V. N. Pastushok

Macroheterocycles. 27. Amidomethylation of benzo-crown ethers

The synthesis of some novel benzo-crown ethers by α-amidomethylation is described.

Study of conformation of cryptahemispherands by two-dimensional NMR spectroscopy

Two-dimensional NMR spectroscopy (NOESY, COSY-DQF) has been used in a study of nitrogen-containing cryptahemispherands and their complexes with alkali metals. On the basis of experimentally established interproton distances, the preferred conformations of these molecules have been established. It has been shown that the important features of structure determining the molecular conformation are (a) the orientation of the N-CH2(Ar) bond relative to the plane of the crown ether and (b) the length of the methylene bridge (spacer). The spatial and torsional angles have been determined. It has been established that as the length of the bridge is increased, the structure of these molecules approaches a betaine structure, with mutually parallel positions of the phenyl rings. Upon complexation, their orientation changes to mutually perpendicular, and this leads to enlargement of the inner cavity of the molecule and a corresponding rearrangement of its dimensions toward the ionic radius of the alkali metal.

Macroheterocycles. 51. Synthesis of macrocyclic polyamines in a biphasic system

Macrocyclic polyamines are conveniently synthesized by condensation of bissulfonamides with ditosylates or dibromides of glycols in the biphasic system toluene(xylene)-aqueous sodium hydroxide.

Macroheterocycles. 7. Synthesis and extraction capacity of some dibenzo-18-crown-6-derivatives

Derivatives that contain vinyl, formyl, acetyl, carboxy, carbethoxy, β-carboxyvinyl, or β-carbethoxyvinyl groups in the benzene rings were synthesized from dibenzo-18-crown-6. The ability of the synthesized crown ethers to extract picrates of alkali metals from the aqueous phase to the chloroform phase was investigated.