An efficient and general strategy for the synthesis of 4-phosphorylated pyrazoles from beta-hydrazono phosphine oxides.

被引:44
作者
Palacios, F
Aparicio, D
delosSantos, JM
机构
[1] Depto. de Quim. Orgánica, Facultad de Farmacia, Universidad del País Vasco, 01080 Vitoria
关键词
D O I
10.1016/S0040-4020(96)00073-7
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
A simple and efficient synthesis of aminopyrazoles substituted with a phosphino oxide and sulphide groups in the 4-position 1 is described. The key step is a regioselective addition of lithiated beta-hydrazonophosphine oxides 2 to isocyanates and isothiocyanates to give functionalized amides 3 and 7. Subsequent cyclization of 3 with phosphorus oxychloride in the presence of triethylamine afforded pyrazoles derived from phosphine oxides 1 and phosphine sulphides 8. Substituted heterocycles 1 can also be obtained in ''one pot'' reaction from phosphine oxides 2 when these compounds are metallated followed by addition of isocyanates and phosphorus oxychloride.
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页码:4123 / 4132
页数:10
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