نتایج جستجو برای: chiral non racemic menthol
تعداد نتایج: 1354057 فیلتر نتایج به سال:
This paper describes a chiral Brønsted acid catalyzed asymmetric 1,2-rearrangement of racemic epoxides via a hydrogen-shift process for the synthesis of chiral aldehydes, and, followed by a reduction, a variety of optically active alcohols can be furnished in moderate yields with up to 50% ee. Especially, a facile one-pot synthesis of chiral alcohols directly from simple alkenes by a sequential...
Over the past fifteen to twenty years, the stereochemistry is gaining prime importance in pharmaceutical practice. As a result of advancement in chemical technologies associated with the synthesis, separation, identification and analysis of single enantiomer present in racemic compound, several chiral drugs are presented as single enantiomer for approval to regulatory authorities. Rather to int...
The first total synthesis of the marine prostanoids clavulolactones II and III is presented from an easily accessible chiral, non-racemic cyclopentenone intermediate. Key steps involve selective TBDMS deprotection, selective reduction of the β-side chain and aldol condensation. Clavulolactones II and III were successfully prepared from (S)-4-((tert-butyldimethylsilyl)oxy) cyclopent-2-en-1-one o...
Phase Transfer Catalysis (PTC) is a powerful tool to perform reactions in practical fashion, both laboratory and industrial scale. Significant cost savings major process improvements can be achieved performed under PTC conditions. In the last few years remarkable results stereoselective were using chiral, non-racemic quaternary ammonium salts. Moreover, use of bulky, chiral phosphate anions pai...
The reaction of chiral chlorido-iridacyclic 2-(4-N,N-dimethylaminophenyl)pyridines with solvato-type [Cp*M(S)(3)](q+) (M = Ru, S = MeCN, q = 1; M = Ir, S = MeC(O)Me, q = 2) complexes produces new cationic racemic planar chiral iridacycles in an efficient and diastereospecific way.
Control of the structural type in metallic enantiopure and racemic radical cation salts is achieved through hydrogen bonding interactions between the chiral donor DM-EDT-TTF and the XF6 anions (X = P, As, Sb), determined by the anion size and the chiral information.
Interaction of the racemic helical homo-octapeptide made by the achiral C(α)-methyl alanine (Aib) amino acid with a chiral enantiopure micellar aggregate made of N-dodecylproline led to the deracemization of the helical Aib sequence thus allowing us to obtain for the first time the CD signature in water of a 310 helix devoid of the contribution of any chiral amino acid.
liquiritigenin is a chiral flavonoid present in plant based food, nutraceuticals, and traditional medicines. it is also an important ingredient present in licorice. the purpose of this study is to explore the pharmacological activity of racemic liquiritigenin utilizing several in vitro assays with relevant roles in colon cancer and diabetes. where possible, the pure enantiomers were tested to i...
In this article we investigate the effect of multivalency in chiral recognition. To this end, we measured the host-guest interaction of a β-cyclodextrin dimer with divalent chiral guests. We report the synthesis of carbohydrate-based water soluble chiral guests functionalized with two borneol, menthol, or isopinocampheol units in either (+) or (-) configuration. We determined the interaction of...
Biocatalytic Aromaticity-Breaking Epoxidation of Naphthalene and Nucleophilic Ring-Opening Reactions
Aromatic hydroxylation reactions catalyzed by heme-thiolate enzymes proceed via an epoxide intermediate. These aromatic epoxides could be valuable building blocks for organic synthesis giving access to a range of chiral trans-disubstituted cyclohexadiene synthons. Here, we show that naphthalene generated fungal peroxygenases can subjected nucleophilic ring opening, yielding non-racemic derivate...
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