Abstract
An enantiomerically pure dimethyl-substituted pyrid ino-18-crown-6 ether containing a hydroxy- methyl group at position 4 of the pyridine ring (( S,S )-1) has been prepared. This by Swern oxidation gave the formyl-substituted (( S,S )-2), then by further oxidation carboxy-substituted (( S,S )-3) pyridino-18-crown-6 ether derivatives. These enan tiopure dimethyl-substituted pyridino-18-crown-6 ethers (( S,S)-1─(S,S )-3) are good candidates for enantiomeric recognition studies and also very useful precursors for enantio selective sensor and selector molecules with wide applications.
Highlights
The term molecular recognition refers to the specific interaction between two or more molecules through noncovalent bonding such as hydrogen bonding, hydrophobic forces, metal coordination, π-π interactions, van der Waals forces, electrostatic and/or electromagnetic[1] effects
Synthesis The synthesis of pyridino-18-crown-6 ether (S,S)-1 containing a hydroxymethyl moiety started from the known enantiopure dimethyl-substituted tetraethylene glycol (S,S)-417,31 (Scheme 1) and the hitherto unreported pyridine derivative 5
The hydroxymethyl-functionalized macrocycle (S,S)-1 was oxidized by Swern oxidation to pyridinocrown ether containing a formyl group at position 4 of the pyridine ring [(S,S)-2]
Summary
The term molecular recognition refers to the specific interaction between two or more molecules through noncovalent bonding such as hydrogen bonding, hydrophobic forces, metal coordination, π-π interactions, van der Waals forces, electrostatic and/or electromagnetic[1] effects. The host and guest involved in molecular recognition exhibit molecular complementarity.[2,3] Molecular recognition plays an important role in biological systems and is observed in between receptor-ligand, antigen-antibody, RNA-ribosome, DNA-protein, sugar-lectin (a sugar-binding protein), etc. Imitating biochemical phenomena using synthetic compounds has demonstrated that biological behavior can be engineered into simple molecules like crown ethers. Enantiomeric recognition as a special case of molecular recognition involves the discrimination of the enantiomers of a chiral guest molecule by a chiral host molecule. Since Cram and co-workers synthesized chiral crown ethers containing the twisted 1,1′-binaphthyl unit,[4] which were the first artificial enantioselective receptors for primary organoammonium salts, a great number of attempts have been made to distinguish the enantiomers of chiral ammonium ions by chiral crown ethers.[5,6,7,8,9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
