Reaction Of 4-hydroxycoumarin Research Articles

Reaction of 4-hydroxycoumarin with 2-acetyloxiranes

The reaction of 4-hydroxycoumarin with 2-acetyloxiranes in dimethylformamide in the presence of triethylamine gave 2,3-dihydro-4H-furo[3,2-c]chromen-4-ones which were converted into 4H-furo[3,2-c]-chromen-4-one derivatives as a result of dehydration or fragmentation.

Synthesis of 4-Aminocoumarin Derivatives with N-Substitutents Containing Hydroxy or Amino Groups

Reactions of 4-hydroxycoumarin (1a) and 4-chlorocoumarin-3-carbaldehyde (1b) with amino alcohols or alkylene diamines led to the formation of the corresponding N-substituted 4-aminocoumarins 3, 5 and 6. However, 4-hydroxycoumarin-3-carbaldehyde (8) reacted with 2-aminoethanol and ethylenediamine to give N-substituted 3-(aminomethylene)-chromane-2,4-diones 9a, b. The structure and the E-configuration of compound 6 were proven by X-ray crystal structure analysis. Products 9a, b displayed signals of both E- and Z-isomers in their NMR spectra. All novel products have been characterized by means of spectral (IR, NMR, MS) data and elemental analyses

ChemInform Abstract: Nano Crystalline ZnO: A Competent and Reusable Catalyst for One‐Pot Synthesis of Novel Benzylamino Coumarin Derivatives in Aqueous Media.

Abstract A green, efficient and facile protocol was developed for the synthesis of a series of benzylamino coumarin derivatives by the reaction of 4-hydroxycoumarin, cyclic secondary amine, and aromatic aldehyde in aqueous media in the presence of nano crystalline ZnO at room temperature. A wide range of functional groups were tolerated in the developed protocol. The target molecules were obtained in good to excellent yield applying the current method. The nano crystalline ZnO can be recycled five times with almost the same catalytic activity.

Nano crystalline ZnO: a competent and reusable catalyst for one pot synthesis of novel benzylamino coumarin derivatives in aqueous media

A green, efficient and facile protocol was developed for the synthesis of a series of benzylamino coumarin derivatives by the reaction of 4-hydroxycoumarin, cyclic secondary amine, and aromatic aldehyde in aqueous media in the presence of nano crystalline ZnO at room temperature. A wide range of functional groups were tolerated in the developed protocol. The target molecules were obtained in good to excellent yield applying the current method. The nano crystalline ZnO can be recycled five times with almost the same catalytic activity.

ChemInform Abstract: 4‐Chloro‐3‐(trifluoroacetyl)‐ and 4‐Chloro‐3‐(methoxalyl)coumarins as Novel and Efficient Building Blocks for the Regioselective Synthesis of 3,4‐Fused Coumarins.

Abstract 4-Chloro-3-(trifluoroacetyl)- and 4-chloro-3-(methoxalyl)coumarins react with electron-rich aminoheterocycles, dimethyl 1,3-acetonedicarboxylate, hydrazines, alkyl thioglycolates, and methyl sarcosinate to give a variety of 3,4-heteroannulated coumarins. The starting materials were prepared by the reaction of 4-hydroxycoumarin with trifluoroacetic anhydride and methyl 2-chloro-2-oxoacetate in the presence of trimethylsilylchloride. An NMR study and X-ray crystallographic analysis are reported.

Synthesis, structure elucidation and DFT studies of new thiadiazoles

A series of previously unavailable derivatives of coumarins were synthesized via the reaction of 4-hydroxycoumarin with ethyl bromoacetate which were then cyclized with thiosemicarbazide. The structures of all synthesized compounds were confirmed by nuclear magnetic resonance (NMR) and infra red (IR) spectroscopic techniques in addition to the use of elemental analysis method (CHN). Selected optimized geometrical parameters, have been reported and highest occupied molecular orbital (HOMO) - lowest unoccupied molecular orbital (LUMO) energies and structures were elucidation. Key words: DFT, HOMO-LUMO energies, 4-hydroxycoumarin, ethyl bromoacetate, nitrous acid, thiosemicarbazide

Gold(III)-Catalyzed Tandem Conjugate Addition/Annulation of 4-Hydroxycoumarins with α,β-Unsaturated Ketones

An efficient and selective approach for the synthesis of functionalized pyranocoumarins has been developed via a gold(III)-catalyzed tandem conjugate addition/annulation reaction of 4-hydroxycoumarins with α,β-unsaturated ketones.

Reactions Between 4-Hydroxycoumarins or 4-Hydroxy-1-Methylquinolinone and Dmad in the Presence of Phosphites. Synthesis of (Chromen-3-YL)- and (Quinolin-3-YL)-(Dialkoxyphosphoryl)Succinates

Dimethyl (chromen-3-yl)-(dialkoxyphosphoryl)succinates are prepared from the reaction of 4-hydroxycoumarin with DMAD and P(OR)3. 4-Hydroxy-1-methylquinolinone reacts with DMAD and P(OEt)3 to give dimethyl (quinoline-3-yl)-(diethoxyphosphoryl)-succinate. GRAPHICAL ABSTRACT

4-Chloro-3-(trifluoroacetyl)- and 4-chloro-3-(methoxalyl)coumarins as novel and efficient building blocks for the regioselective synthesis of 3,4-fused coumarins

4-Chloro-3-(trifluoroacetyl)- and 4-chloro-3-(methoxalyl)coumarins react with electron-rich aminoheterocycles, dimethyl 1,3-acetonedicarboxylate, hydrazines, alkyl thioglycolates, and methyl sarcosinate to give a variety of 3,4-heteroannulated coumarins. The starting materials were prepared by the reaction of 4-hydroxycoumarin with trifluoroacetic anhydride and methyl 2-chloro-2-oxoacetate in the presence of trimethylsilylchloride. An NMR study and X-ray crystallographic analysis are reported.

Task-Specific Ionic Liquid as the Recyclable Catalyst for the Rapid and Green Synthesis of Dihydropyrano[3,2-c]chromene Derivatives

A task-specific ionic liquid, [H3N+–CH2–CH2–OH][CH3COO−], was successfully applied as an efficient and reusable catalyst for the one-pot domino to approach to dihydropyrano[3,2-c]chromene derivatives with atom economy in a condensation reaction of 4-hydroxycoumarin, aldehydes, and malononitrile in a combinatorial fashion. The reaction gave excellent yields within short reaction times at room temperature under solvent-free grinding conditions. The products and ionic liquid could be conveniently separated from the reaction mixture, indicating that the whole process was performed as a green chemical transformation.

Synthesis and Characterization of Some New Azetidin-2-ones Containing Coumarin Moiety and Their Antimicrobial Study

A series of novel azetidinones 5a-i have been synthesized by cyclocondensation of various Schiff bases of coumarin with chloro acetyl chloride in presence of triethyl amine. The reaction of 4-hydroxy coumarin with POCl3 yielded 4-chloro coumarin 2 and 4-chloro-3, 4', 3', 4

ChemInform Abstract: Reactions of 4-Hydroxycoumarin and 4-Hydroxyfurocoumarins with α,β-Unsaturated Nitriles. Mass Spectrometry of the New γ-Pyrano-α-pyran Derivatives.

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Enantioselective direct aldol-type reaction of 4-hydroxycoumarin with ethyl trifluoropyruvate catalyzed by modified cinchona alkaloids

A new enantioselective aldol-type reaction of 4-hydroxycoumarins and ethyl trifluoropyruvate has been developed. In the presence of (DHQD)2PHAL (5 mol%), ethyl trifluoropyruvate could react with various 4-hydroxycoumarins to afford novel 4-hydroxycoumarin derivatives containing a tertiary trifluoromethyl alcohol center in good yields with moderate enantioselectivities.

Molecular iodine-catalyzed C3-alkylation of 4-hydroxycoumarins with secondary benzyl alcohols

Abstract A highly efficient method for the C–C bond formation via molecular iodine-catalyzed C3-alkylation reaction of 4-hydroxycoumarins with benzylic, benzhydrylic, allylic, and propargyl alcohols at 50 °C in MeNO 2 is described. The 3-alkylated-4-hydroxycoumarins were obtained in good yields (up to 97%). By applying this reaction as the key step, a multi-substituted pyranocoumarin can easily be synthesized in a one-pot procedure. The advantages of this method are broad scope, mild conditions, and easy handling since water is the only side product.

Role of various heteropolyacids in the reaction of 4-hydroxycoumarin, aldehydes and ethylcyanoacetate

Abstract The effects of various heteropolyacids including Preyssler, Wells-Dawson and Keggin regarding the yields and types of products in the reaction of 4-hydroxycoumarin, aldehydes and ethylcyanoacetate have been investigated. The results show that dihydropyrano[3,2-c]chromenes were obtained in the presence of Preyssler and Wells-Dawson as the only products while in the presence of Keggins, this reaction led to formation of two compounds including bis-coumarins as major and dihydropyrano[3,2-c]chromenes as minor products.

Pseudo-cyclic Face-to-face Rigid Structure Caused by the Intramolecular Ion Pair Effect

Six 3-methylpyridine zwitterions and six quinoline zwitterions were synthesized through the reaction of 4-hydroxycoumarins, p-benzoquinone and the corresponding N-aromatics. The novel pseudo-cyclic face-to-face rigid structure of the zwitterion was elucidated by 1H-NMR at different temperatures, and assumed to be caused by both the intramolecular ion pair attraction and the steric interaction.

Catalyst-Free Synthesis of α,α-bis(4-Hydroxycoumarin-3-yl)toluene in Aqueous Media Under Microwave Irradiation

An efficient catalyst-free synthesis of α,α-bis(4-hydroxycoumarin-3-yl)toluene was performed by the reaction of 4-hydroxycoumarin with aromatic aldehydes in aqueous media under microwave irradiation. The reaction was completed in short reaction time of 8–10 min with high yields of 76–94, was environmental benign, and had easy workup. Their structures were confirmed by IR spectra, 1H NMR, 13C NMR, and elemental analysis.

Reaction of 4-hydroxycoumarin with arylglyoxals and ureas

One-pot condensation of 4-hydroxycoumarin with arylglyoxals and ureas gave 4-aryl-5-(4-hydroxy-2-oxo-2H-chromen-3-yl)-1H-imidazol-2(3H)-ones. The same compounds may be obtained from aroylbis(4-hydroxy-2-oxo-2H-chromen-3-yl)methanes and urea. The reaction of 4-bromobenzaldehyde with 4-hydroxycoumarin in the presence of urea led to the formation of the corresponding Michael adduct without participation of urea.

Synthesis of 2-Amino-4-Aryl-5-Oxo-4,5-Dihydropyrano[3,2-c] Chromene Derivatives Catalysed by KF-Montmorillonite

A series of 2-amino-4-aryl-5-oxo-4,5-dihydropyrano[3,2- c]chromene derivatives has been synthesised by the reaction of 4-hydroxycoumarin and substituted cinnamonitriles catalysed by KF-montmorillonite. The structures were characterised by IR and 1H NMR spectroscopic data and confirmed by X-ray diffraction analysis.

Proline-Promoted Efficient Synthesis of 4-Aryl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-diones in Aqueous Media

The reaction of 4-hydroxycoumarin with Meldrum’s acid and benzaldehydes in aqueous media in the presence of proline (10 mol%) led to 4-aryl-3,4-dihydro-2 H,5 H-pyrano[3,2- C]chromene-2,5-diones in good yields.