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Search for "pyrazolidine" in Full Text gives 5 result(s) in Beilstein Journal of Organic Chemistry.
Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks
Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127
- activation [108][109][110]. Besides, pyrazolidine and pyrazoline compounds are highly valuable hereocycles which are found in many natural products and bioactive compounds. Among them, CF3-substituted pyrazolidines have already been shown to be highly bioactive [111][112][113]. Thus, Hu et al. chose
- trifluoromethyl acylhydrazones as 1,3-dipolar agents to react with β-nitrostyrenes [114], maleates [115], cyclopentadiene [116] and maleimides [117] for the synthesis of CF3-substituted pyrazolidine derivatives. These reactions were conducted under basic conditions and in the presence of Cu(OTf)2 (Scheme 19a). As
Selective and reversible 1,3-dipolar cycloaddition of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with 1,3-diphenylprop-2-en-1-ones under microwave irradiation
Beilstein J. Org. Chem. 2020, 16, 2679–2686, doi:10.3762/bjoc.16.218
- in the literature [11][13], we have carried out the careful structure analysis of the obtained compounds. So, in the 1H NMR spectrum of compound 3a there are only two signals for the substituted pyrazolidine ring – a doublet (2H) at 4.48 ppm (J = 7.4 Hz) and a triplet (1H) at 4.39 ppm (J = 7.4 Hz
- ). Accordingly, two characteristic signals for carbon atoms of the pyrazolidine ring are present in the 13C NMR spectrum – at 72.2 (2СН) and 68.7 (СН) ppm. The spatial configuration of the adducts 3e and 3g was further determined by single crystal X-ray diffraction analysis (Figure 1 and Figure 2). All products
Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,β-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives
Beilstein J. Org. Chem. 2012, 8, 1710–1720, doi:10.3762/bjoc.8.195
- 65880378 10.3762/bjoc.8.195 Abstract The catalytic synthesis of nitrogen-containing heterocycles is of great importance to medicinal and synthetic chemists, and also a challenge for modern chemical methodology. In this paper, we report the synthesis of pyrazolidine derivatives through a domino aza-Michael
- /hemiacetal sequence with chiral or achiral secondary amines as organocatalysts. Thus, a series of achiral pyrazolidine derivatives were obtained with good yields (up to 90%) and high diastereoselectivities (>20:1) with pyrrolidine as an organocatalyst, and enantioenriched pyrazolidines are also achieved with
- good results (up to 86% yield, >10/1 regioselectivity, >20:1 dr, 99% ee) in the presence of (S)-diphenylprolinol trimethylsilyl ether catalyst. Keywords: aza-Michael; domino; hydrazine; organocatalysis; pyrazolidine; Introduction Pyrazolidines are privileged and valuable heterocyclic compounds, which
Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold
Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181
- effects. We therefore identified the 1,2,4-triazine-containing scaffolds IV and VIII as promising novel target structures (Scheme 1). Depending on the starting material used, e.g., hydantoin I, or pyrazolidine-3,5-dione V, respectively, either 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6-diones IV (route
Ugi post-condensation copper-triggered oxidative cascade towards pyrazoles
Beilstein J. Org. Chem. 2011, 7, 1310–1314, doi:10.3762/bjoc.7.153
- pyrazolidinone under oxidative conditions from simple hydrazone derivatives (Scheme 1) [13]. The cascade features a [3 + 2] cycloaddition coupled with an aerobic oxidation of the resulting pyrazolidine. A further oxidative coupling may be observed according to the substitution pattern of the starting acyl
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