23147-77-5Relevant academic research and scientific papers
Synthesis of 3- and 5-formyl-4-phenyl-1H-pyrazoles: Promising head units for the generation of asymmetric imine ligands and mixed metal polynuclear complexes
Olguin, Juan,Brooker, Sally
scheme or table, p. 1242 - 1253 (2011/08/03)
Two synthetic methodologies are reported for the generation of 4-phenyl-1H-pyrazoles substituted at the 3- and/or 5-positions. Functionalisation of the 4-position of dimethyl-4-iodo-1-(tetrahydropyran-2-yl)- 3,5-pyrazolecarboxylate (10) to produce dimethyl-4-phenyl-1-(tetrahydropyran-2- yl)-3,5-pyrazolecarboxylate (14) was achieved by a C-C Suzuki-Miyaura cross coupling reaction in water. However, low yields for this reaction led us to develop a second methodology wherein functionalisation of N-(tetrahydropyran-2- yl)-4-phenylpyrazole (18), synthesised from inexpensive phenylacetic acid, with formyl or hydroxymethyl groups was achieved by lithiation methods. The resulting monoaldehydes, 4-phenyl-5-pyrazole carbaldehyde (20) and 5-formyl-3-(2′- tetrahydropyranyloxymethyl)-4-phenyl-1-(tetrahydropyran-2-yl)pyrazole (28), should facilitate access to new, asymmetric, imine ligands based on a 4-phenyl-1H-pyrazole moiety. This was proven by the successful synthesis of the heterometallic tetranuclear complex [FeII(NiIIL 2)3](BF4)2·solvents. Likewise, the alcohol isolated en route to 28, N-(tetrahydropyran-2-yl)-5- (hydroxymethyl)-4-phenylpyrazole (24), should facilitate access to new, asymmetric, amine ligands.
Amidination of amines under microwave conditions using recyclable polymer-bound 1H-pyrazole-1-carboxamidine
Solodenko, Wladimir,Broeker, Patrick,Messinger, Josef,Schoen, Uwe,Kirschning, Andreas
, p. 461 - 466 (2007/10/03)
A convenient one-step transformation of primary and secondary amines into the corresponding unprotected guanidines using 4-benzyl-3,5-dimethyl-1H- pyrazole-1-carboxamidine and its polymer-bound variant is described. The scopes and limitations of the method, the microwave-assistance of amidination as well as a recycling protocol are examined. Georg Thieme Verlag Stuttgart.
Syntheses of 4-Benzyl-3,5-dimethylpyrazolylborato Complexes of Molybdenum and Tungsten Nitrosyls: Molecular Structure of >, a Complex with an 'Inverted' Bowl-like Structure
Jeffery, John C.,Kurek, Stefan S.,McCleverty, Jon A.,Psillakis, Elefteria,Richardson, Rob M.,et al.
, p. 2559 - 2564 (2007/10/02)
Reaction of (1-), obtained by reaction of 4-benzyl-3,5-dimethylpyrazole (Hbdmpz) with KBH4, with (M = Mo or W) and p-MeC6H4SO2N(NO)Me afforded >.The molybdenum carbonyl was converted into X(Y)
Studies on Paraionic Compounds. Anhydro-1-hydroxy-3-oxopyrazolopyrazolium Hydroxides. Formation and Stability of a Novel Series of 4n? Heterocyclic Betaines.
Zvilichovsky, Gury,David, Mordechai
, p. 295 - 300 (2007/10/02)
Different substituted anhydro-1-hydroxy-3-oxopyrazolopyrazolium hydroxides were prepared by the reaction of 1,3-dicarbonyl compounds with derivatives of 4-phenyl-3,5-dihydroxypyrazole.These diazapentalene derivatives belong to new series of 4n? cyclic betaines which are named "paraionic" heterocycles.The effects of substituents on the stability of both the anionic and the cationic rings were kinetically studied.Selective cleavage of either the anionic or the cationic ring was achieved by varying the conditions of the reaction with morpholine.Electron releasing groups on the cationic ring and electron attracting groups on the anionic ring enhance the stability of the bicyclic system.They also cause a hypsochromic shift of the visible light absorption.
MIGRATION TENDENCIES OF FUNCTIONAL GROUPS TOWARD SIGMATROPIC REARRANGEMENT IN 3,3-DISUBSTITUTED 3H-PYRAZOLES
Schiess, Peter,Stalder, Henri
, p. 1417 - 1420 (2007/10/02)
3,3-Disubstituted 3H-pyrazoles la - e aromatise through an intramolecular sigmatropic 1,5-(1,2-)shift of one of the quaternary groups.From a kinetic study of the uncatalysed and of the acid catalysed isomerisation reaction migration tendencies of functional groups in sigmatropic rearrangement toward neutral and toward cationic centers are obtained.
