6 research outputs found
Ruthenium(II)-Catalyzed Alkene C–H Bond Functionalization on Cinnamic Acids: A Facile Synthesis of Versatile α‑Pyrones
An
inexpensive rutheniumÂ(II) complex enabled oxidative annulation
of alkynes by using cinnamic acid derivatives to provide diversely
decorated multisubstituted α-pyrones
Carbon–Carbon Bond Cleavage Reaction: Synthesis of Multisubstituted Pyrazolo[1,5‑<i>a</i>]pyrimidines
A new
carbon–carbon bond cleavage reaction was developed for the
efficient synthesis of multisubstituted pyrazoloÂ[1,5-<i>a</i>]Âpyrimidines. This base induced reaction of 1,3,5-trisubstituted
pentane-1,5-diones and substituted pyrazoles afforded good yields
of the pyrazoloÂ[1,5-<i>a</i>]Âpyrimidines
Hydroxyl-Directed Ru(II)-Catalyzed Synthesis of Fused Dihydrofurans Using 1,4-Dioxane and Sulfoxonium Ylides as Annulating Agents
An
unprecedented annulation reaction is developed for the synthesis of
dihydrofuran-fused compounds. In this Ru-catalyzed hydroxyl-group-directed
reaction, easily affordable sulfoxonium ylides and 1,4-dioxane were
used as the annulating partners. This is the first example of the
use of 1,4-dioxane as a methylene source to construct a heterocyclic
scaffold. A wide range of dihydrofuran0fused coumarins and naphthalenes
were synthesized using this three-component reaction
Ru(II)-Catalyzed and Ligand-Controlled C–H Activation and Annulation via 1,2-Phenyl Shift: Synthesis of Quaternary Carbon-Centered Pyrimidoindolones
A novel RuÂ(II)-catalyzed C–H
activation and annulation reaction
of <i>N</i>-arylpyrazol-5-ones and diaryl/arylalkyl-substituted
alkynes is developed. Unlike the reported metal-catalyzed C–H
activation and annulation reactions, in the present bidentate amine-ligand
controlled C–H activation and annulation reaction, the annulation
occurs via a 1,2-aryl shift to afford quaternary carbon-centered pyrimidoindolones
Ru(II)-Catalyzed C–H Activation and Annulation Reaction via Carbon–Carbon Triple Bond Cleavage
An
unprecedented RuÂ(II)-catalyzed C–H activation and annulation
reaction, which proceeds via C–C triple bond cleavage, is reported.
This reaction of 2-phenylÂdihydroÂphthalazineÂdiones
with alkynes, which works most efficiently in the presence of bidented
ligand 1,3-bisÂ(diphenylphosphino)Âpropane, affords good yields of substituted
quinazolines
Novel Bivalent Ligands for D2/D3 Dopamine Receptors: Significant Cooperative Gain in D2 Affinity and Potency
This report describes development of a series of novel
bivalent
molecules with a pharmacophore derived from the D2/D3 agonist 5-OH-DPAT.
The spacer length in the bivalent compounds had a pronounced influence
on affinity for D2 receptors. A 23-fold increase of D2 affinity was
observed at a spacer length of 9 or 10 (compounds <b>11d</b> and <b>14b</b>) as compared to monovalent 5-OH-DPAT (<i>K</i><sub>i</sub>; 2.5 and 2.0 vs 59 nM for <b>11d</b> and <b>14b</b> vs 5-OH-DPAT, respectively). The functional
potency of <b>11d</b> and <b>14b</b> indicated a 24- and
94-fold increase in potency at the D2 receptor as compared to 5-OH-DPAT
(EC<sub>50</sub>; 1.7 and 0.44 vs 41 nM for <b>11d</b> and <b>14b</b> vs 5-OH-DPAT, respectively). These are the most potent
bivalent agonists for the D2 receptor known to date. This synergism
is consonant with cooperative interaction at the two orthosteric binding
sites in the homodimeric receptor