Primary amine-catalyzed enantioselective 1,4-Michael addition reaction of pyrazolin-5-ones to α,β-unsaturated ketones

• Pooja Goyal,
• Akhil K. Dubey,
• Raghunath Chowdhury and
• Amey Wadawale

Beilstein J. Org. Chem. 2024, 20, 1518–1526, doi:10.3762/bjoc.20.136

• organocatalyzed asymmetric Michael addition reaction of 4-monosubstituted pyrazol-5-ones to simple enones for the synthesis of pyrazolone derivatives [25]. Despite these progresses, arylidene/heteroarylideneacetones have remained untapped by 4-unsubstituted pyrazolin-5-ones under asymmetric organocatalytic or

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• -nitrothioacetates in good yields and enantioselectivities [27]. A sulfinylurea catalyst was also applied to catalyze the addition of 3-substituted pyrazol-5-ones to trisubstituted nitroalkenes. The adducts were obtained with good yields and enantioselectivities up to 91:9 er [28]. Inspired by the previous

Microwave-assisted synthesis of biologically relevant steroidal 17-exo-pyrazol-5'-ones from a norpregnene precursor by a side-chain elongation/heterocyclization sequence

• Gergő Mótyán,
• László Mérai,
• Márton Attila Kiss,
• Zsuzsanna Schelz,
• Izabella Sinka,
• István Zupkó and
• Éva Frank

Beilstein J. Org. Chem. 2018, 14, 2589–2596, doi:10.3762/bjoc.14.236

• 10.3762/bjoc.14.236 Abstract Multistep syntheses of novel 17β-pyrazol-5'-ones in the Δ5-androstane series were efficiently carried out from pregnenolone acetate. A steroidal 17-carboxylic acid was first synthesized as a norpregnene precursor by the bromoform reaction and subsequent acetylation. Its CDI

• the reference compound, cisplatin. Keywords: antiproliferative activity; Knorr reaction; microwave; pyrazol-5-ones; steroids; Introduction 17-exo-Heterocyclic androstanes with five or six-membered heterocyclic rings connected directly to C-17 of the sterane core represent a remarkable subclass of

• as the necessity of high temperature or prolonged reaction time and low yields of the desired products [14]. A rate acceleration and yield improvement could be achieved in some cases by performing the reactions under microwave (MW) conditions [15][16][17]. Especially with respect to pyrazol-5-ones