Synthesis of 5-Substituted 1-Hydroxypyrazoles through Directed Lithiation of 1-(Benzyloxy)pyrazole
摘要:
1-Hydroxypyrazoles have been converted to 1-(benzyloxy), [(9-phenylfluorenyl)oxy], [(N,N-diethylcarbamoyl)oxy], and (-silyloxy)pyrazoles. 1-(Benzyloxy)pyrazole was lithiated selectively in the 5-position. Subsequent reaction with electrophiles gives rise to 1-(benzyloxy)pyrazole with carbon, halogen, silicon, sulfur, or tin substituents at the 5-position. 1-(Benzyloxy)pyrazoles could be debenzylated by hydrogen bromide or hydrogenolysis producing 5-substituted 1-hydroxypyrazoles in high overall yield.
Porphyrins with four azole substituents in meso positions. Part 2. X-ray crystal structure of meso-tetrakis {1-[2-(trimethylsilyl)ethoxymethyl]pyrazol-5-yl}-porphyrin at 200 K
作者:Ana Sánchez-Migallón、Antonio de la Hoz、Mikael Begtrup、Cristina Fernández-Castaño、Concepción Foces-Foces、José Elguero
DOI:10.1016/0040-4020(96)00602-3
日期:1996.8
The crystal and molecular structure of meso-tetrakis 1-[2-(trimethylsilyl) ethoxymethyl]pyrazol-5-yl porphyrin 2 has been solved by X-ray analysis. The porphyrin core appears to be distorted from planarity and the conformation of the pyrazole rings is such that pyrazole N2 atoms are situated up, up, down, down with regard to the macrocyclic ring (ααββ atropisomer). A new porphyrin meso-tetrakis[1-
Novel 5-substituted 1-pyrazolol analogues of ibotenic acid: Synthesis and pharmacology at glutamate receptors
作者:Charlotte G. Jørgensen、Hans Bräuner-Osborne、Birgitte Nielsen、Jan Kehler、Rasmus P. Clausen、Povl Krogsgaard-Larsen、Ulf Madsen
DOI:10.1016/j.bmc.2007.02.047
日期:2007.5
5-Substituted 1-pyrazolol analogues of ibotenic acid have been synthesized and pharmacologically characterized on ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs). The syntheses involved introduction of bromide, alkyls, phenyl and arylalkyls in the 5-position of 1-benzyloxypyrazole leading to 5-substituted (RS)-2-amino-(1-hydroxy-4-pyrazolyl)acetic acids (5a-1). The pharmacological activities of the synthesized analogues ranged from the 5-cyclopropylmethyl analogue (5f) with weak but selective affinity for NMDA receptors (IC50 = 35 mu M), over the 5-n-propyl analogue (5c), which was a selective mGluR2 agonist (EC50 = 72 mu M), to the 5-cyclohexylmethyl analogue (5g), which was a selective mGluR2 antagonist (K-i = 32 mu M), and the 5-phenylethyl analogue (5j), which was a weak but apparently selective mGluR1 antagonist (K-i = 230 mu M). This series of compounds afforded GluR ligands with a broad spectrum of pharmacological profiles, and showing potential for development of new compounds with subtype-selective activities at various GluRs. (c) 2007 Elsevier Ltd. All rights reserved.