39190-03-9Relevant academic research and scientific papers
Orthoamides, LXV [1]. Condensation reactions of amidines, guanidines, hydrazine and hydrazine derivatives with orthoamides of alkyne carboxylic acids
Kantlehner, Willi,Mezger, Jochen,Stieglitz, Rüdiger,Edelmann, Kai,Lehmann, Hansj?rg,Vettel, Markus,Kre?, Ralf,Frey, Wolfgang,Ladendorf, Sebastian
, p. 1015 - 1029 (2008/10/09)
The orthoamide derivatives 4 react with amidines 10 and guanidines 11 to give 4-dimethylaminopyrimidines 12. The 3-dimethylamino-pyrazoles 13a - c can be prepared from orthoamides 4 and hydrazine. The hydrazine derivative 14, whose constitution was established by crystal structure analysis, is obtained in low yield when hydrazine is added dropwise to a boiling solution of 4d in THF. Methyl- and Phenylhydrazine, undergo reaction with the orthoamides 4a, c yielding mixtures of the isomeric pyrazoles 19 and 20. The reaction of 4c with acylhydrazines 21a - e affords the pyrazole 13b. The pyrazole 26 is produced in the reaction of 4a and acet-hydrazide according to this scheme, whereas 4a reacts with aromatic acid hydrazides 21c - e to give condensation products, which are presumably amidrazones 28. The 4,5-diaza-octatetraene derivative 30 results from the reaction of 4c with p-toluenesulfonylhydrazide. Ketene aminals 34a-c are the products of the reaction of the orthoamides 4b - d with 4,4-dimethylthiosemicarbazide 34, which cyclize on heating to give high-melting pyrazolethiones 35a - c. According to the crystal structure analysis of 35c the compounds have zwitterionic character and are associated via hydrogen bridges in the solid state.
