Thermal Rearrangements of 3H- and 4H-Pyrazoles Prepared by Reactions of 9-Diazofluoren with Methyl Tetrolate and Methyl 3-Phenylpropiolate
作者:V. A. Vasin、Yu. A. Popkova、Ye. V. Bezrukova、V. V. Razin、N. V. Somov
DOI:10.1134/s1070428018080122
日期:2018.8
methanol, into 3-methyl-2H-dibenzo[e,g]indazole. Auwers adduct of methyl 3-phenylpropiolate at boiling in benzene gives cyclopropenederivative and at boiling in methanol isomerizes into methyl 3a-phenyl-3aHdibenzo[e,g]indazole-3-carboxylate. Anti-Auwers adduct at boiling in benzene isomerizes into methyl 2-phenylpyrazolo[1,5-f]phenanthridine-3-carboxylate.
One-Pot Synthesis of Pyrazoles through a Four-Step Cascade Sequence
作者:Lu Hao、Jun-Jie Hong、Jun Zhu、Zhuang-Ping Zhan
DOI:10.1002/chem.201204322
日期:2013.4.26
A one‐potsynthesis of 3,4,5‐ and 1,3,5‐pyrazoles from tertiary propargylic alcohols and para‐tolylsulfonohydrazide has been accomplished. The pyrazoles are formed through a four‐step cascade sequence, including FeCl3‐catalyzed propargylic substitution, aza‐Meyer–Schuster rearrangement, base‐mediated 6π electrocyclization, and thermal [1,5] sigmatropic shift. In this reaction, the 3,4,5‐ and 1,3,5‐pyrazoles