Search

Comprehensive Summary: An efficient and highly stereoselective synthetic method to access polycyclic chromanes has been achieved through organocatalyzed one‐pot step‐wise reactions involving 2‐hydroxycinnamaldehydes, 2‐aminochalcones, and malononitrile as substrates. The reactions underwent a quintuple process by aza‐Michael/Michael/Knoevenagel/oxa‐Michael/aldol‐type reaction in sequence to give products bearing 3 new generated rings and 5 chiral centers in moderate to quantitative yields with excellent stereoselectivities. A novel retro‐reaction mechanism was discovered in the synthetic transformations of products. [ABSTRACT FROM AUTHOR]

A straightforward and efficient electrochemical method for the anodic oxidative selenenylation of 2-(2-arylallyl)phenols and a 2-(3-arylbut-3-en-1-yl)phenol with diselenides under ambient air conditions has been outlined. This method allows for the synthesis of selenyl-dihydrobenzofurans and a chromane featuring a sterically hindered tetrasubstituted carbon center, demonstrated through 25 examples with yields reaching up to 98%. Initial mechanistic investigations suggest the likely participation of pivotal seleniranium cation species in regulating the reactivity. [ABSTRACT FROM AUTHOR]

This article discusses the visible-light-induced oxidative generation of o-quinone methides (o-QMs) for inverse-electron-demand [4+2] cycloaddition reactions. The authors explore different methods for generating o-QMs and highlight the potential of visible-light-induced generation to overcome issues associated with high-energy irradiation. They present their findings on the reaction of 2-(sulfanylmethyl)phenol with styrene using a thioxanthylium photoredox catalyst under green light irradiation, resulting in the formation of chromanes with high regioselectivity and good yields. The authors believe that this method provides a promising tool for the oxidative generation of o-QMs and has important applications in synthetic organic chemistry. [Extracted from the article]

Visible‐light‐driven C−C bond formation utilizing ketyl radical (Cketyl) species has attracted increasing attention recently, as it provides a direct route for the synthesis of complex molecules. However, the most‐developed homogeneous photocatalytic systems for the generation and utilization of ketyl radicals usually entail noble metal‐based (e. g. Ru and Ir) photosensitizers, which suffer from not only high cost but also potential degradation and hence pose challenges in product separation and purification. In contrast, readily accessible, inexpensive, and recyclable semiconductors represent a class of attractive and alternative photocatalysts but remain much less explored for photocatalytic ketyl radical initiated C−C bond formation. This work demonstrates that a wide range of industrially important chemicals, including substituted chromanes and tertiary alcohols, can be produced on ZnIn2S4 under visible light irradiation through intramolecular cyclization (Cketyl−Csp2) and intermolecular cross‐coupling (Cketyl−Csp3) reactions, respectively, using ketyl radicals. A suite of experimental studies aided by computational investigation were carried out to shed light on the mechanistic insights of these two types of ketyl radical initiated C−C coupling reactions on ZnIn2S4. [ABSTRACT FROM AUTHOR]

Visible‐light‐driven C−C bond formation utilizing ketyl radical (Cketyl) species has attracted increasing attention recently, as it provides a direct route for the synthesis of complex molecules. However, the most‐developed homogeneous photocatalytic systems for the generation and utilization of ketyl radicals usually entail noble metal‐based (e. g. Ru and Ir) photosensitizers, which suffer from not only high cost but also potential degradation and hence pose challenges in product separation and purification. In contrast, readily accessible, inexpensive, and recyclable semiconductors represent a class of attractive and alternative photocatalysts but remain much less explored for photocatalytic ketyl radical initiated C−C bond formation. This work demonstrates that a wide range of industrially important chemicals, including substituted chromanes and tertiary alcohols, can be produced on ZnIn2S4 under visible light irradiation through intramolecular cyclization (Cketyl−Csp2) and intermolecular cross‐coupling (Cketyl−Csp3) reactions, respectively, using ketyl radicals. A suite of experimental studies aided by computational investigation were carried out to shed light on the mechanistic insights of these two types of ketyl radical initiated C−C coupling reactions on ZnIn2S4. [ABSTRACT FROM AUTHOR]

A computational study on the reaction mechanism of the effective synthesis of sulfonated benzo[b]oxepinones and chromanes by radical cascade cyclization is carried out employing the density functional theory (DFT). Based on our computations, the rate‐determining step is the formation of arylsulfonyl radical for the reaction scheme. Our calculations show that the reaction of 1,8‐ and 1,7‐enynes with arylsulfonyl radical proceeds by forming more thermodynamically stable intermediates. Therefore, 1,8‐enynes prefer 7‐exo‐trig cyclization, while 1,7‐enynes prefer 6‐exo‐trig cyclization. Our computations are consistent with experimental results of the radical cascade cyclization of 1,8‐ and 1,7‐enynes. Moreover, our computations show that if the reaction is carried out in a proton‐free solvent, the elimination product can be obtained from the cascade radical cyclization of the 1,7‐enyne. [ABSTRACT FROM AUTHOR]

Background: To evaluate biological activity of synthesised new chromane and its analogues. Materials and Methods: New chromane {3,5,7-trihydroxy 2-(4-hydroxy benzyl) chroman-4-one} isolated from dried leaves of Dillenia indica Linn., family Dilleniaceae is structurally relating with various reported chroman-4-one derivatives displaying remarkable in vivo antidiabetic activity. But the literature reveals that 0.8 - 1.0% yield of pure new chromane was obtained in isolation. Following reported literature data of synthesis and in silico study; Synthesized new chromane and its derivatives (S23-S32) were investigated for in vitro (a-amylase and a-glucosidase) as well as in vivo antidiabetic evaluation respectively. Result and Conclusion: in vitro hypoglycaemic study also displayed the significant antidiabetic potential of new chromane and its O-alkyl substituents (especially S23) while other synthesized compounds (S27-S32) reported for moderate to mild effects w.r. t. reference drug (acarbose). Moreover, synthetic new chromane and O-alkyl substituent (S23) exhibited maximum antidiabetic activity also in terms of lowering glucose concentration while others (S27-S32) showed mild anti-diabetic effect in comparison to reference drug (metformin). [ABSTRACT FROM AUTHOR]

Three new chromanes, malloapeltas J–L (1–3), and one new flavone C-glycoside, malloflavoside (4), together with four known compounds, apigenin 6-C-β-D-xylopyranosyl-8-C-α-L-arabinopyranoside (5), apigenin 6-C-β-D-glucopyranosyl-8-C-α-L-arabinopyranoside (6), apigenin 7-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (7), and acantrifoside E (8) were isolated from the methanol extract of the leaves of Mallotus apelta. Their chemical structures were determined using spectroscopic methods, including 1D, 2D NMR, and HR-ESI-MS methods. All the isolated compounds were evaluated their cytotoxic activity against human prostate cancer (PC-3) and human breast cancer (MCF-7) cells, but none of them showed cytotoxicities on both human cancer cell lines. [ABSTRACT FROM AUTHOR]

Alkene difunctionalization featuring an intramolecular carbometallation step has been developed into a powerful transformation in organic synthesis. The 5‐exo‐trig carbometallation is in general highly favored over the alternative 6‐endo‐trig cyclization. We report herein a formal 6‐endo‐trig carbofluorination protocol by combining the conventional 5‐exo‐trig carbopalladation with a chemoselective 1,2‐aryl/Pd dyotropic rearrangement. Treatment of 2‐(2‐alkylallyloxy)phenyl boronic acid derivatives in the presence of a catalytic amount of Pd(dba)2, 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine and Selectfluor affords chromanes with concurrent generation of a tertiary alkyl fluoride function. A σ‐alkyl‐PdII species resulting from the 5‐exo‐trig carbopalladation process is isolated and characterized by X‐ray crystallographic analysis. Its oxidation to PdIV complex triggers the chemoselective dyotropic rearrangement leading to the ring expansion product. [ABSTRACT FROM AUTHOR]

(E)-3-(2-(4-methylthiazol-2-yl)hydrazineylidene)chromane-2,4-dione was synthesized for the first time and the compound was characterized by 1H and 13C spectroscopy, IR spectroscopy, and UV-Vis. The chemical structure and isomeric configuration of the molecule were confirmed by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

(E)-3-(2-(4-methylthiazol-2-yl)hydrazineylidene)chromane-2,4-dione was synthesized for the first time and the compound was characterized by 1H and 13C spectroscopy, IR spectroscopy, and UV-Vis. The chemical structure and isomeric configuration of the molecule were confirmed by single-crystal X-ray diffraction.

Novel 2‐[2‐(chroman‐4‐ylidene)hydrazinyl]‐4/5‐substituted thiazole derivatives (2a–i) were synthesized and investigated for their anticancer activity. Cytotoxic activity on A549 and NIH/3T3 cell lines was determined, most of the compounds exhibited high cytotoxic profile with selectivity. Selected compounds 2b, 2c, 2e, 2g, 2h, and 2i were tested to determine induction of apoptosis, mitochondrial membrane depolarization, and cell cycle arrest. The results showed that the compounds induced apoptosis intrinsically that they triggered loss of mitochondrial potential through increasing the accumulation of cells in G2/M. Besides, intrinsic apoptotic pathway was supported by down‐regulation of anti‐apoptotic protein Bcl‐2 and up‐regulation of proapoptotic protein Bax. Molecular docking study for compounds 2b, 2c, and 2g was promoted experimental outcomes. [ABSTRACT FROM AUTHOR]

The direct formation of aryl C−O bonds via the intramolecular dehydrogenative coupling of a C−H bond and a pendant alcohol represents a powerful synthetic transformation. Herein, we report a method for intramolecular arene C−H etherification via an umpoled alcohol cyclization mediated by an I(III) N‐HVI reagent. This approach provides access to functionalized chromane scaffolds from primary, secondary and tertiary alcohols via a cascade cyclization‐iodonium salt formation, the latter providing a versatile functional handle for downstream derivatization. Computational studies support initial formation of an umpoled O‐intermediate via I(III) ligand exchange, followed by competitive direct and spirocyclization/1,2‐shift pathways. [ABSTRACT FROM AUTHOR]

A new electrophilic selenocyanation reagent N -seleno-cyanato-dibenzenesulfonimide was readily prepared in two steps from commercially available dibenzenesulfonimide for the first time. A variety of electrophilic selenocyanato reactions of nucleophiles have been achieved using it as selenocyanato source under mild and simple conditions. Numerous SeCN-containing compounds were obtained in moderate to excellent yields. Meanwhile, a Lewis acid mediated tandem selenocyanation/cyclization reaction of alkenes with phenols, which provided simple methods for the formation of various SeCN-containing chromanes and dihydrobenzofurans in moderate to good yields, has also been developed. [ABSTRACT FROM AUTHOR]

The coumarin scaffold is an important structure in medicinal chemistry because it is found in several naturally occurring molecules which exhibit a variety of biological activities, such as anti-cancer, anti-inflammatory, anti-diabetic, antimicrobial, and antiviral, antifungal. In addition, various synthetic coumarins motifs are present in marketed drugs. They are also involved in the actions of the photosynthesis, control of respiration, plant growth hormones and growth regulators, and also defense against infection. This review will provide an overview of coumarin moieties with medicinal aspects synthesized in the last 15 years and will cover the most potent molecule in each report. In this review, different synthesis methods of coumarin and their derivatives have been covered. [ABSTRACT FROM AUTHOR]

In the title compound, C16H14N3OSCl, a Schiff base derivative of a thiosemicarbazide with a flavanone, the 4-chlorophenyl ring is inclined to the benzene ring of the chromane ring system by 30.72 (12)°. The pyran ring has an envelope conformation with the methine C atom as the flap. The mean plane of the thiourea unit is twisted with respect to the benzene ring of the chromanone ring system, subtending a dihedral angle of 19.78 (19)°. In the crystal, molecules are linked by two pairs of N—H...S hydrogen bonds, forming inversion dimers enclosing R22(8) ring motifs, which are linked to form ribbons propagating along the b-axis direction. The intermolecular contacts in the crystal have been analysed using Hirshfeld surface analysis.

An efficient approach for the synthesis of pyrazolopyridines containing the aminochromane motif through a base-catalyzed cyclization reaction is reported. The synthesis was carried out through a three-component reaction of (arylhydrazono)methyl-4H-chromen-4-one, malononitrile, primary amines in the presence of Et3N at room temperature. However, carrying out the reaction under the same conditions without base led to a fused chromanyl-cyanopyridine. High selectivity, high atom economy, and good to high yields in addition to mild reaction conditions are the advantages of this approach.

Gold-catalyzed reactions of conjugated haloacetylenes are well known and usually result in the formation of addition or dimerization products. Herein, we report a gold-catalyzed reaction of non-conjugated- haloacetylenes, which leads exclusively to the halogenated cyclization products. Remarkable is the gold-catalyzed reaction of tritylhaloacetylenes to haloindene derivatives, as mechanistic studies reveal that an 1,2-aryl shift occurs in the initially formed gold complex. The potential functionalization at the halogen atom and the wide scope of these cyclization reactions make them an attractive method for the construction of cyclic systems. [ABSTRACT FROM AUTHOR]

Phytochemical investigation of the ethanol extract of underground parts of Iris tenuifolia Pall. afforded five new compounds; an unusual macrolide termed moniristenulide (1), 5-methoxy-6,7-methylenedioxy-4-O-2′-cycloflavan (2), 5,7,2′,3′-tetrahydroxyflavanone (3), 5-hydroxy-6,7-dimethoxyisoflavone-2′-O-β-d-glucopyranoside (9), 5,2′,3′-dihydroxy-6,7-dimethoxyisoflavone (10), along with seven known compounds (4–8, 11–12). The structures of all purified compounds were established by analysis of 1D and 2D NMR spectroscopy and HR-ESI-MS. The antimicrobial activity of the compounds 1–3, 5, 9, and 10 was investigated using the agar diffusion method against fungi, Gram-positive and Gram-negative bacteria. In consequence, new compound 3 was found to possess the highest antibacterial activity against Enterococcus faecalis VRE and Mycobacterium vaccae. Cell proliferation and cytotoxicity tests were also applied on all isolated compounds and plant crude extract in vitro with the result of potent inhibitory effect against leukemia cells. In particular, the newly discovered isoflavone 10 was active against both of the leukemia cells K-562 and THP-1 while 4–6 of the flavanone type compounds were active against only THP-1.

American trypanosomiasis (Chagas disease) caused by the Trypanosoma cruzi parasite, is a severe health problem in different regions of Latin America and is currently reported to be spreading to Europe, North America, Japan, and Australia, due to the migration of populations from South and Central America. At present, there is no vaccine available and chemotherapeutic options are reduced to nifurtimox and benznidazole. Therefore, the discovery of new molecules is urgently needed to initiate the drug development process. Some acetophenones and chalcones, as well as chromane-type substances, such as chromones and flavones, are natural products that have been studied as trypanocides, but the relationships between structure and activity are not yet fully understood. In this work, 26 compounds were synthesized to determine the effect of hydroxyl and isoprenyl substituents on trypanocide activity. One of the compounds showed interesting activity against a resistant strain of T. cruzi, with a half effective concentration of 18.3 µM ± 1.1 and an index of selectivity > 10.9.

Das Chromangerüst findet sich in einer Vielzahl von kleinen, bioaktiven Molekülen, in denen die 3‐Position häufig oxidiert wird. Motiviert durch die Wichtigkeit dieser Position für die Wirksamkeit sowie die Bedeutung der Bioisosterie in der Wirkstoffforschung wurde eine Iod(I)/Iod(III)‐Katalysestrategie für den Zugang zu enantiomerenangereicherten 3‐Fluorchromanen entwickelt (bis zu 7:93 e.r.). Die In‐situ‐Erzeugung von ArIF2 ermöglicht die direkte Fluorzyklisierung von Allylphenylethern, um neue Molekülgerüste zu erzeugen, die den stereoelektronischen gauche‐Effekt zeigen. Mechanistische Untersuchungen unter Verwendung von deuterierten Substraten bestätigen einen stereospezifischen Prozess, der mit einem Reaktionsverlauf des Typs IIinv übereinstimmt. [ABSTRACT FROM AUTHOR]

A copper/(R)‐DTBM‐SEGPHOS‐catalyzed enantioselective hydroamination of 2H‐chromenes employing hydrosilanes and hydroxylamine esters has been developed. This protocol offers a highly efficient and direct route for accessing a series of 4‐aminochromanes in 50–88 % yields with 59–99 % enantioselectivities under mild reaction conditions. [ABSTRACT FROM AUTHOR]

A new series of biologically active 3-[(2R*)-2-[(2S*)-6-fluoro-3,4-dihydro-2H-chromen-2-yl]-2-hydroxyethyl]-urea/thiourea derivatives (1) have been designed and synthesized in four steps from 6-fluoro-3,4-dihydro-2-(oxiran-2-yl)-2H-chromene (2). The structures of newly synthesized compounds (1a–j) were confirmed by 1H, 13C NMR, and HRMS. The major advantages of the present article include the development of an efficient eluent system for good separation of diastereomers (2a and 2b) with high yields and synthesis of (R*)-2-(benzylamino)-1-((S*)-6-fluoro-3,4-dihydro-2H-chromen-2-yl)ethanol (3) in high yields (87%) from epoxide (2a) through new reaction conditions. The synthesized compounds (1a–j) exhibited moderate to excellent antimicrobial activities against both bacterial strains (gram + Ve and gram –Ve strains) and fungal strains. Among the tested compounds, promising lead compounds were identified (compounds 1a and 1d against bacterial strains and compound 1h and 1j against fungal strains) and their antimicrobial activities are comparable with the reference standard. [ABSTRACT FROM AUTHOR]

[Display omitted] Reactions of dialkoxy-2-phenylchroman-4-ones (2,3-diethoxy-3-hydroxy-2-phenylchroman-4-one (1) and 2,3-dimethoxy-3-hydroxy-2-phenylchroman-4-one (2)) with various phenylenediamines in refluxing chloroform led to quinoxaline ring formation to produce racemic mixtures of chromenoquinoxaline molecules in good to moderate yields (3 – 10). The proposed mechanism involves the hemiacetals (1 and 2) rearranging upon heating to form a reactive dione intermediate that subsequently reacts with phenylenediamine derivatives to produce the title compounds. Reactions of 1 and 2 with asymmetric phenylenediamines led to mixtures of two regioisomers, for which the major products were dictated by the relative reactivity of the nucleophilic amine and the electrophilic carbonyl groups. The chromenoquinoxaline products were characterized by 1H, 13C, 19F (when necessary), nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, melting point determination, and in some cases (compounds 6 – 10) single crystal X-ray diffraction studies. Herein, the synthesis, characterization, and reactivity of this new class of molecules are discussed. [ABSTRACT FROM AUTHOR]

The first example of triflometallate ionic liquids, named in analogy to chlorometallate ionic liquids, is reported. Trifloaluminate ionic liquids, synthesized from 1-alkyl-3-methylimidazolium triflates and aluminum triflate, were characterized by multinuclear NMR spectroscopy and FT-IR spectroscopy, revealing the existence of oligonuclear, multiply-charged trifloaluminate anions, with multiple bridging triflate modes. Acceptor numbers were determined to quantify their Lewis acidity, rendering trifloaluminate ionic liquids as medium-strength Lewis acids (AN = ca. 65). Used as acidic catalysts in the cycloaddition of 2,4-dimethylphenol and isoprene (molar ratio 2:1) to prepare chromane, trifloaluminate systems outperformed literature systems, showing high activity (conversions 94–99%, selectivities 80–89%) and at low loadings (0.2 mol%) at 35°C. Using these new systems as supported ionic liquid phase (SILP) on multi-walled carbon nanotubes (ionic liquid loading 16 wt%) delivered a recyclable catalytic system, with activity enhanced with respect to the homogenous regime.

A nickel(II)/diamine‐catalyzed diastereo‐ and enantioselective Michael/hemiacetalization cascade reaction of α‐ketoesters with 2‐(2‐nitrovinyl)phenols has been established, thus providing a range of structurally diverse polysubstituted chromanes in good yields and excellent stereoselectivities (up to 89% yield, >20:1 dr, >99% ee). Moreover, the gram‐scale experiment was performed with only 0.5 mol% of catalyst, and tricyclic furanobenzodihydropyran compound was gained by the derivatization of product, which showed the great synthetic potential of this strategy. [ABSTRACT FROM AUTHOR]

The title compound (UGCl 001) has been prepared by the multicomponent reaction of chromanes (U-4CC) without using catalyst. The compound has been characterized by ¹H and 13C NMR, IR and MS techniques. X-ray crystallographic technique has been applied and the results show that the crystal belongs to the triclinic system having space group P-1(#2) with unit cell parameters, a = 10.704(2) Å, b = 12.843(2) Å, c = 13.179(2) Å, α = 116.968(4)°, β = 103.203(4)°, γ = 95.788(5)°, V = 1527.8(4) ųand Z = 2. In the title compound, dihedral angles between the planes of the chromane ring (A), substituted aniline ring (B), substituted benzaldehyde (C) and tert-butyl isocynides (D) are 121.2 (3), 123.0(2) and 113.0(3) respectively. Intermolecular N--O, C--Cl and C--F interaction has been found in the crystal structure and results in a three dimensional network structure. [ABSTRACT FROM AUTHOR]

In the title compound, C16H14N3OSCl, a Schiff base derivative of a thiosemicarbazide with a flavanone, the 4-chlorophenyl ring is inclined to the benzene ring of the chromane ring system by 30.72 (12)°. The pyran ring has an envelope conformation with the methine C atom as the flap. The mean plane of the thiourea unit is twisted with respect to the benzene ring of the chromanone ring system, subtending a dihedral angle of 19.78 (19)°. In the crystal, molecules are linked by two pairs of N--H···S hydrogen bonds, forming inversion dimers enclosing R2²(8) ring motifs, which are linked to form ribbons propagating along the b-axis direction. The intermolecular contacts in the crystal have been analysed using Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

We describe herein a conceptually novel, cooperative Brønsted acid/base catalyzed process for the conjugate addition of cyclic β‐keto esters to ortho‐quinone methides both generated in situ. Upon hemiacetalization, densely functionalized chiral chromans with two adjacent quaternary and additionally a tertiary stereogenic center were obtained with very good diastereoselectivity (up to >95:5 d.r.) and typically excellent enantioselectivity (up to >99 % ee). The striking feature and key to success is the dual catalytic activation of both nucleophile and electrophile in two separate cycles with a single chiral catalyst. [ABSTRACT FROM AUTHOR]

In the first of the compounds reported herein, namely 6′-ferrocenyl-6a′-nitro-6′,6a′,6b′,7′,9′,11a′-hexahydro-2H-spiro[acenaphthylene-1,11′-chromeno[3′,4′:3,4]pyrrolo[1,2-c]thiazol]-2-one, [Fe(C5H5)(C29H21N2O4S)], (I), the thiazolidine ring adopts a twist conformation on the methine N—C atoms. In the second compound, viz. 6′-(4-methoxyphenyl)-6a′-nitro-6′,6a′,6b′,7′,9′,11a′-hexahydro-2H-spiro[acenaphthylene-1,11′-chromeno[3′,4′:3,4]pyrrolo[1,2-c]thiazol]-2-one, [Fe(C5H5)(C26H19N2O5S)], (II), the thiazolidine ring adopts an envelope conformation with a methine C atom as the flap. In both compounds, the pyrrolidine ring adopts a twist conformation on the thiazolidine and tetrahydropyran C atoms. The mean planes of the thiazolidine and pyrrolidine rings subtend angles of 67.30 (1) and 62.95 (7)° in (I) and (II), respectively, while the mean plane of the pyrrolidine ring makes dihedral angles of 76.53 (1) and 87.74 (7)° with the acenaphthylene ring system in (I) and (II), respectively. In both compounds, an intramolecular C—H...O hydrogen bond forms an S(7) ring motif. In the crystal of (I), molecules are linked via two different C—H...O hydrogen bonds, forming chains along [001] and [100]. In (II), they are linked through C—H...O hydrogen bonds, forming dimers with an R22(10) ring motif while C—H...π interactions link the molecules in a head-to-tail fashion, forming chains along the a-axis direction.

The chemical constituents of Dillenia indica were isolated together with evaluation of their antioxidant and antidiabetic activity. Alcoholic extract of D. indica (DAE) was subjected to column chromatography for the isolation of compounds and it yielded a new chromane 3,5,7,-trihydroxy-2-(4-hydroxybenzyl)-chroman-4-one. The structure was determined by 1H, 13C-NMR and ESIMS. DAE (100, 200 and 400 mg/kg) and chromane (5 and 10 mg/kg) were administered to streptozotocin (STZ) (50 mg/kg) induced diabetic rats to assess their effect on fasting blood glucose, serum insulin and lipid levels. Oral administration of chromane and DAE significantly attenuated the elevated fasting blood glucose, lipid levels and oxidative stress. The results indicated that DAE and chromane isolated from D. indica possessed antioxidant and antidiabetic activity and could be a therapeutic agent for regulating several pharmacological targets for management of diabetes.

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 interactions 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 quantify the supramolecular interactions.

In the title compound, C12H10O4, the dihedral angle between the coumarin ring system [maximum deviation = 0.033 (8) Å] and the propionate side chain is 78.48 (8)°. In the crystal, weak C—H...O hydrogen bonds generate inversion dimers and and C—H...π and π–π interactions link the dimers into a three-dimensional network. A quantum chemical calculation is in good agreement with the observed structure.

Abstract Because of the complex biological networks, many pathologic disorders fail to be treated with a molecule directed towards a single target. Thus, combination therapies are often necessary, but they have many drawbacks. An alternative consists in building molecules intended to interact with multiple targets, called designed multiple ligands. We followed such a strategy in order to treat metabolic syndrome, by setting up molecules directed towards both type 1 angiotensin II (AT 1) receptor and peroxisome proliferator-activated receptor-γ (PPAR-γ). For this purpose, many molecules were prepared by merging both pharmacophores following three different strategies. Their ability to activate PPAR-γ and to block AT 1 receptors were evaluated in vitro. This strategy led to the preparation of many new PPAR-γ activating and AT 1 blocking molecules. Among them, some exhibited both activities, highlighting the convenience of this approach. Graphical abstract Image 1 Highlights • New molecules directed towards both AT 1 and PPAR-γ receptor were designed and synthesized. • Their interactions with both receptors were evaluated in vitro and some exhibited dual activity. • Docking experiments revealed their tight interactions with the PPAR-γ receptor. • Preliminary in vivo experiment showed potent antihypertensive activity for one compound. [ABSTRACT FROM AUTHOR]

An efficient and straightforward synthesis of novel (Z/E)-3-[(heteroarylamino)methylidene]chromane-2,4-dione derivatives via a one-pot three-component condensation of 4-hydroxycoumarin, triethyl orthoformate, and heteroaryl amines in the presence of guanidinium chloride as organocatalyst under solvent-free conditions is described. Investigation of spectroscopy data indicated that coumarin enamines exist in the ketoenamine tautomeric form and undergo Z/E-isomerization in respect to the C=C bond in CDCl3 and DMSO-d6 at room temperature. Furthermore, intramolecular hydrogen bonds have been observed in the synthesized compounds. Also, 1H NMR spectra indicated that E-ketoenamines are the major isomers. High to excellent yields, short reaction times, simple workup, and very easy purification of products by non-chromatographic methods are advantages of this synthetic procedure. [ABSTRACT FROM AUTHOR]

We report here the crystal and molecular structure of a new chromane-derivative, namely isopropyl(2R*,3S*,4S*)-4-(benzo[d]thiazol-2-ylamino)-2-hydroxy-2-ethylchromane-3-carboxylate (I), C21H22N2O4S, which crystallizes as racemate in the space group C2/c. Its structure has been solved using X-ray diffraction data obtained at low temperature (100(2) K). In this compound, the chromane moiety consists of a benzene ring fused with a six-membered heterocyclic ring which adopts a distorted half-chair conformation. The molecules are linked by a combination of O-H . . . N and N-H . . . O hydrogen bonds, resulting in a two-dimensional network which helps stabilizing the crystal structure of the compound (I). Dihedral angle between the chromane and benzothiazol rings is 80.6(1)o. [ABSTRACT FROM AUTHOR]