Skip to content
2000
Volume 22, Issue 4
  • ISSN: 1570-1794
  • E-ISSN: 1875-6271

Abstract

Unsaturated pyrazolones can participate in organocatalytic reactions with various substrates to form spiro-cyclic pyrazolones, and fuzed-pyrazolone heterocycles. The present review describes progress since 2013 in the organocatalysis transformations of unsaturated pyrazolones. Pyrazolones are prevalent structural motifs in a wide variety of natural products and drug or drug-like molecules. A series of nitrogen-containing pyrazolones exhibits anticancer, antimicrobial, anti-inflammatory, anticonvulsant, antidepressant, antidiabetic, and antipyretic activities. Especially, chiral spiro-cyclic pyrazolones are recognized as targets in natural products and clinical pharmaceuticals. Organocatalytic systems are powerful and reliable approaches that allow us to build structurally complex molecules in an enantioselectively and diastereoselectively manner. Avoiding the use of transition metal catalysts, readily available bifunctional organocatalysts, and the performance of the reaction at ambient temperature are other advantages of these catalytic systems. Despite considerable progress in this field, it is still one of the challenging goals for chemists to make new biologically active heterocyclic molecules.

Loading

Article metrics loading...

/content/journals/cos/10.2174/0115701794307025240521114902
2024-06-21
2025-09-04
Loading full text...

Full text loading...

References

  1. LiuS. BaoX. WangB. Pyrazolone: A powerful synthon for asymmetric diverse derivatizations.Chem. Commun. 20185482115151152910.1039/C8CC06196C 30225504
    [Google Scholar]
  2. CastagnoloD. ManettiF. RadiM. BechiB. PaganoM. De LoguA. MeledduR. SaddiM. BottaM. Synthesis, biological evaluation, and SAR study of novel pyrazole analogues as inhibitors of Mycobacterium tuberculosis: Part 2. Synthesis of rigid pyrazolones.Bioorg. Med. Chem.200917155716572110.1016/j.bmc.2009.05.058 19581099
    [Google Scholar]
  3. DewanganD. KumarT. AlexanderA. NagoriK. TripathiD. Pyrazole: Their chemistry and pharmacological potentials: A review.J. Curr. Pharm. Res.20111436937710.33786/JCPR.2011.v01i04.010
    [Google Scholar]
  4. WuS. LiY. XuG. ChenS. ZhangY. LiuN. DongG. MiaoC. SuH. ZhangW. ShengC. Novel spiropyrazolone antitumor scaffold with potent activity: Design, synthesis and structure–activity relationship.Eur. J. Med. Chem.201611514114710.1016/j.ejmech.2016.03.039 27016707
    [Google Scholar]
  5. SayedG.H. AzabM.E. AnwerK.E. RaoufM.A. NegmN.A. Pyrazole, pyrazolone and enaminonitrile pyrazole derivatives: Synthesis, characterization and potential in corrosion inhibition and antimicrobial applications.J. Mol. Liq.201825232933810.1016/j.molliq.2017.12.156
    [Google Scholar]
  6. SayedE.M.T. ShariefE.M.A.M.S. ZarieE.S. MorsyN.M. ElsheakhA.R. VoronkovA. BerishviliV. HassanG.S. Design, synthesis, anti-inflammatory activity and molecular docking of potential novel antipyrine and pyrazolone analogs as cyclooxygenase enzyme (COX) inhibitors.Bioorg. Med. Chem. Lett.201828595295710.1016/j.bmcl.2018.01.043 29426771
    [Google Scholar]
  7. GaoM. QuK. ZhangW. WangX. Pharmacological activity of pyrazole derivatives as an anticonvulsant for benefit against epilepsy.Neuroimmunomodulation2021282909810.1159/000513297 33774633
    [Google Scholar]
  8. SecciD. BolascoA. ChimentiP. CarradoriS. The state of the art of pyrazole derivatives as monoamine oxidase inhibitors and antidepressant/anticonvulsant agents.Curr. Med. Chem.201118335114514410.2174/092986711797636090 22050759
    [Google Scholar]
  9. DatarP. JadhavS. Development of pyrazole compounds as antidiabetic agent: A review.Lett. Drug Des. Discov.201311568670310.2174/1570180810666131113212354
    [Google Scholar]
  10. UramaruN. ShigematsuH. TodaA. EyanagiR. KitamuraS. OhtaS. Design, synthesis, and pharmacological activity of nonallergenic pyrazolone-type antipyretic analgesics.J. Med. Chem.201053248727873310.1021/jm101208x 21121633
    [Google Scholar]
  11. XieX. XiangL. PengC. HanB. Catalytic asymmetric synthesis of spiropyrazolones and their application in medicinal chemistry.Chem. Rec.201919112209223510.1002/tcr.201800199 30821425
    [Google Scholar]
  12. ZakiR.M. Abdul-MalikM.A. SaberS.H. RadwanS.M. El-DeanA.M.K. A convenient synthesis, reactions and biological evaluation of novel pyrazolo[3,4-b]selenolo[3,2-e]pyrazine heterocycles as potential anticancer and antimicrobial agents.Med. Chem. Res.202029122130214510.1007/s00044‑020‑02635‑z
    [Google Scholar]
  13. Abd-EllaA.A. MetwallyS.A. ul-Malik, M.A.A.; Ossaily, E.Y.A.; Elrazek, F.M.A.; Aref, S.A.; Naffea, Y.A.; Abdel-Raheem, S.A.A. A review on recent advances for the synthesis of bioactive pyrazolinone and pyrazolidinedione derivatives.Current Chemistry Letters202211215717210.5267/j.ccl.2022.2.004
    [Google Scholar]
  14. ZeaA. AlbaA.N.R. MazzantiA. MoyanoA. RiosR. Highly enantioselective cascade synthesis of spiropyrazolones.Org. Biomol. Chem.20119196519652310.1039/c1ob05753g 21842077
    [Google Scholar]
  15. WangY. LiE.Q. DuanZ. Ligand-dependent, palladium-catalyzed stereodivergent synthesis of chiral tetrahydroquinolines.Chem. Sci. 202213278131813610.1039/D2SC02771B 35919424
    [Google Scholar]
  16. LiJ.H. DuD.M. Phosphine‐catalyzed cascade reaction of unsaturated pyrazolones with alkyne derivatives: Efficient synthesis of pyrano[2,3‐ c]pyrazoles and spiro‐cyclopentanone‐pyrazolones.Adv. Synth. Catal.2015357183986399410.1002/adsc.201500675
    [Google Scholar]
  17. YavariI. SheykhahmadiJ. BahematS. HalvagarM. A convenient synthesis of functionalized 2,3-diazaspiro[4.4]nona-1,6,8-trienes.Synlett201829152019202210.1055/s‑0037‑1610549
    [Google Scholar]
  18. LuoW. ShaoB. LiJ. SongD. YiX. LingF. ZhongW. Divergent synthesis of spirocyclopentene-pyrazolones and pyrano[2,3-c]-pyrazoles via Lewis base controlled annulation reactions.Tetrahedron Lett.2019604415120610.1016/j.tetlet.2019.151206
    [Google Scholar]
  19. XuJ. YangW. ShiW. MaoB. LinY. XiaoY. GuoH. DMAP-catalyzed [4+2] annulation of α-substituded allenoates with unsaturated pyrazolones.Tetrahedron201975263609361610.1016/j.tet.2019.05.028
    [Google Scholar]
  20. WangH.X. WuL.L. WangY.M. ZhouZ.H. Organocatalyzed asymmetric tandem Michael-cyclization reaction of 4-benzylidene-3-methylpyrazol-5-ones and malononitrile: stereocontrolled construction of pyrano[2,3-c]pyrazole scaffold.RSC Advances2015553428364284210.1039/C5RA04356E
    [Google Scholar]
  21. BeukeawD. RattanasupaponsakN. KittikoolT. PhakdeeyothinK. PhomphraiK. YotphanS. Metal‐free site‐selective direct oxidative phosphorylation of pyrazolones.Adv. Synth. Catal.2022364173066307310.1002/adsc.202200533
    [Google Scholar]
  22. ChengC. ZhangJ. WangX. MiaoZ. DBU-promoted [4 + 4] domino cycloaddition of ynones with benzylidenepyrazolones to access eight-membered cyclic ethers.J. Org. Chem.201883105450545710.1021/acs.joc.8b00352 29699396
    [Google Scholar]
  23. KhairnarP.V. WuC.Y. LinY.F. EdukondaluA. ChenY.R. LinW. Diversity-oriented synthesis of spiropentadiene pyrazolones and 1 H -Oxepino[2,3- c]pyrazoles from doubly conjugated pyrazolones via intramolecular wittig reaction.Org. Lett.202022124760476510.1021/acs.orglett.0c01552 32515972
    [Google Scholar]
  24. KhairnarP.V. SuY.H. ChenY.C. EdukondaluA. ChenY.R. LinW. Organophosphane-catalyzed direct β-acylation of 4-arylidene pyrazolones and 5-arylidene thiazolones with acyl chlorides.Org. Lett.202022176868687210.1021/acs.orglett.0c02408 32809836
    [Google Scholar]
  25. MaoB. XuJ. ShiW. WangW. WuY. XiaoY. GuoH. Pd-Catalyzed [4 + 2] cycloaddition of methylene cyclic carbamates with dihydropyrazolone-derived alkenes: Synthesis of spiropyrazolones.Org. Biomol. Chem.202220204086409010.1039/D2OB00535B 35545885
    [Google Scholar]
  26. XuJ. ShiW. LiuM. LiaoJ. WangW. WuY. GuoH. Palladium‐catalyzed [4+2] cycloaddition of hydroxy‐tethered allylic carbonates with alkenes: Synthesis of functionalized tetrahydropyrans.Adv. Synth. Catal.2022364122060206610.1002/adsc.202200160
    [Google Scholar]
  27. LiuL. ZhongY. ZhangP. JiangX. WangR. Core scaffold-inspired stereoselective synthesis of spiropyrazolones via an organocatalytic Michael/cyclization sequence.J. Org. Chem.20127722102281023410.1021/jo301851a 23072426
    [Google Scholar]
  28. ReddyY.P. AnwarS. Synthesis of fully functionalised spiropyran pyrazolone skeletons via a formal [4 + 2] cascade process using β-nitro-styrene-derived MBH-alcohols.RSC Advances20221253346343463810.1039/D2RA06076K 36545601
    [Google Scholar]
  29. AwasthiA. YadavP. TiwariD.K. A three-component, general and practical route for diastereoselective synthesis of aza-spirocyclic pyrazolones via a decarboxylative annulation process.New J. Chem.20214552374238310.1039/D0NJ05915C
    [Google Scholar]
  30. BaoX. WangX. TianJ.M. YeX. WangB. WangH. Recent advances in the applications of pyrazolone derivatives in enantioselective synthesis.Org. Biomol. Chem.202220122370238610.1039/D1OB02426D 35234777
    [Google Scholar]
  31. LiangJ. ChenQ. LiuL. JiangX. WangR. An organocatalytic asymmetric double Michael cascade reaction of unsaturated ketones and unsaturated pyrazolones: Highly efficient synthesis of spiropyrazolone derivatives.Org. Biomol. Chem.20131191441144510.1039/C2OB27095A 23262465
    [Google Scholar]
  32. ZhangJ.X. LiN.K. LiuZ.M. HuangX.F. GengZ.C. WangX.W. Enantioselective synthesis of unsymmetrical diaryl‐substituted spirocyclohexanonepyrazolones through a cascade [4+2] double michael addition.Adv. Synth. Catal.2013355479780810.1002/adsc.201200925
    [Google Scholar]
  33. SunP. MengC.Y. ZhouF. LiX.S. XieJ.W. Organocatalytic asymmetric one-pot sequential reaction: Synthesis of highly substituted spirocyclohexanepyrazolones with six contiguous stereogenic carbons.Tetrahedron201470499330933610.1016/j.tet.2014.10.038
    [Google Scholar]
  34. ChauhanP. MahajanS. LohC.C.J. RaabeG. EndersD. Streocontrolled construction of six vicinal stereogenic centers on spiropyrazolones via organocascade michael/michael/1,2-addition reactions.Org. Lett.201416112954295710.1021/ol501093v 24840166
    [Google Scholar]
  35. LiJ.H. DuD.M. Organocatalyzed cascade aza-Michael/Michael addition for the asymmetric construction of highly functionalized spiropyrazolone tetrahydroquinolines.Chem. Asian J.20149113278328610.1002/asia.201402706 25204540
    [Google Scholar]
  36. HanB. HuangW. RenW. HeG. WangJ. PengC. Asymmetric synthesis of cyclohexane‐fused drug‐like spirocyclic scaffolds containing six contiguous stereogenic centers via organocatalytic cascade reactions.Adv. Synth. Catal.20153572-356156810.1002/adsc.201400764
    [Google Scholar]
  37. ZhengW. ZhangJ. LiuS. YuC. MiaoZ. Asymmetric synthesis of spiro[chroman-3,3′-pyrazol] scaffolds with an all-carbon quaternary stereocenter via a oxa-Michael–Michael cascade strategy with bifunctional amine-thiourea organocatalysts.RSC Advances20155111911089111310.1039/C5RA17792H
    [Google Scholar]
  38. WangB. LengH.J. YangX.Y. HanB. RaoC.L. LiuL. PengC. HuangW. Efficient synthesis of tetrahydronaphthalene- or isochroman-fused spirooxindoles using tandem reactions.RSC Advances20155107882728827610.1039/C5RA15735H
    [Google Scholar]
  39. YetraS.R. MondalS. MukherjeeS. GonnadeR.G. BijuA.T. Enantioselective synthesis of spirocyclohexadienones by NHC‐catalyzed formal [3+3] annulation reaction of enals.Angew. Chem. Int. Ed.201655126827210.1002/anie.201507802 26487242
    [Google Scholar]
  40. MondalS. MukherjeeS. YetraS.R. GonnadeR.G. BijuA.T. Organocatalytic enantioselective vinylogous Michael-aldol cascade for the synthesis of spirocyclic compounds.Org. Lett.201719164367437010.1021/acs.orglett.7b02085 28749676
    [Google Scholar]
  41. LengH.J. LiQ.Z. ZengR. DaiQ.S. ZhuH.P. LiuY. HuangW. HanB. LiJ.L. Asymmetric construction of spiropyrazolone skeletons via amine‐catalyzed [3+3] annulation.Adv. Synth. Catal.2018360222923410.1002/adsc.201701035
    [Google Scholar]
  42. SunJ. JiangC. ZhouZ. Optically active 4‐substituted 5‐nitropentan‐2‐ones: Valuable chiral building blocks for the stereocontrolled construction of spiro‐pyrazolone scaffolds with five contiguous stereogenic centers.Eur. J. Org. Chem.2016201661165117210.1002/ejoc.201501449
    [Google Scholar]
  43. JiY.L. LiH.P. AiY.Y. LiG. HeX.H. HuangW. HuangR.Z. HanB. Enantio- and diastereoselective synthesis of spiropyrazolones via an organocatalytic [1 + 2 + 3] multicomponent reaction.Org. Biomol. Chem.201917419217922510.1039/C9OB01927H 31595928
    [Google Scholar]
  44. YangW. SunW. ZhangC. WangQ. GuoZ. MaoB. LiaoJ. GuoH. Lewis-base-catalyzed asymmetric [3+ 3] annulation reaction of morita–baylis–hillman carbonates: Enantioselective synthesis of spirocyclohexenes.ACS Catal.2017753142314610.1021/acscatal.7b00320
    [Google Scholar]
  45. LiuJ.Y. ZhaoJ. ZhangJ.L. XuP.F. Quaternary carbon center forming formal [3+ 3] cycloaddition reaction via bifunctional catalysis: Asymmetric synthesis of spirocyclohexene pyrazolones.Org. Lett.20171971846184910.1021/acs.orglett.7b00610 28339213
    [Google Scholar]
  46. MeninnoS. MazzantiA. LattanziA. Asymmetric synthesis of pyrazolone fused spirocyclohexeneimines via a vinylogous Michael/cyclization cascade reaction.Adv. Synth. Catal.20193611798410.1002/adsc.201801337
    [Google Scholar]
  47. LiX. ChenF.Y. KangJ.W. ZhouJ. PengC. HuangW. ZhouM.K. HeG. HanB. Stereoselective assembly of multifunctional spirocyclohexene pyrazolones that induce autophagy-dependent apoptosis in colorectal cancer cells.J. Org. Chem.201984149138915010.1021/acs.joc.9b01098 31267754
    [Google Scholar]
  48. ZhaoC. ShiK. HeG. GuQ. RuZ. YangL. ZhongG. NHC-Catalyzed asymmetric formal [4+2] annulation to construct spirocyclohexane pyrazolone skeletons.Org. Lett.201921197943794710.1021/acs.orglett.9b02927 31513417
    [Google Scholar]
  49. JiD.S. LuoY.C. HuX.Q. XuP.F. Enantioselective synthesis of spirorhodanine-pyran derivatives via organocatalytic [3+3] annulation reactions between pyrazolones and rhodanine-derived ketoesters.Org. Lett.20202231028103310.1021/acs.orglett.9b04571 31939306
    [Google Scholar]
  50. SunB.B. ChenJ.B. ZhangJ.Q. YangX.P. LvH.P. WangZ. WangX.W. Organo-catalyzed asymmetric cascade annulation reaction for the construction of bi-spirocyclic pyrazolone and oxindole derivatives.Org. Chem. Front.20207579680910.1039/D0QO00001A
    [Google Scholar]
  51. PrasadM.S. SivaprakashM. PalanichamyA. Aminocatalytic asymmetric [4 + 2]-annulation to access functionally rich hexahydrospiroindole pyrazolones.Org. Biomol. Chem.202220326329633310.1039/D2OB01085B 35876851
    [Google Scholar]
  52. PrasadM.S. SivaprakashM. Asymmetric synthesis of the perhydroepoxyethanoindole core via sequential [4 + 2]-addition/reduction/fluoroannulation reactions.Org. Biomol. Chem.202321233934410.1039/D2OB02058K 36477116
    [Google Scholar]
  53. CebanV. OlomolaT. MeazzaM. RiosR. Highly diastereoselective synthesis of spiropyrazolones.Molecules20152058574858210.3390/molecules20058574 25985358
    [Google Scholar]
  54. ChenQ. LiangJ. WangS. WangD. WangR. An asymmetric approach toward chiral multicyclic spirooxindoles from isothiocyanato oxindoles and unsaturated pyrazolones by a chiral tertiary amine thiourea catalyst.Chem. Commun. 201349161657165910.1039/c3cc38386e 23334197
    [Google Scholar]
  55. CuiB.D. LiS.W. ZuoJ. WuZ.J. ZhangX.M. YuanW.C. Quinine-catalyzed asymmetric domino Michael-cyclization reaction for the synthesis of spirocyclic oxindoles bearing two spiro quaternary centers and three consecutive stereocenters.Tetrahedron201470101895190210.1016/j.tet.2014.01.036
    [Google Scholar]
  56. WangL. LiS. ChauhanP. HackD. PhilippsA.R. PuttreddyR. RissanenK. RaabeG. EndersD. Asymmetric, three‐component, one‐pot synthesis of spiropyrazolones and 2,5‐chromenediones from aldol condensation/NHC‐catalyzed annulation reactions.Chemistry201622155123512710.1002/chem.201600515 26864437
    [Google Scholar]
  57. LiS. WangL. ChauhanP. PeuronenA. RissanenK. EndersD. Asymmetric synthesis of five-membered spiropyrazolones via N-heterocyclic carbene (NHC)-catalyzed [3+ 2] annulations.Synthesis2017490818081815
    [Google Scholar]
  58. LiJ.H. WenH. LiuL. DuD.M. Diastereo‐ and enantioselective synthesis of spiro‐pyrrolidine‐pyrazolones by squaramide‐catalyzed cascade aza‐michael/michael reactions.Eur. J. Org. Chem.20162016142492249910.1002/ejoc.201600316
    [Google Scholar]
  59. ZhangX.L. TangC.K. XiaA.B. FengK.X. DuX.H. XuD.Q. One‐pot organocatalytic michael addition/I2 ‐mediated cyclization sequence: Metal‐free synthesis of spiropyrazolones from 1,3‐diketones and unsaturated pyrazolones.Eur. J. Org. Chem.20172017223152316010.1002/ejoc.201700474
    [Google Scholar]
  60. XiaA.B. ZhangX.L. TangC.K. FengK.X. DuX.H. XuD.Q. One-pot asymmetric synthesis of a spiro[dihydrofurocoumarin/pyrazolone] scaffold by a Michael addition/I 2 -mediated cyclization sequence.Org. Biomol. Chem.201715275709571810.1039/C7OB00986K 28650044
    [Google Scholar]
  61. LattanziA. MeninnoS. OvergaardJ. Amine thiourea catalysed double michael reaction: An approach for the asymmetric synthesis of spiro[pyrazolone-4,3′-tetrahydrothiophenes.Synthesis20174971509151810.1055/s‑0036‑1588725
    [Google Scholar]
  62. ChenN. ZhuL. GanL. LiuZ. WangR. CaiX. JiangX. Asymmetric synthesis of bispiro[γ‐butyrolactone‐pyrrolidin‐4,4′‐pyrazolone] scaffolds containing two quaternary spirocenters via an organocatalytic 1,3‐dipolar cycloaddition.Eur. J. Org. Chem.20182018232939294310.1002/ejoc.201800404
    [Google Scholar]
  63. MondalB. MaityR. PanS.C. Highly diastereo- and enantioselective synthesis of spiro-tetrahydrofuran-pyrazolones via organocatalytic cascade reaction between γ-hydroxyenones and unsaturated pyrazolones.J. Org. Chem.201883158645865410.1021/acs.joc.8b00781 29812940
    [Google Scholar]
  64. LinY. ZhaoB.L. DuD.M. Bifunctional squaramide-catalyzed asymmetric [3+ 2] cyclization of 2-(1-methyl-2-oxoindolin-3-yl) malononitriles with unsaturated pyrazolones to construct spirooxindole-fused spiropyrazolones.J. Org. Chem.20198416102091022010.1021/acs.joc.9b01268 31318546
    [Google Scholar]
  65. WangC. WenD. ChenH. DengY. LiuX. LiuX. WangL. GaoF. GuoY. SunM. WangK. YanW. The catalytic asymmetric synthesis of CF 3 -containing spiro-oxindole–pyrrolidine–pyrazolone compounds through squaramide-catalyzed 1,3-dipolar cycloaddition.Org. Biomol. Chem.201917225514551910.1039/C9OB00720B 31115424
    [Google Scholar]
  66. DengY. DongZ. GaoF. GuoY. SunM. LiY. WangY. ChenQ. WangK. YanW. The regiocontrollable enantioselective synthesis of chiral trifluoromethyl-containing spiro-pyrrolidine-pyrazolone compounds via amino-regulated 1,3-proton migration reaction.J. Org. Chem.20218618130111302410.1021/acs.joc.1c01705 34494838
    [Google Scholar]
  67. KhairnarP.V. SuY.H. EdukondaluA. LinW. Enantioselective synthesis of spiropyrazolone-fused cyclopenta[ c]chromen-4-ones bearing five contiguous stereocenters via (3+2) cycloaddition.J. Org. Chem.20218617123261233510.1021/acs.joc.1c01215 34346685
    [Google Scholar]
  68. LiuR.M. ZhangM. HanX.X. LiuX.L. PanB.W. TianY.P. PengL.J. YuanW.C. Catalytic asymmetric Michael/cyclization reaction of 3-isothiocyanato thiobutyrolactone: An approach to the construction of a library of bispiro[pyrazolone-thiobutyrolactone] skeletons.Org. Biomol. Chem.202220255060506510.1039/D2OB00773H 35703322
    [Google Scholar]
  69. OrdóñezG.M. MaestroA. OrtegaP. JambrinaP.G. AndrésJ.M. NHC-catalysed [3 + 2]-asymmetric annulation between pyrazolin-4,5-diones and enals: Synthesis of novel spirocyclic pyrazolone γ-butyrolactones and computational study of mechanism and stereoselectivity.Org. Chem. Front.20229242042710.1039/D1QO01462E
    [Google Scholar]
  70. DengY. YangC. ShiS. CaoY. JiaP. LiY. HuangJ. YanW. Efficient enantioselective synthesis of CF2H-containing dispiro [benzo[b]thiophene-pyrrolidine-pyrazole]s via organocatalytic cycloaddition.Tetrahedron202314413358010.1016/j.tet.2023.133580
    [Google Scholar]
  71. LiJ.H. FengT.F. DuD.M. Construction of spirocyclopropane-linked heterocycles containing both pyrazolones and oxindoles through Michael/alkylation cascade reactions.J. Org. Chem.20158022113691137710.1021/acs.joc.5b01940 26491953
    [Google Scholar]
  72. MeninnoS. RoselliA. CapobiancoA. OvergaardJ. LattanziA. Diastereodivergent and enantioselective access to spiroepoxides via organocatalytic epoxidation of unsaturated pyrazolones.Org. Lett.201719195030503310.1021/acs.orglett.7b02189 28906120
    [Google Scholar]
  73. ZhangH.M. LvH. YeS. N-Heterocyclic carbene-catalyzed highly enantioselective synthesis of substituted dihydropyranopyrazolones.Org. Biomol. Chem.201311376255625710.1039/c3ob41455h 23959516
    [Google Scholar]
  74. WangS. EscrichR.C. PericàsM.A. H-bond-directing organocatalyst for enantioselective [4+ 2] cycloadditions via dienamine catalysis.Org. Lett.201618355655910.1021/acs.orglett.5b03575 26794848
    [Google Scholar]
  75. MaityR. PanS.C. Enantioselective aminocatalytic synthesis of tetrahydropyrano[2,3-c]pyrazoles via a domino Michael-hemiacetalization reaction with alkylidene pyrazolones.Org. Biomol. Chem.201715388032803610.1039/C7OB02170D 28936511
    [Google Scholar]
  76. ChengC. SunX. WuZ. LiuQ. XiongL. MiaoZ. Lewis base catalyzed regioselective cyclization of allene ketones or α-methyl allene ketones with unsaturated pyrazolones.Org. Biomol. Chem.201917123232323810.1039/C9OB00179D 30840009
    [Google Scholar]
  77. MutyalaR. ReddyV.R. DonthiR. KallagantiV.S.R. ChandraR. Direct catalytic asymmetric method for the synthesis of tetrahydropyranopyrazoles through allene zwitterion chemistry.Tetrahedron Lett.2019601070370610.1016/j.tetlet.2019.01.008
    [Google Scholar]
  78. BaniaN. MondalB. GhoshS. PanS.C. DMAP catalyzed domino rauhut–currier cyclization reaction between alkylidene pyrazolones and nitro-olefins: Access to tetrahydropyrano[2,3- c]pyrazoles.J. Org. Chem.20218654304431210.1021/acs.joc.0c02871 33593067
    [Google Scholar]
  79. BaniaN. BarmanD. PanS.C. Organocatalytic asymmetric inverse-electron-demand diels–alder reaction between alkylidene pyrazolones and allyl ketones: Access to tetrahydropyrano[2,3- c]pyrazoles.J. Org. Chem.202388139584959310.1021/acs.joc.3c01063 37262311
    [Google Scholar]
  80. WangS. IzquierdoJ. EscrichR.C. PericàsM.A. Asymmetric [4+ 2] annulation reactions catalyzed by a robust, immobilized isothiourea.ACS Catal.2017742780278510.1021/acscatal.7b00360
    [Google Scholar]
  81. GengZ.C. ChenX. ZhangJ.X. LiN. ChenJ. HuangX.F. ZhangS.Y. TaoJ.C. WangX.W. Asymmetric michael/aromatization reaction of azlactones to α,β‐unsaturated pyrazolones with C‐4 regioselectivity catalyzed by an isosteviol‐derived thiourea organocatalyst.Eur. J. Org. Chem.20132013224738474310.1002/ejoc.201300524
    [Google Scholar]
  82. GengZ.C. ZhangJ.X. LiN. ChenJ. HuangX.F. ZhangS.Y. LiH.Y. TaoJ.C. WangX.W. Construction of highly substituted pyrazole derivatives with P–C bond: Access to racemic and enantioselective forms by conjugate addition of diarylphosphane oxides to α,β-unsaturated pyrazolones.Tetrahedron201470241742610.1016/j.tet.2013.11.038
    [Google Scholar]
  83. MaityR. GharuiC. SilA.K. PanS.C. Organocatalytic asymmetric Michael/hemiketalization/retro-aldol reaction of α-nitroketones with unsaturated pyrazolones: Synthesis of 3-acyloxy pyrazoles.Org. Lett.201719366266510.1021/acs.orglett.6b03823 28121452
    [Google Scholar]
  84. WeiR. GaoL. LiG. TangL. ZhangG. ZhengF. SongH. LiQ. BanS. Squaramide-catalysed asymmetric Friedel–Crafts alkylation of naphthol and unsaturated pyrazolones.Org. Biomol. Chem.202119153370337310.1039/D1OB00347J 33899883
    [Google Scholar]
  85. FerrerC.L. VilaC. BlayG. MuñozM.C. PedroJ.R. Catalytic diastereo-and enantioselective vinylogous Mannich reaction of alkylidenepyrazolones to isatin-derived ketimines.Org. Lett.202123197391739510.1021/acs.orglett.1c0257134553948
    [Google Scholar]
/content/journals/cos/10.2174/0115701794307025240521114902
Loading
/content/journals/cos/10.2174/0115701794307025240521114902
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error
Please enter a valid_number test