23901-60-2Relevant academic research and scientific papers
Regioselective synthesis of 6-trifluoromethyl-1,4,5,6-tetrahydropyrazolo[3,4-b]pyran derivatives
Li, Dongmei,Song, Liping,Song, Shaodi,Zhu, Shizheng
, p. 952 - 957 (2007)
A facile two-step procedure for the synthesis of 6-(trifluoromethyl)-1,4,5,6-tetrahydropyrazolo[3,4-b]pyran derivatives (4) from the reaction of 4-arylidene-3-methyl-1-phenyl-5-pyrazolones (1) with ethyl trifluoroacetoacetate (2), a versatile fluorinated
NHC-Catalyzed Asymmetric Formal [4 + 2] Annulation to Construct Spirocyclohexane Pyrazolone Skeletons
Zhao, Chengtao,Shi, Kuangxi,He, Gao,Gu, Qingxiu,Ru, Zhenyuan,Yang, Limin,Zhong, Guofu
, p. 7943 - 7947 (2019)
A chiral N-heterocyclic carbene (NHC)-catalyzed [4 + 2] annulation of γ-chloroenals and α-arylidene pyrazolinones was developed in the absence of expensive oxidants. The reaction proceeds smoothly via a vinyl enolate intermediate to afford spirocyclohexan
Amphiphile catalysed selective synthesis of 4-amino alkylated-1H-pyrazol-5-ol via Mannich aromatization preferred to the Knoevenagel-Michael type reaction in water
Kumar, Atul,Maurya, Shivam,Gupta, Maneesh Kumar,Shukla, Ratnakar Dutt
, p. 57953 - 57957 (2014)
An economic and efficient amphiphile (SDS) catalysed one pot synthesis of the aromatized 4-amino alkylated-1H-pyrazol-5-ol via a Mannich type reaction that is preferable compared to a Knoevenagel-Michael type reaction, i.e. aromatic aldehyde, secondary amine and 3-methyl-1-phenyl-5-pyrazolinone in water, has been developed. In this selective Mannich aromatization, the reaction proceeds via a micelle stabilized imine intermediate, followed by the nucleophilic addition of 3-methyl-1-phenyl-5-pyrazolinone and aromatization in water.
Enantioselective Synthesis of Spiropyrazolone-Fused Cyclopenta[ c]chromen-4-ones Bearing Five Contiguous Stereocenters via (3+2) Cycloaddition
Khairnar, Pankaj V.,Su, Yin-Hsiang,Edukondalu, Athukuri,Lin, Wenwei
, p. 12326 - 12335 (2021/08/24)
An enantioselective synthesis of spiropyrazolone-fused cyclopenta[c]chromen-4-ones is demonstrated via a (3+2) cycloaddition reaction. The reactions of 3-homoacylcoumarins and α,β-unsaturated pyrazolones in the presence of the cinchona-alkaloid derived hy
A three-component, general and practical route for diastereoselective synthesis of aza-spirocyclic pyrazolonesviaa decarboxylative annulation process
Awasthi, Annapurna,Yadav, Pushpendra,Tiwari, Dharmendra Kumar
, p. 2374 - 2383 (2021/02/16)
An efficient, general, and practical route for highly diastereoselective synthesis of aza-spirocyclic pyrazolones from easily available α-amino acids, aldehydes, and alkylidene pyrazolones by means of a decarboxylative annulation process is reported. This
Enantio- and Diastereoselective Synthesis of β-Aryl-β-pyrazolyl α-Amino Acid Esters via Copper-Catalyzed Reaction of Azomethine Ylides with Benzylidenepyrazolones
Gong, Yan-Chuan,Wang, Yue,Li, Er-Qing,Cui, Hao,Duan, Zheng
supporting information, (2019/02/07)
A fully stereoselective synthesis of unnatural chiral β-aryl-β-pyrazolyl α-amino acid esters via copper-catalyzed addition reactions of azomethine ylides with benzylidenepyrazolones bearing two contiguous stereogenic centers was developed. A 1H-pyrazol-5-ol was introduced by the aromatization of 3H-pyrazol-3-one in the reaction. The transformation operated at room temperature and afforded β-1H-pyrazol-5-ol-α-amino esters in high yields with good to excellent levels of diastereo- and enantioselectivity.
Enantio- And diastereoselective synthesis of b-Aryl-b-pyrazolyl a-amino acid esters via copper-catalyzed reaction of azomethine ylides with benzylidenepyrazolones
Gong, Yan-Chuan,Wang, Yue,Li, Er-Qing,Cui, Hao,Duan, Zheng
supporting information, p. 1389 - 1393 (2019/10/28)
A fully stereoselective synthesis of unnatural chiral b-aryl-b-pyrazolyl a-amino acid esters via copper-catalyzed addition reactions of azomethine ylides with benzylidenepyrazolones bearing two contiguous stereogenic centers was developed. A 1H-pyrazol-5-ol was introduced by the aromatization of 3H-pyrazol-3-one in the reaction. The transformation operated at room temperature and afforded b-1H-pyrazol-5-ol-a-amino esters in high yields with good to excellent levels of diastereo- and enantioselectivity.
Bisphosphine catalyzed sequential [3 + 2] cycloaddition and Michael addition of ynones with benzylidenepyrazolones: Via dual α′,α′-C(sp3)-H bifunctionalization to construct cyclopentanone-fused spiro-pyrazolones
Zhang, Jiayong,Miao, Zhiwei
, p. 9461 - 9471 (2019/01/03)
A bisphosphine-catalyzed sequential [3 + 2] cycloaddition and Michael addition reaction of ynones with benzylidenepyrazolones has been developed. Under the catalysis of DPPB [1,4-bis(diphenylphosphino)butane], the reaction proceeded smoothly to give spiro-[cyclopentanone] pyrazolone derivatives in moderate to good yields with good diastereoselectivities via sequential dual α′,α′-C(sp3)-H bifunctionalization annulation. This strategy provides a novel route toward the synthesis of spiro-[cyclopentanone] pyrazolones containing three contiguous stereocenters which possess potential pharmaceutical activities.
Tosylmethylisocyanide (TosMIC) [3+2] cycloaddition reactions: A facile Van Leusen protocol for the synthesis of the new class of spirooxazolines, spiropyrrolines and Chromeno[3,4-c]pyrrols
Shaabani, Ahmad,Sepahvand, Heshmatollah,Bazgir, Ayoob,Khavasi, Hamid Reza
, p. 7058 - 7067 (2018/11/02)
The reactivity and chemo-, regio- and diastreo-selectivity of tosylmethyl isocyanides (TosMIC) are investigated in Van Leusen type [3 + 2] cycloaddition reactions with the various activate cyclic ketones and double C–C bonds in the synthesis of spirooxazolines, spiropyrrolines and chromeno[3,4-c]pyrrols in good to excellent yields under catalyst-free conditions without any activation at ambient temperature.
Lewis-Base-Catalyzed [1 + 2 + 2] Annulation Reaction of Morita-Baylis-Hillman Carbonates with Unsaturated Pyrazolones: Construction of All-Stereogenic Carbon Cyclopentane-Fused Dispiropyrazolones
Liang, Jin-Yan,Shen, Shou-Jie,Chai, Xiao-Qian,Lv, Ting
, p. 12744 - 12752 (2018/10/09)
The first Lewis-base-catalyzed unexpected [1 + 2 + 2] annulation reaction between Morita-Baylis-Hillman carbonates and unsaturated pyrazolones was developed. The multicyclic cyclopentane-fused dispiropyrazolone constructions containing five contiguous ste
