysis against three target cell lines was examined for the novel compounds. Compounds 4a, 4b, 4c, and 7c possessed significant antiproliferative activity against three cell lines with an IC50 of 0.3 to 2 µg/mL. Apoptotic analysis was performed for the most potent compounds via caspase enzyme activity assays as a potential mechanism for their antiproliferative effects. Finally, the computational 2D QSAR and docking simulations were accomplished for structure-activity relationship analyses.

Chromane isolated from leaves of Dillenia indica improves the neuronal dysfunction in STZ-induced diabetic neuropathy

Ethnopharmacological relevanceAccording to the Indian traditional medicine, Dillenia indica L. has shown therapeutic efficacy in various diseases. Fruits and leaves of the plant possess anti-oxidant and anti-inflammatory properties. Reactive oxygen species, formation of advanced glycation end products (AGEs) and apoptosis are implicated in the pathogenesis of diabetic neuropathy. Aim of the studyThe aim of the present study was to explore the effect of D. indica and its isolate, chromane (CR), on thermal and mechanical hyperalgesia, allodynia, MNCV and oxidative-nitrosative stress in streptozotocin-induced experimental diabetes. Material and methodsDiabetes was induced by intraperitoneal administration of Streptozotocin (STZ; 65mg/kg) for the development of diabetic neuropathy. Chronic treatment with DAE (100, 200 and 400mg/kg, p.o.) and CR (5 and 10mg/kg, p.o.) for 30 days was started from the 60th day of STZ administration. Development of neuropathy was evident from a marked hyperalgesia and allodynia; reduced MNCV associated with increased formation of AGEs and reactive oxygen species. Resultssignificantly attenuated behavioral and biochemical changes associated with diabetic neuropathy. Present study suggested that DAE and CR ameliorated hyperglycemia and diabetic neuropathic pain via modulation of oxidative-nitrosative stress and reduction in AGEs formation in the diabetic rats. ConclusionThus D. indica might be beneficial in chronic diabetics, ameliorate the progression of diabetic neuropathy and may also find application in diabetic neuropathic pain.

Chemical composition and antibacterial activity of essential oil from the leaves of Murraya koenigii (L.) Spreng.

Chemical composition and antibacterial activity of the leaf essential oil of Murraya koenigii were investigated against clinically isolated bacterial strains. Fourteen compounds were identified by GC and GC-MS accounting for about 98.1% of the total essential oil. a-pinene (49.3%), 2H-1-benzopyran (24.3%), 2- ally l-4-methylphenol (16.7%) and D-isomenthol (2.1%) were identified as the major chemical compounds. The essential oil produced mean zone of inhibition ranged between 14.0 and 7.6 mm. The essential oil showed antibacterial activity against all the bacterial strains tested with the MIC values of 125-500 µg/ml. Although, the activity of the essential oil against the clinical isolates were much less than of Ciprofloxacin, the standard drug used, the demonstrated antibacterial activities of M. koenigii leaf essential may support the folkloric uses of the plant.

Asymmetric [4+2] Cycloaddition of Isochromene Acetals with Boronates

Asymmetric [4+2] Cycloaddition of Isochromene Acetals with Boronates

Syntheses of 4-Aryl Chromanes: A Rearrangement Approach

4-Aryl chromanes are synthesized from 4-Aryloxy chromanes via a rearrangement methodology.

ChemInform Abstract: An Efficient Regioselective Reaction of Indole with 2H‐Chromenes for the Synthesis of New 4H‐Chromenes in Environmentally Benign Media.

AbstractMono‐ and disubstituted chromenes with methoxy‐, nitro‐, chloro‐, and bromo‐ groups as well as benzochromene are reacted with indole and N‐methylindole.

6-Chloro-2-hydroxy-2-trifluoromethyl-2H-chromene-3-carboxylic acid (5-allylsulfanyl-[1,3,4]thiadiazol-2-yl)-amide

A new chromene containing 1,3,4-thiadiazole and trifluoromethyl(CF3), 6-chloro-2-hydroxy-2-trifluoromethyl-2H-chromene-3-carboxylic acid (5-allylsulfanyl-[1,3,4]thiadiazol-2-yl)-amide was synthesized and its structure was characterized by IR, 1H-NMR, 13C-NMR, 19F-NMR and HRMS.

ChemInform Abstract: PbO as an Efficient and Reusable Catalyst for One‐Pot Synthesis of Tetrahydro Benzo Pyrans and Benzylidene Malonitriles.

PbO nanoparticles have been employed as an efficient catalyst for the solvent-free synthesis of tetrahydrobenzo pyrans (yields 81–91%) and benzylidene malonitriles (yields 90–96%) at room temperature using green chemistry approach. PbO nanoparticles were found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst. PbO nanoparticles were prepared by hydrothermal method and characterized by IR, XRD, BET Surface area, SEM, EDAX and TEM with SAED techniques.

PHOTO- AND THERMOCHROMIC SPIRANS. 38. NEW (1-ALKYL-4,5-DIPHENYL)IMIDAZOLYL-SUBSTITUTED SPIROBENZOPYRANS

3-Diphenylimidazolyl-substituted 2-hydroxybenzaldehyde has been obtained by the formylation of 2‑diphenylimidazolyl-substituted phenol. From the obtained compound, new photochromic spiroindolinebenzopyrans containing a 4,5-diphenylimidazole group at the position 8 of the benzopyran fragment were synthesized. The obtained compounds possess photochromic properties in solution. Authors: E. V. Solov'eva, A. V. Chernyshev, N. A. Voloshin, A. V. Metelitsa, and V. I. Minkin English Translation in Chemistry of Heterocyclic Compounds, 2013, 48 (10), pp 1533-1538 http://link.springer.com/article/10.1007/s10593-013-1169-5

PbO as an efficient and reusable catalyst for one-pot synthesis of tetrahydro benzo pyrans and benzylidene malonitriles

PbO nanoparticles have been employed as an efficient catalyst for the solvent-free synthesis of tetrahydrobenzo pyrans (yields 81–91%) and benzylidene malonitriles (yields 90–96%) at room temperature using green chemistry approach. PbO nanoparticles were found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst. PbO nanoparticles were prepared by hydrothermal method and characterized by IR, XRD, BET Surface area, SEM, EDAX and TEM with SAED techniques. One-pot synthesis of tetrahydro benzo pyrans and benzylidene malonitriles using PbO nanoparticle under solvent-free condition at room temperature has been presented. PbO nanoparticles were found to be highly efficient, ecofriendly and recyclable catalyst.

Synthesis of 3-methoxy-6-phenyl-6, 6a-dihydro-[1] benzopyrano- [3, 4-b] [1] benzopyran.

Synthesis of 3-methoxy-6-phenyl-6, 6a-dihydro-[1] benzopyrano- [3, 4-b] [1] benzopyran.