Reaction of 3-aryl iminocoumarins with diacid chlorides as C-electrophilic reagents under mild co... more Reaction of 3-aryl iminocoumarins with diacid chlorides as C-electrophilic reagents under mild conditions novel bis-iminocoumarins in good yields. When the reaction was performed with alkylene dibromides by heating them in toluene in the presence of IRA 900 resin, bis-ether compounds were obtained by way opening the pyranic ring. The structures of the product obtained were characterized by Fourier transform infrared, H NMR, C NMR, and elemental analysis.
Aldol-type addition of α-triethylsilyl-α-diazoacetone was achieved under nucleophilic activation ... more Aldol-type addition of α-triethylsilyl-α-diazoacetone was achieved under nucleophilic activation by tetrabutylammonium fluoride (TBAF). The use of a semistoichiometric amount of TBAF (protocol P1) provided the corresponding β-hydroxy-α-diazoacetone as the sole product. Alternatively, the use of a catalytic amount of TBAF led to a mixture of β-hydroxy- and β-silyloxy-α-diazoacetone products, which was cleanly desilylated with Et3N·3HF (protocol P2). The weakly basic conditions employed tolerate a wide range of substrates and constitute a high-yielding, convenient complementary procedure to the low-temperature LDA-promoted aldol-type addition of diazoacetone.
New rearrangements of 3-ethoxycarbonyl iminocoumarin into benzopyrano[2,3-c]pyrazole under the ac... more New rearrangements of 3-ethoxycarbonyl iminocoumarin into benzopyrano[2,3-c]pyrazole under the action of various hydrazines and hydrazides as N-nucleophiles, were described. The structures of all the synthesized products were characterized by IR, 1 H NMR, 13 C NMR and elemental analysis. RESUME: De nouveaux réarrangements de la 3-éthoxycarbonyliminocoumarine sous l'action de N-nucléophiles tels que les hydrazines et les hydrazides ont été décrits. Toutes les structures obtenues ont été clairement établies par les techniques spectroscopiques RMN 1 H, RMN 13 C, IRTF et analyse élémentaire. INTRODUCTION Compounds containing pyrazole scaffold have been shown to exhibit a wide spectrum of biological activity, such as antihyperglycemic [1], antibacterial [2], anti-inflammatory [3-4], antipyretic [5-6] and analgesic [7] activity. In addition, several studies dealing with the varied biological activities of benzopyran derivatives have been reported. They described their antiallergic, an...
ABSTRACT Copolyesters containing aliphatic units in the main chain were obtained by reacting Bis(... more ABSTRACT Copolyesters containing aliphatic units in the main chain were obtained by reacting Bis(2-hydroxy ethyl terephthalate) (BHET) with -caprolactone (-CL) at a high temperature in bulk in the presence of tin octoate as catalyst. Various copolyesters were synthesized by using BHET/-CL mass ratio ranging from 90/10 to 10/90. Thermal properties were studied by DSC and TGA, and structural characterization was carried out by 1H-NMR spectroscopy. These techniques confirm the insertion of lactones units in PET chains. The degree of randomness of 30/70 to 60/40 copolyesters, determined by 1H-NMR, shows a random microstructure. The other copolyesters exhibit some block copolymer character.
RESUME: Cet article présente une étude structurale détaillée réalisée sur trois échantillons de l... more RESUME: Cet article présente une étude structurale détaillée réalisée sur trois échantillons de lignine (brute, purifiée et hydrolysée) extraite à partir de l'alfa tunisienne par le procédé CIMV. Les techniques spectroscopiques IRTF, RMN 1 H et 13 C ont été utilisées dans la détermination des structures de ces lignines. La chromatographie à exclusion stérique ainsi que la spectrométrie MALDI-TOF/MS ont été employées dans la caractérisation de la distribution des masses molaires (M n , M w , I p) et l'identification des fragments de lignine. Les teneurs en groupements phénoliques et alcooliques ont été également déterminées. Les résultats obtenus montrent la présence d'oligomères principalement des associations du type (β-O-4), (β-5) et (γ-O-γ). La teneur en OH phénoliques est plus importante que celle en OH alcooliques. ABSTRACT: This paper presents a complete structural investigation of three lignin samples (crude, purified and hydrolyzed) isolated from Tunisian alfa li...
A novel, environmentally eco-friendly and high yielding method for the preparation of furfurylami... more A novel, environmentally eco-friendly and high yielding method for the preparation of furfurylamine by one-pot reductive amination of furfural is reported. The reaction is carried out using hydroxylammonium chloride as amination agent and cheap zinc powder as reducer in the presence of zinc chloride and ammonium chloride. This practical procedure has been carried out in water and in neat conditions.
RESUME: Une nouvelle série de benzopyrano [2,3-c] pyrazole 2-carboxamides a été préparée avec de ... more RESUME: Une nouvelle série de benzopyrano [2,3-c] pyrazole 2-carboxamides a été préparée avec de bons rendements à partir de la réaction de 3-cyano iminocoumarines avec le 4-phénylsemicarbazide. L'étude des effets des différents paramètres physico-chimiques intervenant dans la réaction d'un système modèle conduit à la détermination des conditions les plus favorables à son déroulement. Les structures des composés obtenus ont été caractérisées par IRTF, RMN 1 H et RMN 13 C. ABSTRACT: A novel series of benzopyrano [2,3-c] pyrazole 2-carboxamides was prepared in good yields by the reaction of 3-cyano iminocoumarins with 4-phénylsemicarbazide. A study of the effects of various physicochemical parameters governing the reaction of a model system allowed the most favourable reaction conditions to be determined. The structures of the obtained products were characterized using FTIR, 1 H NMR and 13 C NMR.
A three-step procedure based on the formation of azo aldehydes, Knoevenagel condensation and reac... more A three-step procedure based on the formation of azo aldehydes, Knoevenagel condensation and reaction with isocyanate or thioisocyanate derivatives paves the way towards the synthesis of new N-substituted iminocoumarin derivatives (VII) and (IX).
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 14, 2015
The fluorescence properties of four derivatives of 3-thienyl-2-(N-dicyanovinyl)iminocoumarin, bea... more The fluorescence properties of four derivatives of 3-thienyl-2-(N-dicyanovinyl)iminocoumarin, bearing a diethylamino group in the 7-position or a methoxy group in the 6, 7 and 8 positions, were compared in solution and in the solid state. The 7-diethylamino derivative was strongly fluorescent in various solvents, with marked solvatochromism. Its fluorescence was quenched by aggregation. In contrast, the methoxy derivatives were only moderately or weakly fluorescent in solution, but two of them were strongly photoluminescent in the crystalline state, owing to favourable molecular packing. The 6-methoxy derivative even exhibited spectacular crystallization-enhanced emission, examples of which are particularly rare for this type of dyes. Dyes were tested for biological use. The 7-diethylamino derivative led to particularly strong fluorescence staining of the cytoplasm of HCT-116 colon cancer cells. No fading was observed over prolonged illumination by the microscope light beam, but a p...
ABSTRACT A series of polyesteramides (PEAs) differing in their amide/ester ratio, within a range ... more ABSTRACT A series of polyesteramides (PEAs) differing in their amide/ester ratio, within a range of molar composition from 90/10 to 10/90, have been synthesized by a direct melt polycondensation of 1,4-butanediol, adipic acid and β-alanine. Their structure was fully characterized by FTIR and NMR spectroscopy. The resulting copolymers are amorphous, they are thermally stable to temperatures up to 330°C, and present increasing glass transition temperatures at increasing amide content.
Journal de Chimie Physique et de Physico-Chimie Biologique, 1999
The dissociation rate of O2 was measured at very high temperature (3000 K to 4500 K) for pressure... more The dissociation rate of O2 was measured at very high temperature (3000 K to 4500 K) for pressure between 120 and 450 kPa from atomic oxygen concentration profiles in a shock wave. O concentration was measured using Atomic Resonance Absorption Spectrophotopetry (ARAS) at 130.5 nm. O-ARAS was calibrated by complete and rapid dissociation of N2O in N2+O. Two modified Beer-Lambert
ABSTRACT A series of random polyesteramides (PEAs) within a range of molar composition from 90/10... more ABSTRACT A series of random polyesteramides (PEAs) within a range of molar composition from 90/10 to 10/90 were synthesized by a direct melt polycondensation of glycolic acid and β-alanine. Their structures were fully characterized by NMR spectroscopy. The resulting copolymers are amorphous and present increasing glass transition temperatures at increasing β-alanine contents. The copolymers were also characterized by, FTIR, TGA and viscosimetry measurements.
Reaction of 3-aryl iminocoumarins with diacid chlorides as C-electrophilic reagents under mild co... more Reaction of 3-aryl iminocoumarins with diacid chlorides as C-electrophilic reagents under mild conditions novel bis-iminocoumarins in good yields. When the reaction was performed with alkylene dibromides by heating them in toluene in the presence of IRA 900 resin, bis-ether compounds were obtained by way opening the pyranic ring. The structures of the product obtained were characterized by Fourier transform infrared, H NMR, C NMR, and elemental analysis.
Aldol-type addition of α-triethylsilyl-α-diazoacetone was achieved under nucleophilic activation ... more Aldol-type addition of α-triethylsilyl-α-diazoacetone was achieved under nucleophilic activation by tetrabutylammonium fluoride (TBAF). The use of a semistoichiometric amount of TBAF (protocol P1) provided the corresponding β-hydroxy-α-diazoacetone as the sole product. Alternatively, the use of a catalytic amount of TBAF led to a mixture of β-hydroxy- and β-silyloxy-α-diazoacetone products, which was cleanly desilylated with Et3N·3HF (protocol P2). The weakly basic conditions employed tolerate a wide range of substrates and constitute a high-yielding, convenient complementary procedure to the low-temperature LDA-promoted aldol-type addition of diazoacetone.
New rearrangements of 3-ethoxycarbonyl iminocoumarin into benzopyrano[2,3-c]pyrazole under the ac... more New rearrangements of 3-ethoxycarbonyl iminocoumarin into benzopyrano[2,3-c]pyrazole under the action of various hydrazines and hydrazides as N-nucleophiles, were described. The structures of all the synthesized products were characterized by IR, 1 H NMR, 13 C NMR and elemental analysis. RESUME: De nouveaux réarrangements de la 3-éthoxycarbonyliminocoumarine sous l'action de N-nucléophiles tels que les hydrazines et les hydrazides ont été décrits. Toutes les structures obtenues ont été clairement établies par les techniques spectroscopiques RMN 1 H, RMN 13 C, IRTF et analyse élémentaire. INTRODUCTION Compounds containing pyrazole scaffold have been shown to exhibit a wide spectrum of biological activity, such as antihyperglycemic [1], antibacterial [2], anti-inflammatory [3-4], antipyretic [5-6] and analgesic [7] activity. In addition, several studies dealing with the varied biological activities of benzopyran derivatives have been reported. They described their antiallergic, an...
ABSTRACT Copolyesters containing aliphatic units in the main chain were obtained by reacting Bis(... more ABSTRACT Copolyesters containing aliphatic units in the main chain were obtained by reacting Bis(2-hydroxy ethyl terephthalate) (BHET) with -caprolactone (-CL) at a high temperature in bulk in the presence of tin octoate as catalyst. Various copolyesters were synthesized by using BHET/-CL mass ratio ranging from 90/10 to 10/90. Thermal properties were studied by DSC and TGA, and structural characterization was carried out by 1H-NMR spectroscopy. These techniques confirm the insertion of lactones units in PET chains. The degree of randomness of 30/70 to 60/40 copolyesters, determined by 1H-NMR, shows a random microstructure. The other copolyesters exhibit some block copolymer character.
RESUME: Cet article présente une étude structurale détaillée réalisée sur trois échantillons de l... more RESUME: Cet article présente une étude structurale détaillée réalisée sur trois échantillons de lignine (brute, purifiée et hydrolysée) extraite à partir de l'alfa tunisienne par le procédé CIMV. Les techniques spectroscopiques IRTF, RMN 1 H et 13 C ont été utilisées dans la détermination des structures de ces lignines. La chromatographie à exclusion stérique ainsi que la spectrométrie MALDI-TOF/MS ont été employées dans la caractérisation de la distribution des masses molaires (M n , M w , I p) et l'identification des fragments de lignine. Les teneurs en groupements phénoliques et alcooliques ont été également déterminées. Les résultats obtenus montrent la présence d'oligomères principalement des associations du type (β-O-4), (β-5) et (γ-O-γ). La teneur en OH phénoliques est plus importante que celle en OH alcooliques. ABSTRACT: This paper presents a complete structural investigation of three lignin samples (crude, purified and hydrolyzed) isolated from Tunisian alfa li...
A novel, environmentally eco-friendly and high yielding method for the preparation of furfurylami... more A novel, environmentally eco-friendly and high yielding method for the preparation of furfurylamine by one-pot reductive amination of furfural is reported. The reaction is carried out using hydroxylammonium chloride as amination agent and cheap zinc powder as reducer in the presence of zinc chloride and ammonium chloride. This practical procedure has been carried out in water and in neat conditions.
RESUME: Une nouvelle série de benzopyrano [2,3-c] pyrazole 2-carboxamides a été préparée avec de ... more RESUME: Une nouvelle série de benzopyrano [2,3-c] pyrazole 2-carboxamides a été préparée avec de bons rendements à partir de la réaction de 3-cyano iminocoumarines avec le 4-phénylsemicarbazide. L'étude des effets des différents paramètres physico-chimiques intervenant dans la réaction d'un système modèle conduit à la détermination des conditions les plus favorables à son déroulement. Les structures des composés obtenus ont été caractérisées par IRTF, RMN 1 H et RMN 13 C. ABSTRACT: A novel series of benzopyrano [2,3-c] pyrazole 2-carboxamides was prepared in good yields by the reaction of 3-cyano iminocoumarins with 4-phénylsemicarbazide. A study of the effects of various physicochemical parameters governing the reaction of a model system allowed the most favourable reaction conditions to be determined. The structures of the obtained products were characterized using FTIR, 1 H NMR and 13 C NMR.
A three-step procedure based on the formation of azo aldehydes, Knoevenagel condensation and reac... more A three-step procedure based on the formation of azo aldehydes, Knoevenagel condensation and reaction with isocyanate or thioisocyanate derivatives paves the way towards the synthesis of new N-substituted iminocoumarin derivatives (VII) and (IX).
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 14, 2015
The fluorescence properties of four derivatives of 3-thienyl-2-(N-dicyanovinyl)iminocoumarin, bea... more The fluorescence properties of four derivatives of 3-thienyl-2-(N-dicyanovinyl)iminocoumarin, bearing a diethylamino group in the 7-position or a methoxy group in the 6, 7 and 8 positions, were compared in solution and in the solid state. The 7-diethylamino derivative was strongly fluorescent in various solvents, with marked solvatochromism. Its fluorescence was quenched by aggregation. In contrast, the methoxy derivatives were only moderately or weakly fluorescent in solution, but two of them were strongly photoluminescent in the crystalline state, owing to favourable molecular packing. The 6-methoxy derivative even exhibited spectacular crystallization-enhanced emission, examples of which are particularly rare for this type of dyes. Dyes were tested for biological use. The 7-diethylamino derivative led to particularly strong fluorescence staining of the cytoplasm of HCT-116 colon cancer cells. No fading was observed over prolonged illumination by the microscope light beam, but a p...
ABSTRACT A series of polyesteramides (PEAs) differing in their amide/ester ratio, within a range ... more ABSTRACT A series of polyesteramides (PEAs) differing in their amide/ester ratio, within a range of molar composition from 90/10 to 10/90, have been synthesized by a direct melt polycondensation of 1,4-butanediol, adipic acid and β-alanine. Their structure was fully characterized by FTIR and NMR spectroscopy. The resulting copolymers are amorphous, they are thermally stable to temperatures up to 330°C, and present increasing glass transition temperatures at increasing amide content.
Journal de Chimie Physique et de Physico-Chimie Biologique, 1999
The dissociation rate of O2 was measured at very high temperature (3000 K to 4500 K) for pressure... more The dissociation rate of O2 was measured at very high temperature (3000 K to 4500 K) for pressure between 120 and 450 kPa from atomic oxygen concentration profiles in a shock wave. O concentration was measured using Atomic Resonance Absorption Spectrophotopetry (ARAS) at 130.5 nm. O-ARAS was calibrated by complete and rapid dissociation of N2O in N2+O. Two modified Beer-Lambert
ABSTRACT A series of random polyesteramides (PEAs) within a range of molar composition from 90/10... more ABSTRACT A series of random polyesteramides (PEAs) within a range of molar composition from 90/10 to 10/90 were synthesized by a direct melt polycondensation of glycolic acid and β-alanine. Their structures were fully characterized by NMR spectroscopy. The resulting copolymers are amorphous and present increasing glass transition temperatures at increasing β-alanine contents. The copolymers were also characterized by, FTIR, TGA and viscosimetry measurements.
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