Benzhydryl Ethers of Tartaric Acid Derivatives: Stereochemical Response of a Dynamically Chiral Propeller

Abstract

The benzhydryl (diphenylmethyl) group is a molecular propeller that can act as a chirality reporter if it is introduced nearby a stereogenic center by making an ether bond. The hydrophobic character of the benzhydryl group allows transformation of insoluble natural tartaric acid derivatives into soluble entities in a nonpolar environment. Electronic circular dichroism spectra, recorded within the short-wavelength region of the phenyl B transitions (190-200 nm) shows strong bisignate Cotton effects. The signs and magnitudes of these Cotton effects are a function of absolute configuration and conformation of the molecule and do not primarily arise from exciton coupling of chiral benzhydryl chromophores. In crystals, the main-chain conformation is stabilized by intramolecular hydrogen bonds and CH-CO dipolar interactions. The number of the donor NH groups has a pronounced effect on the preferred conformations and inclusion properties of benzhydryl-(R,R)-tartaric acid diamides. Evidence is shown for the solvent dependency of the conformations of NH amides of tartaric acid diphenylmethyl ethers.

Influence of d-Electron Divalent Metal Ions in Complex Formation with L-Tartaric and L-Malic Acids

“…Malic acid has one hydroxyl group, while tartaric acid has two hydroxyl groups. ( R , R )-tartaric acid and its derivatives are useful in organic pharmaceutical chemistry for drug preparation (granules, effervescent, and others) and as an acidity regulator or stabilizing substance [ 19 , 20 , 21 , 22 , 23 ]. The antioxidant properties and coordination ability of malic acid are also used in medicine and pharmacology [ 24 ].…”

“…The antioxidant properties and coordination ability of malic acid are also used in medicine and pharmacology [ 24 ]. Optical properties naturally occur in tartaric and malic acids, their salts and derivatives play an important role in pharmaceutical and organic chemistry [ 25 ] not only due to their historical significance [ 26 ] but also to their present applications, [ 19 , 20 , 21 , 22 , 23 , 27 ]. Knowing conformational preferences [ 23 , 28 , 29 , 30 ] of these chiral ligands can support and broaden the knowledge of the role of their behavior in biological and chemical systems both in crystals [ 31 ] and in solutions [ 32 ].…”

Thermodynamic and Spectroscopic Studies of the Complexes Formed in Tartaric Acid and Lanthanide(III) Ions Binary Systems

“…The conformational preferences of tartaric acid [19,20] are essential for understanding the role of its properties in biological and chemical systems [21,22]. Only (R,R)-tartaric acid, its salts, and derivatives play an important role in pharmaceutical organic chemistry [23][24][25][26][27]. These different forms of (R,R) and (S,S) tartaric acid affect the differences in the coordination ability of the ligand [28].…”

Optical Activity and Helicity Enhancement of Highly Sensitive Dinaphthylmethane-Based Stereodynamic Probes for Secondary Alcohols

“…Recently, it has been shown that disturbing the local symmetry of triphenylmethane led to a generation of characteristic CD signals observed for a series of nonracemic O -trityl alcohols, N -trityl amines, triphenylacetic acid derivatives, and related compounds. − The structurally simpler diphenylmethane (benzhydryl) probe has been used for the determination of chirality of alcohols and hydroxyacids. − Because of the appearance of the observed induced CEs in the short-wavelength region of the phenyl 1 B transitions, the applicability of the benzhydryl probe is limited.…”