Search results for "Isomerism"

Conformational Isomerism: Influence of the Z / E Isomerism on the Pathway Complexity of a Squaramide‐Based Macrocycle (Small 7/2021)

2021

The internal rotational barrier of biphenyl studied with multiconfigurational second-order perturbation theory (CASPT2)

1995

A detailedab initio study of the molecular structure and rotational barriers of biphenyl has been performed. First, non-dynamical correlation effects involving the π system are taken into account at the CASSCF level. These wave functions are subsequently employed as reference functions in a multiconfigurational second-order perturbation treatment (CASPT2). The performance single-reference approaches is in addition analysed. The molecular geometries of biphenyl in twisted, coplanar, and perpendicular conformations have been optimized at the CASSCF level. A rotational angle of 44.3° is predicted for the minimum energy conformer in agreement with gas-phase electron diffraction data (44.4±1.2°)…

Magnetoelectrochemistry of 4,4′-bis(dimethylamino)biphenyl and 4,4′-dinitrobiphenyl azacrown macrocyclic lactams

2005

Abstract The voltammetric behaviour at carbon fibre microelectrodes under the application of static magnetic fields of two series of macrolactams containing in their structure 4,4′-bis(dimethylamino)biphenyl or 4,4′-dinitrobiphenyl groups in MeCN solution is described. The response of 4,4′-dinitrobiphenyl receptors is dominated by two successive one-electron reduction processes at −0.9 and −1.6 V versus AgCl/Ag. 4,4′-bis(dimethylamino)biphenyl-containing receptors display two one-electron oxidations above +0.8 and +1.0 V. In both cases, a dihedral/planar interconversion precedes the second electron transfer step. Upon application of moderate (0.05–0.2 T) static magnetic fields to the electr…

Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Bisoprolol Fumarate

2014

Abstract Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate-release (IR) solid oral dosage forms containing bisoprolol as the sole active pharmaceutical ingredient (API) are reviewed. Bisoprolol is classified as a Class I API according to the current Biopharmaceutics Classification System (BCS). In addition to the BCS class, its therapeutic index, pharmacokinetic properties, data related to the possibility of excipient interactions, and reported BE/bioavailability problems are taken into consideration. Qualitative compositions of IR tablet dosage forms of bisoprolol with a marketing authorization (MA) in ICH (Inter…

Incorporation and metabolism of dietary trans isomers of linolenic acid alter the fatty acid profile of rat tissues

2000

To study the influence on lipid metabolism and platelet aggregation of the fatty acid isomerization that occurs during heat treatment, weanling rats were fed for 8 wk a diet enriched with 5% isomerized (experimental group) or normal (control group) canola oil. Geometrical isomers of alpha-linolenic acid representing 0.2 g/100 g of the experimental diet were incorporated into liver, platelets, aorta and heart, at the expense of their cis homologue and of 18:2(n-6). The major isomer, 9c,12c,15t-18:3, was also metabolized to 5c,8c,11c,14c,17t-20:5 and to an unknown compound, found in liver, platelets and aorta, which has been identified tentatively as 7c, 10c,13c,16c,19t-22:5. The greater 20:4…

Griffonianone D, an isoflavone with anti-inflammatory activity from the root bark of Millettia griffoniana.

2003

A new isoflavone, griffonianone D (1), and the previously known compounds durmillone and odorantin were isolated from a chloroform extract of the root bark of Millettia griffoniana. The structure of 1 was established as (7E)-(6",7"-dihydroxy-3",7"-dimethyloct-2"-enyl)oxy-4'-methoxyisoflavone on the basis of its spectral data. The chloroform extract of the root bark of M. griffoniana and compound 1 showed anti-inflammatory effects in different experimental models of inflammation.

Haemopoietic effects of 7 alpha, 17 beta dimethyltestosterone.

1979

Some haematic parameters were investigated in female COBS mice treated with 7 alpha, 17 beta Dimethyltestcsterone (DMT). The drug causes an increase of circulating platelets in normal mice. Bone marrow graft from DMT-treated donors facilitates in irradiated mice repopulation of white blood cells and platelets but lowers % survival. These data are interpreted on the basis of a commitment and a loss of self-maintenance induced by DMT on CFUs compartment. © 1979 The Italian Pharmacological Society.

Diisopropyl [(2-hydroxy-1-naphthyl)methyl]phosphonate

2003

The bond lengths and angles in the title compound, C17H23PO4, are in accordance with anticipated values. There are two conformers in the asymmetric unit. They differ from each other in the orientation of the C and P tetrahedra. Analysis of the structure does not reveal any significant differences between the bond distances and angles of the mol­ecules in the asymmetric unit. In the crystal structure, the conformers are linked by O—H⋯O=P and C—H⋯O hydrogen bonds.

The influence of fluorine position on the properties of fluorobenzoxaboroles

2015

5-Fluoro-2,1-benzoxaborol-1(3H)-ol, a potent antifungal drug also known as Tavaborole or AN2690, has been compared with its three isomers in terms of its activity against several fungi as well as pKa and multinuclear NMR characterization. The molecular and crystal structure of 6-fluoro-2,1-benzoxaborol-1(3H)-ol was determined and compared with that of AN2690.

An Efficient Synthesis of γ-Aminoacids and Attempts to Drive Its Enantioselectivity

2008

Addition of carboxylic acid dianions to bromoacetonitrile lead, in good yields,to the corresponding gamma-cyanoacids, which on hydrogenation yielded gamma-amino acids. This two step methodology improves upon previously described results. Poor e.e's resultedfrom our attempts to drive the enantioselectivity of this transformation by chiral amide induction.