Straightforward and regiospecific synthesis of pyrazole-5-carboxylates from unsymmetrical enamino diketones.

[摘要]：A series of 4-substituted 1H-pyrazole-5-carboxylates was prepd. from the cyclocondensation of unsym. enamino diketones RC(O)C(:CNMe2)C(O)CO2Et (R = Ph, 4-MeOC6H4, 4-ClC6H4, 4-FC6H4, 4-O2NC6H4, 2-thienyl, 2-benzofuryl, CCl3, CF3) with Me3CN2H3.HCl or MeO2CN2H3. The compds. were obtained regiospecifically and in good to excellent yields (73-94%). In addn., 1-tert-butyl-1H-pyrazole-4,5-dicarboxylate was synthesized from regiospecific conversion of 4-(2,2,2-trichloroacetyl)-1-tert-butyl-1H-pyrazole-5-carboxylate. The carbonyl substitution was regiospecific for the trichloroacetyl group and did not affect the ester group.

[全文传递流程]：

一般上传文献全文的时限在1个工作日内