Earl, Robert A. published the artcileChemical and carbon-13 nuclear magnetic resonance reinvestigation of the N-methyl isomers obtained by direct methylation of 5-amino-3,4-dicyanopyrazole and the synthesis of certain pyrazolo[3,4-d]pyrimidines, SDS of cas: 54385-49-8, the main research area is pyrazole amino dicyano methylation; methylation aminodicyanopyrazole; pyrazolopyrimidine amino methyl.
The structural assignments for the isomeric N-1- and N-2-methyl derivatives of 5-amino-3,4-dicyanopyrazole obtained by direct methylation by C. L. Dickenson et. al (1964) were reinvestigated. The higher melting isomer was annulated to give 4-amino-3-cyano-1-methylpyrazolo[3,4-d]pyrimidine (I, R = CN), which with alkaline peroxide gave I (R = CONH2). Hydrolysis of I (R = CONH2) under more vigorous conditions gave I (R = CO2H), which was decarboxylated in hot sulfolane to give I (R = H). This established the structure of the N-methylpyrazole as 5-amino-3,4-dicyano-1-methylpyrazole and reversed the structural assignment previously reported. A similar reaction sequence converted the lower melting isomer into 4-amino-2-methylpyrazolo[3,4-d]pyrimidine (II) and established the structure as 5-amino-3,4-dicyano-2-methylpyrazole.
Journal of Organic Chemistry published new progress about Methylation. 54385-49-8 belongs to class pyrazoles-derivatives, name is 5-Amino-1H-pyrazole-3,4-dicarbonitrile, and the molecular formula is C5H3N5, SDS of cas: 54385-49-8.
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics