A solvent-free synthesis of coumarins using a Wells–Dawson heteropolyacid as catalyst

Romanelli, Gustavo Pablo; Bennardi, Daniel Oscar; Ruiz, Diego Manuel; Baronetti, Graciela T.; Thomas, Helen; Autino, Juan Carlos

doi:10.1016/j.tetlet.2004.09.183

Cited by 124 publications

(58 citation statements)

References 20 publications

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“…In addition, coumarins are biologically relevant heterocyclic compounds with many interesting pharmacological properties. They are used as anticoagulants and in preparation of insecticides [6]. Antibacterial, anticancer and anti-HIV activities of coumarins are also known [7].…”

Section: Introductionmentioning

confidence: 99%

Electrical and gas sensing properties of novel cobalt(II), copper(II), manganese(III) phthalocyanines carrying ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate moieties

Köksoy

Aygün

Çapkin

et al. 2018

J. Porphyrins Phthalocyanines

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ABSTRACT:The synthesis of metallophthalocyanines (M = Co, Cu, Mn) bearing four ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate moieties was performed. These novel compounds were characterized by elemental analysis, 1 H-NMR spectroscopy, FT-IR, UV-vis and mass spectral data. DC and AC electrical properties of the films of metallophthalocyanines were investigated in the temperature range of 295-523 K. AC measurements were performed in the frequency range of 40-10 5 Hz. Activation energy values of the films took place between 0.55 eV-0.93 eV. Impedance spectroscopy measurements revealed that bulk resistance decreases with increasing temperature, indicating semiconductor properties. DC conductivity results also supported this result. Their gas sensing properties were also investigated for the vapors of Volatile Organic Compounds (VOCs), n-butyl acetate (200-3200 ppm) and ammonia (7000-56000 ppm) between temperatures 25-100 °C. Sensitivity and response times of the films for the tested vapors were reported. The results were found to be reversible and sensitive to the vapors of n-butyl acetate and ammonia. It was found that Mn(OAc)Pc showed better sensitivity than CoPc and CuPc for n-butyl acetate vapors at all measured vapor concentrations and temperatures. Mn(OAc)Pc also showed better sensitivity than CoPc and CuPc for ammonia vapors at 22 °C.

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Section: Introductionmentioning

confidence: 99%

Electrical and gas sensing properties of novel cobalt(II), copper(II), manganese(III) phthalocyanines carrying ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate moieties

Köksoy

Aygün

Çapkin

et al. 2018

J. Porphyrins Phthalocyanines

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“…We have already used this catalyst for performing the tetrahydropyranylation of alcohols and phenols and their detetrahydropyranylation, 2 cleavage of MOM-ethers of phenols, 3 preparation of acylals, 4 and coumarin synthesis via the Pechmann reaction. 5 On the other hand, the correct choice of an efficient protecting group is often decisive for successfully synthesizing a complex molecule. 6 Protection of the hydroxy functional group is an important procedure 7,8,9 in multistep organic synthesis.…”

Section: Introductionmentioning

confidence: 99%

Silicagel-supported H6P2W18O62.24H2O: a reusable catalyst to prepare diphenylmethyl (DPM) ethers

Romanelli¹,

Ruiz²,

Bideberripe³

et al. 2007

Arkivoc

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In this work, we report an efficient and facile preparation of diphenylmethylethers (benzydryl ethers, DPM-ethers) from benzhydrol and alcohols or phenols. Wells-Dawson heteropolyacid (H 6 P 2 W 18 O 62 .24H 2 O), bulk or supported on silica showed catalytic activity for DPM-ethers preparation in toluene, at 60-80°C, in 0.5-1.5h. In these conditions twelve diphenylmethylethers of alcohols and phenol were obtained which excellent yields (78-96%). The heterogeneous reaction conditions provided a very simple, environmentally friendly, clean, economical and selective protocol, for the preparation of unsymmetrical ethers. The catalyst is easily recycled and reused without loss of the catalytic activity.

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“…In order to show the efficiency of the proposed method, Table 3 compares some of the results with some of those reported in the literature [18,23,24,28]. …”

Section: Methodsmentioning

confidence: 99%

“…Generally, the Pechmann reaction is carried out by the [24], polyaniline supported acid catalyst [25], ZrCl 4 [26], TiCl 4 [27], Wells-Dawson hetropolyacid [28], nano-crystalline sulfated zirconia-microwave [29] and benzylsulfonic acid functionallized mesoporous Zr-TMS [30]. The main disadvantages of the processes using these catalysts are, long reaction times, low yields, harsh reaction conditions, nonreusability of the catalyst, use of excess amounts of the reagent, strictly reactive conditions (N 2 atmosphere), special efforts required to prepare the catalyst and tedious work-up procedures.…”

Section: Introductionmentioning

confidence: 99%

Melamine trisulfonic acid as a new, efficient and reusable catalyst for the solvent free synthesis of coumarins

Shirini

Zolfigol

Albadi

2010

JICS

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A solvent-free synthesis of coumarins using a Wells–Dawson heteropolyacid as catalyst

Cited by 124 publications

References 20 publications

Electrical and gas sensing properties of novel cobalt(II), copper(II), manganese(III) phthalocyanines carrying ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate moieties

Electrical and gas sensing properties of novel cobalt(II), copper(II), manganese(III) phthalocyanines carrying ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate moieties

Silicagel-supported H6P2W18O62.24H2O: a reusable catalyst to prepare diphenylmethyl (DPM) ethers

Melamine trisulfonic acid as a new, efficient and reusable catalyst for the solvent free synthesis of coumarins

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