Polysubstituted 3-trifluoromethylpyrazoles: regioselective (3+2)- cycloaddition of trifluoroacetonitrile imines with enol ethers and functional group transformations

被引：42

作者：

Utecht, Greta ^{[1
]}

Fruzinski, Andrzej ^{[2
]}

Jasinski, Marcin ^{[1
]}

机构：

[1] Univ Lodz, Fac Chem, Tamka 12, PL-91403 Lodz, Poland

[2] Lodz Univ Technol, Inst Gen & Ecol Chem, Zeromskiego 116, PL-90924 Lodz, Poland

来源：

ORGANIC & BIOMOLECULAR CHEMISTRY | 2018年 / 16卷 / 08期

关键词：

FLUORINATED NITRILE IMINES; CATALYZED DIRECT ARYLATION; BIOLOGICAL EVALUATION; SOLVENT; INHIBITORS; PYRAZOLES; ACCESS; ROUTE; CYCLOCONDENSATION; HETEROCYCLES;

D O I：

10.1039/c7ob03126b

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Non-catalysed addition of trifluoroacetonitrile imines to enol ethers provided fully regioselectively (3 + 2)-cycloadducts, which either spontaneously or via Bronsted acid-induced elimination of ROH molecules led to the formation of 3-trifluoromethylated pyrazoles. In the case of 2,3-dihydrofuran, the respective bicyclic intermediate was isolated and its structure was confirmed by X-ray analysis. Using the developed protocol the synthesis of a known antitumor compound SC-560 was performed in 45% yield. Subsequent functionalisations of selected 4-(omega-hydroxyalkyl) pyrazoles at C(5) through lithiation/addition, cross-coupling reactions or via intramolecular Pd-catalysed C-H arylations opened up an access to polysubstituted pyrazoles including unusual tricyclic systems comprising 7-membered rings (oxepane, thiepane and azepane) as the central unit.

引用

页码：1252 / 1257

页数：6

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