نتایج جستجو برای: chiral non racemic menthol
تعداد نتایج: 1354057 فیلتر نتایج به سال:
About more than half of the drugs currently in use are chiral compounds and near 90% of the last ones are marketed as racemates consisting of an equimolar mixture of two enantiomers. Although they have the same chemical structure, most isomers of chiral drugs exhibit marked differences in biological activities such as pharmacology, toxicology, pharmacokinetics, metabolism etc. Some mechanisms o...
Enantiocontrol over Acyclic Quaternary Stereocenters by Acylative Organocatalyzed Kinetic Resolution
In the present paper, we described efficient enantioselective kinetic resolution (KR) of racemic diastereocontrolled secondary alcohols bearing a quaternary stereocenter using commercially available chiral isothiourea organocatalyst. This methodology is general KR leading to enantiocontrol acyclic with high levels stereoselectivity (s up 185) on large scope. The hydroxyl function can easily ser...
Dynamic atroposelective resolution of chiral salts derived from oily racemic nicotinamides and enantiopure dibenzoyltartaric acid (DBTA) was achieved by crystallization. The absolute structures of the axial chiral nicotinamides were determined by X-ray structural analysis. The chirality could be controlled by the selection of enantiopure DBTA as a chiral auxiliary. The axial chirality generated...
This article introduces the concept of chiral ion mobility spectrometry (CIMS) and presents examples demonstrating the gas-phase separation of enantiomers of a wide range of racemates including pharmaceuticals, amino acids, and carbohydrates. CIMS is similar to traditional ion mobility spectrometry, where gas-phase ions, when subjected to a potential gradient, are separated at atmospheric press...
Ligand exchange reactions on size-selected Au(38)(2-PET)(24) and Au(40)(2-PET)(24) clusters (2-PET: 2-phenylethylthiol) with mono- and bi-dentate chiral thiols were performed. The reactions were monitored with MALDI mass spectrometry and the arising chiroptical properties were compared to the number of incorporated chiral ligands. Only a small fraction of chiral ligands is needed to induce sign...
OBJECTIVES To determine what the tobacco industry knew about menthol cigarettes and the initiation of smoking. METHODS Based on Food and Drug Administration staff-supplied research questions we used a snowball sampling strategy to search the Legacy Tobacco Documents Library (http://legacy.library.ucsf.edu) between February and April 2010. Of the approximately 11 million documents available in...
Exposure to low temperatures often causes allergic responses or urticaria. Similarly, menthol, a common food additive is also known to cause urticaria, asthma, and rhinitis. However, despite the obvious clinical implications, the molecular mechanisms responsible for inducing allergic responses to low temperatures and menthol have not been determined. Because a non-selective cation channel, tran...
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