127107-29-3Relevant academic research and scientific papers
Regiocontrolled synthesis of 3- and 5-aminopyrazoles, pyrazolo[3,4-d] pyrimidines, pyrazolo[3,4-b]pyridines and pyrazolo[3,4-b]quinolinones as MAPK inhibitors
Bagley, Mark C.,Baashen, Mohammed,Paddock, Victoria L.,Kipling, David,Davis, Terence
, p. 8429 - 8438 (2013/09/02)
Microwave irradiation of a hydrazine and 3-methoxyacrylonitrile, ethoxymethylenemalononitrile or ethyl acetoacetate provides rapid access to 3- or 5-substituted pyrazoles in excellent yield and with total regiocontrol in a process that can be switched from one regioisomer to the other by choice of conditions. Subsequent reaction, either by microwave-assisted hydrolysis and cyclocondensation with formamide, Hantzsch-type three-component reaction with an aldehyde and ketone, or by cyclocondensation with 2-nitrobenzaldehyde, provides the pyrazolo[3,4-d]pyrimidine, pyrazolo[3,4-b]pyridine or pyrazolo[3,4-b] quinolin-4-one framework, respectively, of inhibitors of mitogen-activated protein kinases.
U.V. and 15N N.M.R. Integrated Study of the Protonation of Aminoazoles
Garrone, Adele,Fruttero, Roberta,Tironi, Carla,Gasco, Alberto
, p. 1941 - 1946 (2007/10/02)
The behaviour on protonation of a series of 3-, 4-, and 5-aminoisoxazoles has been studied by 15N n.m.r. spectroscopy.The results confirm that the first protonation site in the 3- and 5-amino derivatives is located at the endocyclic nitrogen atom, while in 4-amino derivatives it is at the exocyclic nitrogen.In addition, the protonation of 3-, 4-, and 5-amino substituted 1-methyl- and 1-phenyl-pyrazoles has been investigated by an integrated u.v. and 15N n.m.r. approach.The first protonation site in the 5-amino derivatives is the pyridine-like endocyclic nitrogen, while in the 4-amino derivatives it is the exocyclic nitrogen.The 3-amino series behaves exceptionally because a tautomeric equilibrium is possible between the endocyclic and exocyclic monocations.In sulphuric acid the position of this equilibrium is dependent on H2SO4 concentration.Diprotonation of these derivatives in concentrated sulphuric acid solutions has also been studied.
