Browsing by Subject "pyrazole derivative"
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Article
The conversion of isothiazoles into pyrazoles using hydrazine
(2009)The conversion of isothiazoles into pyrazoles on treatment with hydrazine is investigated. The influence of various C-3, C-4 and C-5 isothiazole substituents and some limitations of this ring transformation are examined. ...
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Article
Reinvestigating the reaction of 1H-pyrazol-5-amines with 4,5-dichloro-1,2,3-dithiazolium chloride: A route to pyrazolo[3,4-c]isothiazoles and pyrazolo[3,4-d]thiazoles
(2014)The reaction of Appel salt 1 with 1H-pyrazol-5-amines 2 gives main products N-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)-1H-pyrazol-5-amines 3, and 6H-pyrazolo[3,4-c]isothiazole-3-carbonitriles 5, together with several minor ...
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Article
Synthesis of fused 1,2,4-dithiazines and 1,2,3,5-trithiazepines
(2014)Reacting ( Z)-N-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)-1H-pyrazol-5-amines 5 with Et2NH and then with concd H2SO4 gives 5H-pyrazolo[3,4-e ][1,2,4]dithiazine-3-carbonitriles 7 in good yields (74-85%) and 6H-pyrazolo-[3,4 ...