121909-92-0Relevant academic research and scientific papers
Carbon-13 NMR Chemical Shifts of 1-Alkyl-3(5)-cyano-1H-pyrazole-4-carboxylic Acid Esters
Babbitt, George E.,Lynch, Michael P.,Beck, James R.
, p. 90 - 92 (2007/10/02)
A compilation of 13C NMR chemical shifts for 13 pairs of 3- and 5-cyano-substituted pyrazole regioisomers is reported.All of the ring carbon and cyano carbon 13C chemical shifts show a regular, predictable correlation with the particular isomer, whether 3-cyano or 5-cyano.These shifts occured in very narrow ranges, precluding any confusion of assignment within the group of compounds studied.X-ray crystallographic analysis was performed on one of the samples.
Alkylation Studies with 5-Cyano-1H-pyrazole-4-carboxylic Acid, Ethyl Ester
Beck, James R.,Aikins, James,Lynch, Michael P.,Rizzo, John R.,Tao, Eddie V.P.
, p. 3 - 6 (2007/10/02)
5-Cyano-1H-pyrazole-4-carboxylic acid, ethyl ester (1) was regioselectively alkylated at N-1 by tertiary carbocations utilizing sulfuric acid catalysis and relatively mild conditions.In the presence of boron trifluoride, the alkylation occured regioselectively at N-2.Reaction of 1 with alkyl halides under basic conditions resulted in mixture of the two isomers with alkylation at N-2 predominating.
