Vladimir V. Pirozhenko

Synthesis, Conformation, and Binding Properties of Resorcarene Tetrasulfonates. Asymmetric Reorganization of Pendant Sulfonyl Groups via Intramolecular SO- - -H−O Hydrogen Bonds

The regioselective reaction of resorcarene octaols 1 with 4 equiv of arylsulfonyl chlorides and Et3N in MeCN gives in 30−60% yield the C2v symmetrical tetrasulfonates 3. The mild electrophilic substitution (aminomethylation, bromination) of resorcarene tetrasulfonates 3 and tetraphosphates 2 takes place only in the 2-positions of unsubstituted resorcinol rings yielding distally disubstituted resorcarenes 4. The acylation of hydroxy groups in compounds 2 and 3 gives C2v symmetrical octaesters 5 including large resorcarene tetracrown-ethers. In the minimized boat conformation of tetrasulfonates 3 the two unsubstituted resorcinol rings are vertical and the sulfonyl fragments are arranged in a C2 symmetrical manner via intramolecular SO- - -H−O hydrogen bonds. This structure is proved by NMR and IR spectroscopy. In the case of tetrasulfonate 3c the two enantiomeric conformations interconvert in CDCl3 with ΔG* = 11.6 kcal/mol. This is in agreement with the ΔE* value predicted by molecular mechanics in vacuo.

Inherently chiral calix[4]arenes with asymmetrical superposition of substituents at the lower and the upper rims of macrocycle

Abstract Three types of inherently chiral calix[4]arenes( AAHH BHBH , AHHH HBBH , AAHH HHBH ) with asymmetrical superposition of ethyl, diethoxyphosphoryl groups at the lower rim of the macrocycle and bromine atoms at the upper rim, have been synthesized. The key steps of the synthesis are O,O′-phosphorotropic rearrangements of 1,3-distally disubstituted calix[4]arenes into 1,2-proximal isomers, regioselective bromination of the upper rim and hydrolytic removing of phosphoryl or benzoyl group from the lower rim.

Selective Acylation of Calixresorcinolarene

Abstract Selective acylation of calixresorcinolarene 1 has been performed. The reaction with mild acylating agents such as arylsulfonylchlorides leads to the tetrasubstituted compounds. Stereochemistry of the compounds obtained has been investigated in detail by means of 1 H- and 13 C-NMR.

Symmetrical and inherently chiral water-soluble calix[4]arenes bearing dihydroxyphosphoryl groups

A series of symmetrical and inherently chiral water-soluble calix[4]arenes bearing one, two or four proton-ionisable dihydroxyphosphoryl groups at the narrow rim of the macrocycle has been synthesised by consecutive treatment of appropriate diethoxyphosphoryl derivatives with bromotrimethylsilane and methanol. The calix[4]arene phosphoric acids synthesised possess pKa-values 2.85–3.10 (CH3OH–H2O 70 : 30) and form salts with L-(−)-α-phenylethylamine or (1S,2R)-(+)-ephedrine in methanol solution. The salts of the inherently chiral calixarene phosphoric acids with chiral amines are easily separated into diastereomeric forms by the RP HPLC method on Separon SGX C18 or Partisil 5 ODS 3 achiral columns.

Synthesis and Binding Properties of Phosphorus-Containing Calixarenes and Calixresorcinarenes

Abstract Full and regioselectively phosphorylated calix[4]arenes and calix[4]resorcinarenes were synthesized by Nickel catalyzed Arbuzov reaction of para-bromosubstituted calixarenes as well as by reaction of the hydroxyl-derivatives with chlorophosphates. Stereochemistry, chemical transformations, and complexation of the titled phosphorus-containing macrocycles were examined.

Inclusion Compounds of Octakis-Diphenoxy-phosphoryloxy-, Octakis-Tosyloxytetra methylcalix[4] Resorcinarenes and Bis-(Diisopropoxyphosphoryl) Dibenzo-18-Crown-6 with Benzene Derivatives

Abstract Crystalline complexes of composition 1:1 of calixresorcinarenes 1 and 2, and crown ether 3, with a number of benzene derivatives have been synthesized. By means of X-ray crystallography and NMR-spectroscopy the structures of the host molecules and the complexes in the solid state and solutions have been investigated. It was shown that calixresorcinarenes 1 and 2 exist in the boat conformation both in the solid state and in solution. The guest molecules in complexes of calixresorcinarenes 1 are located within channels in the host crystal lattice. The selectivity of binding of benzene derivatives was investigated and the role of the hydrogen bonds and CH … π interaction was estimated.

Phosphorotropic rearrangement in synthesis of asymmetrically-substituted calix[4]arenes

Monosodium derivatives of 1,3-bis(diethoxyphosphoryl)-calix[4]arenes undergo O,O-phosphorotropic rearrangement into corresponding 1,2-bis(diethoxyphosphoryl)calix[4]arenes which are useful reagents in the synthesis of asymmetrically substituted calix[4]arenes with AABH-type substitution of the lower rim.

Design, synthesis and structure determination of new inherently chiral para-bromoalkoxycalix[4]arenes

Abstract The preparative method for the synthesis of inherently chiral para-bromoalkoxycalix[4]arenes based on para-bromination, stepwise regioselective debenzoylation and the following alkylation of the readily available 25-propoxy-26,27-dibenzoyloxycalix[4]arene with propyl bromide or (R)-N-(1-phenylethyl)bromoacetamide has been developed. Three types of the inherently chiral calix[4]arenes in cone or partial cone conformations with asymmetrical (AHHHHBHH, AAHHHBHH, AHBHHCHH) substitution of both upper and lower rims have been obtained in racemic, diastereomerically pure or enantiomerically pure forms. Their structure and the absolute configuration have been determined by NMR and X-ray.

Topologically chiral calix[4]arene phosphorus acids

Topologically chiral calix[4]arenes possessing asymmetrical placement of achiral substituents at the macrocyclic lower rim or the upper rim due to their bowl-shaped architecture are considering as promising Hosts for enantiorecognition or separation of optically active molecules.1 In this article we present synthesis, properties and RP HPLC enantioseparation2 of the water-soluble topologically chiral calix[4]arene phosphorus acids, bearing proton-ionisable dihydroxyphosphoryl groups at the macrocyclic lower rim.

Phosphorotropic Isomerization of Diphosphoryl Calix[4]Arenes in Synthesis of Their Chiral Derivatives

Abstract Calixarenes are synthetic macrocycles obtainable by joining phenolic units through methylene bridges. Since they have original molecular architecture, they are considered to be important starting materials in design novel host-molecules for molecular recognition and separation. Introduction of chirality into calixarenes seems to be of great value for development of new class of artificial enzymes. Chira1 lower rim trisubstituted calix[4]arenes 2 possessing no plane of symmetry were synthesized with good yields by one-pot procedure consisted in successive treatment of 1,3-di-phosphorylcalix[4]arenes 1 in cone conformation with 1 eq. NaH and benzoyl chloride or methyl monobromoacetate.