Zinc chloride catalyzed stereoselective construction of spiropyrazolone tetrahydroquinolines via tandem [1,5]-hydride shift/cyclization sequence
作者:Tuan Zhao、Huanrui Zhang、Longchen Cui、Jingping Qu、Baomin Wang
DOI:10.1039/c5ra18471a
日期:——
A zinc chloride catalyzed tandem 1,5-hydride shift/cyclization process to form spiropyrazolone terahydroquinoline derivatives is developed. A series of new spiropyrazolone derivatives were obtained in good to high yields with good to excellent diastereoselectivities (up to 95% yield, >95 : 5 dr). Additionally, the spiropyrazolone derivatives could be converted into the corresponding novel spriopyrazolines
To find effective antiprioncompounds, we synthesized and evaluated various pyrazolonederivatives. Seven of 19 compounds showed inhibition of PrP-res accumulation and the remarkably active compound 13 showed an IC50 value of 3 nM in both ScN2a and F3 cell lines. Findings from studies on physicochemical and biochemical properties suggest that the action mechanism of these compounds does not correlate
Synthesis of pyranopyrazoles with a chiral quaternary carbon stereocenter <i>via</i> copper-catalyzed enantioselective [3 + 3] cycloaddition
作者:Meihui Wang、Bo Li、Baihui Gong、Hequan Yao、Aijun Lin
DOI:10.1039/d1cc07058d
日期:——
A copper-catalyzed enantioselective [3 + 3] cycloaddition of propargyl carbonates and pyrazolones has been disclosed. This reaction provided an efficient route to synthesize pyranopyrazoles containing a chiral quaternary carbon stereocenter in good yields with good to excellent enantioselectivities. In addition, the hydroxyl group in the products could be conveniently transformed into a variety of
Enantioselective Synthesis of Spirorhodanine-Pyran Derivatives via Organocatalytic [3 + 3] Annulation Reactions between Pyrazolones and Rhodanine-Derived Ketoesters
A series of novel biselectrophilic β,γ-unsaturatedα-ketoesters were designed and synthesized from rhodanine. Under the catalysis of chiral squaramides, the enantioselective [3 + 3] annulation reaction of these novel ketoesters with pyrazolones was developed. This reaction offers an efficient method for the synthesis of chiral 2'-thioxo-5,6-dihydrospiro[pyrano[2,3-c]pyrazole-4,5'-thiazolidin]-4'-ones
An Organocatalytic Asymmetric Friedel–Crafts Addition/Fluorination Sequence: Construction of Oxindole–Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters
作者:Xiaoze Bao、Baomin Wang、Longchen Cui、Guodong Zhu、Yuli He、Jingping Qu、Yuming Song
DOI:10.1021/acs.orglett.5b02470
日期:2015.11.6
A highly efficient and practical one-pot sequential process, consisting of an organocatalytic enantioselective Friedel–Crafts-type addition of 4-nonsubstituted pyrazolones to isatin-derived N-Boc ketimines and a subsequent diastereoselective fluorination of the pyrazolone moiety, is developed. This reaction sequence delivers novel oxindole–pyrazolone adducts featuring vicinal tetrasubstituted stereocenters