A facile, regioselective synthesis of pyrazolo[1, 5-a]pyrimidine analogs in the presence of KHSO4 in aqueous media assisted by ultrasound and their anti-inflammatory and anti-cancer activities

Kaping, Shunan; Kalita, Utpalparna; Sunn, Melboureen; Singha, Laishram Indira; Vishwakarma, Jai N.

doi:10.1007/s00706-015-1638-x

Cited by 25 publications

(13 citation statements)

References 26 publications

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“…They have been reported to have the advantages of rapid absorption, rapid onset, adequate duration of action, and no residual effect on daytime performance [4][5][6][7][8]. Inspired by this, our group has reported various pyrazolo[1,5-a]pyrimidine hybrids (4a-b, 5, 6, 7, 8(a-c)) all of which exhibit various bio-efficiencies ( Figure 1) [9][10][11][12][13]. Motivated by this notable significance of pyrazolo[1, 5a]pyrimidine and in continuation with our research activities, we settled to further add on to this class of compounds.…”

Section: Introductionmentioning

confidence: 94%

Efficient synthesis of diversely substituted pyrazolo[1,5-a]pyrimidine derivatives promoted by ultrasound irradiation in water and their antibacterial activities

et al. 2020

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A green synthetic route leading to the discovery of a series of diversely substituted pyrazolo[1,5-a]pyrimidines, having CO2Et group embedded at position-2 has been unraveled in this article. A series of formylated active proton compounds that were chosen to react with a carboxylate substituted-3-aminopyrazole under ultrasonic irradiation in the presence of a mild acid as a catalyst and aqueous ethanol medium afforded the desired products. The molecular structures of all these synthesized compounds were established by their spectral and analytical data. A model molecule 3d, subjected to single-crystal X-ray crystallography analysis further confirms their molecular structure. The crystal crystallized to a monoclinic cell with P21/c space group, a = 7.468 (5) Å, b = 27.908 (17) Å, c = 7.232 (4) Å, β = 104.291 (7)o, V =1460.7(15) Å3, Z = 4, μ(MoKα) = 0.096 mm-1, Dcalc = 1.352 Mg/m3 16667 measured reflection (5.63 ≤ 2Θ ≤ 57.57°), 3720 unique (Rint = 0.0965, Rsigma = 0.0945) which were used in all calculations. The final R1 was 0.0750 (I > 2σ(I)) and wR2 was 0.2226 (all data). These compounds were further explored for their antibacterial potential, and a few of them have exhibited encouraging results.

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Section: Introductionmentioning

confidence: 94%

Efficient synthesis of diversely substituted pyrazolo[1,5-a]pyrimidine derivatives promoted by ultrasound irradiation in water and their antibacterial activities

et al. 2020

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“…4-Aminoantipyrine has been used for the protection against oxidative stress as well as prophylactic of some diseases including cancer, and these are found to be important directions in medical applications [22]. In view of these information and in continuation with our research work [23][24][25] on synthesis of pharmacologically important pyrazolo [1,5-a]pyrimidines, it was found worthy to synthesize novel pyrazolo[1,5-a]pyrimidines incorporating the antipyrine moiety to study their biological properties. Ultrasound (US) irradiation has helped researchers tremendously in accomplishing the green goals of chemistry by shortening the reaction time with easy work-up, resulting in high yields of the products and use of readily available solvents and catalysts [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Ultrasound assisted synthesis of pyrazolo[1,5-a]pyrimidine-antipyrine hybrids and their anti-inflammatory and anti-cancer activities

Kaping

Sunn²,

Singha³

et al. 2020

Eur J Chem

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A series of antipyrinyl-pyrazolo[1,5-a]pyrimidines have been synthesized by reactions of aminopyrazole (4) with various formylated active proton compounds in the presence of KHSO4 (aqueous media), under ultrasound irradiation. The structures of the compounds have been established with the help of spectral and analytical data. N-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-7-phenylpyrazolo[1,5-a]pyrimidine-3-carboxamide (6a) was further subjected to X-ray crystallographic studies to avoid any ambiguity of the derived structures. Crystal data for compound 6a, C51H46N12O5 (M =907.00 g/mol): triclinic, space group P-1 (no. 2), a = 9.9554(3) Å, b = 14.0875(4) Å, c = 17.4572(4) Å, α = 79.676(2)°, β = 85.283(2)°, γ = 72.647(2)°, V = 2297.97(11) Å3, Z = 2, T = 296.15 K, μ(MoKα) = 0.088 mm-1, Dcalc = 1.311 g/cm3, 29732 reflections measured (4.174° ≤ 2Θ ≤ 57.068°), 10681 unique (Rint = 0.0400, Rsigma = 0.0533) which were used in all calculations. The final R1 was 0.0566 (I > 2σ(I)) and wR2 was 0.1663 (all data). The novel compounds were also screened for their biological activities.

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“…Also, pyrazolo [1,5-a]pyrimidine nucleus is an interesting and versatile scaffold for the preparation of various drugs like zaleplon, indiplon and ocinaplon [14][15][16]. Realising the importance of these molecules, we have recently reported [17][18][19][20] a general synthetic strategy and demonstrated the applicability for the synthesis of pyrazolo [1,5-a] pyrimidines. In view of the importance of these molecules we have extended our synthetic strategy for 5methyl-4-phenyl pyrazolo [1,5-a]pyrimidine derivatives and the details are presented herein.…”

Section: Introductionmentioning

confidence: 99%

A three step one-pot regioselective synthesis of highly substituted pyrazolo[1,5-a]pyrimidines assisted by KHSO4 in aqueous media under ultrasound irradiation

2020

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A simple and efficient synthesis of substituted pyrazolo[1,5-a]pyrimidine derivatives has been developed by the use of ultrasound. 5-Methyl-4-phenyl-1H-pyrazol-3-amine required for the synthesis of pyrazolo[1,5-a]pyrimidine derivatives has been easily obtained by the reaction of 3-(dimethylamino)-2-phenylacrylonitrile (formed from readily available 2-phenylacetonitrile) with hydrazine hydrate in refluxing ethanol. The 5-aminopyrazole was then reacted with various formylated active proton compounds in presence of KHSO4 in aqueous medium under ultrasound irradiation to give the desired products. The chemical structures of the newly synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and Mass spectral data. X-ray crystallographic study of a selected compound 6-(4-chlorophenyl)-2-methyl-3-phenylpyrazolo[1,5-a]pyrimidin-7-amine (7c) was performed to ascertain the regioselectivity of the reaction. Crystal data for compound 7c: Triclinic, space group P-1 (no. 2), a = 8.0198(3) Å, b = 14.0341(6) Å, c = 14.2099(6) Å, α = 87.672(2)°, β = 83.902(2)°, γ = 89.120(2)°, V = 1588.87(11) Å3, Z = 4, T = 293(2) K, μ(MoKα) = 0.248 mm-1, Dcalc = 1.400 g/cm3, 12918 reflections measured (4.012° ≤ 2Θ ≤ 49°), 5152 unique (Rint = 0.0411, Rsigma = 0.0429) which were used in all calculations. The final R1 was 0.0486 (I > 2σ(I)) and wR2 was 0.1320 (all data).

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A facile, regioselective synthesis of pyrazolo[1, 5-a]pyrimidine analogs in the presence of KHSO4 in aqueous media assisted by ultrasound and their anti-inflammatory and anti-cancer activities

Cited by 25 publications

References 26 publications

Efficient synthesis of diversely substituted pyrazolo[1,5-a]pyrimidine derivatives promoted by ultrasound irradiation in water and their antibacterial activities

Efficient synthesis of diversely substituted pyrazolo[1,5-a]pyrimidine derivatives promoted by ultrasound irradiation in water and their antibacterial activities

Ultrasound assisted synthesis of pyrazolo[1,5-a]pyrimidine-antipyrine hybrids and their anti-inflammatory and anti-cancer activities

A three step one-pot regioselective synthesis of highly substituted pyrazolo[1,5-a]pyrimidines assisted by KHSO4 in aqueous media under ultrasound irradiation

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