404337-42-4Relevant academic research and scientific papers
Conformationally constrained analogues of N-(piperidinyl)-5-(4- chlorophenyl)-1-(2,4- dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR141716): Design, synthesis, computational analysis, and biological evaluations
Zhang, Yanan,Burgess, Jason P.,Brackeen, Marcus,Gilliam, Anne,Mascarella, S. Wayne,Page, Kevin,Seltzman, Herbert H.,Thomas, Brian F.
experimental part, p. 3526 - 3539 (2009/04/07)
Structure-activity relationships (SARs) of 1 (SR141716) have been extensively documented, however, the conformational properties of this class have received less attention. In an attempt to better understand ligand conformations optimal for receptor recognition, we have designed and synthesized a number of derivatives of 1, including a four-carbon-bridged molecule (11), to constrain rotation of the diaryl rings. Computational analysis of 11 indicates a ~20 kcal/mol energy barrier for rotation of the two aryl rings. NMR studies have determined the energy barrier to be ~18 kcal/mol and suggested atropisomers could exist. Receptor binding and functional studies with these compounds displayed reduced affinity and potency when compared to 1. This indicates that our structural modifications either constrain the ring systems in a suboptimal orientation for receptor interaction or the introduction of steric bulk leads to disfavored steric interactions with the receptor, and/or the relatively modest alterations in the molecular electrostatic potentials results in disfavored Coulombic interactions.
Spectroscopic and product studies of the effect of para substituents on the reactivity of triplet bis(2,6-dimethylphenyl)carbenes
Hu, Yingmo,Ishikawa, Yui,Hirai, Katsuyuki,Tomioka, Hideo
, p. 2207 - 2218 (2007/10/03)
A series of diazobis(2,6-dimethylphenyl)methanes (1) bearing eight symmetrical para di-substituents have been prepared and photolyzed to generate the corresponding carbenes (2). Product analysis studies showed that carbenes (2) decay mainly either by dimerization to form tetra(aryl)ethylene (3) or by attack at an o-methyl group to afford 1,2-dihydrobenzocyclobutenes (4) by way of o-quinodimethanes (6) in solution. The zero-field splitting parameters, D and E, were measured in matrices of different viscosities and are analyzed in terms of a sigma-dot (σ.) scale of spin-delocalization substituent constants. Fairly good correlation with σ. was found for the D values of 32 in its minimum energy geometry. Stabilities of 32 were estimated either by measuring the temperature at which the triplet carbene signals disappeared upon thawing the matrix or by analyzing the decay kinetics of 32 in a degassed solution at room temperature. They are examined in terms of the D values in matrix at low temperature and in terms of product distributions in solution at room temperature.
