One-pot synthesis of pyrazole-5-carboxylates by cyclization of hydrazone 1,4-dianions with diethyl oxalate
作者:Tuan Thanh Dang、Tung Thanh Dang、Peter Langer
DOI:10.1016/j.tetlet.2007.03.093
日期:2007.5
The cyclization of hydrazone dianions with diethyl oxalate afforded pyrazole-5-carboxylates.
用草酸二乙酯对的二价阴离子进行环化,得到吡唑-5-羧酸酯。
Synthesis of pyrazole-3-carboxylates and pyrazole-1,5-dicarboxylates by one-pot cyclization of hydrazone dianions with diethyl oxalate
作者:Tung T. Dang、Tuan T. Dang、Christine Fischer、Helmar Görls、Peter Langer
DOI:10.1016/j.tet.2007.12.024
日期:2008.2
The one-pot cyclization of hydrazone dianions with diethyl oxalate allows a convenient synthesis of pyrazole-3-carboxylates and pyrazole-1,5-dicarboxylates.
与草酸二乙酯的一锅法二价环化反应可以方便地合成吡唑-3-羧酸盐和吡唑-1,5-二羧酸盐。
Novel 1,2,3-thiadiazolyl sulfines from the reaction of N-substituted hydrazones with thionyl chloride
作者:Thomas C. Britton、Thomas J. Lobl、Constance G. Chidester
DOI:10.1021/jo00199a006
日期:1984.12
Synthesis of 1,2,4-triazolium salts: Reaction of 1-azo-2-azonia-allene salts with nitriles
作者:A. M. Amer
DOI:10.1007/bf00813205
日期:1995.4
Alkyl ketone hydrazones 1 are oxidized with tert-butylhypochlorite to give geminal chloro azo compounds 2. These react with SbCl5, to give 1-aza-2-azonia-allene salts 3 as reactive intermediates which are intercepted with nitriles to yield 3H-1,2,4-triazolium salts 5. In most cases these salts rearrange spontaneously to form 1H-triazolium salts 6. Hydrolysis of 6e-g by NaOH provide bases 7a-c, which react with picric acid to give 1H-pyrazolium picrates 8.
One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4<i>H</i>-1,2-oxazines and Oxazolo[3,4-<i>b</i>]pyridazin-7-ones
[GRAPHICS]The one-pot cyclization of dilithiated oximes with epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.