20 research outputs found
2,6-Diisopropylanilinium chloride
The title compound, C12H20N+·Cl−, crystallizes with the chloride anions situated on twofold axes, while the cation is on a general position. All conventional hydrogen-bond donors and acceptors are utilized, forming a hydrogen-bonded ladder motif along the c axis. Investigation of the torsion angles between aromatic systems and isopropyl groups reveals unusual geometrical features. One isopropyl groups exhibits an expected eclipsed conformation with respect to the aromatic ring. The other isopropyl group shows a slight twist with respect to the aromatic ring. The short Cl...HC(methine) contact (2.88 Å) observed in the asymmetric unit is the probable reason for the twist feature around the isopropyl area
2-[4-Chloro-3-(4-ethoxybenzyl)phenyl]-1,3-dithiane
In the title compound, C19H21ClOS2, the dithiane ring adopts a chair conformation. The dihedral angle between the benzene rings is 87.88 (4)°. In the crystal, inversion dimmers linked by pairs of C—H...O interactions occur
Substituent Effects on the Amination of Racemic Allyl Carbonates Using Commercially Available Chiral Rhodium Catalysts
Long Directional Interactions (LDIs) in Oligomeric Cofacial Silicon Phthalocyanines and Other Oligomeric and Polymeric Cofacial Phthalocyanines
Crystal structures have been determined for the three-member
set of cofacial silicon phthalocyanines, ((<i>n</i>-C<sub>6</sub>H<sub>13</sub>)<sub>3</sub>SiO)[SiPcO]<sub>1–3</sub>(Si(<i>n</i>-C<sub>6</sub>H<sub>13</sub>)<sub>3</sub>).
The staggering angles between adjacent rings in the dimer and trimer
of this set are ∼16°. The interactions leading to these
angles have been investigated by the atoms-in-molecules (AIM) and
reduced-density-gradient (RDG) methods. The results show that long
directional interactions (LDIs) are responsible for these angles.
A survey of the staggering angles in various cofacial phthalocyanines
described in the literature has revealed the existence of significant
LDIs in a number of them. It is apparent that in many cases the ability
of LDIs to dominate the forces giving rise to the staggering angles
observed in cofacial phthalocyanines depends on their inter-ring separations
Two Routes to 4‑Fluorobenzisoxazol-3-one in the Synthesis of a 5‑HT<sub>4</sub> Partial Agonist
A potent 5-HT<sub>4</sub> partial agonist, <b>1</b> (PF-04995274),
targeted for the treatment of Alzheimer’s disease and cognitive
impairment, has been prepared on a multi-kilogram scale. The initial
synthetic route, that proceeded through a 4-substituted 3-hydroxybenzisoxazole
core, gave an undesired benzoxazolinone through a Lossen-type rearrangement.
Route scouting led to two new robust routes to the desired 4-substituted
core. Process development led to the efficient assembly of the API
on a pilot plant scale under process-friendly conditions with enhanced
throughput. In addition, crystallization of a hemicitrate salt of
the API with pharmaceutically beneficial properties was developed
to enable progression of clinical studies
Long Directional Interactions (LDIs) in Oligomeric Cofacial Silicon Phthalocyanines and Other Oligomeric and Polymeric Cofacial Phthalocyanines
Crystal structures have been determined for the three-member
set of cofacial silicon phthalocyanines, ((<i>n</i>-C<sub>6</sub>H<sub>13</sub>)<sub>3</sub>SiO)[SiPcO]<sub>1–3</sub>(Si(<i>n</i>-C<sub>6</sub>H<sub>13</sub>)<sub>3</sub>).
The staggering angles between adjacent rings in the dimer and trimer
of this set are ∼16°. The interactions leading to these
angles have been investigated by the atoms-in-molecules (AIM) and
reduced-density-gradient (RDG) methods. The results show that long
directional interactions (LDIs) are responsible for these angles.
A survey of the staggering angles in various cofacial phthalocyanines
described in the literature has revealed the existence of significant
LDIs in a number of them. It is apparent that in many cases the ability
of LDIs to dominate the forces giving rise to the staggering angles
observed in cofacial phthalocyanines depends on their inter-ring separations
Long, Directional Interactions in Cofacial Silicon Phthalocyanine Oligomers
Single crystal structures have been determined for the three cofacial, oxygen-bridged, silicon phthalocyanine oligomers, [((CH<sub>3</sub>)<sub>3</sub>SiO)<sub>2</sub>(CH<sub>3</sub>)SiO](SiPcO)<sub>2–4</sub>[Si(CH<sub>3</sub>)(OSi(CH<sub>3</sub>)<sub>3</sub>)<sub>2</sub>], and for the corresponding monomer. The data for the oligomers give structural parameters for a matching set of three cofacial, oxygen-bridged silicon phthalocyanine oligomers for the first time. The staggering angles between the six adjacent cofacial ring pairs in the three oligomers are not in a random distribution nor in a cluster at the intuitively expected angle of 45° but rather are in two clusters, one at an angle of 15° and the other at an angle of 41°. These two clusters lead to the conclusion that long, directional interactions (LDI) exist between the adjacent ring pairs. An understanding of these interactions is provided by atoms-in-molecules (AIM) and reduced-density-gradient (RDG) studies. A survey of the staggering angles in other single-atom-bridged, cofacial phthalocyanine oligomers provides further evidence for the existence of LDI between cofacial phthalocyanine ring pairs in single-atom-bridged phthalocyanine oligomers