Discrimination in resolving systems. VI. Comparison of the diastereomers of deoxyephedrinium and ephedrinium 4'-fluoromandelates

Chirality
E J ValenteM E Harris

Abstract

(-)-(R)-Deoxyephedrine forms poorly discriminating diastereomeric salts with 4'-fluoromandelic acid from 95% ethanol. Both less-soluble (L) (S)-4'-fluoromandelate and more-soluble (M) (R)-4'-fluoromandelate phases are monoclinic and unsolvated. Their solubility ratio (M/L) in 95% ethanol is only 1.2, which correlates with the similarity and small differences in their respective heats of fusion and fusion temperatures. The (R)-deoxyephedrinium and the related (1R;2S)-ephedrinium 4'-fluoromandelate systems show L-salts with higher ion-pair volumes and lower densities than their M-salts. (R)-Deoxyephedrinium salts have higher volumes than the comparable (1R;2S)-ephedrinium salts even though the resolving base (R)-deoxyephedrine lacks the benzylic hydroxy. In the solids, bilayered structures segregate polar and nonpolar molecular regions. The principle interionic interactions are hydrogen bonds between protonated secondary ammonium ions and carboxylates forming infinite chains with a six-atom repeating unit H-N(+)-H...O-C(-)-O [C(2)(2)(6)]. These are buttressed by mandelate hydroxy to carboxylate hydrogen bonds. Differing interactions between phenyl and 4'-fluorophenyl rings in the nonpolar layers of the salts correlate with the de...Continue Reading

References

Aug 1, 1978·Journal of Pharmaceutical Sciences·D B RepkeW J Ferguson
Jan 1, 1992·Chirality·E J ValenteD S Eggleston

❮ Previous
Next ❯

Citations

May 24, 2008·Chemical Society Reviews·Rui XieJin-Gen Deng
Jun 28, 2003·Natural Product Reports·Kenneth W Bentley

❮ Previous
Next ❯

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.