A facile environment-friendly one-pot two-step regioselective synthetic strategy for 3,7-diarylpyrazolo[1,5-a]pyrimidines related to zaleplon and 3,6-diarylpyrazolo[1,5-a]pyrimidine-7-amines assisted by KHSO $$_{4}$$ 4 in aqueous media

Devi, A. Satyapati; Kaping, Shunan; Vishwakarma, Jai N.

doi:10.1007/s11030-015-9606-2

Cited by 17 publications

(9 citation statements)

References 46 publications

(63 reference statements)

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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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“…The similar kind of derivatives of these fused pyrazolopyrimidines were prepared using different substituted starting materials as mentioned in Table 2. [27] Table 1. Different derivatives of pyrazolo [3,4-d] [3,4-d]pyrimidines, using glycerol as a green solvent.…”

Section: Synthesis Of Pyrazolopyrimidines Using Green Reaction Mediamentioning

confidence: 99%

Efficient Green Protocols for the Preparation of Pyrazolopyrimidines

et al. 2021

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Pyrazolopyrimidine with all its isoforms occupy a noteworthy position in medicinal chemistry owing to their proven dominance in the modulation of a vast array of biological receptors, thereby mitigating numerous pathological conditions. The development of sustainable protocols, which integrate the principles of green chemistry in the synthesis process although challenging, offers the most appropriate way to conduct the sustainable synthesis of pyrazolopyrimidines. Due to the effectiveness of this nucleus and striking similarity to purines, they have been accessed using green as well as non-green protocols. Analytical techniques like 2D NMR has been employed for the confirmation of pyrazolopyrimidines and their isomers besides the conventional single-crystal X-ray diffraction (XRD). Here, considering the rising awareness of sustainable protocols, we aimed at exploring this decade for green protocols for the synthesis of pyrazolopyrimidines and furnished products in excellent yields in this review. Protocols covered in this review include synthesis using green solvent, solvent-free conditions, green catalyst, and catalyst-free reactions. Also, synthesis of pyrazolopyrimidines assisted by microwave and ultrasound, as well as ionic liquid mediated synthesis are covered. It is estimated that this review shall throw some light upon the environmentally benign protocols to produce pyrazolopyrimidines which is itself a very important nucleus in the field of medicinal chemistry.

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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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A facile environment-friendly one-pot two-step regioselective synthetic strategy for 3,7-diarylpyrazolo[1,5-a]pyrimidines related to zaleplon and 3,6-diarylpyrazolo[1,5-a]pyrimidine-7-amines assisted by KHSO $$_{4}$$ 4 in aqueous media

Cited by 17 publications

References 46 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

Efficient Green Protocols for the Preparation of Pyrazolopyrimidines

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

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